Stupid question: Back Focusing with MF lenses

Nawty

Nawty

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I've recently put a series e 50mm on my FM2n and 2 rolls of film have come out largely mis-focussed (looks like back focus to me).

In my mind I think logically it can only be user error however I never got a missed focus when manually focussing with my AFD 50mm (so it shouldn't have been my eyes). I had a CPL over the series e if that makes any difference?

So was it just me or can a lens do this?
 
Nawty said:
I've recently put a series e 50mm on my FM2n and 2 rolls of film have come out largely mis-focussed (looks like back focus to me).

In my mind I think logically it can only be user error however I never got a missed focus when manually focussing with my AFD 50mm (so it shouldn't have been my eyes). I had a CPL over the series e if that makes any difference?

So was it just me or can a lens do this?
Click to expand...

If the mirror is not in the right place that could cause errors, but do you wear glasses as for me some magnification glasses are better than others, also focussing wide open then stopping down could cause inaccuracies......but if I have time, I check that when I've focussed on something it agrees with the distance on the lens (not sure if this is a good idea but it works for me on some cameras where the viewfinder is not very good).
 
I wear contacts but have never had a problem with focusing before - the split section in the middle sees to that (?).

Looking at the lens it goes from 5m to infinity in one step so there's a chance I just shot at infinity but (I think) I was sure to check the focus.

Ho hum, nay matter, a few of them are OK so maybe I'll post one or two.

Funny thing is, I got back from holiday last night and already have the films processed yet not even plugged in the memory card from the D90 yet :thinking:
 
Nawty said:
I wear contacts but have never had a problem with focusing before - the split section in the middle sees to that (?).

Looking at the lens it goes from 5m to infinity in one step so there's a chance I just shot at infinity but (I think) I was sure to check the focus.

Ho hum, nay matter, a few of them are OK so maybe I'll post one or two.

Funny thing is, I got back from holiday last night and already have the films processed yet not even plugged in the memory card from the D90 yet :thinking:
Click to expand...

A method I probably use all the time without thinking is:- to focus backward and forward on the subject and select the best focus where it looks sharpest, but after many years I still get some things OOF and wish at that time I had AF.
 
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