Nikon F2: possible to adjust back/front focus?

[nathan_jedinak]

<p>I recently picked up a Nikon F2, my first of the "F" series. Up until now I have used Nikkormats and a FE for my MF/Film shooting. I went out with it this afternoon, and noticed that I could not focus to infinity, or at least that is the way it appears when looking through the viewfinder. The Rangefinder (screen "A"), with the lens at infinity and pointed at an object far in the distance (say, a skyscraper), indicates that the lens needs to be focused further past inifnity which is of course not possible.<br>

While this isn't really an issue when shooting landscapes, I assume that this camera will "backfocus" when I shoot closer objects; the rangefinder will indicate that I should focus further than I really should; by "lining up" the rangefinder I will really be focused further than the intended target. This would, of course, be very bad at large apertures.<br>

I have tried other known good lenses, and a few new focus screens from a local shop. Always the rangefinder, with the lens at infinity and pointed at an oject in the distance, indicates that correct focus has not been achieved.<br>

I assume that there must be a way of adjusting the height of the focus screen, which would affect focus? Perhaps the 4 screws in the 4 corners of the frame the focus screen sits on? Of course, I then have to devise a repeatable test to see if my adjustments are good... In any case, am I on the right track here? I'd be very grateful for any suggestions or thoughts.</p>

[seismiccwave]

<p>If I remember correctly (it was a long time ago) my Nikon F2 was a film camera. It was also a single lens reflex camera with a mirror and a focus screen. So I am not sure where the rangefinder you mentioned came from. A rangefinder camera is a camera that does not have a mirror. Your optical view finder is looking through another hole. A mirror that is hooked up to the focus ring of the lens reflects a ghost image on your view finder. When you turn the focus ring the mirror moves and the ghost image line up with your actual image.<br>

With certain view finder for the Nikon F2 you get a split prism focus screen. Regardless of what you see on your viewfinder the actual focus takes place between the lens and your film plane. So you can't tell if the camera/lens combination is doing front focus or back focus like a digital camera until you shoot and develop a few rolls of film.<br>

If your camera is focusing fine from the lens to the film plane and your focus screen is off you can always shim the focus screen or change the focus screen.</p>

[User_502260]

<p>I also just got an F2 to go along with my Nikkormats, FEs, N2020 and Proneas. Are you sure your focusing screen is installed correctly? Has anyone tried to take your F2 apart? It could be that the front assembly was not reattached properly. The mirror must also be in proper adjustment or your infinity focus will be off. To test things put the camera on a tripod with the back open. Put a piece of ground glass up against the film rails and then focus until the image looks sharp. If the image in the viewfinder is not also in focus then something's wrong. </p>

[pete_s.]

<p>Infinity focus is fine tuned with the mirror stops on lots of different Nikons. I bet the F2 is the same.</p>

[christiaan_phleger___honol]

<p>This could also be a sign that the camera was worked on, and the previous 'repairer' did not properly adjust the body focus when the front mirror box section was replaced. I'd look to adjust/fix this area rather than the screen/finder area, which IMO stays quite stable. Consider sending it to Sover Wong, google him, he's the very best in F2 and your F2 will last another 30 years.<br>

The ground glass trick only works if you can place it on the Inner rails, where the film actually sits rather then the outer rails, there is a difference and that will give you error.</p>

[tibz]

<p>You have to adjust the mirror/prism so that it shows the actual image that will be exposed on the film. If you've lost infinity focus the screen must be too close and must be moved further away on the light path. I believe Nikon can do that for you, maybe not with a camera of such age. IDK if you can DIY that project.</p>

[bob_sunley]

<p>It's also possible the lens mount was shimmed incorrectly as well, if the lens is actually not reaching infinity focus.<br>

You do have to check the focus on the film plane before you adjust anything.</p>

 

[lex_jenkins]

<p>Try the obvious stuff first:</p>

<ol>

<li>Make sure the focus screen is properly seated. Check for debris that might be interfering.</li>

<li>Lock up the mirror. Look for obvious signs of debris such as a bit of broken film that might be interfering with the flip-up mirror fully seating to the stops.</li>

</ol>

<p>Other than that, there's little you can do without risking damage that will only end up costing your more. Take Christiaan's advice and send it Sover Wong. He's pretty much da man now for the F2. With an invoice from him for the adjustments you'll have a nice piece of paper to document it was properly serviced if you decide to resell it later.</p>

[nathan_jedinak]

<p>Wow! Thanks for all the responses. There is definitely no debris interfering anywhere; this F2 is very very clean. Absolutely no wear on the outside of the camera, and nothing inside that indicates it saw much film. No dust, gunk, or anything at all. Mirror box is spotless. Of course, we have this focus issue, perhaps that's why the original owner (it was a 1 owner camera) didn't use it much... I suppose it could have come from Nikon that way.<br>

I'll find out from the original owner's son if the camera was worked on, to his knowledge. If it was, the repairer did a fastidious botch job :)<br>

One thing I do notice is some desilvering on the edges of the mirror. Perhaps that's a clue..? Sadly it sounds like it needs to see a pro. My luck with buying old Nikons hasn't been great lately. I'll look up Sover Wong and send him a message.<br>

Hansen: the "A" focus screen has a central rangefinder. That's what I was referring to.</p>