Nikon FE2 - all lenses indicate short focus

Theo Sulphate · Nov 20, 2016

I'm playing around with a new-to-me FE2 body and I've tried a few Nikkor 50mm lenses on it. I'm focusing on an object that I always focus on whenever I get a new camera or lens. What I'm getting is 4' showing on the distance scale of various lenses when these same lenses on other bodies show the correct distance: 6'.

So, there's something wrong - the only thing I can think of is the focusing screen not being in the right plane. I've looked at it and it seems to be ok.

What say you?

Thanks in advance for help.

Leigh B · Nov 20, 2016

How are you determining correct focus?

The only reliable method is a ground glass at the film plane, and a high-power magnifier.

- Leigh

MattKing · Nov 20, 2016

Theo Sulphate said:
I'm playing around with a new-to-me FE2 body and I've tried a few Nikkor 50mm lenses on it. I'm focusing on an object that I always focus on whenever I get a new camera or lens. What I'm getting is 4' showing on the distance scale of various lenses when these same lenses on other bodies show the correct distance: 6'.

So, there's something wrong - the only thing I can think of is the focusing screen not being in the right plane. I've looked at it and it seems to be ok.

What say you?

Thanks in advance for help.

Is the subject actually 4 feet away (i.e. what does a tape measure indicate)?

ic-racer · Nov 20, 2016

Manual focus lenses are usually collimated at infinity, meaning the focus stop is set exactly for infinity focus. Check a distant object for correlation with either the infinity mark or the hard stop.

Theo Sulphate · Nov 20, 2016

The object is exactly six feet away.

These same lenses on other Nikon bodies indicate six feet.

Other lenses on other bodies (e.g. Leica, Canon, etc.) indicate six feet.

Only when I mount a lens on the FE2 does the lens indicate four feet.

MattKing · Nov 20, 2016

Do lenses focus on distant objects on that body? If not, the problem might be with the mount.

Leigh B · Nov 20, 2016

Theo Sulphate said:
Only when I mount a lens on the FE2 does the lens indicate four feet.

you've still not answered my question about how you're determining the proper and actual focus...

- Leigh

BrianShaw · Nov 20, 2016

Until you answer Leigh's questions, the best guess is that there is a problem with the focusing screen on the body. Either wrong screen or it out of place for whatever reason. You've proven the lens to be okay so it's something with the body.

But Matts question is a good one too!

Dan Fromm · Nov 20, 2016

take the screen out, make sure it is right side up, and put it back in

Theo Sulphate · Nov 20, 2016

Leigh B said:
you've still not answered my question about how you're determining the proper and actual focus...

- Leigh

Just measured it with a tape measure: six feet + one inch.

The screen:

Seems normally seated, right?

To remove the screen I don't have the tool that came with the camera - ok to use tweezers?

frank · Nov 20, 2016

As well as the screen being off, the mirror may be off 45 degrees.

frank · Nov 20, 2016

Screen upside down?

BrianShaw · Nov 20, 2016

Dan Fromm said:
take the screen out, make sure it is right side up, and put it back in

It should be shiny side down; frosted side up... right? Mine looks that way but I'm not taking it out to verify.

BrianShaw · Nov 20, 2016

And just as an aside... it's interesting that the bumper foam is new and pristine. Who last worked on that body????

Mick Fagan · Nov 20, 2016

I pulled out my FE2 which is a very early model as I bought it more or less when they became available.

The tab that sits at the top of the picture, is in a different position on my camera, perhaps your focusing screen is not inserted correctly?

Mick.

Theo Sulphate · Nov 20, 2016

Ok - thanks, everyone, for your replies.

I will attempt to adjust or re-insert the screen later today.

BrianShaw said:
... it's interesting that the bumper foam is new and pristine. ...

Yes, the camera had a recent CLA by someone who's been working on Nikons and other cameras for over 20 years (was authorized Nikon repair shop).

Theo Sulphate · Nov 21, 2016

I've removed and replaced the screen - same results.

Time to send it back to the guy and he can investigate further; I'd like to keep the FE2.

Leigh B · Nov 21, 2016

Theo Sulphate said:
Just measured it with a tape measure: six feet + one inch.

How did you fit the tape measure in the film channel, and how did you see through it?

You obviously did not understand the question.

How did you assess the focus accuracy at the film plane?

- Leigh

Theo Sulphate · Nov 21, 2016

Leigh B said:
How did you fit the tape measure in the film channel, and how did you see through it?

You obviously did not understand the question.

How did you assess the focus accuracy at the film plane?

- Leigh

Yes, I did understand the question and I actually do have a groundglass and magnifier.

However, I also realize I don't need to measure to tolerances much more than an inch because lens barrels don't have precise markings. Four feet versus six feet - that discrepancy is so large I don't need to measure subject to film plane distances more precisely than an inch.

More importantly, and as I stated previously, with at least six different cameras and six different lenses, in various combinations, when the image is in focus in the viewfinder the reading on the barrel of any lens is always six feet.

This cannot be ignored because it is consistent.

Given that, any of those same lenses when used on the FE2 show only four feet. Only the body is changing.

Not only that, I've tested focus at infinity. Several bodies and lenses split-image-focused at a tree 300 feet away has the lens at infinity. Those same lenses mounted on the FE2 show focus on the tree (300 feet away) as being only 30 feet.

Leigh B · Nov 21, 2016

Theo Sulphate said:
...when the image is in focus in the viewfinder...
Given that, any of those same lenses when used on the FE2 show only four feet.
Only the body is changing.

Your method of assessing focus distance is not correct
You cannot rely on the image in the viewfinder because the screen itself might be improperly positioned.

As I mentioned earlier, you must put a ground glass at the image plane after opening the camera back, and examine the focus of that image with a magnifier.

If the image on that ground glass results in a reading error, then your mounting flange is out of position, probably due to an impact. I would not expect the error to be uniform across the frame, more likely canted at some angle.

The flange focal distance on Nikon cameras is 46.5mm.
Generally you need a special gage (which I have) to measure that with sufficient accuracy.

- Leigh

Theo Sulphate · Nov 21, 2016

Leigh B said:
Then your mounting flange is out of position, probably due to an impact.
I would not expect the error to be uniform across the frame, more likely canted at some angle.

The flange focal distance on Nikon cameras is 46.5mm.
Generally speaking you need a calibrated gage to measure that with sufficient accuracy.
...

Ah - I didn't consider that possibility. I do have some decent calipers that measure to 0.001", but they won't fit through the lens mount (mirror up and shutter open).

Even so, it seems as if a solution or repair is beyond my expertise.

Thank you for mentioning this - I will take the camera back and ask that the mounting flange and distance to film plane be checked. They have the instruments to check this issue and the resources to fix it.

frank · Nov 21, 2016

Stick some translucent scotch tape onto a small piece of glass like a microscope slide, or use the focusing screen of another camera, and lay it on the inside film guide rails. Attached to a tripod, focus the camera on a contrasty object. Set the camera on B and lock the shutter open. Check for focus on the film plane.

Theo Sulphate · Nov 21, 2016

Ok - I do have an actual groundglass that can be held against the film rails. Need to go through old boxes to find it...

Leigh B · Nov 21, 2016

Theo Sulphate said:
I also realize I don't need to measure to tolerances much more than an inch because lens barrels don't have precise markings.

Theo Sulphate said:
I do have some decent calipers that measure to 0.001".

The flange focal distance is 46.5mm with a tolerance of +- 0.02 mm. That's pretty tight (= +-0.00078").
To measure that with any certainty requires a measuring instrument with an accuracy spec of half that value or less.

The dial indicator I use for this measurement is accurate to 1/10th that value.

- Leigh

Leigh B · Nov 21, 2016

Theo Sulphate said:
Ok - I do have an actual groundglass that can be held against the film rails.

it must fit against the INNER film rails, which are a bit below the outer rails.

- Leigh

Nikon FE2 - all lenses indicate short focus

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Nikon FE2 - all lenses indicate short focus

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