Sharpness, Detail, Quality, And Old Glass

To varying degrees we all fetishize camera gear, especially glass. Pouring over specs and comparisons, our own testing. All of this in the quest for more better stuff. Are some cameras “better than others” — sure. Are some lenses “better” than other lenses — absolutely. The real question is in what particular way are they better. An even better question is do you give a crap. I’m going to propose that in most cases you probably don’t and in many other cases better is extremely variable on circumstance and so far down the list on any given optical property as to what difference it might make that how much you actually like to carry and use something is actually a better metric. Microscopic optical differences are important only in a narrow slice of real world photographs.

Just for the hell of it I decided to make some quick and dirty non-clinical, non-laboritory comparisons between some new-ish bestest best stuff and the oldest, cheapest glass I have. Not extensive certainly but representative over a broad range.

The image at the top was my Nikon 50mm 1.4G. A lens of reasonable design, reasonable cost, but performs up there with the best of them. Here’s a Nikkor 50mm 1.4 S from some point in the mid-1960’s:

Holy crap they are very very different. Yes but the two biggest differences are the way the light is falling from one minute to the next and color rendition. I shot all these with a fixed daylight white balance to highlight that really really old glass that’s single coated does have differing color characteristics but that’s a nit if you shoot AWB and also RAW. The other differences from there that are way behind that are the completely different vignette characteristics from one to the other. This makes it impossible to do a strait-up comparison exposure over the entire frame. I could monkey around with lens corrections etc but I wanted you to see these unmolested. Neither has corrections of any sort in post.

Here’s the same image from the 60’s lens I made a bit more similar with a tiny tweak to WB. I could get closer by actually measuring but who cares.

With that factor a hair more similar it’s easier to evaluate some other things that are farther down the list. First off is contrast. The newer lens definitely has better contrast overall and better micro contrast. Be careful when evaluating sharpness though. Both are damn sharp on the exact plane of focus but in the real world that’s tough to figure out. They are slightly different with the old lens being higher on the subject and a bit closer to the camera. The two lenses have extremely different focus fall- off properties. With 1.4 lenses close up that’s noticeable. Which is “better”?

It depends on the subject, the mood, etc. In many cases I would like the focus falloff, less micro-contrast, less overall contrast and rendering of the older lens. Let’s take shooting people for instance… If I wanted crazy sharp and crazy micro contrast why the hell would I be shooting at f/1.4 anyway? I kinda like the overall smoother look on the old lens in the mood I’m in today. So yes… the newer lens is “better” unless of course you want a smoother look… Which one’s smaller? Which is built better? Which feels better to use? The old lens by a wide margin. I could show you the obligatory 100% pixel view… could you see the difference? Yep you would see more of the same. More micro-contrast and if we used ever increasing numbers of pixels we might even see more actual detail at some point. Is detail that critical? To what magnification do we want to look at? More pixels doesn’t really give you “sharper” it gives you the ability to look at your image with more magnification when hitting the Z key. Who cares beyond a certain point.

How about a superlative 28mm in the form of my “pro-zoom” compared to my free Nikkor 28 f/3.5 from the later 1960’s. Here’s the pro-zoom — a really good one by any measure wide open…

Here’s the ancient lens…

Again these have very different properties. Take my word for it in the center wide open the old one and new super lens are the exact same in terms of contrast and sharpness and detail with as much magnification as you can get from 16 megapixels. The big difference is the vignette which is extreme and starts immediately on the old lens. Some of this shows up on film but a lot of it has to do with the old design as a far more extreme light-ray to sensor angle than the new one. The newer but still ancient AiS designs for both the 28/2.8 and 28/2 don’t do this. Is this a bad thing? Depends. In this picture it might be a good thing. Color is a bit different but I’m not even going to bother making them closer or even the same.

Here’s a surprise… The old one has less distortion and is actually wider by a hair. Hold on a second you might say, that can be fixed in post. Consider that fixing distortion will make it even less-wide. Hmmmm. Trade offs. I won’t mention that the pro zoom sucks to actually carry around and use. The old lens is tiny — smaller than most micro 4:3 lenses. It’s also a work of art in terms of build quality and feels good.

Okay let’s move to a short tele. I rigged the game here a bit. A really good 105mm — the AF-D 105mm f/2.8 against about the cheapest lens you can buy in old style Nikkor telephotos. The ubiquitous “nobody wants one” 135mm f/4 Q. Here’s the new one close up from where I was standing with the 50mm and 28mm.

Absolutely crazy sharp even wide open at the actual point of focus. Hard to tell looking at the whole frame but very shallow in any case. Hint: A bit above center on the corn husk in the middle of the frame. Now here’s the black sheep, can’t give ‘um away 135 Q.

Wow, that’s crazy sharp. It’s the closest focus distance I could get on that lens so it’s farther away. Poor planning, my bad. The farther away-ness is a bigger reason for the increased DOF and also the perceived increase in sharpness than the f/2.8 to f/4 thing. Really — it is. In fact that stop difference might be close to being cancelled out by the increase from 105mm to 135mm.

Let’s fix the exposure and crop in a bit for similar image sizes to see what happens…

There we go… looks great. Doesn’t it? It’s even rigged in the 105mm macro’s favor which is technically “better” closer up than the non-macro which is not as good at the very closest focus distance as it is farther away. There’s not a huge difference but there. Oh, one more thing… the color is the same too. Strange but true for this single coated hunk of stuff from the dark ages. I’m not going to bother with 100% crops. Your perceptions of things are not going to really change that much, they will be about the same or reinforced. This last example does show something important though. Context plays a huge role in perception of image quality. The longer lens farther away is probably perceived as “better” than the better lens closer.

Just some food for thought. These are extremely exaggerated due to the age of the glass I used. Newer AiS glass is “better” and in a lot of cases on par. If I shot any of them stopped down even a little bit all the differences including the vignette on the 28mm/3.5 would go away. Are you shooting hand-held? Moving subject at all? Like breathing? Remotely on the slower shutter speeds like 1/125s? If so all of that will overwhelm any “quality” difference in glass and perceptions of image quality will be almost entirely dependent on scene, context, light, post processing, etc, etc, etc until we get so far down the list it doesn’t matter.

RB

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