Re: Primer on photographic exposure, etc.
Re: Primer on photographic exposure, etc.
- Subject: Re: Primer on photographic exposure, etc.
- From: Iliah Borg <email@hidden>
- Date: Tue, 21 May 2013 10:13:08 -0400
Hi Lars,
On May 21, 2013, at 3:46 AM, Lars Borg wrote:
>> BTW, shooting targets filling the frame with the target may be not the best approach.
>
> No, don't do that. (flare, vignetting...)
> Or establish the light distribution by also shooting a gray card overlaying the chart, then normalize the light.
>
Flat field helps, most certainly. But it is easier to say than to actually do the flat field shot. The rub is in the word "flat" - current grey targets are not flat enough, and color targets are also not flat. So one needs to use DIY methods.
>
>> Profiles (especially matrix) can be multiplied.
>
> That's probably not accurate for narrow spectra, but may work OK for very smooth spectra.
You can try and see, results are very reasonable for natural scenes and natural objects. For better results one can always use spectral calculations from spectral data.
>> Noise.
>
> Noise can be averaged, by adding more pixels, multiple chart shots.
I mean we need to profile noisy shots.
>> Another yet connected thing is that RGB about 30 (on 0..255 scale, gamma 2.2) is too "light" for what cameras can do now.
>
> Don't quite follow you.
The regular targets do not contain dark enough patches.
--
Best regards,
Iliah Borg
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
References: | |
| >Re: Primer on photographic exposure, etc. (From: Alex Jamison <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Ben Goren <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Iliah Borg <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Ben Goren <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Iliah Borg <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Lars Borg <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Iliah Borg <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Lars Borg <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Iliah Borg <email@hidden>) |
| >Re: Primer on photographic exposure, etc. (From: Lars Borg <email@hidden>) |