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...

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

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

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... 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...

I think you would find http://www.dpreview.com/reviews/canoneos40d/page13.asp an interesting read, though it deals with the 40d, not your camera.

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.

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!