Originally posted by Becks21 Thx.. nice low-light vid.. sadly the youtube-codec is blurring away any luminance-noise I fear..
I did some exposure-tests on my own:
1.) dimmed the lights in my room down until:
2.) I got a on-match exposure in Av with 1/50s f2.8 ISO3200
3.) then switched to video (1080p), set f2.8
4.) stopping further down would immediately lead to under-exposure (f-stops turn red)
So I doubt that video will go beyond ISO 3200 (like the K-7).. but I dont know if my testing was sufficient.. any ideas/comments?
Cheers!
Well, my finding for the K-7 was it uses the unexpanded ISO range, whatever was the actual ISO Auto range setting.
Assuming somewhat the same for the K-5, it would be relatively safe to assume that base ISO in video is ISO 100.
Then, one should videograph a dim enough target with a moving element. Ideal is an LED lamp swinging and hanging from a cord or something similiar.
Then, superimpose two consecutive frames. The ratio of length of the dark gaps to the bright LED traces (in between) gives the exposure time t.
t = px-bright / (px-bright + px-dark) * 40ms where 40ms is the frame duration at 25fps (PAL).
Once the exposure lowest exposure time is known (and base ISO) is known, everything else follows from exposure reciprocation.
1. Find the stop where the slowest shutter time is used. That's usually the time where a plasma TV stops banding in the resulting video.
2. Stop the aperture down to find the highest available ISO (before red blinking).
3. Open the aperture up to find the shortest available electronic shutter speed. You may additionally need a brighter target for this test though
I've not done this kind of tests yet. Another aspect worth to look into is noise.
My very first tests seem to suggest that the K-5 does NOT do row skipping in creating the video feed (i.e., line skipping only). There may be some sort of binning but I've to do more tests. If this turns out to be true, the K-5's low light performance should be able to rival the one of a D5mkII.