[Elphel-support] DC auto-iris

[support-list]

Hello Shane,

I was thinking of adding lens control to the camera, but then I realized that with the 2.2 um pixels (and the modern sensors have even smaller ones) the usable aperture adjustment is very limited because of the diffraction - the maximal F# is just the ratio of the pixel size to the light wavelength, so in our 5MPix cameras it is about 3.5. If you close more - the resolution will be degraded. On the other hand - it is a strong side of the electronic rolling shutter sensors - there is no penalty for going to very short exposure time (something common for global shutter CCD and CMOS sensors).

So I would not recommend using of any motorized iris lenses, they woulld provide little if any benefit, while degrading the image sharpness.

Andrey

---- On Sat, 13 Oct 2012 18:32:39 -0700 Shane Sanford<shane.sanford at concurrent.us> wrote ---- 


I have a outdoor application were we think we need a auto-iris lens with our Elphel camera.  Is there a existing relatively inexpensive solution for controlling the lens using the Elphel camera?  After doing some looking around I have not found anything that fits the bill but before I go and try to reinvent the wheel I thought I would ask to make sure there was not a obvious solution I was overlooking.  
 
My current plan is to build a circuit interfaced to a arduino and connect to the camera in the case of the NC353L-369 camera or if we end up going without the 10369 board then use a netduino (or arduino with a network shield) and communicate via the network.
 
Input would be appreciated!
 
Shane

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