Focusing problems on SLRs

Judge Sharpe

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In reading the various post, I have become confused as to the problem. Is it:
1. That the focusing screen and the film plane do not match up so that when you have an indication of focus in the view finder, the film is out of focus?

2. That the view finder and the film are both in focus but the distance indication at Infinity is off for use on a particular body?

If the view finder and film are not both in focus at the same time, the first thing I would check is the doppler adjustment. Is it adjusted for your particular eyesight? +1, 0 or -1. If that is OK then I would find a focus target and shoot a roll of BW film, fine grain. Set the target at a known measured distance from the film plan ( this is usually indicated on the camera body.) and record the settings as you shoot through the distance indicators. If one distance is off, the others should be off by a proportionate amount. You should get softness at five feet and at infinity, providing the lens does not have an internal problem.

If the problem is that focus is good on the view screen and the film, but the problem is the distance indicator, carefully calibrate the lens for the body you are using by making reference marks on the lens.

The film plane should be the same for all cameras that interchangeably use the same lenses. I do not think that the use of a digital caliper will accurately measure a potential difference. The way to compare is with a calibration target to establish differing points of sharpest focus.

Having a shop preform these checks should not be costly, a repain might be.

Judge Sharpe
 
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David R

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Sjixxxy - I have checked to make sure it isn't the focusing screens. I have had them out several times, swapped them and tried a third screen. There are two bodies that have this odd behavour, FE2 and FE.

Judge Sharpe - I guess I muddied the waters with an observation about the differences of the different bodies. The factory fix bodies, N2000, FT and N6006 don't agree with their view finders. Their view finders critically focus on a far target a little after the film plane is critically focused. Were as the FEs are in sync. (could be the nature of my test setup, but still a difference)

My primary issue is that the focus scale is way off, for the FEs compared to the factory fixed models. Check the (worst case) N2000 with 20mm verses FE2 with 20mm. The FE2 focus does appear to be fine, just not were it should. If I were to measure off targets for 5, 10, infinity the camera setup would be out of focus.

You may be correct about caliper measurements, as they did measure pretty much the same.

Alternate scales afixed to the lens maybe the answer.

Shops up here charge way to much, $125 was the quote to look at the camera.

David R
 

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