Faded color spot with Industar-26?

[Blake Werts]

Hi folks,

I've just scanned a couple of rolls of images that I took while in Charleston, SC this weekend and am noticing that in some of the images, I'm getting a spot of discoloration--more like a "bleached out" spot near the center of my images. I've always shot black and white with this FED-2 / Industar-26 combination and have never noticed it before.

Any suggestions on what may be causing it? I've looked at the lens as best I can and I do not see anything abnormal on the front lens. On the rear lens, however, I can detect a very very small glass abnormality that has two teeny-tiny (and I mean TINY!) things that look like air bubbles but they are not in the center of the lens--more like 35/65 from center. Could this be causing something like this?

Thanks Much,
Blake

[brachal]

I have noticed similar spots with some of my Jupiters. I think it may be flare. I definitely don't notice it as often, if at all, when I use a lens hood.

[oscroft]

I had the same problem with an old Jupiter-9, which I'm pretty sure was caused by flare - possibly from internal reflections because not all the internal surfaces were properly blackened.

[Brian Sweeney]

I suspect that it is flare, and the aperture blades are probably the culprit. They tend to reflect light back onto the front elements. I blackened the aperture blades of my Helios (and Menopta) lenses to greatly reduce this issue.

Thread with the blackened aperture blade experiment:

http://www.rangefinderforum.com/forums/showthread.php?t=51076&highlight=helios

[Blake Werts]

Ahhh. You know, I did not use a hood and there was quite a bit of sunlight around. Lightmeter was telling me 1/250 at f16... and sometimes 1/500. Most of the B&W shots have been in situations where I'm opened up to no smaller than f8 and try to stay around f5.6.

[Blake Werts]

So here is a digital image of the lens set at f16. You can see that the blades do take on a mugh lighter color near the very small opening...

[radiocemetery]

This is interesting. I have a roll of film in my FED 2 with a FED collapsible lens mounted that has some pretty well polished aperature blades. I will soon know if I will have this flare problem too. Maybe I will get to take this lens apart again!
Steve

[imajypsee]

Just so we're on the same page, the Industar 26 I'm referring to here is the 52 f/2.8 Industar. The only time I didn't have the big hazy blob in the center of the frame (as illustrated below) was when I was in complete shade. In the photo below the light was behind me (and it may have been a bright overcast day, can't recall any more)
http://www.pbase.com/jypsee/image/95814503.jpg

I've since bought a Jupiter 50 f/2 (Jupiter 8) and haven't finished the roll of film yet (it's so blasted HOT here in SW Florida already that I rarely go out for any length of time :mad:)

Mary in Florida, USA

[ath]

Welcome to the club. I have it with my Jupiter 12 and have no clue.
See my older question and my findings here (http://www.rangefinderforum.com/forums/showthread.php?threadid=56456)

[Blake Werts]

Just so we're on the same page, the Industar 26 I'm referring to here is the 52 f/2.8 Industar. The only time I didn't have the big hazy blob in the center of the frame (as illustrated below) was when I was in complete shade. In the photo below the light was behind me (and it may have been a bright overcast day, can't recall any more)


Yes, this is what this lens is as well. Can't really see the inscription in the image that I posted.

I've not noticed the hazy blob with my B&W shots as I believe that the lighting situations that I've always been in at that time was such that I could open up the lens pretty wide.