Fuji X10: exposure bias expressed in 100th's

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  • Updated 6 years ago
The issue is quite self explanatory: if you set -1/3 EV on the dial, under Lightroom the value is expressed as -33/100 EV.

It doesn't occur with my other cameras.
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Paolo Avezzano

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Posted 6 years ago

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jdv, Champion

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Is Preferences -> Interface -> Use typographic fractions checked? It shouldn't matter, but we should know for the sake of completeness.

Of course, this is actually the same value. I suspect Lr is just reading it from the Exposure Compensation metadata and not scaling it. What does exiftool say the EC is? Or you can share the images (out of the camera) and post the link here.
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Paolo Avezzano

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"Show typographic fractions" is set. Unsetting it doesn't change the string.

Exiftool reads the exposure compensation for the X10 photo like this:

   Exposure Compensation           : -0.33


On a Nikon DSLR photo it reads:

   Exposure Compensation           : -2/3


...and shown correctly under LR.
It's definitely a UI glitch.
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jdv, Champion

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Well, -0.33 is -33/100.

The EXIF field is actually "ExposureBiasValue" which can have an "APEX" value from -99.99 to +99.99. So, technically, Fuji is scaling this number incorrectly. It should use the correct APEX value, or follow convention and use a well-formed fraction. Lr is handling this weird value in a very well-behaved manner.

Lr has no way of knowing what the denominator is on the knob, but it knows that it should represent it as a fraction (doing this probably allows the UI to scale the sidebar item easier).

So, I suspect bare APEX values are shown as their trivial fraction representation, as this will always be correct. Actual fraction values are displayed verbatim.

The alternative is to take the value, and then lookup a camera specific scaling factor to mathematically transform the value to some *new* value that is based on the possible camera settings. Which means now we have to handle corner-cases, like what if the value/100 does not match the new fraction we create based on the camera settings. This is the problem with adding more camera specific cruft that is subject to change w/o notice, and is out of the hands of Adobe.

Lr tries as much as it can to show you the well-formed actual data. Whenever you have to do any transforms, you run the risk of introducing errors. In this case, the error would result in the UI displaying an incorrect value for this metadata. (Or, at least, a situation where the metadata cannot be resolved, causing us to fall back to the value/100 notion anyway.)

I don't see how this is any better. As we can see, Lr is reporting on the EXIF data correctly.
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Paolo Avezzano

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Trying no to sound harsh, you're really making it more complex than it is.
-33/100 is the approximation of -1/3 and, as for the rest of the cameras, to keep the UI coherent, the should use the fractional syntax, IMHO.

16/100 = 1/6 Ev
33/100 = 1/3 Ev (most common)
50/100 = 1/2 Ev

...and so on. Values other than them (not just multipliers) may be left in hundredths notation, but I haven't encountered one so far.
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Paolo Avezzano

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I discovered that the Sony DSC-RX100 has a similar UI glitch.

+1/3 Ev is expressed in tenths: +3/10 Ev

To me it's a test that should be made for future cameras support. As long a new model is added to the list, check it's grammar :)