lightmetering problems with J-12

[JT2007]

Hello!

I've just gotten a very nice Jupiter-12 (black, 1986) lens. Can't complain about the image quality: it's great with the R-D1! But I do have a problem with the R-D1's lightmeter while using the J-12. The lightmeter sometimes (irregularly for what I can tell) recommends three stops under the correct exposure (for example 1/30 is correct but the meter shows 1/4).

Now my problem is i'm not sure about the reason for this so that I could compensate for the problem. Well, yes it's probably beacuse of the rear element disturbing the lightmeter but the question is when does it bother it. First I thought it had to do something with the focus but no: infity or one meter doesn't really affect it. Would it be possible it's about the lighting conditions? More often in low-light?

I would greatly appreciate it if you could share on your experiences so that I could find a pattern and be able to know when to compensate for the incorrect metering before taking the picture. Thanks!

 

[89rzweig]

Hi JT2007,

this behaviour is normal, the rear element just blocks the camera meter, especially when focused on infinity. When close-focused, the meter reading is about 1/2 stop underexposure, which is Ok. As it is pre WWII design, the lens was apparently made for meterless cameras.

Because the wide-open performance of J-12 is far from stellar, I keep it stopped down from f/4 to f/8, depending on the light conditions. What I do then is, I close-focus, then cock the shutter, take the meter reading, adjust shutter speed, focus and take the picture. If you normally use AE mode, then you'll probably start to hate this lens very soon... I do not use AE, but still I'm currently choosing more usable 35mm lens.

Regards,

-P.

 

[JT2007]

Thanks 89rzweig for the answer.

I still think it might be more complex than this. First, when close focused my r-d1&j-12 combination doesn't underexpose a half stop. It works irregularly, sometimes it's correct, sometimes it overexposes three stops. Infinity I haven't really tried but while focusing at further distances it's still mainly irregular for me.

I don't use AE, so your advice to get around the problem would have been great but..

I still believe it has to do something with highly uneven lightingconditions (strong contrast). Is this possible in anyone's opinion?