wierd spot with Industar 52/2.8

[imajypsee]

There's another thread that's sorting out the issues with a Jupiter lens and I'm having the same sort of issues with an Industar 52 f/2.8 lens. There's a spot in the center of the frame if the lens has bright light from either the front or the side, which means also reflected light. The spot goes away if both subject and camera are in total shade. Here's my example of the issue

Should I assume that this will go away if I buy a lens hood and a filter for this lens? I've seen examples made with this particular lens that were very good. I can't see any cleaning marks or scratches on the lens. I'm using it with a Zorki 4, which I bought because I've never used a RF with interchangeable lenses and wanted to try the gear before jumping in and buy something more expensive. I actually like the Zorki 4, and have the sore fingers to prove it 😱

Mary in Florida

 

[xayraa33]

the Zorki 4k is a little easier on the fingers if you do not change shutter speeds often.

 

[imajypsee]

swell

swell

but, what are your thoughts on the lens "spot" ?

the Zorki 4k is a little easier on the fingers if you do not change shutter speeds often.

 

[xayraa33]

the only thing similar that I experienced, was condensation on the lens element.
when going from a cool air - conned house to outsided in the heat of summer.

 

[fidget]

The light source in the pic looks to be behind you, so i don't think a hood will help here.
I think that you would do well to check it for light leaks, through the curtains via holes or between the curtains as it is wound on.
To check for these I usually run off several frames of a film dedicated to trapping these. Try few frames which include:
one that has had the curtain uncocked over it in the light, then fire it with the lens cap on,
Another with the curtain cocked, fired in the same way. These could help to trap which curtain is letting light in,
One more which is unexposed (fired with cap on) then wound fairly slowly with open aperture in light to test for light getting between the laths as the curtains move across the frame......anyway, you get the idea, various ways to check for leaks.
It would be easier to check without film against a strong small light...
But, you don't say if it's ok with a different lens...

Dave...

 

[imajypsee]

I don't think that's it

I don't think that's it

but, perhaps it's holes in the shutter curtain? Here's something I found on my umpteenth google search

http://jay.fedka.com/index_files/Page389.htm

Before I buy a new lens, I want to be sure it's not the camera. Any idea how to look at the shutter curtains on a Zorki 4?

 

[xayraa33]

you can check your Z4 for pin holes or cracks easy since the back comes off.
look at the shutter curtain from the back with a lupe while the lens is off and the lens opening has a strong light shining on it.
do this with unwound shutter and also with wound shutter.

the spot could be reflection coming from the shiny aperture blades as Brian Sweeney discovered and corrected on his Helios 103 lens.

 

[imajypsee]

shutter holes and light sources

shutter holes and light sources

Hi, thanks to both of you; fidget and xayraa33

Fidget: I only have this lens for the Zorki and I don't want to buy another lens at the moment. The "spot" is in the frame if there's any bright light, whether from the side or reflected from the subject (in the case of the example, sun is to my back and is reflecting off the white wall). The only time I don't see the spot is when both the camera and the subject are in complete shade. I got the lens without a cap so I don't have one....

xayraa33: thanks for the help; I've given the curtains a quick look with a flashlight and can see no leaks, but I need to use a loupe (gotta go buy one...😡) and will do the examination again when I get one.

Anyhow, I sorta like a "real" RF so maybe I'll buy something newer...

Mary in Florida, USA