There’s a saying in the digital era of photography: “You date cameras, but marry lenses.” There’s certainly a lot of truth to that. There’s another, stronger adage: “Glass is forever.” How true is that? I decided to investigate my equipment cabinets for clues.

Let’s start with the oldest, if we don’t count the 5cm f/2 Nikkor that is joined at the hip to a Nikon S2 that I keep for mostly sentimental reasons.

I have a lot of 80s-era 4×5 view camera lenses, mostly made by Schneider and Nikon. I’ve sold off my 8×10 view camera glass, along with the Arca-Swiss monorail gear I used to use with it. Now I use the old 4×5 lenses mostly on a Linhof Technika with the BetterLight Super 6K scanning back. Is it a marriage made in heaven? Not really. When faced with an imaging area smaller than they were designed for, and one that has greater resolution than most film, the 4×5 lenses are not all that sharp. Even the 120mm Nikkor-M macro lens, which can’t cover a 4×5 sheet at infinity, isn’t as sharp as it could be with the BetterLight back, and has a lot of lateral chromatic aberration to boot.

In addition, when I use the BetterLight back for infrared photography, I get hot spots in the center with some of my lenses.

If I used the BetterLight back more and ultimate sharpness were important to the kind of images I make with it, I’d upgrade some of my lenses to modern ones intended for use with digital sensors. Glass is forever? In this case, not really.

I had a bunch of V-series Hasselblads from 1980 through 2006, which I used with film and with the Kodak 16 MP back. I had 40, 50, 80, 120, 150, 250, and 500 mm lenses of various vintages. When I bought my first H-series ‘blad, I sold all but the 250 and 500 APO lenses. I have the B-to-H adapter, but I have never used either V lens on an H body. I think the 250 could give good performance with the H2D-39, but don’t know for sure because I’ve never tried it. Strike two against the “glass is forever” argument, but with an asterisk, since the long lenses that I kept don’t seem to fit the way I use the H-series ‘blad.

I had an extensive collection of Nikon F mount manual focus glass. I sold almost all of it when I converted to autofocus film Nikons, which didn’t do manual focus well. Now that I have Sony a7x cameras, I could use all that glass. Most of it is still pretty cheap on the used market, so I could repurchase it should it suit me. I have not bought any old manual focus Nikon lens except the 8/2.8. I still have a old 500/5 cat lens, but haven’t used it in years. The reason: modern Zeiss lenses, plus old Leica R and M lenses are just so good. I should note that the Leica lenses that I favor are the ones with more modern designs.

Those are a few examples of a trend that I notice in my photographic history. If image quality is the long pole in the tent, I don’t hang on to glass for more than 10 or 20 years. Why is that?

Sensors are getting smaller. In the film era, if you wanted top quality images, you used at least a 4×5 inch piece of film. Many of the greats (AA, EW, etc) preferred 8×10. Some of the next generation (Huntington Witherill, John Sexton) settled on 5×7 as a good compromise, with the advantage/disadvantage/difference that the aspect ratio wasn’t as squarish. Then came scanning backs, which were closer to 2 ¼ by 3 ¼ in size. When medium format areal backs showed up, they weren’t as big as even 6×4.5 cm film.

In 35mm shaped cameras, full frame sensors were a rarity until a few years ago.

Smaller sensors don’t require smaller lenses, but it’s hard to make a lens with a big image circle that does a good job if you only use a fraction of that coverage.

I don’t see this trend slowing anytime soon. The new – and seemingly ubiquitous — Sony medium format CMOS sensor, at 33x44mm, is not hugely larger than full frame (24x36mm) ones.

Sensor pitch is falling. When full frame sensors began to make deep inroads into the market in the ought’s, they had pitches of about 8.5 micrometers (um), arguable equivalent to the resolving power of Ektar 25 film. The D810’s pitch is 4.88 um. The a7RII’s is 4.5 um. It turns out that many of the older lenses reveal new resolution capabilities when used on high resolution sensors. It’s also true that many look soft at the pixel level. Thus new, sharper lenses are desirable.

I believe sensor pitch will continue to drop in the foreseeable future.

Lens coatings continue to improve. If you go back to before WWII, most lenses weren’t coated at all. Coatings are continuing to get better. Zeiss has just introduced new materials in their Milvus line. Nikon has nanoscale coatings. Like much material-science based technology, this looks like is can go on for a long time.

Manual focusing is now much more precise than it ever was. When autofocus lenses came out, SLR manufacturers started to remove focusing aids from their finders, with the result that manual focus became more hit-and-miss (mostly miss, in my experience). But SLR autofocus wasn’t constantly as good as manual focus with good focusing aids (the gold standard of which was a clear (unground) center with an etched cross). That amounted to a step backwards for some kinds of work. The introduction of mirrorless cameras changed that game, with highly magnified sensor-level focusing and focus peaking. Now focusing can be more accurate than it ever was, with the exception of the clear center with cross approach, which few took the trouble to use. Focusing is certainly more accurate than it was with a loupe on the ground glass of a view camera. That’s a good thing, since, because of the increased sensor resolution in the digital age, loupe focusing doesn’t cut it any more.

Computer design of lenses is now universal. Have you noticed the element count of lenses rising over time? I sure have. We now have lenses that would have been completely impractical to design by hand. Thanks for computer aided design and simulation programs, and also to improved coatings to allow us to have all those elements without everything dissolving into low-contrast mush.

Because of the improvements in mirrorless manual focusing, there is now a big market for manual focus lenses. Zeiss has stepped up in a big way here. Leica never stopped emphasizing MF lenses. There will be others.

Third party lenses now can outshine the camera makers’. The Zeiss lineup, especially the Otus brand, is the poster child for this, but Sigma is doing some amazing things as well with their ART lenses. This rich ecosystem means that, if you’re, say, a Nikon shooter who cares a lot about image quality, Nikon is not the only game in town anymore. Nikon realizes this, and is stepping up to the plate. Everybody wins, except to the people holding on to their ancient glass.

New lens mounts continue to be introduced. Leica SL. Sony E. Hasselblad H. MFT. The list goes on.

So, although I foresee lenses having a longer life than digital bodies, I don’t think lenses, like diamonds, are forever.

Postscript. Two caveats.

First, all the above assumes that sharpness, freedom from flare, smooth OOF transitions, correction for many disparate wavelengths, low LaCA and LoCA, low distortion, high MTF scores and the like are desirable characteristics in a lens. There are many — new and old — lenses whose deviations from the standard lens quality measures is prized among some photographers for some purposes. I don’t mean to rain on that parade.

Also, whenever I go on and on about image quality as I’m doing here, there’s a voice in the back of my head that reminds me that image quality alone never made a great picture, and that image quality must serve some greater photographic goal in order to be useful. I’m now reminding you all of that.