FPS and Shutter speed

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Archive 2008 · FPS and Shutter speed

4honor
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p.1 #1 · FPS and Shutter speed

I have an XSi, and it has the 3.5 FPS continuous shooting capability. Well, I am just a bit confused, because I am somehow relating the shutter speed to FPS...

If I shoot 1/100 exposure, doesn't that mean the shutter is open for 1/100 seconds, which means I can have theoretically 100 pictures in 1 second? I tried 1/50 and 1/2000 on my camera, and still getting the ~3.5 fps...

I thought 1/2000 sec was faster than 1/50 sec, because when I listen to the shutter sound, 1/50 is definitely way faster than say, 3 second exposure...

Also then, does the 3.5 fps also mean I have to stay above ~1/30 exposure to get that 3.5 fps?

Maybe I am confused with some concept... I am still new to this, so maybe someone can explain. I don't know if Canon gear was the correct forum for this question...

Oct 13, 2008 at 06:42 AM

Ian.Dobinson
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p.1 #2 · FPS and Shutter speed

No as far as as FPS is concerened its more to do with the amount of time it takes the camera to go thru the flip mirror up, open shutter flip mirror down cycle. thats why the more expensive bodies have better mechanisms and generally have a faster FPS.

Also although as you say you tried 1/2000th it actually takes longer for the the shutter to go thru the full cycle so it gets no faster than the the x sync speed of the camera 1/200th this is because beyond that the shutter is not fully open but just sweeps a letter box across the sensor/film, and the smaller the letter box the shorter the amount of time that part of the sensor seees the light.

http://www.camerapedia.org/wiki/Focal_plane_shutter

Oct 13, 2008 at 06:59 AM

4honor
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p.1 #3 · FPS and Shutter speed

Interesting... I will have to read up on that camerapedia later, thanks!

Oct 13, 2008 at 12:52 PM

invalid2
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p.1 #4 · FPS and Shutter speed

4honor wrote:
I have an XSi, and it has the 3.5 FPS continuous shooting capability. Well, I am just a bit confused, because I am somehow relating the shutter speed to FPS...

If I shoot 1/100 exposure, doesn't that mean the shutter is open for 1/100 seconds, which means I can have theoretically 100 pictures in 1 second? I tried 1/50 and 1/2000 on my camera, and still getting the ~3.5 fps...

Oct 13, 2008 at 01:14 PM

Esquire08
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p.1 #5 · FPS and Shutter speed

Haha I wish!

The time the camera spends to take and store the picture is much longer than the shutter speed is actually open. The button must first trigger the event, mirror must move away, the exposure ensues, mirror moves back, and image processor converts the light-footprint into a digital file and stores it.

Think about it in terms of an American football game. The game itself is only 60 minutes, but takes a span of three hours to complete. There's more to the game than just the plays on the field. And like with football, there's more to continuous shooting than the exposure rate.

Oct 13, 2008 at 08:41 PM

4honor
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p.1 #6 · FPS and Shutter speed

Esquire08 wrote:
Think about it in terms of an American football game. The game itself is only 60 minutes, but takes a span of three hours to complete. There's more to the game than just the plays on the field. And like with football, there's more to continuous shooting than the exposure rate.

Heh, now that's an analogy that I can understand!

Oct 13, 2008 at 10:23 PM


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