It is also very easy to determine with the script at which aperture a lens is the sharpest. In doing so, I simply created shots of a noisy picture. It is then sufficient to sort only the JPG images by size. The largest JPG is then the sharpest picture. I compared that to other methods. That's pretty good. The following plot shows the curves of a 50mm lens on the EOS M3. The first curve is the JPG size.
Good idea.
Not sure if the Script could log the JPG size of the image.
You can get the file name:
string.format('%s/IMG_%04d.JPG',get_image_dir(),get_exp_count())
and then get the size with os.stat
Interestingly, the SX50 goes beyond aperture f8. The Canon Interfacce is only available until f8.
range=3.50-11.31 (347-672)
Yes, most powershots work to somewhat higher f numbers than the UI max, and much higher when zoomed.
On high apartures the script delivers wrong values as I descript in Reply #27
range=6.44--24.-3 (516-1032)
This should be fixed in trunk 5126. I don't think any powershots get close f/32 but maybe you could put something on the Ms that does.
For the 6D and EF 50mm f1.8 USM this does not happen in LiveView. When focusing, the aperture is also set on the 6D. I have never noticed that. I always thought, it is focused with an open aperture. The break in the sharpness in the center is then no longer available. Maybe that's why the S110 does not focus on open aperture.
I wonder if this depends on available light. With good light, then using the same aperture as the shot should be best, but at some point the SNR probably matters more?
Presumably there is no way with CHDK to close the aperture when focusing?
If setting CHDK overrides doesn't, then probably not. Hooking into the AF process could be useful, but I'm not aware of any work in that area. One thing I'd love is to be able to limit the range of the AF scan, so if you are shooting far away it can just sweep say 100m+ instead of the whole range.
