Lens influence in the camera measurement files

[antond-weta]

Do we know if the camera measurement files have the lens transmission factored out?
If not, would it be able to get the corresponding lens' spectral transmission data for each (or at least some) camera?

Would it be worth adding the lens ID attribute to the schema, in case if we know that a camera has been measured through a lens, but we don't have the lens transmittance data yet?

Ideally, I'd like to have the lens spectral transmission as a separate entity type in the database (data/lens/*.json). We could fetch the lens ID from a source image metadata and use the corresponding lens transmittance if we have it in the database, or the 'ISO standard lens' otherwise.

[antond-weta]

@scottdyer, @KelSolaar could you please comment on this

[thomasmansencal]

The data provided by the Academy has been measured by a monochromator and should not have, afaik, a camera lens in the optical path.

[antond-weta]

The data provided by the Academy has been measured by a monochromator and should not have, afaik, a camera lens in the optical path.

Thanks Thomas. This document does mention measuring with a monochromator through a lens, hence me asking. I don't know if the process used for the rawtoaces data had been the same or different.

Would you have a feedback on having lens transmission data as a part of normal rawtoaces operation? This is separate from the issue of how the camera files were created; but rather accounting for the lens transmission of the lens a photo was taken with.

[thomasmansencal]

I remember this document, I don't think any its the CMFS are "shipped" and it was just for Scott to revalidate the measurement process. Maybe @aforsythe can also chime in.

As for shipping lenses, it would be great to have some for sure.

[scottdyer]

It is true that I used lenses when doing my verification of the process.
After reviewing the data in this repository, I can not guarantee any insight as to the provenance of any of it. Some of these look like they were derived from files that I inherited or were given, and did not capture myself.

I do agree it is a good idea to have a provision for the lens data, whether it was measured separately or assumed as part of the imaging system.