25p

Lawrence Stevens · October 7th, 2004, 05:19 PM

Hi
On a pal XL2, if you are shooting on 25p progressive mode, should your shutter speed be 1/25th or 1/50th of a second?

What would the difference be?

I normally shoot 1/50th when in 50i mode.

Regards
Lawrence

Barry Green · October 7th, 2004, 06:17 PM

1/50th will simulate the film look.

1/25th will add a lot of motion blur, but also give you an additional f-stop of light sensitivity.

David Lach · October 7th, 2004, 10:42 PM

1/25th can give you a very nice smooth (but blurry) look on very fast pans. It can eliminate the jerkiness of the movement that occurs when moving too fast in progressive mode with a shutter speed set at 1/48th or 1/50th.

If you know how to use it, you can get pretty good results out of it. Thing to remember is, when shooting with a slow shutter speed (which should only be for very specific uses), you need to either move fast or not move at all. Because a little amount of movement, like the one you would get on a handheld shot, will give the impression you're watching the image while being drunk.

Experiment with both settings and see the difference by yourself, but the normal setting should be 1/50th.

Marty Hudzik · October 8th, 2004, 08:41 AM

I don't know for sure if it is possible on the XL2 but on the original DVX you could go into the sync scan mode (designed to match refresh rate and shutter speed for filming CRT type monitors) and actually set the shutter to 1/36 which is halfway between 1/48 and 1/24. SoOme people used this to eliminate some of the strobing without getting that "drunken" blur look. I never did but I have heard of many others.

While the XL2 has a "sync scan" type of mode, I am not sure what shutter speeds you can reach in 24P mode.

FWIW

Daniel von Euw · October 9th, 2004, 03:33 AM

In the Pal-Version the "sync scan" goes from 50 to 200.

regards
Daniel

Marty Hudzik · October 9th, 2004, 02:39 PM

<<<-- Originally posted by Daniel von Euw : In the Pal-Version the "sync scan" goes from 50 to 200.

regards
Daniel -->>>

So in 24P NTSC it is probably only capable of 1/48.

Oh well.

Lawrence Stevens · October 10th, 2004, 07:42 AM

Ok it seems to be as i thought

If you shoot at 50i (mine is a PAL vesrion) and drop the shutter pseed to 1/25th, then it increases the 'blur'.

Fine

If however you are shooting 25p, then the camera is moving as slow as if you had 1/25th shutter, so if you put the camera from 1/50thto 1/25th shutter, the is no increase in 'blur'

I think this is confirmed, as in the XL2 viewfinder, there is an LED that lights up whenever the shutter speed is not at a standard setting. i.e if it is not 1/50th in 50i mode, it lights up.

Now in 25p mode, it only stays UNLIT when you use 1/25th.

So it seems going from 1/50th to 1/25th in 25p mode will not add any extra 'blur', but will instead give you an extra stop. If I am not mis-understanding this, then the camera can be set to be more sensitive to light in 25p mode without degrading image. This is great is it not?

Lawrence

David Lach · October 10th, 2004, 09:26 AM

Lawrence, regardless of whether you shoot 50i or 25p, slowing down the shutter from 1/50th to 1/25th will definitelly increase motion blur. I don't know why the XL2 is set at 1/25th by default for 25p, but this isn't the way to go for normal use. Film runs at 1/48th shutter speed in normal use (180° shutter blades) and it records 24p. And as you can probably tell, there's a lot of motion blur in film.

Think of it this way:

If you use the 25p mode and use a 1/25th shutter speed, that means that each image is exposed 0.04 of a second. If you use 1/50th, each frame is exposed 0.02 of a second. Since you photograph movement, the image will expose the CCD during the laps determined by the shutter speed and every variation in position in the shot, whether subjet or camera, will be recorded on one single frame, rather than deconstructed over many frames. Exposing each frame during 0.04 seconds will create a lot of motion blur, unless both your camcorder and your subject are dead still. Test it for yourself and you'll see the difference.

October 7th, 2004, 05:19 PM	#1
Lawrence Stevens Regular Crew Join Date: Apr 2004 Location: London, UK Posts: 67	25p - 1/25th or 1/50th Hi On a pal XL2, if you are shooting on 25p progressive mode, should your shutter speed be 1/25th or 1/50th of a second? What would the difference be? I normally shoot 1/50th when in 50i mode. Regards Lawrence __________________ Canon XL2 Vinten Vision 3 tripod Own Build High End PC with RT.X100

October 10th, 2004, 07:42 AM	#7
Lawrence Stevens Regular Crew Join Date: Apr 2004 Location: London, UK Posts: 67	Ok it seems to be as i thought If you shoot at 50i (mine is a PAL vesrion) and drop the shutter pseed to 1/25th, then it increases the 'blur'. Fine If however you are shooting 25p, then the camera is moving as slow as if you had 1/25th shutter, so if you put the camera from 1/50thto 1/25th shutter, the is no increase in 'blur' I think this is confirmed, as in the XL2 viewfinder, there is an LED that lights up whenever the shutter speed is not at a standard setting. i.e if it is not 1/50th in 50i mode, it lights up. Now in 25p mode, it only stays UNLIT when you use 1/25th. So it seems going from 1/50th to 1/25th in 25p mode will not add any extra 'blur', but will instead give you an extra stop. If I am not mis-understanding this, then the camera can be set to be more sensitive to light in 25p mode without degrading image. This is great is it not? Lawrence __________________ Canon XL2 Vinten Vision 3 tripod Own Build High End PC with RT.X100

October 7th, 2004, 06:17 PM	#2
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	1/50th will simulate the film look. 1/25th will add a lot of motion blur, but also give you an additional f-stop of light sensitivity.

October 7th, 2004, 10:42 PM	#3
David Lach Major Player Join Date: Oct 2002 Location: Montreal, QC, Canada Posts: 570	1/25th can give you a very nice smooth (but blurry) look on very fast pans. It can eliminate the jerkiness of the movement that occurs when moving too fast in progressive mode with a shutter speed set at 1/48th or 1/50th. If you know how to use it, you can get pretty good results out of it. Thing to remember is, when shooting with a slow shutter speed (which should only be for very specific uses), you need to either move fast or not move at all. Because a little amount of movement, like the one you would get on a handheld shot, will give the impression you're watching the image while being drunk. Experiment with both settings and see the difference by yourself, but the normal setting should be 1/50th.

October 8th, 2004, 08:41 AM	#4
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	I don't know for sure if it is possible on the XL2 but on the original DVX you could go into the sync scan mode (designed to match refresh rate and shutter speed for filming CRT type monitors) and actually set the shutter to 1/36 which is halfway between 1/48 and 1/24. SoOme people used this to eliminate some of the strobing without getting that "drunken" blur look. I never did but I have heard of many others. While the XL2 has a "sync scan" type of mode, I am not sure what shutter speeds you can reach in 24P mode. FWIW

October 9th, 2004, 03:33 AM	#5
Daniel von Euw Regular Crew Join Date: Jul 2004 Location: Köln, NRW, Germany Posts: 70	In the Pal-Version the "sync scan" goes from 50 to 200. regards Daniel

October 9th, 2004, 02:39 PM	#6
Marty Hudzik Trustee Join Date: Jul 2004 Location: Canton, Ohio Posts: 1,771	<<<-- Originally posted by Daniel von Euw : In the Pal-Version the "sync scan" goes from 50 to 200. regards Daniel -->>> So in 24P NTSC it is probably only capable of 1/48. Oh well.

October 10th, 2004, 09:26 AM	#8
David Lach Major Player Join Date: Oct 2002 Location: Montreal, QC, Canada Posts: 570	Lawrence, regardless of whether you shoot 50i or 25p, slowing down the shutter from 1/50th to 1/25th will definitelly increase motion blur. I don't know why the XL2 is set at 1/25th by default for 25p, but this isn't the way to go for normal use. Film runs at 1/48th shutter speed in normal use (180° shutter blades) and it records 24p. And as you can probably tell, there's a lot of motion blur in film. Think of it this way: If you use the 25p mode and use a 1/25th shutter speed, that means that each image is exposed 0.04 of a second. If you use 1/50th, each frame is exposed 0.02 of a second. Since you photograph movement, the image will expose the CCD during the laps determined by the shutter speed and every variation in position in the shot, whether subjet or camera, will be recorded on one single frame, rather than deconstructed over many frames. Exposing each frame during 0.04 seconds will create a lot of motion blur, unless both your camcorder and your subject are dead still. Test it for yourself and you'll see the difference.