Spyderman
Well-known
There's a removable round light baffle in the back of the lens. As I did a CLA to it, I had to remove the baffle. I'm just wondering if I should put it back, as it seems that it will block some light and cause light fall off at wide open apertures.
Has anyone here encountered a light fall off problem with this lens? and with the light baffle?
Has anyone here encountered a light fall off problem with this lens? and with the light baffle?
Attachments
Kim Coxon
Moderator
Hi,
The baffle is there to stop unwanted internal reflections. Some lenses have lost theirs as they are a push fit. They will not cause any light falloff and it is best to replace it.
Kim
The baffle is there to stop unwanted internal reflections. Some lenses have lost theirs as they are a push fit. They will not cause any light falloff and it is best to replace it.
Kim
Spyderman
Well-known
I know what it's for 
Anyone else have any recommendations or experience to share?
Anyone else have any recommendations or experience to share?
P
pshinkaw
Guest
I replaced mine when I cleaned and lubricated the lens. Having it in does not appear to have any bad effects.
-Paul
-Paul
Spyderman
Well-known
So I put it back in.
But still I was curious whether you were right. So I removed the back cover, openned the shutter at Bulb and looked from corner of the frame hrough the lens. Sure the baffle was an obstacle in the way! As looking from the corner of the frame, it obscured about 10 or 20 % of the area of the glass! Just try it yourself if you don't believe me.
So I removed the baffle for good.
But still I was curious whether you were right. So I removed the back cover, openned the shutter at Bulb and looked from corner of the frame hrough the lens. Sure the baffle was an obstacle in the way! As looking from the corner of the frame, it obscured about 10 or 20 % of the area of the glass! Just try it yourself if you don't believe me.
So I removed the baffle for good.
Last edited:
P
pshinkaw
Guest
You don't think that the baffle was installed for a reason? The Soviets seldom put in things for frivolous reasons.
-Paul
-Paul
Jocko
Off With The Pixies
Today's new word: Hubris
Ian
Ian
Kim Coxon
Moderator
If the light baffle was cutting down the light, then removing it will affect the exposure and you f stop markings will no longer be valid unless you use it on a later Leica, Bessa or other camera with TTL metering. Un fortunately, the test you applied does not show the true optical path. Put a frosted screen on the film plane and see if there is a difference in the image. I suspect not. A little while ago, I serviced a batch of about 10 I61's both black and Panda. In the subsequent test run done at full aperture, there was no difference in exposure between those with and those without the baffle.
If you feel better with it out, it will do no harm apart from the increased chance of flaring or ghosting.
Kim
If you feel better with it out, it will do no harm apart from the increased chance of flaring or ghosting.
Kim