Serene Life

by garik

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234 reputation
16
bio website turra.web.cern.ch/turra
location Italy
age 30
visits member for 1 year, 9 months
seen Apr 4 at 11:59

PhD student in particle physics


Feb
2
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
"the stacking doesn't fix the underexposure", why not? The amount of light entering the camera in 1000 x 0.001s is the same in 1 x 1s
Jan
24
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
dear user1207217, I am a particle physicist, let me say that the Heisenberg inequality really doesn't fit with this case. Since the sum over many frames is linear and since they are uncorrelated the noise you obtain integrating many frame is exactly the same with the one using an equivalent single shot.
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
interesting, I have found only this surveillance camera using a double exposure: video.boschsecurity.com/video/Introducing-the-new-HDR-camera/…, do you know specific model?
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
@BBking: with lens cap in both cases, in such a way to don't have light (signal) but only noise
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
@MattGrum: so with the Canon 1DX sensor this technique could be interesting for example when shooting a city in the night. In this way I can integrate 100 frames for the sky and 10 for the city (just an example)
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
@jrista: you can reach the same effect superimposing many fast frames.
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
@whatsisname: so you mean that if I shoot with 1/8000 ISO 6400 or 1s ISO 6400 with lens cap on I will get the same result?
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
@whatsisname: sorry, I don't understand your point. The noise is a random process with a certain rate depending on the ISO and other parameters. The rate of noise should be the same for short or long exposure. Maybe this is not completely true because it depends on the temperature and so for long exposure you could have more noise rate. By the way, supposing constant noise rate you should obtaing more noise for longer exposure.
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
I think File size is not a big issue, in my mind you can choose to shoot in integral mode or in differential mode. Timelapse need a lot of memory, this doesn't mean people are not doing it. For the Exposure I think you are wrong as mattdm said and I think the noise is the same in the case you do only one shoot or summing more shoots, the only difference is that you open and close your shutter. When summing different frames you are summing the signal and the noise. I think the proof is that the sum of two independent Poissonian random variable is a still Poissonian distributed.
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
@BBKing: my numbers were just an example, probably you should use the faster speed as you can. Each frame should be underexposed to be able to get te correct exposure summing different frames. Probably I have to change the title of my question from "why do I need shutter speed?" to "why do I need mechanical shutter speed".
Jan
23
comment Why do cameras use a single exposure rather than integrating across many very quick reads?
what is the present read-out speed? 1 s, 0.1 s, ... ? Since normal cameras are able to record 25fps video I would say ~0.04s. It seems too slow for normal photos.
Jan
20
comment What can I edit in postprocess and what not
two questions: from JPEG or from RAW