Zenit 3m M39 SLR focus problem, Jupiter-9, Helios-44

The old Helios 44 f/2.0 58mm "Biotar" lenses will be my downfall. If

it weren't for them, I probably would not buy old Zenit SLRs.

 

Recently I received in the mail two lenses, a Jupiter-9 f/2 85mm and

a Helios-44 f/2 58mm, both in the M39 screw-mount that only fits the

old Zenit M39 SLRs (not the M39 rangefinders - right?).

 

Of course I tried them on my old Zenit 3m M39 SLR body. The "good"

one, not the derelict one that has a problem with focusing because

the prism isn't seated right.

 

The good one does not have a split image focusing screen or

anything. Just plain glass. I focus as best I can.

 

To my dismay, my "good" Zenit 3m seems to have a focus problem,

mostly (but not only) close up. There does seem to be a

little "play" when I reach in and push up on the prism.

 

Is this a common problem with old Zenits? Is there a simple fix?<div></div>

Out of focus shot.<div></div>

Another out of focus shot.<div></div>

BTW: I see a horizontal line in the photos. A pinhole leak in the curtains? (?)

 

Here's one more. It was wide open at 2.0, of course. Maybe this one was as in-focus - on the front croissant - as I hoped.

 

I'm pretty sure all of these shots were taken with the Jupiter-9.<div></div>

Here is an out of focus close-up, taken with the Helios-44.<div></div>

Really the last: In-focus, with Helios-44.<div></div>

Daniel do you have a junk focus screen that you can tape into the film gate? You need to first determine whether the lenses are properly collimated. Basically you sight through the lens at infinity on a distant object (e.g. the moon) and check focus at the film plane. If you have a suitable focus target, you can do the same at minimum focus but do ensure that the distance to the film plane is accurate and square against the target. (I use a drywall square)

 

If the lenses are good, your focusing screen could be improperly installed (upsidedown is common) or your mirror may require adjustment. (I'm basing this on general SLR experience, I don't use Zenits)

Mike,

 

This is likely to sound really dumb: I don't think there is a focusing screen in there. Just the prism glass. There is no split screen, nothing fresnel-ish.

I've never seen an SLR without a focusing screen, even if its a simple ground glass. The prism takes the image formed on the screen and projects it through the eyepiece with the correct right/left up/down image.

Perhaps the "good" one has the focusing screen missing, or that piece of "glass" that you have in there is not the right thickness.

 

Try the old scotch tape on the film gate trick, and see if it's even close... I don't think it is.

 

Depending on how brave you feel, you can try pulling the focusing screen from the derelict and putting it in the "good" one?

1.The zenits have a badly made matte focusing screen that reflects 64% of the image on film

 

2.the difference between m39 for slrs and m39 for rangefinders is the working distance(and some diafragm automation in later slr lenses),in short the rf lenses mounted on slrs will be dark(no aperture automation) and will have focusing problems.

 

3.the best m39 slr is "start" with an adapter which you can get for about 40-80 $ on ebay or from a licensed merchant

Hi Dan:

 

If your body is good, your lenses should focus properly regardless of a problem in the lens itself: if the lens is out of register it will show the same in the finder as on the film and you'll correct for it automatically. So, the problem must be in the body, either the screen position or the mirror stops.

 

If the problem is in the body, then it should affect both lenses more or less equally.... unless it's something loose, erratically landing in different positions for different shots; in this case it will vary all over the place, again regardles of the lens in use. A loose screen or mirror stop might create this effect.

 

I'm not familiar with the 3M. I do have an older Zenit S, which is an excellent camera. Mine at least has no fautls and produces great pictures. I have the 85/2 Jupiter9 and the 50/3.5 Industar50 for it, and love them both.

 

rick :)=

Thanks all for your comments. And a Happy New Year, of course.

 

I compared the focus distances, between my new-ish Bessa-Flex and the M39 Zenit, and they did not match. What showed up as .9 on the Bessaflex showed up as .9 on the Zenit. I'm guessing that the screen is the problem, though I don't really have a clue as to how to attack that. (Wife says we're late. Later.)

I meant what showed up as almost .9m on the Bessaflex shows up at just over .8m on the Zenit. (See what happens when I'm in a rush to get out the door?)