There has been a lot of interest in using old film camera lenses on new DSLR or mirrorless cameras. Although this isn't a comparison of that it is an old vs new example. Neither is right or wrong just the way it is. I won't say which is which so the guess or decision is in the eye of the beholder. One side is a newer DSLR with a ef 50mm f1.4 lens and the other side is a film F1n with a FD 50mm f1.4 lens. One caveat, the film photo was scanned on a Canon 9000f photo scanner to create a digital image.
This is a comparison of a new Canon EF 50mm f/1.8 STM with adaptor and an approximately 45 year old Minolta MC ROKKOR-X PG 1:1.4 f=50mm with adaptor. I attempted to keep as much the same as I could. F number set to 2.8 for both. Manual focus with assist from EOS R5 for both. The Minolta lens is much larger and heavier than the Canon lens.
I put them on a tripod and the tripod moved slightly when I changed lenses. F2.8, manual focus, auto ISO. One crop is from near the center and the other crop is from near the upper left corner. The crop was done in DPP. Lens ID was added to exif data for photos made with the Minolta lens using exiftool.
My impressions are
photos were made with EOS R5 and "clarity" set to 1. Unsharp mask disabled. Electronic first curtain.
First image is Canon lens with digital lens optimization and all corrections turned off.
Second image is Minolta lens:
Next is Canon lens, upper left corner:
Next is Minolta lens, upper left corner:
Next is Canon lens with digital lens optimization enabled in DPP:
Man you lost me. Just what exactly are you trying to show here? Perhaps I am missing something.
Personally I would not use either of the lenses you tested if that is what they produce. I could not sell, nor would I try, any photo from either of those choices.
I am sorry that I did not express my intent clearly.
I was attempting to show the difference between an old lens and a new lens with as many other variables as possible kept constant. These are not photos to sell, but to demonstrate a difference. A quick experiment when there is nothing interesting to photograph. There have been comments by others that there is no point in using an old lens on a new camera. It seems to me that some old lenses are better than some new lenses on a new camera body.
Here is an image made with the 45 year old Minolta MC ROKKOR-X PG 1:1.4 f=50mm lens (reduced in size so not too large to upload). I cannot make the same image with the Canon EF 50mm f/1.8 STM
"There have been comments by others that there is no point in using an old lens on a new camera."
I tend to agree with that. Depending on the choice of lenses. There usually is no benefit to gain and a great deal to lose using old film lenses.
"It seems to me that some old lenses are better than some new lenses on a new camera body."
Again choice of lenses. " I cannot make the same image with the Canon EF 50mm f/1.8 STM"
Perhaps not but what if the choice was the Sigma 50mm f/1.4 DG HSM Art Lens and the old Rokkor. You see you made a comparison between an entry level lens and a top tier lens.
My Minolta lens is likely in better condition than one available on Ebay for less than $100.00. I understand that not everyone has an old high quality lens in their closet.
Mirrorless cameras have made adaptors for the old lenses more practical than they were before.
It seems to me that design tradeoff choices on some of the older lenses were weighted more toward resolution at the expense of contrast. A modern sensor and software can take advantage of that, especially for black and white.
"...especially for black and white."
That may be the bet for use of old out dated film lenses because most, all, suffer form lots of chromatic aberration. A spec that is far better controlled by a top of the mark lens like the Sigma 50mm f/1.4 DG HSM Art Lens.
Always keep in mind the total ability of any lens. Most of the time people get caught up on a single spec. Usually it is IQ but not always. If any lens old or new serves your purpose it is a great lens! Right?
The Seven Laws of Lenses