shutter speed & ASA questions at DVinfo.net

Leonard Levy · April 1st, 2010, 10:18 PM

I imagine these questions have been asked before but I can't find the answers so please bear with me.

I just bought a T2i so these questions are best suited to the T2i or the 7D.

When do you feel you start to see noise in the ASA rating? Is 1600 still clean?
Can you see the difference between 800 & 1600?.
How bad is 3200?
Could you compare them to noise levels say on an EX-1 in gain?

Likewise what shutter speeds work OK.
Is 1/30 or 1/25 any worse on the Canon then it is on the EX-1?
I will use those speeds if I need the stop on an EX-1 or HVX. Is it equally OK on the canon?
what about shorter speeds like 1/100 and shorter. I've heard that you can get bad choppy movement as you shorten the shutter speed.

Oh yeah - one more. I'm running a picture setting with contrast and sharpness all the way down. Is that pretty typical? - will you need to add some sharpness back later?

Thanks -

Lenny Levy

Bill Pryor · April 2nd, 2010, 09:14 AM

You should do some tests to see for yourself what's acceptable. Some people shoot at 1250 all the time and like it. I shoot most things at 100 or 160 and on occasion 320, and did one shot at 640, which looked fine.

Shutter speed for 24p video should always be 1/50 (since the camera doesn't have 1/48). Just as with any video camera, a different shutter speed will cause different things to happen, like blurring or strobing. Using shutter speed on a video camera to adjust exposure is generally not done if there is anything moving in the shot. Most small video cameras start showing noise levels at around +6 db gain. On some cameras a +9 might be OK but +12 is usually pretty noisy. The 7D will allow you to crank up the ISO to gain more stops than a traditional small video camera before you start seeing problems. But what's acceptable and what's not is in the eye of the beholder. Depends on the project, what other shots it intercuts with, etc.

Norman Pogson · April 2nd, 2010, 10:40 AM

I have shot 1600 iso on the 7D and was very pleased and surprised by the results. Unless you are doing special effects such as "Saving Private Ryan" type effects, just double your fps for a shutter speed.

The T2i/550 misses out on some of the iso steps that the 7D has, so the choices are more limited with the T2i and some have said the iso that are missing are the least nosiest choices on the 7D.

April 1st, 2010, 10:18 PM	#1
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	shutter speed & ASA questions I imagine these questions have been asked before but I can't find the answers so please bear with me. I just bought a T2i so these questions are best suited to the T2i or the 7D. When do you feel you start to see noise in the ASA rating? Is 1600 still clean? Can you see the difference between 800 & 1600?. How bad is 3200? Could you compare them to noise levels say on an EX-1 in gain? Likewise what shutter speeds work OK. Is 1/30 or 1/25 any worse on the Canon then it is on the EX-1? I will use those speeds if I need the stop on an EX-1 or HVX. Is it equally OK on the canon? what about shorter speeds like 1/100 and shorter. I've heard that you can get bad choppy movement as you shorten the shutter speed. Oh yeah - one more. I'm running a picture setting with contrast and sharpness all the way down. Is that pretty typical? - will you need to add some sharpness back later? Thanks - Lenny Levy

April 2nd, 2010, 10:40 AM	#3
Norman Pogson Regular Crew Join Date: Feb 2010 Location: Ottawa, Canada Posts: 140	I have shot 1600 iso on the 7D and was very pleased and surprised by the results. Unless you are doing special effects such as "Saving Private Ryan" type effects, just double your fps for a shutter speed. The T2i/550 misses out on some of the iso steps that the 7D has, so the choices are more limited with the T2i and some have said the iso that are missing are the least nosiest choices on the 7D. __________________ My Stock Video Blog Linkedin

April 2nd, 2010, 09:14 AM	#2
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	You should do some tests to see for yourself what's acceptable. Some people shoot at 1250 all the time and like it. I shoot most things at 100 or 160 and on occasion 320, and did one shot at 640, which looked fine. Shutter speed for 24p video should always be 1/50 (since the camera doesn't have 1/48). Just as with any video camera, a different shutter speed will cause different things to happen, like blurring or strobing. Using shutter speed on a video camera to adjust exposure is generally not done if there is anything moving in the shot. Most small video cameras start showing noise levels at around +6 db gain. On some cameras a +9 might be OK but +12 is usually pretty noisy. The 7D will allow you to crank up the ISO to gain more stops than a traditional small video camera before you start seeing problems. But what's acceptable and what's not is in the eye of the beholder. Depends on the project, what other shots it intercuts with, etc.