Low temperature affect the rangefinder?

[optikhit]

I emcountered a very strange thing today when I took photos with a Zeiss Ikon Super Ikonta 631. The temperature outside was -10C or so. After few shots the viewer of the rangefinder became dark only a bright yellow patch existed there. The rangefinder became totally unuseable.

After I came back home, I thought it may be something dropped inside in the way of one arm (direct one). I tried to open the up-cover, but minutes later the rangefinder came back as normal. This situation happened twice.

I just wonder the reason but I do not understand it fully. Maybe the beam splitter is temperature dependent, so that the transmittance of light getting lower with the low temperature. Anybody has such experience?

Thanks a lot.

[luketrash]

As the temperature drops, anything that moves with the help of lubricants tends to start hating life.

I killed my Rolleicord II in 20F weather this winter.

Meanwhile, my M2 seems to have worked fine with -40F windchills.

My Hasselblad lenses are old C style ones and they slow down in the cold. I have to be careful using antiquated equipment that I'm aware of what's going on so I don't ruin it. I've gotten into the habit of storing my camera inside my coat when I'm outside in the cold.

In humid locales, I've had lenses fog up. Especially between the lens and a filter I had in place. Perhaps your viewfinder was fogging up internally?

[optikhit]

Originally Posted by luketrash

As the temperature drops, anything that moves with the help of lubricants tends to start hating life.

I killed my Rolleicord II in 20F weather this winter.

Meanwhile, my M2 seems to have worked fine with -40F windchills.

My Hasselblad lenses are old C style ones and they slow down in the cold. I have to be careful using antiquated equipment that I'm aware of what's going on so I don't ruin it. I've gotten into the habit of storing my camera inside my coat when I'm outside in the cold.

In humid locales, I've had lenses fog up. Especially between the lens and a filter I had in place. Perhaps your viewfinder was fogging up internally?

Foggy inside? But why the yellow patch was so bright? If the windows getting foggy internally, all the glasses should be clouded and thus the yellow patch should be also unclear and dim. But...no.

[FallisPhoto]

Unless moisture in there is freezing on just one side of your semitransparent mirror, and doing it thickly enough to obscure the viewfinder with frost, I can't think of anything that would do this.

Edit: Unless... Is it possible that some sort of viscous fluid (maybe one of those glycerine-based fluids used for hiding scratches in eyeglasses) has been applied to the front window of the viewfinder? Are you using a lens cleaning solution that contains glycerine? It would have to be pretty cold for this to be the problem (we use farenheit here instead of celsius, so I'm not sure how cold -10c is).

[ZeissFan]

Is this the 531? The 6x4.5 model? If so, there would be no mirrors, just prisms.

It's possible that you might have some separation somewhere in the main prism. I can't recall if that's a single piece of glass, or two cemented pieces.

Has the viewfinder ever been cleaned? If not, maybe it's just some debris that isn't normally visible until condensation forms.

[FallisPhoto]

Originally Posted by ZeissFan

Is this the 531? The 6x4.5 model? If so, there would be no mirrors, just prisms.

Same thing. Is there glycerine on whatever is in that viewfinder mechanism that splits the light path? In very cold conditions, some glycerine compounds (that absorb moisture) can go from clear to white.

Edit: whatever it is, it would be on the plain glass in front of the mirror or prism, not on the mirror or prism. It could be on either the front or the back of the glass.

[geek]

I have a Tokina 24/2.8 lens for my OM that gets a slow aperture in cold weather (-5°C / 20°F), all my other gear (Bessa R with lenses, OM-1/2 and other lenses, the whole digital stuff) worked flawless, some in even colder enviroments.

[optikhit]

Originally Posted by FallisPhoto

Same thing. Is there glycerine on whatever is in that viewfinder mechanism that splits the light path? In very cold conditions, some glycerine compounds (that absorb moisture) can go from clear to white.

Edit: whatever it is, it would be on the plain glass in front of the mirror or prism, not on the mirror or prism. It could be on either the front or the back of the glass.

Yes, personally I agree that analysis, even though I have no prove of it. Thanks for the hint.

However, besides that problem I have met another more serious one with my Super Ikonta 531. The lens seems assembled a little bit near to the film (maybe less than 0.5mm) so that it over focused at the infinity. Actually when the rangefinder tells the distance of 8m, it is the infinity! When an object of 1m away was focused, the real focal object may be 1.3-1.5m away. I got one roll of unclear photos for the first try.

I wonder if I can move the front part of lens a little bit forward with the rangefinder system unchanged. If so how to do it? Thanks a lot.

[FallisPhoto]

Originally Posted by optikhit

Yes, personally I agree that analysis, even though I have no prove of it. Thanks for the hint.

However, besides that problem I have met another more serious one with my Super Ikonta 531. The lens seems assembled a little bit near to the film (maybe less than 0.5mm) so that it over focused at the infinity. Actually when the rangefinder tells the distance of 8m, it is the infinity! When an object of 1m away was focused, the real focal object may be 1.3-1.5m away. I got one roll of unclear photos for the first try.

I wonder if I can move the front part of lens a little bit forward with the rangefinder system unchanged. If so how to do it? Thanks a lot.

Oh no! Everything up to this point has been minor, but now we are talking about major damage -- reasonable cause for a camera to be discarded. Are you an expert at sheet metal work?

[Windscale]

Originally Posted by optikhit

Yes, personally I agree that analysis, even though I have no prove of it. Thanks for the hint.

However, besides that problem I have met another more serious one with my Super Ikonta 531. The lens seems assembled a little bit near to the film (maybe less than 0.5mm) so that it over focused at the infinity. Actually when the rangefinder tells the distance of 8m, it is the infinity! When an object of 1m away was focused, the real focal object may be 1.3-1.5m away. I got one roll of unclear photos for the first try.

I wonder if I can move the front part of lens a little bit forward with the rangefinder system unchanged. If so how to do it? Thanks a lot.

It may just be a minor problem of adjusting the focus and the rangefinder. Adjust both to infinity and hopefully they will couple.

Also, in very cold places, as in Harbin, China, where I went for the ice structure festival a few years ago, be careful when you go in and out of buildings. All your lenses are not built for sudden changes of temperature. They may just crack. Best to have a warm pouch in your gadget bag to keep them warmer. Or when you go outside, open your zipper slowly so that the temperature does not drop so quickly.

[FallisPhoto]

Originally Posted by optikhit

I wonder if I can move the front part of lens a little bit forward with the rangefinder system unchanged. If so how to do it? Thanks a lot.

Windscale is right in that it may just need a focus adjustment. To move the whole lens assembly forward requires sheet metal work though. You'd have to modify the forward part of the body half.

[optikhit]

Thank you, Windscale and FallisPhoto, I have finished the adjustment today, together with a technician. Yes, firstly removing all the covers and turn a little bit of the lens to infinity and then set the rangefinder to infinity. The camera seems correct now. i will test it tomorrow.

[Windscale]

Originally Posted by optikhit

Thank you, Windscale and FallisPhoto, I have finished the adjustment today, together with a technician. Yes, firstly removing all the covers and turn a little bit of the lens to infinity and then set the rangefinder to infinity. The camera seems correct now. i will test it tomorrow.

Good luck. These are quite easy adjustments and they should work UNLESS your lens assembly has been tampered with, that is, lens parts replaced. But such tampering is rather rare. So you should be OK. If all the parts are original then once the rangefinder is set to infinity and the lens is also set to infinity (and checked by ground glass + loupe on B), then it should be Bingo.

[FallisPhoto]

Originally Posted by chippy

frankly, the whole thing seemed very straight forward, a few shims, a bit of RF calibration, and bobs your uncle!

if ya know bob!

Yeah, but he's my cousin, not my uncle, so there! If the lens needs to be moved forward, and the guy said that something was wrong with the frame, my point is that the frame is probably bent. To fix that requires sheet metal work. You'd have to take the body apart and straighten the frame. It would take a real artist with body hammers, picks and dollies to do that.

Edit: In the original post, Optikhit said that the lens assembly was a little closer to the film plane than it should be. Well, to me, that means it has probably been dropped on the lens. That is a serious problem.

[optikhit]

Thank you all my friends. Yes, I understand what FallisPhoto said, but maybe I did not express myself clearly. Only the front lens elements should be adjusted. And it has been done by calibrating the lens and the rangefinder, respectively.

Now the testing roll has been develped and show that it works nearly perfect. My 531 is with a Xenar lens. Is this lens a little bit softer than Tessar?

[FallisPhoto]

Originally Posted by chippy

i doubt you would notice any differance easily with xenars or tessar , that would be for picky people like me (haha).

If anyone wants to see the difference, just set up your tripods and shoot comparative photos of flat spread-out newspapers. The Xenar and Tessar photos , well, there won't be a whole lot of difference and I'm really not sure which would come out better, especially given their periodic changes. Good Skopars will usually beat both, by at least a little.

Edit: The above should be understood to be on average. Since all the lens manufacturers, with few exceptions, periodically changed their designs, sometimes significantly, you can't just go by the name. Some Tessars are sharper than Xenars and some Xenars are sharper than Tessars.

[Windscale]

I think it is a matter of personal preference and very much depends on the lenses one have. I have used a few Xenars and my experience is that they may not be as sharp as the Zeiss Tessars, yet they produced better shadow details.

[optikhit]

Originally Posted by chippy

i doubt you would notice any differance easily with xenars or tessar , that would be for picky people like me (haha).

Haha...I AM really a picky man. The technician told me that he had never seen such people like me who goes outside in winter and calibrate the camera to infinity with a ground-glass and a tripod (and a magnifying glass), bit by bit. But I think it is not the most rigorous method. It should be tested on an OPTICAL BENCH!

Together with the 531, I have also calibrated my Bessa RF which also has the same problem as the 531. But for Bessa RF, I only adjust the rangefinder without touching the assembly of the lens. It may be possible to reset the position of the gear wheels but it seems difficult, and maybe not accurate. Now it works fine.

Originally Posted by Windscale

I think it is a matter of personal preference and very much depends on the lenses one have. I have used a few Xenars and my experience is that they may not be as sharp as the Zeiss Tessars, yet they produced better shadow details.

Yes, it may be a issue of personal preference. Some people said that the Tessar provides a nicer shadow details than the Xenar. But it depends on lot of conditions.

Thanks a lot friends.

[Windscale]

it is easy to find out if you have done the right thing. Take 2 pics, one at infinity and one at an object say 6 feet away. Use the widest aperture in both cases. If both pics turned out sharp then Bob really is your uncle!

I also noticed you wrote "I really want a Leica". I can tell you that since I have moved into medium format I have rarely used my Leica!

Good luck.

[Gabriel M.A.]

Low temperature affect the rangefinder?

Simple answer: if it affects you strongly, physically, don't do it.

[FallisPhoto]

Originally Posted by chippy

yeah, no worries there, i know what your saying, but its no as straight forward as that though is it, unless you want pictures of newsprint . so many other variables come into play
the 75mm (and others) xenars on some just prior to pre-war camera and a few 80m post war xenar are suberb lenses, 5 element, but instead of the rear group having three like some other tessar type copies (to to get round patents), these had an extra element in front, with an air space...they were known by shnieder in the factory as the S-xenar, but they only wrote xenar on the front of the lens , even in their common literature. these are very sweet high quality lenses, great results.

my guess is they fell out of favour by the factory to make, because of cost, in comparison to the standard tessar type with 4 element xenar or schneiders 6 element xenon, why bother with the more expensive to make S-xenar, that they didnt market as such. it has the same type of glass index on the front as xenons that reduces flare but the trick is to get one that is clear and without marks....not unlike getting a xenon or leitz summar that are 60-70+ years on often showing signs of age and wear.

search all you want ..you possibly wont find this info around the net, so you will have to take my word for it (or not, i'm not offended-do as you like lol), but there it is. also it is understood that the s-xenar was so nice that kodak had it labled as xenon on some of thier early retina! i want to pull one apart before i state it as fact (and i will probably), but that is what is written in some stuff i have as fact, so it seems resonable to say

Well, I guess that explains why "Some Tessars are sharper than Xenars and some Xenars are sharper than Tessars."

BTW, I would never believe anything Kodak said. This wouldn't be the first time they have lied through their teeth. There are probably a dozen lenses labled Kodak that are not what they say they are, they lie about other people's lenses too, they have a well-deserved reputation for lying to their customers and then yanking the rug out from under them -- and their reps have lied to me personally on two different occasions. Anyone who knows how 620 film came to be, who remembers the disc cameras, who remembers the APS cameras, and on and on and on, and remembers their continual reassurances that they would continue making film for all that stuff, right up to a matter of hours before the stuff dissappeared off of the shelves, knows that a large part of Kodak's business "ethic" is based on lying to and cheating their customers.