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I just tried that, and I still can't see vignetting. I guess I just got lucky...

The step down ring arrived by post. Against my expectations, I can't see any vignetting in the viewfinder. Neither at full aperture or when stopped down to f/22. It isn't quite what I expected with as extreme step-down as 67mm -> 52mm is. Well, I guess I should take a test picture with and without the step down ring.

It sounds surprising that stopping down will make vignetting more prominent, usually vignetting is reduced when a lens is stopped down. Regardless, I bought a cheap step-down ring from eBay, I guess I can just test it with it.

Basically how badly using a step-down ring will cause vignetting if the lens is stopped down as well? Specifically, I have got a Mamiya-Sekor C 80mm f/1.9 lens, which has 67mm filter ring, and I would like to try IR photography in medium format. The problem is that my IR filter is 52mm, and as Heliopan filters aren't exactly cheap, I'd prefer to use a step down ring instead if I can get away with it. Now obviously it would vignet a lot if you used it at full aperture, but how about stopping it down to say f/5.6? If I have understood correctly, that would basically mean that only the centre third of the lens would be used, so would this reduce the vignetting to manageable levels?

Aaaand now it's working. I basically just set the frame spacing to max and it was just fine in the next roll. :)

Looks like it works. In the next film I tested it with, the frames overlap the same amount (about 2-3mm) throughout the film. So I guess it's time to adjust the frame spacing according to the calibration guide. :D However, that guide tells to test it by loading a backing paper to the camera, and advancing it four times when the back is open. However, the counter doesn't advance while the back is open, so wouldn't this change the amount of the film advanced? I tested this with both the back closed and open. F and I marks mean full and initial, respectively, and the leftmost marks are with back open, and rightmost back closed. So, with back closed adjusting frame spacing to max would be a pretty good amount, while it would be a bit much if you go with the measurement done back open. On the other hand, if you measure it back open, it should have been about right at the beginning, so I guess that can't be correct...

Actually I managed to get the frame counter to work. First I tried to bend the part of the hook that connects to the release mechanism, as I didn't find any other easily accessable way to fix it. Unfortunately it broke, as apparently it was some hardened metal and it couldn't take bending. But I managed to make a fix by gluing beer can aluminium to it, as the forces involved aren't that large. It even works, so I guess I'll test it with film...

Unfortunately Pentacon 6 seems to have different frame spacing mechanism than Kiev 60. If I have understood correctly, Pentacon 6 attempts to actually measure the amount of film that is advanced, while Kiev 60 just estimates the compensation based on the frame counter. Which is why it being stuck is a problem. But anyways, I think I might have found what's the issue. The spring being a bit loose doesn't seem to be it, but the mechanism which resets the counter when you open the back. It pulls the hook, which stops the frame counter, when you open the back. But it looks like it doesn't go all the way down even when you close the back, so that the hook doesn't properly connect to the gears in the frame counter wheel. The next question would be how to fix it...

No, it can't be that because the film spacing consistently increased towards the end of the film. If it was due to advance lever stop missing, it should have varied from one shot to the next.

I have read that page earlier, but it seems to be about adjusting the fixed part of the frame spacing, while counter affects compensating the amount of film that is already on the spool. As the latter is not working, the spacing increases towards the end of the film.

Looks like spring loaded hook which should stop the counter as long as the back is closed, is very loose. It also looks like the spring has been already bent by someone else...

I opened the camera, and at least the frame counter moves when the top panel is removed. But it still doesn't lock into the next frame, but just slides back... so there's something else wrong as well.

So I got a good deal on a Kiev 60, which has frame counter stuck, but which seems to otherwise work fine. However, it turned out that the frame counter also adjusts frame spacing, so currently besides not knowing how many frames are left in the roll, I end up getting only 10 instead of 12 frames on a roll, as without the compensation spacing increases towards end of the roll. Which is a bit annoying. So, does anybody know if it's difficult to fix it? Looks like the camera is a bit banged up around the counter, so perhaps with good luck it might be just stuck due to the top being bent? It does look like the counter tries to move when you wind the lever.

Looks like the shutter adjustments were out of whack. When I set three turns of tension to both, everything is now working.

Oh, and looks like I have problems with shutter capping at speeds of 1/125 and faster. It used to have some problems with capping earlier with 1/500 and 1/1000s, but it was only one edge in the picture getting darker. There's some visible dirt on the shutter curtains, I take it that they need cleaning? So, what would be the correct way to clean them, and presumably also lube them afterwards?

I don't know what exactly I did, but I was tinkering around with it a bit, and now 1/60s speed works fine. 1/30s and x-sync work as manual mode first time you use them after turning the dial, but they work the second time. So something's probably still sticking, but I don't know what. I guess this is good enough, even though it would be neat to get them all working. That would have surely been easier. Well, I guess I should consider this a learning experience. :rolleyes:

Also, I forgot to mention that the x-sync speed was not working before the repair attempt, either. Sorry for double posting, but I couldn't edit the message anymore.

I have been attempting to repair an old Miranda Fv camera. Basically, the issue was that during cold weather the mirror stuck up when using some exposure speeds, such as 1/60 or 1/125. Because it happened only on cold weather, I figured out that nothing is actually broken, and that it's just about some grease getting sticky over all the years, and the internals need a cleaning. Now, I managed to disassemble and reassemble it, and it even seems to mostly work. But, for some odd reason 1/60, x-sync and 1/30 work as manual exposure, ie. the second shutter curtain closes only after you release the button. So any suggestions where to look at? Here is a picture of the mechanism when I was disassembling it. The brass discs here are the timing discs, the upper is for the escapement system on the bottom of the camera, and the lower is for fast shutter speeds. These could go there only one way due to positioning of the screw holes, so that shouldn't be the problem. Here it's a bit more dissassembled. The large cog on the left is driving the first shutter curtain, and during winding it's coupled to the cog under it driving the second curtain with rods on the cogs. However, the cogs must be aligned so, that the mechanism which prevents the shutter from firing before the mirror has gone up is also coupled to the rod. Ie. one of the levers on top left part of the picture is on the rod and preventing the cog from rotating counter-clockwise. In addition to this, the curtains need to be aligned so, that they are at correct distances to each other. But what is the cam on top of the cog doing? Presumably it's somehow connected to the timing mechanism, but could its positioning be relevant, too? However, when I tried to position the cog similarly as in the picture, the rods weren't properly coupled. Here's a picture of the mechanism before the dissassembly.