I gotta say, I think there is much more of a visual difference between various lenses than there is between camera sensor looks. I see it when I interchange older lenses and newer lenses on the same camera body. A recent, Zeiss 24-70mm f4.0 on the Sony a6300 renders very clean colors with open shadows and, since the camera corrects for lens faults automatically everything seems geometrically rectilinear and sharp. When I put a film era lens on the same camera the shadows tend to block up, the saturation can be much higher and while the resolution isn''t the same the sense of smoother, richer color transitions comes through. There is a heaviness to the older film era lenses that isn't a fault or design flaw but a consciously designed look. Maybe it's a look that is no longer in style but in an age where lens design can sometimes seem in lockstep (output wise) from maker to maker it's delightful to have more choices.
These images come from one afternoon when I got curious about what the a6300 would do with the 25mm f2.8 Pen F Half frame lens from 45+ years ago on the front of it. I expected less. I got more.
The top image shows what I've come to think of as a classic older lens design look. It's really sharp but not in a high resolution way (there is a difference between apparent sharpness and total resolution. It has to do with the intersection of tones. Think in terms of big radius vs. small radius in sharpening...). The older lens gives a high impression of sharpness but digging in to 100% shows less superfine detail than I might get from a new formulation.
I think one reason that the lens performs as well as it does in the above image is that I'm using it with the light behind me (no chance of flare or veiling glares) and I'm using the lens at f8.0, an f-stops that's almost guaranteed to make any lens look good. I love shooting this old, manual focusing gem with the new a6300 body because I can punch in to magnify, and even set a hyperfocal distance, and then walk around shooting without having to worry about refocusing as long as I stay in the same camera-to-subject distance parameters (as dictated by depth of field).
The lens has plenty of barrel distortion which is NOT corrected by the camera but, since it's not a modern lens design (with attendant physically uncorrected compromises) it's a very simple barrel distortion with no "mustache" wavy lines and so it's a quick and easy correction in Lightroom or Photoshop. (See below).
The lens itself is much smaller than modern lenses and is attached to the a6300 via a very small and inexpensive adapter ring. The lens is 100 % metal body construction and the glass on my copy is clean and sparkly. Remember that the lens DOES NOT cover a full frame sensor and, on an APS-C sensor provides the equivalent field of view as a 37.5mm on a full frame camera. A bit short for me but just right for those folks who swear that they love a 35mm lens on their full frame rig.
Looking back to 1985 when I bought this lens I am happy to report that I spent a whopping $48 at KEH.com and it came in pristine condition. I still have my collection of Pen lenses and often think of buying one of the new Pen F digital cameras just to use with the collection. It's a novel approach to creating a system.
But I will say that I do think the ancient lens works very, very well in the new world of high res and well behaved sensors. I think I'll continue to keep it...