Fujica ST705 - Problems with infinity focus - please help!

[Lassehn41]

Hey!
Some time ago i bought a Fujica ST705, and it's a very nice little camera!
But, it got some issues with infinity focus... I don't own a Fujinon lens, but i have other m42 lenses, and those should not cause any problems, or what?
Currently I'm using a Helios 44M, and i have tried it out on my Zenit EM (no problems with focus on that or my two Canons), but on the Fujica it seems to be 3-4 meters off focus. When focusing on the same spot, my Zenit says about 7 meters, the Fujica says a little over 10 meters.
And if I use a different lens with the Fujica, it will still not reach infinity...

On this picture, you can see, that the red line on the lens does not line up with the center of the camera (it does that on all my other cameras)

On this picure, it looks like the lens is missing about 1 millimeter to fit the mount correctly. But i can't tighten it more than that! And if i could tighten this more, the red line would be even more off center...

I hope, that you can help me out, i have done a lot of searching about it, but i can't find anything about this problem.

Thank you!

Greetings from Lasse

 

[E. von Hoegh]

So, no matter which lens you put on the Fujica, it will not tighten down to the flange?? That's a problem with that body then. IIRC the 705 allows open-apertue metering with the correct Fujinon lenses, but other M42 lenses should work in stopdown mode. Look to see if there is anything on the body/mount interfering, otherwise you'll have to wait for someone more familiar with this particular camera.

 

[Kirks518]

One thing about the Fujica M42 lenses that I've encountered is that they have a small locking tab, that may be the problem. Not having the tab would allow a regular M42 lens to be tightened more than a Fujica lens, which would account for your first image. It would also throw the distance of the lens to film plane distance off, to the point where infinity focus wouldn't be achievable.

First thing I would do is either loosen the lens so that the red line is in the center of the camera (like a normal lens), or put a shim between the lens and body, and see if either of those then allow for infinity focus.

I think I would then make sure all the screws on the mounting flange on the camera) are tight.

If you back off from infinity, does infinity come into focus? ie., move the focus ring off infinity, and see if it will focus on infinity, ignoring what distance the lens is saying. If it never focuses at a distant object (moon is a good candidate), then my guess is the flange is too far off the camera, causing the lens' point of infinity focus to be in front of the film plane.

Another possibility is that it does focus to infinity, but the focusing screen in the prism is out of whack (or even the mirror possibly).

Also, camerapedia says about the ST705 -

Nearly all M42 lenses will work on it, but most (non-Fuji) lenses will not permit open-aperture metering.

I realize metering is not the issue at hand, but it makes me wonder if there are some M42 lenses that have other issues.


I'll go measure that little lip on the back of a Fujica lens, and also snap a pic of it, so you can see it.

 

[Kirks518]

Ok, the little lip is about 1-1.5mm high, so not much.
Here's the lip on the back of a Fujinon EBC 55mm 1.8:

 

[Kirks518]

...

 

[John Koehrer]

There are some M42's that won't fit the Fujica. I've seen it about a hundred years ago when I was in the trade.
The gap you see between the lens & body won't let the lens focus to infinity.

For giggles open the shutter on B, mount the lens and see if there's an obstruction in the mirror box.

 

[Lassehn41]

Hello Again!
Thanks for all your replies!
E. von Hoegh: Yes, all my m42 lenses does not fit the camera, i only own five m42 lenses, but having the same problem with them all seems strange..?

Kirks518: thank you for measuring your lens, now i have something to compare mine with. From what you say, i think, that the point of infinity focus is in front of the film plane, because distant objects never comes in focus! it wont focus more than 10-15 meters away.
i haven't thought about problems with the prism... when i'm done with the current film, i'll try to check the mirror and prism for flaws.

John Koehrer: thank you, when i'm done shooting the film inside it, i'll look for obstructions in the box!