A Tale Of Two 50mm Lenses

Had a few people ask me about 50mm lenses in the last few days. I had a few moments free today so I thought I would share a few opinions I gave as well as expand on those just a hair. I thought doing a giant scientifically controlled set of exhaustive tripod mounted tests for a moment but then decided completely against it. Scientific tripod mounted tests are pretty much pictorially irrelevant for actual photography. Instead what we have for illustrations are absolutely unscientific handheld illustrations that will hopefully illustrate my points far better than loosing the forest by closely examining trees under high magnification.

The discussions I have had centered somewhat around which particular 50mm for Nikon cameras. That one's easy I'll just skip to the chase on that… The 50mm 1.4G as long as you can find a reasonable deal on it. If not the 50mm 1.4 AF-D is perfectly fine and probably a little faster focusing as long as it works on your body. If you have a DX camera then go for the 35mm 1.8G it's the bargain of the century and quite good. There you have it - discussion over. Kidding.

Now for some of the other bits of conversation along with my rationale. Specifically regarding any of the above 50's vs say the 50mm f/1.2 AIS or heaven forbid switching camera systems to Canon go get the 50mm f/1.2L. Take a look at the image at the top. Now take a look at the next one…

One is my 50 1.4G the other the 50 1.2 AIS. Can you tell which is which? Are they different? Sure let's go through the differences in order of significance.

  • First off I botched the framing because it was hand held and I decided to have a cigarette in-between the two shots. Hence the 3 minute difference. Not mad for having moved around a bit and guessing it. I am sure I would win a prize if the goal was reproduction without references. Too bad there's no prize for that.
  • Next up we have the fact that one is warmer than the other by a nit. This could be a slightly different color rendering of the lens but is probably more likely due to the color of the scene shifting a bit because of the time of day and less/more sun reflecting of shit or a partial cloud or something. Either way any adjustment of WB will overwhelm a slightly different color rendering.
  • I'll save you the trouble of looking at the EXIF, one is a 1/3 stop different in exposure. The faster lens consistently exposes 1/3 of a stop more. Strange isn't it? So we have 1/400 second for the f1.2 wide open and 1/500 second for the 1.4 wide open. You would expect the 1.2 to have somewhat of a higher shutter speed. If you look closely you will see the edges of each photo are about the same but the center of one is brighter. I just did what the matrix metering told me to do in this case I could have just as easily done something different… What's going on here is a combination of two things - the newer lens has a better T-stop meaning actual light transmission wide open is a hair better and even though it has visible vignetting it's less than the older "faster" lens. All in all they are really about the same speed depending on how you use it. If you correct for the vignette in post the faster lens may be a hair faster but nothing that's going to make any difference in the real world.
  • What about focus rendering? Sharpness? DOF? What about all those critical things that we all pay really good money for? You judge for yourself.

Wait a second - I cheated you guys - no 100% views how are you supposed to figure out which one is sharper and which has the least DOF and all that. Well here's my point - they are practically the same except the new lens has AF, is bit bigger, much lighter and cheaper if you buy it new. Wide open they give the same practical impression in terms of focus rendition and DOF unless you are a 50mm fetishist like I am. Even so I would have a 50/50 shot at telling you which was which if I didn't have the EXIF and even at 100% I would probably guess wrong depending on the actual shots still 50/50 at best.

I will give you my subjective/objective verbal experience that includes real world shooting as well as more scientific-ish comparisons that I have done to satisfy my curiosity. You will just have to trust me here otherwise I would have to post 1000 images to give you the same sort of overview considering my take would change had I only had one set of "tests" or another both of which I did.

Generally speaking the new AF-G lens overall gives you the impression of consistently sharper images at the plane of focus when both are wide open. I use the word impression because I honestly cannot say that it for sure has more resolution or it's because the 1.2 has less DOF when examined at a microscopic level. It really is hard to say. In the real world it doesn't matter for most shots.

This point brings us to the DOF difference. Both have crazy narrow real DOF when used at close ranges where I happen to work most of the time. For normal picture viewing where you are actually looking at the whole picture and not zoomed in looking with a magnifying glass they look about the same - check out my two examples of the stuff that is farthest away from the focus point. The difference comes into play as you get closer and closer and closer to the actual real focus plane. The biggest difference is say within an inch or half an inch of the actual real focus point. As you move out of that very narrow band they are more and more and more the same and I would say you would be hard pressed to know one way or another on any given picture I showed you. Which brings us to why I bothered to buy a brand new 50mm 1.2 AIS…

  • I am nuts and I wanted it.
  • I got a really really great deal on it brand new.
  • I love the way the manual focus feels on AIS lenses. It's perfect.
  • My hobby that is only partly related to actually making pictures is buying every 50mm lens ever made. Thank god I am not into super-tele's a 50mm lens obsession is relatively cheap and I do use them all - or most of them at least.

Are there any real advantages to the 1.2? Not really. Will I still use it? Absolutely - mostly on my film bodies but also occasionally it sees use on my D600. It does look a little different and that is what my 50mm fetish is all about. Mostly for me not really any different for image viewers. So there you have it. My thoughts on Nikon 50mm lenses of the moment.

As an aside I also want to discus Canon and their 50mm lenses briefly. I have experience with both the 1.4 and the 1.2L auto-focus lenses. I rented them along with a body a while ago and spent a substantial amount of time with the system. I won't go into everything I took away from it like how Canon color is pretty much the same as Nikon color as long as the WB is actually neutral between the two and you are working with RAW files. I will say that every thing I just said regarding the major differences is about the same. About the only one that is going to know the difference between the 1.2 and 1.4 is you under a microscope - even in the DOF department you really have to look critically at the same exact shot to tell and if you had to guess you would have about a 50/50 chance. Being able to tell without a comparison shot… forget it.

Having said all that the 50mm L comes with all sorts of headache if you ever want to use it at any aperture between f/5.6 or so and f/1.4… It has a focus shift as it's stopped down that is not at all hidden by increases of DOF. I have verified this myself and it's well known. You can even see it in liveview on the camera. This makes AF absolutely useless for this lens for the most part at anything other than > f/5.6 or f/1.2 It's and exercise in liveview or attempting one of the many voodoo guesswork work-arounds suggested by various users. It also has significant field curvature that makes it a bugger to work with focus/recompose AF. All in all it's way more dicey in actual use than the 1.4 and from my practical experience more dicey than the much cheaper Nikon MF 1.2 AIS.

Does the 50 1.2 AIS have focus shift? Field curvature? Probably but if it does it seems to be neck and neck with increases in DOF. All I know is it's crazy sharp at f/2 probably better than the 1.4G at the same aperture. Focus/recompose seems to anecdotally work more consistently but wide open any of these lenses is within a breath of OOF - quite literally. Even the 1.4 lenses are like this and you really have to practice a lot to use them effectively wide open with consistency if you are used to 2.8 as shallow.

Why bring up the Canon? Well I just wanted to give any of you that have the grass is greener syndrome a bit of the real world. A $1500 lens that has some serious usability issues that only confound the already dicey situation of using any thing remotely this fast wide open and all is well on the Canon side of the world? Don't get me wrong - perfectly competent cameras/lenses/etc. In fact if I did/will shoot Canon ever I would most likely buy a 50mm 1.2L, why? See above nuttiness. It's also one of maybe 3 lenses I would ever buy and use. I would probably have the 1.4 as well.

For normal people that want to produce results that are indistinguishable or at least 50/50 even to those that know what's what go with the 50mm 1.4 for either system. Trust me on this. Have a 50mm fetish? A bunch of cash lying around and want a lens - sure go for the 1.2 lenses why not.

RB

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