Problem with FM2n

[OldBodyOldSoul]

Hi,

I've been reading these forums for a while now and the problem I am having made me take the next step and register. I am lazy that way.

I am having problems with my newly acquired FM2n and what I am hoping to hear from you knowledgeable people is ideas about what could be wrong. At first I blamed the local 1-hour lab for ruining the test rolls, then I switched to blaming myself and now I think it's actually the camera. Could be all three, could be something fourth...
Anyway, I also have F3 and D90 and assortment of MF Nikkor lenses. My eyes are still in great shape and I never (ok, almost never) miss focus, especially if the subject is still, which was the case in all test shots. What is definitely true is that I don't miss focus this much and from this distance, as seen in the attached photo. Most other shots from these test rolls show the same problem, but this one is most obvious.

I was about 3 meters (10 feet) from the guy, he was not moving and I was sitting. The lens was 85/1.8 shot (I think) at f/2.8, used successfully about million times. As you'd expect, I focused on his eyes and face.

Problem: Look at the in-focus area. Facts:
- The guy is entirely out of focus.
- The wall at the right edge of photo is in focus and then gradually blurs out as you move to the left along the wall (ie as distance increases).
- Look at the fence in the bottom left corner of the picture - it's sharp(ish). However, the branch/tree along the left edge of photo is out of focus.

From what I see here, for one the in-focus layer is not perpendicular to the lens. For two, I think it's not even of same width everywhere as it appears to be much thicker along the wall than along the fence that the guy is leaning against.

I have never had a problem like this, before or after shooting with this camera. Is this the prism, the focusing screen, black magic or do I just generate extraordinary and unnatural suck in combination with FM2n? Any ideas?

I do intend to send the FM2n to an authorized Nikon repair shop and let them see if something's wrong, but it would be nice if I could have some ideas beforehand.

Thanks and sorry for the long post.

 

[CGW]

I'm guessing misaligned focus screen? It's a DIY thing to straighten it out assuming the frame holding it isn't bent.

 

[OldBodyOldSoul]

Yeah, I took a look and everything seems normal.

Now that I think about it, if the in-focus area really is slanted, then it can't be just the focus screen or prism. My guess would be that the film is not perpendicular to the lens axis so focused light doesn't fall where it should. But I dont see a bent inside the camera either...
If the in-focus area is of same depth everywhere, and is just behind the guy, then it could be a user error (or focus screen, prism etc).

 

[vpwphoto]

Are you saying all the pictures are like this?
To me it looks like you are focused wide open on the close stuff and things are falling off as expected with an 85mm f 1.8
I was going to say that the lens mount/body flange is bent, but I would need to see more photos to say that might be the case. IF the focus screen were un-seated, this would not effect the images.. just the accuracy of focusing.

 

[brucemuir]

I cant tell for sure from this low rez but it looks back focussed.
That would indicate the focus screen as mentioned.

The nikon F mount is pretty damn strong but I guess a long enough telephoto could bend/tweak it out of square but I cant tell if the focussed area is relative to the film plane.

If you had a decent metal square you could lay it across the mount but I'm sure they have precision tools for this.

 

[OldBodyOldSoul]

Are you saying all the pictures are like this?
To me it looks like you are focused wide open on the close stuff and things are falling off as expected with an 85mm f 1.8
I was going to say that the lens mount/body flange is bent, but I would need to see more photos to say that might be the case. IF the focus screen were un-seated, this would not effect the images.. just the accuracy of focusing.

No, not all of them are like that but most are out of focus and from those that I can say with any certainty, they all suffer from back focus.

Just back focusing would be grand as it would mean either a user error or, more likely considering the consistency at which this problem occurs and my easy focusing with other cameras, misaligned focus screen.

What I am worried about is the possibility that the light is not falling on film under proper angle because something's bent. To me it looks like the in-focus area in that picture suggest something of that sort, but I am not 100% sure that I see what I think I see plus I wondered if something else could be the reason.

 

[OldBodyOldSoul]

I cant tell for sure from this low rez but it looks back focussed.
That would indicate the focus screen as mentioned.

The nikon F mount is pretty damn strong but I guess a long enough telephoto could bend/tweak it out of square but I cant tell if the focussed area is relative to the film plane.

If you had a decent metal square you could lay it across the mount but I'm sure they have precision tools for this.

Yeah, I think I will just send it to repair shop and let them decide if something is amiss. I'll shoot another roll first and develop it on my own and see from there.

It just feels bad because the camera looks great, not a single scratch except a couple small ones on the back door and I was immensely enjoying it. That is, until the rolls came back from that bad, bad place.

Thanks everyone. If you feel you can add something, please do.

edit: Oh, and another thing. I looked at the camera from all possible angles, inside and outside and saw nothing. The screen seems to be in place and nothing looks bent.

 

[Rol_Lei Nut]

Best thing you could do is run a proper test.
Put a chart (or a newspaper or...) on a flat wall.
Have your camera on a tripod *perfectly* perpendicular to said chart (measure and/or use bubble levels). Fairly close up is good as it'll reduce DOF.
Focus very carefully and shoot at full aperture (you could try other disphragms and vary the focus, but then take careful notes).

Results:
You might get slightly soft corners because of your lens (curvature of field or other abberations), but it should be the *same in all 4 corners*.
If so, nothing is out of alignment. Otherwise, suspect a bent mount or or decentered or loose element in lens (do test with more than one lens).
If the center is sharp (as it should be with the 85mm 1.8), focus is spot-on. Otherwise the ocussing screen or the mirror is out of adjustment.