SL2 with Voigtlander 35mm f1.4 - how to capture correct aperture used?

[pthean]

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Hi All, 

I put the Voigtlander 35mm f1.4 Classic on my SL2. It is not a recognized lens, so I chose the Summilux M1:1.4/35 ASPH. 11873 lens profile.  Everything works great except the Aperture setting recorded on the shot does not match the aperture setting that I used on the Lens. I have also tried the 2 other M 35mm lens profiles in the menu with different but still incorrect Aperture recorded in the shot.

Can someone share with me how to capture the right Aperture used? Do I need to create a custom lens profile? And if so, how do I do that?

Thanks much for your help.

-patrick.

[Donzo98]

You can’t... the aperture shown in EXIF is an estimate only. Even 6 bit coded M lenses are inaccurate. 

[pthean]

32 minutes ago, Donzo98 said:

You can’t... the aperture shown in EXIF is an estimate only. Even 6 bit coded M lenses are inaccurate. 

Thank you. How does it estimate?  I did notice that the f16 was good,  but the f1.4 came out as f1.7. Does it matter which of the M Lens profile I choose?

[Donzo98]

5 hours ago, pthean said:

Thank you. How does it estimate?  I did notice that the f16 was good,  but the f1.4 came out as f1.7. Does it matter which of the M Lens profile I choose?

No... it doesn’t matter at all. Even an M lens with M-L adapter is still wrong. There are no electrical contacts of the lens or adapter. 

[BernardC]

16 hours ago, pthean said:

How does it estimate? 

It uses an extra light sensor on the body and compares the ambient light level with the amount of light going through the lens.

It doesn't have to be accurate. The only practical use for the information is to apply vignetting correction to JPEGs and DNGs. 

[pthean]

Thank you sharing. So... what does the Lens Profile do? How does the SL2 use that? And does it matter which Lens Profile I set when I use this lens? Thanks again!