Back focus problem D70?

I am not 100% sure if the well known D70 back focus issue is only when shooting

in AF mode but my problem is when shooting in MF mode.

 

I took some portrait shots using the 75-150 Series E and saw that everything

had a back focus bias. After reading some posts and the manual, I tried the

Electrontic Range Finder option (p74) and to my surprise the shots that look

slightly out of focus to my eye were in focus on the computer screen. My eye

sight is still good enough to know when the subject in the VF is in focus or

not.

 

I have tested the 18-70 DX in AF mode and believe that it is accurate. However,

this lens, the 75-150 and also a third lens which will remain unnamed (ok, it's

a borrowed Zeiss CF 80mm) all show that when focusing manually all three are

accurate when the focus indicator comes on (actually most of the time it only

flashes), but not when I think it is in focus.

 

My problem is that photographing a moving child is basically an impossible task

to have to wait for the focus indicator to lock, or even just flash. I believe

that if I see the subject in the VF to be in focus - and with all things being

equal - the final image should/must be in focus.

 

So, my questions are:

 

A. Is this normal with all D70s and all lenses when manually focusing

 

B. Can it be fixed. And if so will Nikon foot the bill

 

I attach 4 files.

 

1. 75-150mm @ f3.5 using the focus indicator lock vs my eye sight

 

2. 500% crop of D70 determined focus showing just how good the Series E is

 

3. 500% crop of my determined focus spot which shows that the tyre is better in

focus

 

4. Why I am now really interested in using this lens for portrait work

 

And as a side question, how on earth does the D70 know whether or not the

subject is in focus when the lens such as the 75-150 doesn't have a CPU chip?

file 2.

file 3

file 4

Have you tried adjusting your view finder's diopter?

Hi Garry. Yes, that was the first thing I tried. I have it pushed as far down as it will go.

 

I have read that some third party lenses have this back focus problem, but when I can show clearly that the problem exist on the 18-70, I believe that it will happen on all lenses on my camera. I am just asking if others have experienced this and am especially interested if Nikon will repair free of charge.

Ok, so if the focus indicator is correct, but your eye through the viewfinder says it isn't, and yet the image still comes out correct, I'd guess it's either a problem with the viewfinder or an improperly adjusted diopter.

 

If that's the case, then I'd think it would be under warranty.

Garry, thanks for the reassurance that if it is only the diopter or VF that needs adjusting then I will be very relieved. My unit is due for a checkup so hopefully it will be sorted out. Judging by the lack of responses it obviously doesn't seem to be a common problem.

Good luck. Let us know how it comes out for archiving. :)

I sent Nikon UK an email describing the problem and they advise that I do some further testing using test charts which they provided. After this I am to send Nikon my results and they will then take it from there. So, I will document this for the archives.

Nikon confirmed that there is a problem and I bascially need to get it serviced.

 

Oddly enough they claim that there is no back focus problems with the D70, even in the past, and that this can happen with any camera.

I managed to stumbled accross Mr Leon Goodman's site who helped me fix the problem I mentioned above.<p>

The link where you can find the help is <a href="http://www.leongoodman.com/d70focusnew.html" > HERE</a>

<p>

Although my D70 problem is manual focus related, Leon's page addresses both AF as well as MF back focus problems.

<p>

Also this link below helped me with a focus chart, so please check it out.

<a href="http://focustestchart.com/" > Focus Test Chart download </a>