| My second question: My 70-300 mm lens works for FX format, so I can
| use it on my D800, but the lensfun database for this lens refers to
| using it in DX format. I presume that means that I can't just use the
| D7000 Lens Correction for this lens on a D800. Could I go far off if
| I did that anyway? Is there any chance of an entry for my lens on a
| D800 appearing any time soon? Or, if I need it, should I do my own
| lens calibration?
I would be wary of trusting a lens calibration made from a DX camera
on an FX picture, since such calibration would have been made from only
the DX image area of the picture. I don't know enough about how lensfun
models distortion and so on, but I can see any number of things that
could go wrong with this:
* the distortion visible in the DX area is not the same as the
distortion in the full FX image.
* simply telling lensfun that your FX image is a DX image probably
'stretches' the DX distortion out over the FX image instead of
extrapolating from the DX distortion information out to FX data.
* any real distortion extrapolation being done may not work completely.
With that said you can certainly give it a try. Possibly it might be
worth examining reports of the 70-300 VR to see how much distortion
it has from reports and how much DX distortion it's claimed to have in
lensfun.
Also, are you sure that the lensfun database actually has this lens?
The very latest database in the lensfun source does explicitly list
it (for DX) but only with vignetting information as far as I can see,
and the older lens databases seem to not have it at all; they just have
entries for the older 70-300 variants.
- cks
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