@ Guy & Jamie & Sean

[dhoelscher]

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Ithink this is the series that was being talked about

 

Yep,

 

That's the stuff !!!! :)

 

DH

[rvaubel]

According to LFI , the fonction of the blue dot is to make a non-TTL measurement of the light to compare it with the TTL measurement.. This comparison estimates the aperture in use so as topermit this to be taken into account by th vignette correctin software.

Sorry for the typos.

Alwyn

 

The whole blue dot controversy had a life of its own at one time. The LFI information was supposedly incorrect. But the IR issue has swamped what was a pretty good controversy at the time. Now that we have the camera it should be pretty easy to gind out what is happening, by putting one's finger over the blue dot and seeing if it changes anything.

 

Rex

[wattsy]

Now that we have the camera it should be pretty easy to gind out what is happening, by putting one's finger over the blue dot and seeing if it changes anything.

 

It certainly does function as an ambient light sensor to vary the brightness of the viewfinder information (obscuring the blue dot with my finger noticeably dims the viewfinder information). I can't say whether it also functions to guess the aperture in use because I don't have any coded lenses to try it with.

[wparsonsgisnet]

My shameful admission is that I don't use AWB on the Leicas, since the DMR was terrible at guessing WB.

 

For RAW, I set the thing to daylight so I get a predictable preview, then set WB in the raw converter.

 

For JPEG, I shoot custom WB.

 

I also don't know where the sensor is !!

 

Jamie, when you preset the M8 do you use daylight or a specific Kelvin number?

 

tnx,

[marknorton]

I agree with Ian, the blue dot certainly changes the finder display brightness; this mythical sensor in the viewfinder is the self-timer LED and obscuring the entire top of the camera with black tape does not change the WB of a shot. I think they are estimating the WB from the CCD data.

[scott kirkpatrick]

I can't say whether it also functions to guess the aperture in use because I don't have any coded lenses to try it with.

I think I saw this one checked out. No information about the aperture used appears in the EXIF for coded or noncoded lenses. There's no way to know for a non-coded lens, and there is apparently nothing being reported for coded lenses as well.

 

scott

[jaapv]

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I agree with Ian, the blue dot certainly changes the finder display brightness; this mythical sensor in the viewfinder is the self-timer LED and obscuring the entire top of the camera with black tape does not change the WB of a shot. I think they are estimating the WB from the CCD data.

 

Which would mean that LFI had it totally wrong... Let's mob them!