Why Image Quality Is No Longer the Most Important Aspect of a Lens

In any given lens review, the most valued and sought-after tests performed are those pertaining to image quality. I believe we have already begun to shift away from this, and here's why.

If the camera body is the brain, then the lens in the eyes. Without a lens, the brain can't see anything, but how good those eyes are has been of paramount importance for the entire history of photography. People would press their face against prints in decades passed and magnify the pixels in recent times, all trying to decipher lens (and camera) performance. Us photographers wanted to know how every lens stood up to being wide-open, at the optimum aperture, and in high-contrast scenes. We would scrutinize and compare similar lenses to a peculiarity with the express intention of bleeding every iota of image quality out of our hard-earned cash. But, I believe I've noticed a shift, particularly in the last 10 years or so. That is a move away from absolute image quality, to other marketable areas. Before I discuss what I think the primary focus now is (or at least will become), I want to justify my position on why there has been a move away from image quality as the number one aspect of any lens.

Diminishing Returns

It's first important to note that image quality is still important to a lens; more than that, it's vital. I'm by no means claiming that image quality is no longer important, but rather that it is no longer the most important aspect. The reason for this is simply diminishing returns. Diminishing returns is an economical principle that is often borrowed elsewhere as it is so often applicable. Put simply, it is when the yield of any given action reduces over time and with increased production. It is essentially the opposite of something scaling infinitely. With regards to photography, you might look at memory card size.

In 1994, SanDisk (known as SunDisk then) launched their first CompactFlash cards, which were between 2 MB and 15 MB in size. It seems absurd now, but a storage device that didn't require a battery was no small feat back then. By 1996, these cards were being used in digital cameras. In 2004, SanDisk launched the largest capacity CompactFlash card on the market at 4 GB. The small numbers here can fool you into not realizing just how much space was gained in 10 years. A gigabyte has 1,024 megabytes in it, which means in 10 years, the CompactFlash memory cards had increased in storage space by over 270 times. Now, we have CompactFlash cards with a capacity of 512 GB, which is another mighty achievement, but notice the scaling is not exponential here — it's diminishing. In the first 10 years of CF cards, the capacity increased to be 270 times that of the first card. From 2004 to 2021 — 17 years — it has increased by less than half of that, at only 128 times 2004's 4GB cards. From 2004 to 2021, storage space increased 7.5 times. Nearly twice the time and less than half the gains.

Now, memory cards can be a little misleading as the technology changes drastically — CF cards play second fiddle today for the most part — but the optical performance of a lens has been relatively stable for nearly a century. However, we have certainly reached a stage where it has either begun to stagnate or has nearly fully stagnated, and I'm inclined to believe we're closer to the latter. I'm not going down the "everything that can be invented has been invented" line of thinking here. (An aside, that quote is attributed to Charles Holland Duell, and it is wholly inaccurate, as he actually said: "In my opinion, all previous advances in the various lines of invention will appear totally insignificant when compared with those which the present century will witness.") While there can and will still be gains in image quality, they will be minimal.

Gains Past, Present, and Future

In early 2014, I bought a Canon 75-300mm f/4-5.6 — the earliest version for EF mounts — and I got a fairly cheap second-hand copy. I can't swear that the lens I owned was typical for that lens — there are "bad copies" — but I used it a lot. When shooting wide open, which with a zoom lens that has that high a maximum aperture was necessary, it was softer than blowdried alpaca. Even back then, I was disappointed with what it could do when paired with a Canon 5D Mark II. Fast-forward to the present day and even the cheapest zoom lenses are significantly sharper at their worst. The higher-end market for lenses saw far less in gains, it's true, with many top Zeiss lenses even 20 years ago performing well by today's standards. But now, even the lower end of the lens market has nearly caught up on image quality. And it is at this point where the key selling point of a lens has to shift.

There are of course other important metrics that dictate the popularity and effectiveness of a lens — for example, speed. A wide maximum aperture is as desirable today as it always has been, but even that has experienced its own diminishing returns. Few lenses are slower than f/2.8 these days unless they're specialty or medium format. Moreover, much-coveted sub-f/1.0 lenses are far more prevalent and no longer cost a house deposit to attain.

So, when the lenses are fast and sharp with few unwanted artefacts, what else do we want from a lens? What can manufacturers aim for in their design and market? My guess is "character."

The Rise of Character

There have been lenses over the decades that have become cult classics. Yes, it's often in some way tied into the image quality they help produce, but that alone does not raise them into the rarefied atmosphere of revered lenses. Usually, there is some undefined quality that people call the "X factor" or in my case, "character," a visual hallmark of the lens. One of the most modern examples of this is a Fujifilm prime from 2012.

The Fujifilm XF 35mm f/1.4 R is widely regarded as one of the best modern lenses made. It is fantastically sharp even wide open, suffers very few common flaws, and manages to remain humble in both form and price. However, there's a word that is often used when describing it: "magic." I managed to trace this back to Fujifilm themselves, when Billy Luong, Senior Technical Brand Manager at Fujifilm Canada went on the FujiLove podcast and discussed the lens. In fact, it wasn't him alone that said it, but other Fujifilm employees responsible for this lens. There was the goal of creating a unique, "magic" look, and this was done, in part, by deliberately creating a lens that was not optically perfect. Of course, it performs well with regards to image quality, which makes it a good lens, but its character, its "magic" is what sends it into a different league.

Whether you consider them overpriced or not, Leica has more or less built an empire off of the pursuit of magic. The Leica look is loved by many, but not because it is the sharpest, or has the least distortion, or the least chromatic aberration. In my own work, I have been gravitating towards lenses with character more often than not when it comes to my portraiture. Sharpness, in particular, is only desirable to a point; once it's at a serviceable level, I don't really care if it increases much further. I want some other quality — something special — to draw my eye. Having the sharpest lens on earth doesn't give you a fluttering feeling of excitement when you look at the back of your camera after a shot, but "magic" might.

In Summary

The diminishing returns of optical quality from lenses mean that the lowest, cheapest lenses on the charts have risen up the ranks enough to close the gap on the higher-end lenses. With image quality from a $5,000 lens varying less and less from the image quality of a $500 lens, the most important aspect of a lens will (and I argue has already begun to) shift. If the only way you can tell an expensive lens from a budget lens, with regards to the images they help take, is by zooming in 500%, few will care. Whereas, if one lens has this difficult-to-define character — that magic — that evokes a response in the photographer and viewers, it will fly off the shelves. Sharpness is, to a degree, expected in modern lenses, so with only marginal gains to be had from great effort, the focus from lens manufacturers will shift to a different metric, and I believe that to be character.

Do you agree that modern lens' image quality is now high enough even at their worst that they are no longer the most important selling point? Do you think I am off base and that image quality will always be the most important aspect of a lens? Share your thoughts in the comment section below.