got me thinking critically about something that I've noticed for a while: I don't think my cameras are calibrated correctly for accurate focus. But read on, there's a catch!
The electronic rangefinders of both my N90s and N8008s seem to agree with the viewing image when my Nikkor lenses are mounted. The N8008s might actually be a hair off, actually, even with the Nikkors, but it's not so bad. The N90s seems perfect, but then again I don't have a magnifier to check the finder image more critically. (My vision is totally corrected.) (AF 24/2.8 D, AF 50/1.8 second version, and AF 300/4. Barely noticeable with the N90s; slightly more apparent with the N8008s.
But here's the strange part. With my Tokina lenses, the cameras seem to be noticeably off target. The finder appears to be in focus when the electronic rangefinder/AF is indicating that it should actually be focused 1/2 cm or so closer to the film plane. When I get the confirmation dot, the focus is noticeably off by a touch. (Tokina AF 28-70/2.6-2.8II and MF 80-200/2.8.) Both cameras are off by a similar amount with the Tokinas.
I'm starting to wonder what is correct...the electronic rangefinder, the viewfinder, or neither. (Who knows, maybe they are both miscalibrated in opposite directions!)
Any ideas what is happening? I cannot see why this should happen with the Tokinas and not the Nikkors. I'm really stumped.
Interesting. I was thinking that perhaps sliding diopters in the viewfinder may be the culprit, but neither camera, to my knowledge has a built in diopter adjustment. Then you state that the Nikkors view better than the Tokinas...
I'm stumped. How do the prints come out? Have you done any critical tests?
Al, does the aperture indexing tab on the N8008s move freely and snap back all the way when released? Maybe there is a difference between lenses that causes the variation/error. It seems aperture related to me anyway.
Mark, I don't think it's the aperture indexing tab on the camera's mount. It seems fine.
I actually have noticed slight softness at full aperture with the Tokinas. It's hard to tell on small prints, though. And it could have been partially due to other factors that would throw the focus off, like the subject shifting a few cm right before exposure.
I guess when I have time, I'll have to do a critical test...something to the effect of photographing a flat plane with lots of writing on it, and then view the resulting film under magnification.
What would be the way to go about such a test? I've never done one before.