The SX230 has 14x magnification, I’m curious how this feature will translate to actual per inch pixel size at some reasonable vertical distance to give me a good starting point before I strap in the camera to my fixed wing for some real tests.
For my test, I took pictures at 0%, 20% and 50% optical zoom from height of about 100m. I have 2 objectives: to get a good inch per pixel estimate and second, to get the approximate ‘footprint’ or area of the image of each zoom rate.
SHOT 1: Unprocessed 0% zoom rate:
SHOT 2: Unprocessed 20% zoom rate:
SHOT 3: Unprocessed 50% zoom rate:
SHOT 1A: pixel at 0% zoom rate:
SHOT 2A: pixel at 20% zoom rate:
SHOT 3A: pixel at 50% zoom rate:
1) 0 and 20% zoom does not have any real footprint difference.
2) 0 and 20% zoom has a good sized foot print from 100m and probably will do for aerial mapping purposes which requires 3-6 inch pixel resolution.
3) 50% zoom actually has only 25% of the footprint of 0% zoom (not 50%!) however, the resolution is good, I suspect less than 1 inch per pixel as shown in shot 3A.
4) Finally 100m is too low for real aerial mapping work, 400m-700m is probably more appropriate.