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M8 and aperture info?

francishmt

New member
When you take a picture in M8, does the aperture information show up correctly when you open in C1? For some reason, mine is all screwed up. For example, showing F6.7 for a F4 shot.

This happen regardless of which lens I use. WATE, 28 Cron, 50 Lux or 90 Summarit. All screwed up. All have lens detection on.

Doesn't affect exposure or other things. Just the EXIF info.

Any ideas?
 

carstenw

Active member
I don't know where C1 gets its info from, but the M lenses have no way to communicate the aperture to the body. The body just measures the light to make the shot, and ignores the aperture.

However, the little blue glass window next to the red dot also measures the light, this time not through the lens, and based on the difference between the two light measurements, the camera can guess what the aperture might be. This is course doesn't work well for all focal lengths, since the focal length affects the real measurement through the lens, but not the measurement through the blue dot. Thus the blue dot might have a wider or narrower view of the world than the lens. Additionally, the lens can actually partly block the blue dot's view of the world, thus making the world seem darker than it really is.

Anyway, if C1 is reporting the guesstimate from the Maker's notes part of EXIF, it is not surprising that it is often off by some amount.
 

cam

Active member
C1 does guess... it's actually pretty good and not an issue for me as i pretty much shoot in only a few stops so i always know what it means... you kind of get used to it.
 

Seascape

New member
Why doesn't the light meter record the EV, and then since it knows the shutter speed, the F stop should not only be simple to calculate, but also accurate........am I missing something :confused:
 

Arjuna

Member
To expand a little on what Carsten has already explained, EV is not independent of angle of view, unless the scene has an even level of brightness. The blue glass meter has an unknown, to me at least, angle of view, but it is unlikely to match the lens' angle of view except for one particular focal length of lens. If, for example, the blue lens meter has a quite wide angle of view, then it might typically measure more sky than the in-camera meter. This would mean that it would likely report a higher EV reading than the in-camera meter (which is also fairly centre-weighted), even when the lens is wide open. In this case, the calculated aperture would be smaller (larger number) than the real aperture.
 

Maarten

Member
Lightroom 3 Beta also guesses at f stop. It also provides the Leica name of M lenses which is nice.
Lightroom 2.6 Release Candidate also guesses the F-stop and extended lens info. At least for my M9 images. The previously imported M8 images do not show this.
 
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