Circling back on the
"how does the aperture vary with zoom" question ... and thanks
@steve1225 for your info.
I'm debating replacing a ZE (2.7-12mm) with a
Z4E (8-16mm). The "Zoom Level" on the Z4's go from 0-2275 (wide-tele)... and one of mine is at 400 ... which I suspect is wayyyy wider than the Z4E can go.
However, the other ZE is at a zoom of 1400 ... so I'm wondering if the Z4E can show the same field-of-view?
I know there are some rough calculations you can do ... but what I'm REALLY interested in is given the same field-of-view (ZE zoomed in, Z4E wide), what is the difference in low-light gathering capability ... since the ZE aperture probably closes down (possibly a fair amount) whereas the Z4E's aperture should be wide-open.
Any chance someone has BOTH camera's (ideally S3 versions) mounted in about the same place and could do a night-time shoot-off?
I.e. start with the exact same settings across the board and same field-of-view/target. Then assuming the Z4E is brigher, adjust the shutter speed (increase Z4E or decrease Z4) until the brightness is about the same. Note that you want a fast enough shutter speed so it isn't varying the gain (ISO) on 'ya ... probably easiest to set that to zero. Assuming similar sensor/processing/etc., this should tell us what the difference in Aperture is - the ratio will be the square root of the shutter speed ratio.
I.e. as a camera guy, F/2.0@1/400s is the same exposure as F4.0@1/100s.
I think this would be of general interest.