Why does it vignette

[BMbikerider]

I have my main photographic kit arranged around Nikon equipment with a selection of cameras and lenses. For film use I have a F100 and a F6. The lenses I use are a 20/35AFD, 28/105AFD and a 70/200AFD. When used with film there is no problem what so ever.

If I use the 28/105 with either of my Nikon Digital cameras, which are a D300s and a D700, I get quite noticeable vignetting when using either camera bodies. On the D700 I could almost expect it, but not on the D300S which has the smaller sensor.
I say 'almost' expect it on the D700 because it is a full frame sensor, but why display the vignetting on digital images anyway and not film?

It isn't so bad, that I cannot get rid of it with Photoshop CC, but I would rather not have to do so in the 1st place. Any ideas?
Oh yes, it is in the main only visible on light areas such as sky or clouds

 

[Kawaiithulhu]

(I may be remembering older tech) A baseline answer is that film records light at the surface of the emulsion and spreads it downwards through the gelatin, while sensors are a bunch of toilet paper tubes with lenses at the top that only collect light at the bottom of the tube. The farther away from the central axis the more obliquely light from "standard" lenses hits the sides of the tubes instead of going all the way down.

"Modern" lenses are designed to shoot light down the back end straighter than film designs but the effect is unavoidable. Note that even on film you'll get vignetting but not as severely, and that several extreme wide angle lenses have graduated ND filters to counter the vignetting... Even high end Red cameras exhibit this effect, as seen here in their literature: http://www.red.com/learn/red-101/lens-vignetting

Physics is a harsh Goddess and demands much from her followers.

 

[BMbikerider]

Thank you for that appraisal I had never thought of the sensors as 'tubes'. However I am still not sure why this should appear when using my 28/105 lens only, the 20/35 and 70/200 are not similarly affected. Whilst the 28/105 is not one of the 'higher end' Nikon lenses it is still a respectable (very) performer and my preferred lens I take when out walking. Ah well, I will just have to use more film.

 

[Sirius Glass]

(I may be remembering older tech) A baseline answer is that film records light at the surface of the emulsion and spreads it downwards through the gelatin, while sensors are a bunch of toilet paper tubes with lenses at the top that only collect light at the bottom of the tube. The farther away from the central axis the more obliquely light from "standard" lenses hits the sides of the tubes instead of going all the way down.

"Modern" lenses are designed to shoot light down the back end straighter than film designs but the effect is unavoidable. Note that even on film you'll get vignetting but not as severely, and that several extreme wide angle lenses have graduated ND filters to counter the vignetting... Even high end Red cameras exhibit this effect, as seen here in their literature: http://www.red.com/learn/red-101/lens-vignetting

Physics is a harsh Goddess and demands much from her followers.

Thank you for that appraisal I had never thought of the sensors as 'tubes'. However I am still not sure why this should appear when using my 28/105 lens only, the 20/35 and 70/200 are not similarly affected. Whilst the 28/105 is not one of the 'higher end' Nikon lenses it is still a respectable (very) performer and my preferred lens I take when out walking. Ah well, I will just have to use more film.

To amplify on the tube structure, the Hasselblad SWCs did not photograph well with many digital sensors. Play it safe and stick to film.

 

[BMbikerider]

Actually I am becoming more and more dissafected towards digital and I may well almost abandon it altogether except for occasions when I do need a quick result (not necessarily the best result), only a quick one.