Shutters peed, Exposure and other settings - is my set-up plan correct? at DVinfo.net

Alex Wren · June 14th, 2006, 05:45 AM

Hi Forum,

I am very keen to understand the best order to set-up my Canon XM1 (PAL). Having researched this forum and other resources I have reached some sort of set-up plan which I would love to hear comments on.

Excuse my ignorance in some areas - I am learning fast!

Assume camera positioned, white balanced and lighting (if needed) setup:

1. Turn optical stab off if tripod mounted

2. Turn off auto focus unless absolutely required

3. Select 'frame mode' or 'normal' (still testing best uses for each)

4. Choose shutter speed - I have a question here, if I am using PAL (25fps) should I be choosing 1/50s rather than the 1/60s that all the NTSC users are recommending on this forum? I assume that higher speeds are really only needed to create sharper footage for fast moving objects?

5. Choose aperture to offer correct exposure (using built in exposure meter), to achieve small DoF then use ND filter (if needed) to allow smaller F number to be used.

I am really trying to understand the relationship between the different combinations of shutter speed and aperture. I could do with some guidance on the reasons why I hear preferred values mentioned. Is it as simple as saying use 1/50 for... use 1/100 for ... etc or is it a bit more situation dependant?

Thanks in advance

Alex

Tom Hardwick · June 14th, 2006, 06:56 AM

OK Alex, here are my thoughts.

1) The Canon VAP OIS is one of THE very best optical stabilisers around, and you may well find you don't need to turn it off when the cam's used on a tripod. Connect your XM to a good TV and do some panning and tilting - do you see any lag or overshoot? If not, leave the OIS on, and let it take out the blips of a not2perfect tripod head.

2) The autofocus is a fast acting device, but it will zero in on the highest contrast. So the brick wall may be sharper than the face in front of it. Manual focus is best, if things aren't happening too fast around you.

3) Shoot normal footage of action, then shoot the same with frame mode. Which do you prefer? There will be slight quality losses when you use the frame mode but you may like the look (I don't).

4) Yes, use 1/50th sec. Delight in the fact that your XM2 is better in low light as well as having noticeably higher resolution than the NTSC GL2 model. Higher shutter speeds don't give 'sharper footage' as you suggest, they only cut down on motion blur.

5) Use the ND even before it's called for. Much better to shoot at f/4 than to shoot at f/8 - less DOF as well as less diffraction losses.

Remember that video cameras are designed to be used in the shutter-priority mode. If you slow the shutter speed below 1/50th you lose resolution, and if you raise it you'll head for CCD smear and get stacatto footage into the bargain.

tom.

John Miller · June 14th, 2006, 09:43 AM

The aperture setting determines the depth of field - the smaller the aperture, the more you can get in focus. But changing the aperture means you have to adjust the shutter speed to keep the amount of light constant. See http://www.cambridgeincolour.com/tut...h-of-field.htm for a discussion.

Very often, the exposure modes offered in camcorders ("helpfully" identified with little icons of a golfer or the sun setting or two heads) prioritise one setting over the other ("shutter priority mode", as Tom indicated). e.g., keep the shutter speed constant and vary the aperture as much as possible.

Tom Hardwick · June 14th, 2006, 10:49 AM

I'd modify John's conclusion slightly. Keep the shutter speed at the default setting and use the ND to keep you at f/4 or wider. You have tiny 1/4" chips, and difraction losses are very real at f/8 or smaller.

Alex Wren · June 14th, 2006, 11:38 AM

Quote:

Originally Posted by Tom Hardwick

You have tiny 1/4" chips

Thanks - nicely put...

June 14th, 2006, 05:45 AM	#1
Alex Wren Regular Crew Join Date: Nov 2004 Location: UK Posts: 161	Shutters peed, Exposure and other settings - is my set-up plan correct? Hi Forum, I am very keen to understand the best order to set-up my Canon XM1 (PAL). Having researched this forum and other resources I have reached some sort of set-up plan which I would love to hear comments on. Excuse my ignorance in some areas - I am learning fast! Assume camera positioned, white balanced and lighting (if needed) setup: 1. Turn optical stab off if tripod mounted 2. Turn off auto focus unless absolutely required 3. Select 'frame mode' or 'normal' (still testing best uses for each) 4. Choose shutter speed - I have a question here, if I am using PAL (25fps) should I be choosing 1/50s rather than the 1/60s that all the NTSC users are recommending on this forum? I assume that higher speeds are really only needed to create sharper footage for fast moving objects? 5. Choose aperture to offer correct exposure (using built in exposure meter), to achieve small DoF then use ND filter (if needed) to allow smaller F number to be used. I am really trying to understand the relationship between the different combinations of shutter speed and aperture. I could do with some guidance on the reasons why I hear preferred values mentioned. Is it as simple as saying use 1/50 for... use 1/100 for ... etc or is it a bit more situation dependant? Thanks in advance Alex

June 14th, 2006, 06:56 AM	#2
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	OK Alex, here are my thoughts. 1) The Canon VAP OIS is one of THE very best optical stabilisers around, and you may well find you don't need to turn it off when the cam's used on a tripod. Connect your XM to a good TV and do some panning and tilting - do you see any lag or overshoot? If not, leave the OIS on, and let it take out the blips of a not2perfect tripod head. 2) The autofocus is a fast acting device, but it will zero in on the highest contrast. So the brick wall may be sharper than the face in front of it. Manual focus is best, if things aren't happening too fast around you. 3) Shoot normal footage of action, then shoot the same with frame mode. Which do you prefer? There will be slight quality losses when you use the frame mode but you may like the look (I don't). 4) Yes, use 1/50th sec. Delight in the fact that your XM2 is better in low light as well as having noticeably higher resolution than the NTSC GL2 model. Higher shutter speeds don't give 'sharper footage' as you suggest, they only cut down on motion blur. 5) Use the ND even before it's called for. Much better to shoot at f/4 than to shoot at f/8 - less DOF as well as less diffraction losses. Remember that video cameras are designed to be used in the shutter-priority mode. If you slow the shutter speed below 1/50th you lose resolution, and if you raise it you'll head for CCD smear and get stacatto footage into the bargain. tom.

June 14th, 2006, 09:43 AM	#3
John Miller Major Player Join Date: Oct 2005 Location: Hillsborough, NC, USA Posts: 968	The aperture setting determines the depth of field - the smaller the aperture, the more you can get in focus. But changing the aperture means you have to adjust the shutter speed to keep the amount of light constant. See http://www.cambridgeincolour.com/tut...h-of-field.htm for a discussion. Very often, the exposure modes offered in camcorders ("helpfully" identified with little icons of a golfer or the sun setting or two heads) prioritise one setting over the other ("shutter priority mode", as Tom indicated). e.g., keep the shutter speed constant and vary the aperture as much as possible.

June 14th, 2006, 10:49 AM	#4
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	I'd modify John's conclusion slightly. Keep the shutter speed at the default setting and use the ND to keep you at f/4 or wider. You have tiny 1/4" chips, and difraction losses are very real at f/8 or smaller.