M7 meter accuracy

[Danielnotnow]

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Hello,

I just received a used black chrome M7 in beautiful condition. I believe it was made for the Japanese market because it has the top engraving. It appears to be a newer model because it has the optical DX reader.

 

After running 2 rolls of Provia 100f through it I found all the shots to be consistently over exposed by about 1 stop. Checking the camera’s meter against my Digisix2 I find a similar discrepancy in readings. It remains the same if I use the DX reader or manually set the ISO, and in auto or manual metering modes.

 

So my question: is this within the normal range of deviation for the Leica TTL meter? Should I just set the EV adjustment ring down a full stop and live with annoying flashing light, or does it need to go in for servicing.

Thank you,

Daniel

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[Steve Ricoh]

The meter on my M6 recommends a stop and a half underexposure against a reference grey card compared to my Sekonic 758. In this test situation I'm not interested in focus and can therefore fill the frame to be fairly confident the camera's reflected meter is seeing exactly as the hand held Sekonic. At other times, in real life shooting, the discrepancy has dependency with FoV, as expected. For the moment I live with it, but I will have the lightmeter calibrated when the camera goes for a CLA.

 

Is the offset you described constant for all ISO sttings, have you verified?

[Danielnotnow]

There are huge gaps in my knowledge, but I may have found the issue.

 

When I received the M7 I also switched from Velvia 50 to Provia 100f. The new slides looked pretty good with a casual perusal on the light box at the Photo Store when I picked them up. I don’t have any way to view them at home, I just scan them on my Epson 850 with Silverfast AI Study and view the digital images on screen. It was the digital files that were overexposed.

 

When I reset the Histogram to original factory setting, the slides all of sudden were beautiful and correctly exposed.

 

The M7 meter still reads a stop off compared to my Digisix2, but it seems moot with the new Silverfast setting.

 

Any thoughts?

Thank you,

Daniel

[Steve Ricoh]

Looking at the spec for the digisix2 it has both incident and reflected modes, with a 25 degree angle of view for the latter. The M7 like all metered M's is centre weighted (the handbook for the camera describes the coverage relative to the frameline) so it depends how and at what you point the camera, and similarly with the digisix2 in reflected mode. If you point both the camera and the handheld at grass (which isn't far off being middle grey) you should expect similar readings - within 1/2 stop would be a good outcome.

Slide film is sensitive to exposure and care needs to be taken not to blow the highlights. From the sounds of it you managed to get good results, albeit with a bit of histogramm manipulation. However I'm not sure how much contrast you had in the scene(s), and whether you metered for the average tone or the highlights and compensated (remembering all lightmeters are grey meters).

 

Anyway the question in your mind is whether the M7 is accurate, and I think I've outlined a test you could perform using grass as the target (assuming you don't have an average grey 18% reflectance card).

[Danielnotnow]

Thanks, Steve. I will test it against the grass (as you surmised I don’t have an 18% grey card).

d.