Exposure bracketing on Leica M-P (Type 240)

[tommytan]

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I have a question on exposure bracketing on Leica M-P (type 240). I've set the exposure bracketing to 3 frames, plus minus 0.5 EV, Auto. ISO is either auto or manual at various levels. When looking at the meta-data for the shots, the brackets invariably come in at plus minus 0.3 rather than 0.5 EV. It seems to work ok with plus minus 1 EV. Is this a bug or is there an explanation for this. I speculate that perhaps the shutter speed cannot vary finely enough to achieve plus minus 0.5 so the closest it gets to is 0.3. If that is the case then the setting should say plus minus 0.3 rather than 0.5. This was the case with firmware 2.0.1.7 as well as with 2.0.2.5

 

Thanks in advance for any explanation.

[andybarton]

I assume that the shutter speeds in the EXIF show the half stop difference?

 

The EV "anomaly" may be due to the fact that the aperture is only ever estimated and may vary from shot to shot slightly.

 

Just guessing.

[pop]

I did a quick test (only one). Exposure bracketing with three exposures spaced at 0.5 EV gave me three frames:

Exposure times: 180, 250, 360

relative EV: 0,  -0.47, -1.

[jaapv]

I think Andy has nailed it: The bracketing is correct, but as the aperture is only a guesstimate, Lightroom cannot calculate precisely.

[algrove]

Bracketing less than one f stop is negligible, why waste your time?