Leica R4 camera only meters in f/2 unless I press the depth of field preview lever?

[petmeiamirish]

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I recently picked up a Leica R4 with a serial number of 1603616 with a 50mm summicron-r with a serial number of 2039145, and I was testing out the light meter and noticed that the camera only meters probably when I pull the depth of field preview lever. I noticed that the camera only meters in f/2 unless I pull the depth of field preview lever. Does this only happen if I’m in manual mode? Also, could this be happening due to the lens being made before the camera? Responses are appreciated.

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[TomB_tx]

Yes - the lens serial indicates it is a version I lens with 2 cams, made for the Leicaflex cameras. As you found, it can still be used on the "Leica R" models, but only meters in stop-down mode using the DOF button to close to shooting aperture. The Leica R cameras use a "3rd cam" on the lens to read the f stop set. This started on Summicron serials above 2758826, although it was possible to have earlier lenses converted. I had a 135mm 2-cam lens converted to 3 cam when I added an R4 body.

[petmeiamirish]

3 minutes ago, TomB_tx said:

Yes - the lens serial indicates it is a version I lens with 2 cams, made for the Leicaflex cameras. As you found, it can still be used on the "Leica R" models, but only meters in stop-down mode using the DOF button to close to shooting aperture. The Leica R cameras use a "3rd cam" on the lens to read the f stop set. This started on Summicron serials above 2758826, although it was possible to have earlier lenses converted. I had a 135mm 2-cam lens converted to 3 cam when I added an R4 body.

Quick question. If I were to use an aperture priority mode, would the camera know which aperture I have selected? And if I were to use program, would the camera be able to change the aperture of the lens? Thanks.

[TomB_tx]

I believe manual mode and stop down is the only way to get correct exposure with this combination, unless you leave the lens at f2.

[petmeiamirish]

1 minute ago, TomB_tx said:

I believe manual mode and stop down is the only way to get correct exposure with this combination, unless you leave the lens at f2.

Ah, okay. Well I shot a roll with aperture priority so I’ll see how that comes out. I’ll most likely sell the lens and get a more modern one if it’s a problem. 

[hepcat]

On 5/7/2023 at 5:12 PM, petmeiamirish said:

Quick question. If I were to use an aperture priority mode, would the camera know which aperture I have selected? And if I were to use program, would the camera be able to change the aperture of the lens? Thanks.

No.  You need 3 cam lenses for the metering to work in any mode other than stop-down.  I have had several two-cam lenses converted to three-cam for that reason for use with my R5 and R6.2.

[petmeiamirish]

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On 5/7/2023 at 6:18 PM, petmeiamirish said:

Ah, okay. Well I shot a roll with aperture priority so I’ll see how that comes out. I’ll most likely sell the lens and get a more modern one if it’s a problem. 

I finally got the roll back and the images were properly exposed? Even ones I took outside on f/16.

[hepcat]

15 hours ago, petmeiamirish said:

I finally got the roll back and the images were properly exposed? Even ones I took outside on f/16.

Well. Hmm.  Strange as that sounds, apparently your R4 is not the only one to do that.  I found this thread from 2008:  https://www.photo.net/forums/topic/330377-2-cam-lens-on-leica-r4/

I guess that if it ain't broke, don't fix it!

[petmeiamirish]

1 hour ago, hepcat said:

Well. Hmm.  Strange as that sounds, apparently your R4 is not the only one to do that.  I found this thread from 2008:  https://www.photo.net/forums/topic/330377-2-cam-lens-on-leica-r4/

I guess that if it ain't broke, don't fix it!

Definitely strange.

[tobey bilek]

DAG used to add the third came almost on a production line basis. I guess he has these parts and you will get a fast turn around.

The early ones took a ser 6 UV filter.  Use it.  performance is much improved with it on.  Hard to believe, but true.  After I was told I tried it myself.