sloppy Canon nFD24mm f2.8

This lens is one of the best Manual Focus legacy lenses that you can get for use on a Mirrorless camera. On the Sony A7 its more attractive because 24mm is quite wide and affords very useful shallow depth of field control on a full frame.

Its a great lens and well regarded optically for a "legacy lens" (which has no AF nor any electronic reporting of anything to the camera for recording in the EXIF field of the image). If you can live with that then its been a great low priced lens for ages.

However everything dies and in attempting to photograph stars the other night I stumbled on a problem which makes this lens near unusable for that role.

The problem is that the bushings which hold one of the groups are collapsing with age, meaning it moves around inside. This is bad because even a small amount of movement is a big deal for shorter focal length lenses. This manifests itself when the camera is tilted back from "horizontal" (you know, like when one photographs stars) and flops back again when pointed back down.

I've made this quick video on youtube to demonstrate this:

(if you're on a mobile view, go here https://youtu.be/71Hxj--1m94)

So as long as one is aware of this the lens is still entirely usable, but just watch out when looking up at buildings or the sky, because this shift will be enough to render critical focus absent on infinity (which isn't far away with a 24mm) and even stopping down won't be sufficient to bring back that detail when using a camera with such image detail as an A7 provides

A detailed pull down of the lens showing what needs to be fixed and where it is will perhaps help too. I found this great link on DPReview forums here.

I believe that eventually almost all the lenses will fall prey to this problem because its a plastics issue.

So, now you know

how I'm feeling about my Sony A7 experiment

Nutshell

In a word: Good.

Impressions

From the day that I first read impressions various of the A7 and its use with legacy FD lenses (and wasn't it handy that E-Mount adapters from the APS-C cameras just worked, kudos Sony) I was attracted to it. However I didn't feel it would be as suitable camera for travel compared to my well proven over years m43 rig and perhaps would not provide anything valuable compared to my scanning of 35mm film taken with my OM1 camera {which could survive days out in -20C in Finland on ski sled trips}.

In the intervening time things happened (I sold my Nikon Film scanner for one) and the A7 camera system has improved and the prices dropped. So I bought one back in October (as documented on my blog here).

I've been writing my thoughts about the A7 since they came out, one such post is from 2014 (here) where I wrote in anticipation of using my FD lenses:

My $20 Canon FD 50mm f1.4 (a beautiful lens) married up with this body would be superb. It would give the wonderful Bokeh I know it does and give better shallow DoF than the (commonly dribbled about by King Wangs subjects) Nocticron lens for micro43 (which costs nearly as much as just this body is likely to).

and of course it has exactly delivered that ... (actually that post is interesting in other ways)

So as a "Shallow Normal" I've got exactly what I was always seeking in that Field of View and Depth of Field.

Normals are good for a variety of things, but really for head and shoulder portraits a 100mm provides a bettter "working distance" in some ways.  So since buying the A7 I've decided to add a 100mm lens (again, I sold my OM100f2.8) and this shot taken with my FD 100mm f2.8 shows how good it can be as a portrait lens

Having already had a collection of FD lenses (from use in my early days of micro43 because no native prime lenses existed in 2009) I was able to pretty much bring them to bear with no extra expenditure than an adapter.

Since then I've added two more to my collection, a 24 and a 100 (mentioned above).

As I mentioned earlier, I had been procrastinating (since like 2014) about buying the A7 because I was using still using 35mm film, I anticipated that the A7 would give me fairly equal tonal range to Colour Negative, and nearly all the benefits of an almost perfect Nikon LS-4000 film scanner scan, The Nikon returned 5546 x 3784 pixels while the Sony 6000 x 4000. An image from this post on my full frame camera is film.

I say nearly because of course Digital Cameras suffer from dust and the Nikon ICE system essentially removed that. Of course one gains all the other benefits of digital (like speed of access for those who just can't wait).

None the less, I'm very happy to again have a a "35mm Full Frame" back in my hands as its nice to be able to get images which I just can't with smaller formats for such reasons as:

• shallow depth of field issues when seeking that)
• higher ISO (when needing that)
• better contrast (with legacy lenses where natives don't exist or out out of my price range)

Indeed I'd go one more and say that exactly due to the profound differences in lens rendering at differing aperture setting combined with the greater possibility to use higher ISO I now have more control over my 35mm lenses as imaging tools than I ever could have had with film (but sort of did because I used a tripod far more) in choosing to open up for a "look", rather than for a needed shutter speed.

GAS Traps

Speaking for myself (and observing what I read) there is a tendency to want to "standardize" ones system and have "One Camera System", perhaps its because it makes the decision of what to "take" when you walk out the door easier, perhaps its because one doesn't like to have gear sitting around "going stale" and deprecating.

The reality is for me however that neither of my digital camera systems are going to significantly further depreciate (like I paid $800 for my GH-1, $70 for my GF-1, recently got given another GF-1 body) and indeed with respect to micro43 I'm now (after 10 years of horse trading lenses) comfortable with exactly what I have and why ... so much so that nothing newly released looks even interesting to me (usually because its too big).

Its important that to avoid falling into this trap that I need to keep focus (pun) on the fact that I wanted to add the A7 not to have a Full Frame Camera which is more amenable to travel, but simply to have one when I wish to explore aspects of photography to which it provides some actual real benefits (and trust me, they are fewer than you might think).  

This is a concept which I enumerated in my 2014 blog post Gearing towards a Photographic Vision, which still underscores my view.

Enjoy

Portrait lenses - native vs legacy

Since my entry into micro 43, over 5 years ago, I have been interested in the fact that I can take advantage of a pool of very well priced 35mm lenses which perform fantastically on micro 43. To me back then m43 was what 35mm was to Medium Format: lighter and smaller but with good image quality. For exactly the same reasons as 35mm had advantage over medium format too. You see a "standard" lens for medium format is 100mm but a standard lens for 35mm is 50mm and needs to cover a fraction of the area (making it cheaper to make optically good).

why

In the past I have been a user of legacy lenses on m43 simply because when (in 2009) the system was launched there were no alternatives. My G1 came with a 14-45mm zoom and that about rounds out what was available then too. Wanting to have a bit more telephoto and a more shallow DoF I turned to the ready supply of 35mm lenses to "test the water" ... my first purchase was an nFD 50mm f1.8, soon to be followed by an OM 50mm f1.8 ... I wasn't satisfied with the FD image quality. I picked the OM because in the past I'd had OM gear and loved the image quality.

Since then I've tried and tested many 35mm legacy lenses and often been left wondering what the native alternative would be like (where it existed) but was reticent to drop the money onto it.

Reticent because (despite how it seems) I don't have GAS and because the prices of the native lenses were just more than I felt they would yeild in benefits.

Having compared the FD 50 f1.4 (note that's not the first one mentioned above) to my OM 50 f1.8 quite favorably , and compared my FD 50mm f1.4 to a OM 100mm f2.8 on a full frame (because they are equivalent) I have always wondered how well the relatively new native 45mm f1.8 would compare to my OM 50mm f1.8

A recent drop in prices for a sale made me decide to put $300 into this question and see if I'll keep a valuable lens or learn that I'll just sell it again (as I did with my Sigma 30mm).

Quick Summary

I have not made a decision on this yet, but I'll probably keep the 45mm because it works so well on my GF series camera in helping it be a compact system. I have a GH1 and a GF1 which while similar, perform entirely different roles for me. There really is nothing like this sort of lens on the GF (or say a GM if I was inclined) to give me a compact and excellent camera system.

Were I to have just an SLR-alike body (such as my GH or an OM-D) then I would simply sell this as to me the 45mm offers so little benefit as to be pointless. If you are hopeless at manual focus and unwilling to learn then the 45mm fills that role, but if you engage with your subject and are a photographer (not a snapper) then the legacy OM lens (at 1/10th of the price) offers equal quality.

The contrast and bokeh of the 45 is not significantly better than my OM, which I know is almost as good as using a 100mm on a full frame.

The Lenses

Ok, so below is my OM 50mm f1.8 beside the Olympus 45mm f1.8. I think there is not much in it for size between them. Certainly when mounted on a SLR style body ...

You can see that they are both compact lenses and for manual focus work to be honest the OM lens is nicer to use. The only benefit that the Oly 45 has is that it activates the focus by wire viewfinder zooming as soon as you turn the focus ring (assuming you don't have the camera in AF mode ...)

The fact that you have to put the camera into MF mode to do this is a drag because you need to remember to do that when you change back to another lens (or want it to AF when you pass it to your wife / husband or friend).

Neither has a substantial advantage over the other in terms of carrying in a pocket or backpack.
While the Oly 45 has integrated Aperture control (its a native electronic mount right), if you are going to dial in anything less than f2.8 then the differences between it and the kit 14-45mm zoom rapidly vanish. Seriously don't under estimate how good the 14-45 is at the 45 end. When you compare the Oly at f5.6 its no longer at its "DxO" best anymore.

Sample Images

Ok, I went over to my neighbors place and took a bunch of shots of him working in his shed on some task. I didn't focus on his face, because I'd like to preserve his privacy. Howver these are about the sort of distance where a f1.8 setting will set a 45mm aside from a f5.6 setting on a zoom. Further away and the DoF differences shrink, closer and the DoF will be too shallow to be useful on the f1.8 (a point often ignored or simply not understood)

So, lets look at the thumbnails from the images without telling you which is which ..

all look similar to you? Yep me too ... So this will tell you straight up that unless there is some major issue in 'fine details' that when it comes to making an image these lenses are in the same ballpark.

Details

Ok ... lets pick two images, one from the 45 and one from the 50. The images were shot hand held and I was standing more or less in the same spot (moved a little to the left or right as one may do when doing a portrait shoot).

The overview:

and then a 50% magnification (because I've found that at 50% pixel view it translates to just about what you'd see on a print).

Now another image from the other lens:

and the 50% pixel view...

So which was which?

I used the Oly 45 exclusively on AF because I wanted to test also how well the camera picks its focus location. That's a critical point when considering the 45, because one of the key selling points for me is AF ... I mean what else am I paying that extra $250 for? How it feels in my hand?

I found that while the Oly 45 was good, it picked focus slightly differently to where I exactly wanted it to be. That caused the point of human interest to be softer for me than I wished it. If you look at the screen grabs of the 50% pixel view (at 100% which means you'll need to open the image in a new tab) you can see that evident in the shots here.

Well perhaps knowing that you can see it, but in case you still can't I'll tell you that image p1110278.jpg was from the 45mm and p1110281.jpg was from the OM 50

Conclusions

Well to me this makes clear that I'd already been standing in the field with the greener grass. The OM50mm f1.8 has given me many great keepers (and almost no duds) in the years I've already been using it for. The image quality is undifferentiable from the 45 and to be honest the 45 AF speed is vin ordinair, quite to contrary to what people seem to Wang on about....

You'll have to make your own decision about the relative merits of even having AF, but for me (and my eyesight) to use this lens on my GF means I can get AF (and I need it on a compact) but if I wasn't going to use the lens there and was only using it on my GH body I would perhaps not bother.

To me the combination of:

• 14mm f2.5 + GWC-1 wide adapter
• 20mm f1.7
• and this 45mm f1.8

makes the GF (or similar compact) into a great light and compact travel outfit. I had a GF which I sold and soon then rebought another GF because I realised that its nice to have both. In the world of second hand stuff the $100 that I paid for the GF body makes it irresistible for what it provides. So I'll probably be keeping the 45 ... however if I had (as one of my friends does) an OM-D body I'd likely be selling the 45 as the OM50mm f1.8 is just so bloody good.

Lastly, the only other similar comparison I've found is this one over at Tyson Robichaud's site. I think I've known Tyson for some time (assuming its the same Tyson who commented on a post some years ago) and its been interesting to see his development too.

I find that Tyson has summed up (in a slightly different manner to me) well with these comments:

The ease and usefulness of auto focus is something that many of us may take for granted.  It isn’t until I remove that feature that I begin to realize how differently I tend to shoot, compose and interact with subjects. I often enjoy shooting with a manual focus lens as it tends to slow me down and add an air of intentionality in my shooting that often gets overlooked when I’m out and about firing away.

 Indeed, and I'd add to that the by having "stop down" view engaged "automatically" in the manual focus lens you can see immediately the changes in DoF and look of the image which you may forget to do when blazing away with an AF lens.

Either way, and depending on how you look at it, one could be “better” than the other depending on personal taste.  To me, both are good, but different showing that different lenses at the same focal length can indeed produce two very different looking pictures.

 although with my lens comparison I'd change that to "produce slightly different looking images"

Its also a good post and provides many other comparisons of static identical targets (where the subject does not move nor the position does not move unlike here) for those who would like to see things done that way. I recommend reading his post if you have are considering the Oly 45.

Hope that Helps

Past its Prime?

Over the years discussion on the benefits / penalties for using a mirror lens (or Catadioptric lens) just "keeps on keeping on".

The reasons for this are the obvious attraction of having that extra reach of 600mm when taking photos of small things (often birds) at a distance at insanely cheap prices, also that they weigh less is an additional bonus. When one can't get closer the appeal of the extra focal length is just hard to dismiss.

Discussion on this has usually revolved around those who have used them making observations (to the negative) while those who have not used them remain in the wishful thinking stage.

Back in the daze of film there were limitations which more or less do not exist today, one such limitation is the issue of "enlargement". If you wanted to make a print (say 8x10) and you wanted things to be magnified even more (or what is called cropping) you simply had to extend the enlarger further away from the paper or use a different enlarging lens which was itself more telephoto (yes it works the same both ways, in camera : in darkroom). This always resulted in contrast losses (among many other losses) and thus a difficulty getting a good print.

Thus, and perhaps I'm hinting at the conclusion already, there was the appeal / need for using a longer lens when you actually wanted a longer lens.

I sorta expected this outcome but I wanted to "get it out of my system", as well as to present the observations in a meaningful and more thorough manner than I've seen. Perhaps it will help others if they can see.

So the main use of such a lens for me is normally birds, like this little guy:

... clearly with bloody small birds more reach is really on the wish list.

quick summary

I've done all this on micro43, which is in my opinion the best system to test this on. Without the ability to use the EVF (I'm using a GH1, but your OMD would be the same) to magnify the image from the sensor to ensure critical accurate focus you will only get worse results than I've got here. Just forget about this whole idea if you are still in the 20th century with Optical view finders on winky dink DSLR sized viewfinder optics - its just not accurate enough.

The diameter of the aperture of a 300mm f4 lens (at f4) is exaclty the same as the diameter of a 600mm lens at f8. Thus when cropping the guts out and upscaling the DoF is more or less the same. NB the 300mm does not have a shallower DoF than a cropped into 600mm 300mm.

I find that with respect to the image quality, the optics of the magnification are just not there, might be this lens, but that is not supported by what I see on the web. Essentially magnification can be done by one set of maths or by another set of maths.

• One set of maths is the maths involved in making the optical enlargement.
• The other set of maths is that in the bicubic upscales in software.

This last set of maths was not available to the film DAZE period of time.

Bottom line: get a good quality 300mm f4 refracting lens (you know, the normal ones) and upscale in software as needed.

OK ... enough blabbering show me something

I took these images using my GH1 on a tripod and with a cable release. I picked a fully sunny day to ensure that I could use the best ISO possible for details and used manual control to ensure that my resulting exposures would be consistent and easily dissectable.

The differences in the lenses (well the refracting 300mm and the mirror 600mm) are like this:

The weights are:

• Canon = 1.11kg
• Sigma = 767g

so nearly (just shy of) double. Neither is really "backpack" material for "just in case" so both are going to be used (by me) when I'm planning something.

The basic exposure facts are that using the 300mm f4 at f4  I can get an exposure of 2000th of a second while with the 600mm f8 at f8 I'll be needing 500th ... that's really a tight number and even assuming a solid tripod bloody small birds are usually twitchy ... and subject movement is not something which any wanky Image Stabilization system is going to help with (see here).

pass me a nail for the coffin on the mirror lens.

So, planning around birds, I worked at 8 meters (to my American readers; you can do the conversions to feet and shoes as I'm too slack to do it) which is about as close as I can (without heaps of prep) get to a good shot of bloody small bird.

300mm f4 @ f4

nice and sharp ... good detail shutter = 1/2000th of a sec

600mm @ f8 (and f8's all you get btw...)

Well the 600mm sure looks like it delivers twice the magnification (who'd a thought) but of course it being f8 we are now at 1/500th of a sec. I can assure you that even while attempting to focus (with my EVF zoomed in of course) I could see the problems with the image softness and the effects of such optical magnification on the DoF). So lets look at the:

FD300mm @ f4 cropped to effectively 600mm

Well shit a brick but that's clearer and sharper even at this size isn't it. (by the way, I spent most of yesterday taking images and re-taking images to confirm I'm not going spakko and making mistakes in focus or whatever).

However the astute will observe that there is some chromatic distortions on the branch that's out of focus over to the left at the back ... its purply on the FD lens while has no such colour casts on the Sigma.

The out of focus areas are showing some "colour fringing" (shit I hate that term) which is essentially caused by the fact that lenses bend light (refraction) and mirrors bounce it (reflection).

Think of the Pink Floyd album "Dark Side of the Moon).

Its a fact of optics, and generally lens makers go to to great effort to fix this issue.

BTW lenses which manage to focus red and violet together are called APO or Apohromatic. Get deep pockets for such lenses in longer focal lengths.

Normally a stop down a wee bit (say f5.6) will fix many such ills...

FD300mm @ f5.6 cropped to effectively 600mm

Even sweeter again. I think its cleared that chromatic aberration up a little bit, but man its REALLY cleared up the image. And we still got a shutter speed of 1/1000th of a second.

So to me at this point, for WWW delivery its clearly better to use the 300mm f4 and crop it. My camera is 4000x3000 pixels, and so one doesn't even need an upscale to do this. Just cropping is plenty.

OK, lets look more closely

Prints (unlike the web) need more pixels, an 8x10 printed to 300dpi will need 3000 pixels in length. Because there is always some bleeding of pixels in prints (and not on screens) I normally pre-view my images at 50% enlargement not the typical pixel peeping 100% ... I figure that if I can't see it at 50% on the screen then I won't see it on the print.

This is what the 50% pixel view of a center portion of the 600 image looks like

Thts's not pretty ... so now lets push the image taken from the 300mm and look at 100% pixels and see what raw materials we get:

300mm @ f4

wow ... totally sharper in the center of the flower, in fact totaly sharper everywhere.

Ok, you didn't have to fuss and fiddle with focus on the 600mm Mirror Lens like I did, so you didn't get to see how the image went in and out of horrible showing just the sorts of distortions seen here on things just out of the focal plane. This may look to some like motion blur, but if you look around at some of the other factors you can see that its not totally consistent with shake (which usually takes a vector).

Cleaning things up optically

 Since you (should) know that stopping down a stop covers some evils and reveals a better image from the this lens than its "hot chikz-over-the-bonnet advertising special highly-desireable-fully-open aperture" f2.8 version (which still btw clears up by stopping down). Note, this is of course something you can't do with the Mirror Lens: its f8 and that's all its is baby

So the 300mm @ f5.6

well ... that's really an improvement. At f4 its better than the 600 by a margin, but at f5.6 its scorchingly better. So now we have even better raw material available here for a bicubic upscale. This is streets ahead of the 600mm mirror lens and we've still got a shutter speed that's twice as fast as the 600mm (in case our bird twitches ... and you know he want's to)

Hand me another nail for the 600mm mirror lens coffin will you please?

The actual upscale

Ok, lets get our pixel-peeping gum boots on and dig around in the dirt for a bit for those who aren't already convince or have a few "what if you .." questions.


First, lets just do that upscale and see (600mm on top, upscaled 300mm on bottom):

Far less detail in the center of the flower ...well everywhere really.

So then with our pixel peeping gum boots already on viewing at 100% (same image order as above)

I see texture in the flower petals on the upscaled 300mm f5.6, but not on the 600mm

hmmm ... another nail for the mirror lens coffin it seems.

Then someone may ask "well what if you used ISO to increase the shutter speed on the 600mm capture, that could be vibration blur". Personally I already see enough fine detail in the red parts of the flower petal to make it obvious to me that there is no camera shake ... but what the hell, its a fair question, so here it is:

another nail please ... and can you get the nail bucket while you're there please?

Of course with the increase in ISO (to get that speed) what happens to details? Well lets step back to 50% and have a look at the RED channel noise.

Oh dear ... more noise and (of course) an erosion of detail caused by the increase in ISO (well of course).

So what you speed may pick up with increase in ISO (to equal the shutter speed of the faster 300) you'll loose even more detail than you're already loosing anyway.

Another nail ...

Costs:

Bang for buck is an important consideration too. I paid US$120 (or something like that) for my FD300f4, and I paid US$120 for my Sigma 600mm f8 ... so the costs are about equal.

Olympus also makes a lovely 300mm f4.5 lens which I have owned and found it equal to the FD300, its also around for about the same money (between US$200 and US$120). I have a comparison of the only differences worth mentioning between those two lenses here.

You got the bucket  of nails didn't you? Cos I think we're about done here and can hammer the lid closed.

Conclusion

Perhaps back in the daze of film when attempting to do optically what we now can do digitally (different maths path for the same objective) there was a better case for the 600mm catadioptric. Especially given that a 600mm reflecting lens is and was huge and expensive. To me nowadays there is really no advantage in the mirror 600mm over the refracting 300mm f4.

Sure the Sigma is a bit smaller but since you'll definitely need a tripod using it the minor weight advantage evaporates quickly. Remember that for us with micro4/3 a 300mm is effectively a 600mm for the full frame guys, which means we are already pushing the limits of the optics (more so with legacy optics). So having an effective (to full frame) 1200mm lens is really amazing stuff.

However the ability to now do upscales in photoshop means that I can use my 300mm and make it effectively a 600mm and gain many of its other benefits such as having an aperture to stop down and alter the image appearance as well as the 2 stop faster aperture it has.

In summary the Coffin Nails were:

•  such a lack of sharpness even its extra length does not cover its arse
• slower shutter speed (leading to potential subject movement blur) applying sufficient ISO to solve the 2 stop loss of light erodes detail more
• minor weight advantage lost when you need to use a tripod (or attempt to handhold and lose even more)

To me a prime lens is all about having the maximum image quality without compromise. As I've just shown in the digital age the catadioptric (mirror) lenses are a prime lens which in my view is past its prime. Perhaps there may be some newer lenses which will be better than this, perhaps the Canon or Olympus brand catadioptric lenses do better ... if you have one why not contact me and or write it up your self.

What I have not discussed here is the handling of the lens and the difficulty in focusing with the lens not on a tripod. Personally I've been able to hand hold and get good shots with my FD300 (and my OM300) - even bearing such upscales as here. Clearly my hand holding technique is adequate.

(sidebar: many newbies experienced photographers on the internet say they can't focus and hand hold because the image jumps all over the place. The answer to their question is this "Yes, it is you. Yes, you do need to work on your technique. You can learn to observe the target in the image and not be seeing the frame. No you can't hand hold a 300mm tele and focus off the back of the screen like a girl with an iPhone. Yes you can learn it if you put a little effort into it and adjust your technique)

So, now you can tick mirror lenses off your list :-)

Lastly some shots with my FD300mm, which I am somehow more happy with after doing this. In the main the images below are hand held (or monopod).

Young Kookaburra (just out of the nest)

Woodpecker in Finland

 

Ducklings (Telkka)

Tawny Frogmouth

Plovers with a newly hatched chick

telephoto by cropping - or why have a telephoto

why?

The question arose of "I have a high quality prime such as a 20mm f1.7, so why would I bother buying a telephoto?", so I thought I'd have a whack at answering it. The asker professed to have some years experience with 35mm and seemed happy with just cropping. I covered this from another angle back in 2010 here, but as my purpose was different I thought I'd redo it entirely.

To some extent you can "increase" the focal length of your lens by cropping - which is exactly why cameras with smaller sensors than the 35mm standard format are called "crop cameras" and exactly why there is the idea of a focal length multiplier (or effective focal length). This is often a bewildering topic for beginners (and even seasoned 35mm photographers who never dealt with 645, 6x7 and large format).

The confusion often comes from the misunderstanding of f-numbers. These (often called f-stops, but that's also confusing) were designed to allow photographers to determine exposure back when a hand held light meter was used to determine exposure and the photographer wanted to change lens (and keep the exposure the same).

Commonly the confusion comes from discussions involving  Depth of Field (DoF)

Its the size of the hole

When it comes to DoF the important factor is the size of the hole (old page of mine but better javascript), not the f-number on the lens (of course magnification is the other important factor), remember that an f-number is just a ratio. It is the focal lengh divided by the aperture size (in whatever units you like, inches or mm). I thought I'd compare two lenses, a 20mm (as I have a 20mm f1.7 Panasonic lens) and a 50mm f1.4 (as I have one of them too). So the iris diameter of the aperture on a 20mm lens at f1.7 is 11.76mm and the aperture needed to make a 11.76mm diameter iris on a 50mm is f4.3 ... such a setting is not available on my 50mm lens so I picked f4.5 which is a little bit bigger at 11.11mm

So if all things were equal then a standard lens could work as a telephoto by just cropping. However, if we use cropping (essentially maths) to make our 20mm into a virtual 50mm then we would just set our apertures to be the same and all will work out the same. Of course all things aren't equal, so I thought I'd explain this with pictures.

Firstly, lets take a shot of my mate with a 20mm f1.7 lens on my GH1

This was taken with the camera on a tripod, using the Panasonic 20mm f1.7 @ f1.7 and focused with face recognition.

Now, lets put on a 50mm lens (which is telephoto for 4/3) and have a look at that.

A quick glance at the image seems to show that DoF is quite similar to the central portion of the image taken with the 20mm ... so, lets crop the guts out of it and have a look.

Well actually its close isn't it, perhaps if I'd stopped the 50mm down to 5 it would be even closer. But you can see the point here (I hope).

Whats different?

Firstly I encourage you to "right click" on the above images and open them up in separate tabs (or windows).  I think you'll see quickly that even at the modest sizes we have that there is much more information (look at hair strands) in the image from the 50mm and not much at all in the image from the 20mm (cropped image). This is because we are essentially concentrating the image to be clearer with the scaled down 50mm image, but dilluting the 20mm image with magnification (and pushing its limits). Essentially we are pixel peeping with the 20mm but giving the 50mm room to breath.

Next the 50mm is able to stop down to further  ... so lets look at that

Which  I'm sure you can see is even more shallow DoF with the focus being drawn to the eyes and the background is just a diffuse background. Personally I prefer the look of this lens at f1.8 or f2, which is still more shallow DoF than f4 yet has a higher contrast.

Then there is the point that the image from the 20mm started out at 4000x3000 pixels and just by cropping alone wound up at 1512 x 1181  pixels .. which is a paltry 1.8 MPixels and really only good for a 4x5 postcard print (or the web).

In a tight corner that may be enough ... but should you shoot for that? Well that's up to you.

Clarity

Lastly there is the amount of clarity available. The 20mm is a sharp lens, but it has a maximum of about 7Perceptual Megapixels, while the Olympus 45mm has more like 9 ... by cropping you end up with 2 and given that the Panasonic had less to start with you may end up with less Perceptual Megapixels.

I'm really pleased with my legacy FD 50mm f1.4 lens(well and for that matter even more pleased with my legacy OM 50mm f1.8 which is just as sharp (see post here) and cost so little (like $18) its ridiculous. Indeed for folks now (such wasn't available to me when I got into micro43) the Olympus 45mm f1.8 is available in good condition used from around $300 or the Sigma 60mm f2.8 even less ... great optics well within grasp of many and if not then the legacy option is IMO fantastic value. Hell this portrait was taken with my Pentax 110 50mm f2.8 in another mates garage.

and that lens is ultra compact and light (and cheap too).

So, why have a telephoto? 

I guess I've answered that now.

lenses which are gold

Since the late 70's the price of Gold has gone from about US$200 per Oz to about US$1300 per Oz, which many finance people will tell you is not really growth, but a reflection of lack of losses (while the value of money falls)

Such store of value can also exist it seems in the photographic world with some items.

I have a friend and fellow blogger who is also interested in camera gear, and in a recent discussion on his blog discussed the Minolta 250mm f5.6 mirror lens. His words were to the tune of:

It has proven itself for the purpose of its design: small, lightweight, and inexpensive. The inexpensive part does not apply any more because this lens is selling at a few times more than its original price, but it's truly small and light

Which had me curious, I know well the advantage / disadvantage set of the mirror lenses. As the owner of a 'regular optical' legacy FD 200mm f4 lens (which is quite opitcally good btw) I thought I'd dig out the current selling price and found that its gone up like Gold.

To quote form JarJar Binks ... "Exqueeze me!"

Mirror lenses have an optical mirror which is coated in Silver ... but somehow this lens is Gold.

I understand the value of compact, and I also understand the downsides of donught bokeh and no aperture control. I don't know if the advantages are driving this price or if its "Kingdom of Wang" buyers. I understand that my friend picked it up back when the prices were sane ... but at these prices I genuinely expect that owners get more "joy of ownership" than use.

Like the ebay ad says "no signs of use"

I sincerely hope that the 4/3 rumor site is on the money with Olympus bringing out a new and current version. For that should restore some balance to the market.

Meantime I'll keep using my FD200mm as it cost me about $60, and I get to take pictures that I like with it. But be careful in picking your FD200mm because there are substantial differences between the New FD and the old FD editions. The more modern one weighs about half (at 440g) and has much better lens coatings. It also has a built in retractable lens hood and uses a more modern Inner Focusing design. Worth every penny of $56

I sometimes wish I could examine the Minolta and give it a test use, but at the current prices its out of my interest zone.

All taken with the FD200mm f4

Teles with Teleconverters (on x2 crop factor cameras)

Too much is never enough - or is it?

why

Many photographers starting out into 'birding' or other telephoto work always lament that their lens just isn't long enough. I grew up in the time of 35mm film (well and other films too) and a 300mm lens was something exotic that I just dreamed of.

For a long time I had to make do with a 80-200mm zoom (which actually did some good work for me) and eventually (as time passed) bought a few 300mm zooms to see. I liked them but they were often not as good at f5.6 (looking better at f8). The step up to a high quality fast (like f4) prime lens was out of my league.

Much later in my life (like a few years ago) I discovered the benefits of rapid obsolescence: NB the wealth of older Manual Focus lenses the market.

By this time I've moved over to Panasonic micro4/3 and could take advantage of insanely low prices in FD lenses (which pretty much could not be used on anything else previously {except NEX}).

The 300mm class is a good one (especially in micro4/3)  for a number of reasons:

• lighter weight (have you picked up a 600mm)
• lower prices (I paid sweet-F-all for my 300mm)
• good handling characteristics
• bright

I have owned both the Canon FD300mm f4 and the Olympus OM 300mm f4.5 (see my views on that here), and found them both neck and neck. Back in that article I made the observation that using the 300mm on a G1 body was like using it on a 35mm Full Frame camera with a teleconverter (and perhaps perfect film scans for those of us using film still).

Actually I've personally found that 300mm is enough to get you good shots of BSB's (that's Bloody Small Birds) and that Manual Focus actually helps you to get images of the thing you want in focus. In this image an AF system would drive you nuts focusing on the branches either side of the bird and after struggling with the camera the bird will be gone.

I often don't think there's more point in getting more than effectively 600mm as being closer actually gets you a better shot.

Well, since teleconverters exist (and can be quite good back in the Film Daze) I wondered about how it would actually work (in reality) on the smaller format digital, especially considering we are already doing an effective optical x2 anyway.

I went out and got a Canon x2-A teleconverter (there is also an x2-B, but the A is designed specifically with 300mm in mind) and had a look at the images. The excellent MIR site shows more information on the Canon x2-A extender here. I picked that teleconverter because I was using a Canon lens which it was designed for and its well regarded. I would expect that any other teleconverter would likely give me only equal or inferior results.

summary

• Is it worth the effort? to me, not really ... you'll need to work it out for yourself and your needs
• you don't get something for nothing, there is an exact x2 tradeoff ... perhaps more
• can upscaling solve the problem for you? Upscaling does have advantages.

the data

So, I took two shots (well more really, I took f4 and f5.6 and the bloody wasp kept moving around so actually I took lots more) one with the Canon x2-A teleconverter.

FD300 overview

FD300 + x2-A

Well it sort of looks like a x2 enlargement doesn't it ;-) Considering that these are scaled back for the WWW if you aren't printing them large, then a crop of the 4000x3000 native image will look just as good. For your interest here is the FD300 image cropped to match the x2-A image (bringing it to 2000 x 1500) and then resized down again to 1600 for web.

Similar isn't it. If you're only shooting for WWW (and not street side signage or posters) then of course the native sizes allow a x2 'enlargement' by being so bloody good at 100% pixels that you can crop the guts out of the images and still have room for a good size.

But that's not the whole picture (of course), as the exposure data is important. Firstly I used 400ISO for this test because I personally feel that after 400ISO the image quality falls off.
FD300@f4 gave - 2500th of a sec (handy to seize movement)
FD300@f4 + x2-A gave - 800th of a sec which is starting to push shit up hill with a fork because as this is effectively a 1200mm that's below the 1 over focal length rule. Actually I had to use a cable release as well as my most stout tripod (and yes, that means I took more pictures, evaluated them found camera shake and took more again).

So yes, you do loose 2 stops of speed (recalling that a stop is either halving or doubling the speed) so two stops down from 2500th - 1250 - 625th (assuming stepless shutter speeds). Now if I'd used 2 stops more ISO to bring the speed up on the x2-A shots I'd need to be 1600, which is like popcorn if you ask me ... YMMV

Ok, so lets look at 50% pixel enlargements. Why do I choose 50%? Well my personal experience is that looking on the screen @50% is very similar to looking at a print closely.

Also its important that if you want to look at these images as I screen grabbed them, then right click the image and open it into a new tab: because blogger scales them down to fit onto the screen.

Ok, so again its still clear that its a x2 enlargement, but something else is starting to become clear ... the x2-A makes the image appear a little less sharp (or perhaps viewed another way, magnifies the "we've already reached" the limits of the lens point).

To be honest contrast isn't as good on the x2-A image either (if you ask me).

Ok, so lets do the mathematical version of the x2 enlargement using a bicubic upsample of the plain 300mm lens image (on the right still)

Actually its not too different if you ask me ... however ultimate pixel peeping (like why?) shows that its not actually exactly the same:

and we see that the bicubic upscale has added a little gritty noise to the image (in the greens even!) and so it may just be that in the ultimate call on this: if you need every last pixel of the image and you really need to get in closer then the x2-A works better than a bicubic upscale.

IF you can live with the much slower shutter speed (cos a blurry image from subject motion blur will suck worse) then there seems to be a slight advantage to the TC, but if you really need the speed (like say under forest cover) then crop and upscale will allow you 2 stops more speed (with perhaps only little difference in quality).

As it happens (not presented here) I prefer the look of the FD300 stopped down to f5.6, it was that bit sharper and more contrasty. However I didn't present that here because on the x2-A version the shutter speed was down to 320th of a sec and most images weren't clear.

Conclusion

Its a tough call to say one is better than the other but if shutter speed counts then upsampled images will work as well (and you won't need the adapter :-)

Lastly, I'm not disappointed that I have it as I've used it on the FD200f4 that I have and found that its not bad. So when I'm not wanting to drag along my FD300 (which is not only physically large, but weighs about 1Kg) I can put the FD200f4 (440g and something I'm likely to carry anyway actually ) and my adapter (200g) in instead.

Have Fun

Sigma 30mm f2.8 EX DN review and thoughts

Ok, up front I'm a geek, but I'm a geek who's a photographer. So this isn't a typical review, if you want one of them you'll find plenty of sales blurb reviews out there.

For the impatient:

• its a great lens for the money
• image quality is good
• if you are into legacy lenses then it may not be a useful buy
• comparing to legacy lenses its makes me wonder why?
• I might have an explanation for the DXO rating
• I reckon this lens sucks battery due to its AF system (and conversely why I get lunatic long battery life out of legacy lenses on my GH and GF camera)

bottom line: the DMW-GWC1 is r.r.p of nearly the same as this lens, and that is just an attachment wide angle converter. So what I'm saying is you won't find much available new that's this price.

what I want it for

As it happens back in time when I used a 35mm film camera for my general photography, my favorite travel combo was a 24mm and a 50mm (with perhaps a 75-300 zoom if I was allowing myself more). So with the 14mm under my wing (and the x0.79 adapter) a 30mm would give me almost the same in my micro4/3 outfit as the 24 and the 50 did.

So, lets have a look at them, below is the Sigma 30mm beside the 14mm pancake and the 14-45 zoom

The astute observer will soon see that the 14mm prime is one end of the zoom range and the 30mm sort of close to the middle. The obvious question is that as I have the zoom why bother?

Basically its because:

1.  the shallow depth of field rendering is there if I want it
2. I like things more compact if I can

So it makes a difference which camera I use it all on if its to make any difference. I mean if I use the GH1 then the extra size of the 14-45 sort of vanishes. So basically this lens makes more sense on my GF1 (or your GFx or GX or other smaller Olympus pen) than on my GH1 or a Olympus OM-D

Now, just pause for a moment and think about that.

In my view the ultracompact side of micro4/3 is about quickly whip it out, use it and move on - while the OM-D GHx series cameras is more about photography where the photographer engages more seriously and more closely with the subject.

Knowing that makes a difference as to how you think about this lens and what the significance of my following points are. If you're a whip it out fast user then the answer is simple. Stop reading and go grab the 30mm, especially if you have the 14mm f2.5 ... its a great combo.

One of the first things that struck me when I opened the box and looked at the lens was how small the front element was, especially with respect to the OM 28mm I'd been using (you didn't seriously think I'd been without a 50mm equivalent all this time did you?)

Actually if you take another moment to look at that picture you can see that the newer lens coatings really make a difference to lens flare (something which my 28mm is better controlled than my 21mm, but that's another story).

Of course the lens element size is easily explained by the fact that the OM lens is designed to cover the 35mm area and the Sigma lens is only designed to cover 4/3 (and APS).

But it raises an interesting point, why is it so much bigger when something so much smaller can do? Like this is my Pentax 110 system 24mm f2.8 lens beside the Sigma.

I mean seriously if the 14mm can be as it is and have AF mechanism and an aperture, and this 1979 24mm lens is smaller than the 14mm, why is the Sigma this big?

The next thing I noticed was how much larger the Sigma's rear element was:

substantially larger than the element on the OM lens and way bigger than the rear element on the Pentax 110 lens.

The only thing I can attribute it to is that one needs to keep the light hitting the sensor as parallel as possible (a problem full frame digital Leica owners know about) as sensors (unlike film) do not like light arriving at off angles (and thus going through layers of glass at an angle ... if you don't get this go look at an aquarium close and look left and right ... distortions?). See this post for a little more detail.

For instance this is the OM28mm beside the Sigma 30mm

The lens cap on the OM lens is thicker than that of the Sigma and even then its shorter. So looking at the base plate you can see the Sigma is not "compact" (and wasn't the promise of micro 4/3 to have compact stuff?? Oh sorry ... banging on about this again ... its like I feel lied to).

However when you use the OM, because it was designed to work on a 35mm OM1 camera with a reflex mirror flopping around in there, it needs an adapter to 'space it off' the right distance.

So with the adapter on the OM lens and the lens caps off we can see that the 'whole thing' in legacy OM mount is actually bigger than the Sigma is.

So this seems like a good time to mention "SLRalike" bodies vs "compact" bodies. For on the GH1 using the OM lens feels quite natural but on the GF "compact body" the Sigma is much nicer. As the Sigma has AF that is also a real benefit there too.

Lens performance

I naturally took a series of shots at f2.8 f5.6 and f8 with both lenses confirming the already known (the lens vignettes as DXO have also reported) and curiously found something else.

When I do focus tests I tend to use manual focus and the "magnification assist" feature. When one manually focuses the Sigma lens one can hear the stepper motor moving the element in a series of "ticks" when the lens is moving in small steps (you can hear it too when its in AF right about when it snaps into focus inthe AF cycle.

What I found was that Sigma was often unable to focus exactly where I wanted to focus on, it would be a step either side of perfect. I would suggest that this has implications for why the newer Sigma 30mm seems may not perform as well on DXO testing. Now to be sure the differences are slight, but when you're suggesting that a lens / camera combo is 8P-Mpix vs 9P-Mpix you are talking slight.

So, lets look at 100% crops of the exact area I carefully focused on at f2.8 ... First the 100% crop from the Sigma

Then the 100% crop from the OM lens

You'll need to right click and open in new tab (or center click) to view these at the 100%.

Now the OM lens has a slight colour cast issue just on the edge of focus when its at f2.8, but this clears up when stopped down. The Sigma did not exhibit this.

Perhaps you can see that the Sigma focus is not exactly where I wanted it, on the chain. I could get it in steps either side, but I just could not get it right there.

Will this effect picture taking? No it won't ... I'm mentioning it because I believe that it may be a factor in effecting the DXO rating of the lens, for it they can't focus it perfectly (on a flat printed test sheet it will score lower.

How often do you photograph test targets?


The Sigma does vignette a little more than the OM lens.

Shallow normal

I happen to like the shallow DoF rendering in normal focal lengths (well and wide too) compared to the Kit 14-45mm zoom you just won't get shots like this

The background would be much sharper and the trees would be lost amid the background. Now personally I'd like even better separation than this, but in my view that can only realistically be had with larger formats. So the so called Full Frame (which ironically is only the full 35mm frame which was once regarded as miniature) is the only way to get this. In theory a f1.4 30mm lens would do it, but

1. I've never seen a f1.4 lens in micro 4/3 between 24mm and 35mm focal length
2. the 20mm f1.7 is close, but as its a bit wider then you need to work closer or you'll loose the effect.
3. f1.4 still isn't quite as shallow as f1.8 is on a 35mm because the 2 fstop guidelines for determining the effective DoF of the micro 4/3 vs full fame is only really a guideline (see posts here, here, and here)

Conclusion

Basically I like the Sigma a lot. If I was using only a ultracompact body (like say one of the EP series) I'd definately have it and the Panasonic 14mm. It would be a great combo. It really helps cameras like GF1 attain the 'compact' dimensions and become convenient and powerful tools.

However for anyone using the SLRalike bodies who also happen to have some legacy lenses, the case for ownership becomes less compelling. Then the things which stand out are:

• AF
• flash compatibility (I don't have any native flash)
• focus by wire more immediately (although bringing up focus assist is usually quick)
• better colour balance (with JPG) and exposure decisions (compared to legacy lenses)

I paid €124 for my lens, but as you may know its now discontinued and the newer model is selling for €199, to me that's enough to change the equation. Lets look at some money figures:

A 28mm lens such as an OM or FD or Pentax screw mount lens will cost you about 60 bucks, less if you buy a non branded lens like a Tamron / Tokina / Vivitar .. probably 30 bucks. A reasonable quality legacy adapter will cost you anywhere between 30 and 60 bucks.

So if you have no other legacy lenses and no interest in fiddling in this area then there is no benefit to the older glass, so just grab the Sigma 30mm f2.8, it's your cheapest way to get a prime fast 'normal'.

However if you perhaps wanted to add some other lenses (like say a 50mm and a 100mm for some mid telephoto work) then you can share that adapter across the other lenses. If you are interested in that path then it would be something like this:

• 30 bucks for the adapter
• 30 bucks for a 28mm f2.8
• 30 bucks for a 50mm f1.8 (seriously, don't get a 1.4 you'll be disappointed with the softness and weight)
• 90 bucks for a good quality branded 100mm or less for a non-camera branded one

So for about 180 bucks (about the same price as just the Sigma 30mm) you'll get three lenses and add heaps more creative potential to what you may do.

So it all depends on what floats your photographic boat.

I may just end up selling the Sigma.

PS: I did sell it as the DoF differences compared to my 14-45 were in 99.9% of cases un-identifiable.