Suppositions vindicated! Blue Dot revealed.

[Ben Z]

I don't understand how an "approximation" of the f-stop in use can do any kind of meaningful calculation for any type of exposure, and an "approximation" is all that an external sensor can provide, because of parallax. It is the same situation with an external meter like the MR-4 or an auto flash. It reads a fixed angle and not necessarily that which the lens "sees". If this is Leica's idea of a workaround for the inability of the lens to transmit aperture data to the camera, I sincerely hope it is like the lens coding and doesn't affect the RAW files, only for the JPEG users, or at least that it can be disabled.

 

[Mark Norton]

I'm still not convinced that this is what the blue dot is for...

 

[rvaubel]

I sure hope the blue dot is an external sensor. If it could help JPEG users with vignetting and lateral color correction, it would help make the M8 more saleable. For myself, as a raw user, I wouldn't want it screwing around with the RAW data. However, it would be nice to have the data in the EXIF file.

As for it only being approximate, so what? The corrective algorithms are just approximates themselves.

The real reason that I hope the blue dot is an external sensor is because I think it would be cool. It wouldn't do me much good, but getting the approximate F# in the EXIF file would save me time when posting pictures and I have to quess or remember. DSLR users don't have to do that!!

Rex

 

[Ben Z]

As for it only being approximate, so what? The corrective algorithms are just approximates themselves.

Just my opinion but an external sensor with the potential to see something several stops different from what the lens sees is in another world compared to the sort of approximation you might find with an algorithm. I've used handheld or clip-on meters, and auto flashes for many years and they can be "fooled" much easier and much greater than eg. matrix metering.

 

[rvaubel]

Just my opinion but an external sensor with the potential to see something several stops different from what the lens sees is in another world compared to the sort of approximation you might find with an algorithm. I've used handheld or clip-on meters, and auto flashes for many years and they can be "fooled" much easier and much greater than eg. matrix metering.

Ben

The external meter is claimed to be accurate to +/- 1 stop, not "several stops". As for matrix metering being more accurate, the M8 doesn't have it and I'm glad. I can never tell what my 20D is "thinking" when its in matrix mode, so I set it for spot or center weighted. I'll bet a lot of us on this forum avoid matrix mode (if even available) except for action shooting. I don't like to let the meter rule the camera. I frequently apply exposure compensation to override the meters recommendation.

Rex

 

[Ben Z]

Ben

The external meter is claimed to be accurate to +/- 1 stop, not "several stops". As for matrix metering being more accurate, the M8 doesn't have it and I'm glad. I can never tell what my 20D is "thinking" when its in matrix mode, so I set it for spot or center weighted. I'll bet a lot of us on this forum avoid matrix mode (if even available) except for action shooting. I don't like to let the meter rule the camera. I frequently apply exposure compensation to override the meters recommendation.

Rex

Mention of matrix metering was just an example, I don't use it either, preferring as many do, to use spot or partial metering and my brain to adjust the reading for differences in tonality of the subject and/or contrast range of film or sensor. Matrix metering however, is much more consistently accurate than spotmetering in the hands of someone unfamiliar with metering and exposure theory.

As to the external sensor being "claimed" to be accurate to +/- 1 stop I'm sure it is so in the best-case. However, given the invariability of parallax between the "dot" and the lens, the invariability of the fov of the sensor, and the variability of lens focal length and variability of arrangement of light sources within the respective views of sensor and lens, I can't see how anyone could claim the potential isn't there for a difference of more than one stop.

 

[jaapv]

So there we have it 100% official: The Leica technical data sheet, no 1.4: The blue dot is the brightness sensor. 🙂

 

[Nachkebia]

Corrections corrections..... to make digital images look even more "clinical" and boring 😀

 

[Stan98103]

Jaap,

Yes the blue dot is an ambient light sensor, but it's only used to control the brightness of the LEDs in the viewfinder. It has no effect whatsoever on how the image is captured or processed. This is according to the M8 user manual.

Stan