M9 metering

[LeicaBraz]

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As per the instructions manual:

"Metering on the Leica M9 is strongly center-weighted, essentially only an area in the center of the picture is calibrated to an average gray scale value".

 

I'm sort of confused: if it is "heavily center-weighted" one would believe the whole frame is measured but heavy importance is given to the center when determining the exposure. But then if only the center area of the picture is calibrated, then only that center area is taken into account.

 

So which is it? Any idea what size the central area is on a 50mm lens? Believe film cameras usually showed this area size.

 

Thanks

[lars_bergquist]

Leica call it "selective metering". It is not immune to light outside the central pattern, but it is more discriminating than the classical center-weighted metering.

 

Remove the lens and take a look at the shutter. The white center lamella and the two adjoining light grey ones are what the exposure sensor meters. It does not give much weight to the extreme right and left portions however.

 

So what you get is actually a kind of airship or bratwurst shaped metering pattern. It's size is not fixed. From looking at the shutter, you can get an idea of how large the pattern is relative to any lens you mount. So if it takes up, say, 15% of the area of the shutter, it takes up 15% of the image field of a 18mm, 21mm, 24mm, 28mm, 35mm, 50mm, 75mm, 90mm and 135mm lens! Imagine it floating inside the bright frame of the lens you are using, always at the same size relative to it.

 

The old man from the Age Before TTL

[LeicaBraz]

Very clear, as usual. Thanks.

 

The man from the age of the M9Ti

[mn4367]

... bratwurst shaped metering pattern ...

 

Rotflol! You should definitely apply this term for a patent .

[Double Negative]

Any coincidence that a German camera meters like a bratwurst? Hmm.

[zeitz]

For completeness, the M6 and M7 use a circle instead of a bratwurst, giving a semi-spot reading. I don't know why Leica changed for the M8 and M9. I always liked the semi-spot reading better. It seemed to be more selective and easier to point.

[LeicaBraz]

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Agree with zeitz. That´s why thought M9 was the same. If one dare take off the adjoining grey ones maybe it does revert to the circled reading.

[zlatkob]

Has Leica published a diagram of the M9's metering pattern? I thought there might be a diagram of the metering pattern in the manual, but there isn't.

[ho_co]

The M9's metering pattern was changed from that of the M8 to make it like that of the M7, according to Stefan Daniel in the Reichmann M9 intro video.

 

That is, the M7's pattern is circular. The M8's pattern is elongated. The M8's pattern is approximately circular.

 

This is because the sensor reads the center of the curtain far more strongly than the edges.

[lars_bergquist]

The real reason why the metering 'spot' of the M8 and M9 cameras is not circular is clearly that you cannot print a pattern on the metal blades of the shutter. They have to be one colour -- in this case, one white and two grey.

 

The old man from the Age of the Leicameter MC

[dwbell]

I'd love to see someone's educated guess at the 35mm (or other) frame lines with the "spot" represented to scale.

[giordano]

You can get a very good idea of it yourself by putting a small bright light in dark surroundings, the camera in A mode, and watching how the shutter speed varies as you track the light across the field of view.

[ho_co]

Mis-typed above. I said:

... That is, the M7's pattern is circular. The M8's pattern is elongated. The M8's pattern is approximately circular....

 

I meant, of course:

... That is, the M7's pattern is circular. The M8's pattern is elongated. The M9's pattern is approximately circular....

 

 

On the M8, there is a single white meter stripe on one blade of the shutter. Reading that with the sensor presents the Würstchen-shaped pattern Lars mentioned above.

 

On the M9, two gray blades have been added, one above and one below the white one. Reading now with the same sensor gives additional sensitivity above and below the center of the frame, producing a more rounded primary metering area.

 

M8 left, M9 right:

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BTW, don't try to be too specific with diagramming the sensitivity pattern, because it varies with the lens in use, tending to be more spotlike with longer lenses, and more averaging with shorter lenses, according to Scott Geffert at the M8 introduction in Irving TX.

[lars_bergquist]

In case of coubt I whip out my trusty Colt-Gossen and meter incident light.

 

The old man from the Age of the Selenium Meter

[gjames9142]

I am really mistrustful of these in camera meters. Using my internal meter, otherwise known as my eyes, I establish a good level, and shoot manually as I have on my trusty M4, chimping only occasionally at the histogram to see how I am doing. It can be useful to use the incamera meter to meter various areas, and then hold the shutter down halfway to hold the right setting. BTW I have found this difficult to do with the Beep, a nifty little item that makes it possible to use slower shutter speeds