Hallöchen! Chris Chiappa writes:
> [...] > > I'm actually having a bit of difficulty with this bit, actually. > I'm trying to do calibration of a fairly wide angle lens (14mm > with a 2.0 crop) and am finding it hard to get what appears to be > even illumination - I certainly don't have a light source that can > apply an even enough illumination to my ceiling. Does this mean > that my diffusion material isn't diffusy enough (I have tried a > white plastic trash bag)? Doesn't such a plastic trash bag wrinkle up? The diffuser must be even. As far as illumination is concerned: Two steps of diffusing are enough. So, illuminate your ceiling, and point the diffusor on the lens to the ceiling. Then, the ceiling scatters the light, and the diffusor does it again. It wouldn't work if the left half of the diffuser area got less light than the right half. But this should only happen if you point a lamp directly to the diffuser, possibly even in short distance. Therefore, the ceiling as an intermediate step: It enlarges the effective distance to the light source, and adds scattering. Tschö, Torsten. -- Torsten Bronger Jabber ID: [email protected] or http://bronger-jmp.appspot.com ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
