Why do you want to do that? You can always point the camera to the object you want to have in focus and then move it back to the position where you where before to take the shot.

Alternative would be to do manual focusing, you can do that through v4l2 driver API.

I noticed that the N900 native camera app does much better auto-focusing compared to the Gstreamer "photography.h" auto-focusing functionality? Does anybody know how they do it?

Cheers,
Klen

I would also like to know that.

Klen

I have never implemented the contrast based autofocusing, but I don't think the overall image contrast level would help here, I would filter out the low frequencies and maybe also some amount of high, to avoid detection of sensor noise.

You would also like not to process the whole image but limit to the smaller area or number of areas.

So the simple version may look like:

total contrast of some area = sum( ( very slightly blurred or denoised image - more blurred image )^2 )

I was just reading through some documentation on the camera of the N900 and it said the I2C command is used to adjust the delay of data and strobe signal in CCP2 to compensate skew between data and strobe.

Can someone explain what this means please thanks