Turret finder problem

payasam · 09-25-2009

I have today received a Soviet turret finder from the Ukraine. The frame mask, I think properly called the graticule, is rotated clock-wise so that horizontals are not horizontal. My impression is that I shall need to open the unit from the back, as the mask is the same for all focal lengths. Would someone who knows please tell me what I must do?

payasam · 09-26-2009

If I send the finder back to the seller, he will have it set right. This means paying postage one way and waiting for three weeks or more, but it is better than having no finder.

Dave Wilkinson · 09-26-2009

Quote:

Originally Posted by payasam

If I send the finder back to the seller, he will have it set right. This means paying postage one way and waiting for three weeks or more, but it is better than having no finder.

Mukul, I have had a couple of these finders - over the years, they are usually trouble free, and I can't quite remember the method of access to the 'innards', and it would seem everyone else is in the same 'boat', so it looks like a return!

Cheers, Dave.

wolves3012 · 09-26-2009

I've never attempted to do anything beyond cleaning the graticule and optics on one of these so I can't say how it can be rotated. However, I can tell you how to get at the back and front of it (which will probably make it obvious how to move it).

From the front: slacken the small grub-screw set within the main screw. Now remove the main screw. Next, pull the rotating turret out BUT BEWARE of losing the detent ball which WILL fall out somewhere! It's possibly better to remove it beforehand by taking off the small retainer on the side.

From the back: Remove the three screws from the eyepiece surround, holding it front-downwards. Remove the eyepiece/lens assembly. Now, tip out the two prisms and spacer but make a VERY careful note of how they come out! Handle the prisms carefully, preferably with cotton gloves, they are coated and easily marked or scratched.

I suspect that the "front access" method will probably lead you to be able to correct the problem. Be warned beforehand that getting it all back together, whilst keeping it dust-free, is a real PITA! Otherwise it's no great difficulty.

flip · 09-26-2009

It's not so bad. I fixed this with a Nicca Universal finder. Essentially, you'll be removing a lot of little screw until the main mask portion is free. You'll find that assembliing everything at first leads to either the choice of finer or the alignment being off. With a little physical convincing, you can nudge them both into proper position. If it's like mine, it's a pretty simple device, so just dig in.

payasam · 09-26-2009

Thank you, all. I did open up the finder from the back, but there was no visible means of rotating the graticule. The inner, smaller prism could have been tricky, but I had seen how it came out and so could simply reverse the procedure. I cannot open the finder from the front as I have no screwdriver small enough for the grub screw. However, I can sit back now as the seller has promised to do what is necessary.

payasam · 11-10-2009

Five weeks later, the finder is back. While earlier the graticule was rotated only a little, now it is rotated about 45 degrees. The seller's name is Vladimir Kuzyakin and his eBay handle is vladimir5129. I do not know what, if anything, he did: but the finder is unusable and I have wasted time and money.

wolves3012 · 11-10-2009

Time to invest in that small screwdriver set? Sorry to hear of your troubles, hope it gets sorted...

rxmd · 11-10-2009

Quote:

Originally Posted by payasam

Five weeks later, the finder is back. While earlier the graticule was rotated only a little, now it is rotated about 45 degrees. The seller's name is Vladimir Kuzyakin and his eBay handle is vladimir5129. I do not know what, if anything, he did: but the finder is unusable and I have wasted time and money.

The culprit might well have been the transport. I used to have a similar problem with a Voigtländer viewfinder, whose frame mask is on a circular lens that would rotate inside the finder when it was shaken. In the end I opened the viewfinder and fixed the mask with some double-sided sticky tape. While I don't have a turret finder, it might well look similar inside.

payasam · 11-10-2009

Wolves, does the retainer act as a leaf spring to hold the "detent ball" in place?

You could be right, Philipp, but reason suggests that there would be some means -- a notch or two, perhaps -- to keep the thing in the right position.

wolves3012 · 11-10-2009

The spring that holds the detent ball is the silver piece on the outside rim (sorry to be vague, I'm at work and my finder is at home!) so yes, you're right it does act as a leaf spring. There are (I think) 2 screws that retain it. The ball is damned tiny so work over some sort of container! The front turret then comes off by loosening the tiny grub screw in the main screw on the front, then undoing the main screw itself...

payasam · 11-10-2009

Thank you, Wolves. The leaf thingy is held by a single screw, and that should not be a problem. I shall put a bit of sticky tape on the tiny ball part before I undo the screw. For the tiny screw I shall have to visit the friendly neighbourhood watch-maker.

ethics_gradient · 11-10-2009

Quote:

Originally Posted by payasam

Thank you, Wolves. The leaf thingy is held by a single screw, and that should not be a problem. I shall put a bit of sticky tape on the tiny ball part before I undo the screw. For the tiny screw I shall have to visit the friendly neighbourhood watch-maker.

I picked up an 16 (or was it 18?) piece set of screwdriver/torx/other mini accessory heads for less than $20 at my local Home Depot, has been invaluable with many small fixes/DIY camera projects.

How are those turret finders? My only experience with an FSU finder was the 85mm one that came with a J-9. Lens had fungus and wouldn't couple with the RF so I returned it, can't say I was tempted to keep the finder: it was a tiny, squinty affair. If I remember correctly, just a little circular hole at the end, seemed like it'd be terrible for framing so I've been guestimating with the 90mm framelines on my R3a and new J-9 since.

payasam · 11-10-2009

This turret finder was originally a Zeiss design and was meant for their Contax cameras. If you look around, you are unlikely to find anything other than praise.

Given the inaccuracy of all viewfinders other than reflex ones, 90mm and 85mm are pretty much the same thing.

payasam · 11-11-2009

Done. Thank you, Wolves, for the warning about the little detent ball. It would have been easily lost, and its loss would have been a disaster.

You were right about access from the front. There's a small lens which is strongly convex on one side and has engraving on its other, flat, side. This crucial chap had rotated. Not surprising, as there was nothing to hold it in place. The threaded wall of the hole in which it fits makes it pretty obvious that a locking ring was there at one time. Now there's a small piece of sticky tape, well pressed down. No idea how long it will hold.

I wouldn't trust this finder for architectural work, but buildings will no longer lean at quite 45 degrees; and certainly for portraits with an 85mm lens, not stopped down much or maybe wide open, it should be all right.

rxmd · 11-11-2009

Great! Good to know about the innards.

wolves3012 · 11-11-2009

Quote:

Originally Posted by payasam

Done. Thank you, Wolves, for the warning about the little detent ball. It would have been easily lost, and its loss would have been a disaster.

Happy to have helped! I speak from personal experience about losing that ball...despite considerable care there's one on my carpet somewhere (actually, it's more likely gone up the vacuum cleaner long ago). I managed to get a replacement from a local bearing supplier. The guy in the shop had quite a laugh when I asked for ONE and gave me several for no payment!

payasam · 11-11-2009

It worked for you, Wolves, even though they were all balls...

I have been speculating about the decision of Zeiss to use a circular lens (with rectangular etching on it) rather than a rectangular lens which could not rotate even by accident. Must be something to do with the manufacturing methods of the time when the turret finder was designed for the Contax.

rxmd · 11-12-2009

Quote:

Originally Posted by payasam

I have been speculating about the decision of Zeiss to use a circular lens (with rectangular etching on it) rather than a rectangular lens which could not rotate even by accident. Must be something to do with the manufacturing methods of the time when the turret finder was designed for the Contax.

Well, people use circular lenses even today - the Voigtländer finder was designed in the late 1990s.

It seems that designers consider friction reliable enough. At least if they're made from glass, it's probably significantly easier to grind circular lenses rather than grinding rectangular lenses, or putting a notch in them.

payasam · 11-12-2009

That's probably correct, Philipp. My understanding is that computer control of manufacturing processes has made possible some pretty remarkable things, but then cost of production might go too high.