Viewfinder display on R8 shows wrong f stop

[David N. VanMeter]

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Hello,

While I have my suspicions about what the problem may be, I wanted to ask here for an opinion without my biasing the answer. I own an R8 (love it) which is the second one I have had because I had to get rid of my original a number of years ago. I have a 50mm Summicron-R (early style) which has 3 cams. The problem I see, and I don't know yet if it is actually affecting exposures, is that the f-stop reading on the viewfinder display is off compared to what it is set at. For instance, when the lens is set at f16, the viewfinder says f22, same at the bottom, f2 on the lens says f4 on the display. Any thoughts?

Thx, DV

[masjah]

14 hours ago, David N. VanMeter said:

Hello,

While I have my suspicions about what the problem may be, I wanted to ask here for an opinion without my biasing the answer. I own an R8 (love it) which is the second one I have had because I had to get rid of my original a number of years ago. I have a 50mm Summicron-R (early style) which has 3 cams. The problem I see, and I don't know yet if it is actually affecting exposures, is that the f-stop reading on the viewfinder display is off compared to what it is set at. For instance, when the lens is set at f16, the viewfinder says f22, same at the bottom, f2 on the lens says f4 on the display. Any thoughts?

Thx, DV

It rather sounds as if there is some sort of mechanical mistracking of the cam. Have you tried it with a different lens? My initial thought would be that either the cam in the lens is misaligned, or the cam follower in the camera is misaligned. If it does it with a different lens, it's likely to be the camera; if it doesn't then it's likely to be the lens. (Alternatively, have you tried the lens on a different camera?)

PS: Welcome to the Forum!

Edited October 13, 2020 by masjah

[gbealnz]

Yes, welcome.

Are you sure it's three cam? Having said that I'm not sure a 2 cam lens will mount?

I have an early 50 Summicron and it is 2 cam.

Gary 

[David N. VanMeter]

3 hours ago, gbealnz said:

Yes, welcome.

Are you sure it's three cam? Having said that I'm not sure a 2 cam lens will mount?

I have an early 50 Summicron and it is 2 cam.

 

I believe you have partly hit on the nub of the problem. You are correct that this lens was originally 2 Cam, all my research supports that but it is clearly 3 on inspection. I think when it was converted that it may have been done wrong but that is really a guess. I will be able to test a second lens at end of week and will know for sure where the problem lies then. Thanks for the input.

[David N. VanMeter]

On 10/13/2020 at 4:39 AM, masjah said:

It rather sounds as if there is some sort of mechanical mistracking of the cam. Have you tried it with a different lens? My initial thought would be that either the cam in the lens is misaligned, or the cam follower in the camera is misaligned. If it does it with a different lens, it's likely to be the camera; if it doesn't then it's likely to be the lens. (Alternatively, have you tried the lens on a different camera?)

PS: Welcome to the Forum!

It turns out to be the lens. I tested 2 other 3 Cam lenses and they were fine so now I need to find out who can fix this lens in the US. Thanx for the inpit

[spydrxx]

Call DAG...I'm sure it will be a breeze for him to adjust