Any difference between tv and aperture? at DVinfo.net

Gary Douglas · May 12th, 2009, 08:53 PM

When I use TV, if I magnify to the cameras capacity the f stop changes from 1.8 to 2.8.

Other than not being able to control the f stop doing this is there any fundamental difference between the TV and Ae mode?

and also
If exp + is adding gain, what is exp - doing? Closing the iris? Thus changing the shutter speed value right?
Sometimes it seems the camera is bringing the shutter speed down as opposed to adding sensor gain aswell, is this correct?

Gary Douglas · May 12th, 2009, 11:27 PM

Another thing
Does cinemode stay consistant. I set the exposure but when zooming in and out the shutter speed and f stop are constantly changing.

Alan Craven · May 13th, 2009, 12:00 AM

Using "Tv mode", which is better described as shutter priority, you set the desired shutter speed, the camera selects an appropriate aperture for correct exposure. It will also increase gain in poor light.

Using Av mode, which is better described as aperture priority, you select the desired aperture, and the camera then selects an appropriate shutter speed for correct exposure.

The camera also rotates a variable neutral density filter in the light path to avoid extremes of aperture in Tv, or shutter speed in Av.

If you have an SD card in the camera, half pressing the PHOTO button with exposure lock selected via the joystick will show you what the selected aperture and shutter speed are.

Ray Bell · May 13th, 2009, 04:59 AM

Quote:

Originally Posted by Gary Douglas

Another thing
Does cinemode stay consistant. I set the exposure but when zooming in and out the shutter speed and f stop are constantly changing.

This is normal for most cameras when you zoom in or out.... it just means that the lens
is not a constant aperture lens with zoom.

Gary Douglas · May 13th, 2009, 11:46 PM

aRghh this camera is a nightmare.
Whats the deal with me setting f2.8 it adding 9db without me even touching gain and then me filming in the exact same conditions a day later and it filming with 0db?

Another thing. If I have exp set on, the gain levels won't change, the image will stay consistantly at the same settings right?

Nick Gordon · May 18th, 2009, 11:51 AM

The camera defaults to auto, and takes its best guess at what's needed to get the best exposure. If you fix shutter and aperture, it will move gain around to try to get it right.

Check the manual - there is a way to fix everything - gain, shutter, aperture. Can't remember what it is.

It's a consumer camera; slightly illogically, you generally have to pay more money to get a camera that makes you do it all yourself.

Luke Gates · May 29th, 2009, 02:49 PM

Quote:

Originally Posted by Ray Bell

This is normal for most cameras when you zoom in or out.... it just means that the lens
is not a constant aperture lens with zoom.

Yes! Its the same as a standard slr lens being 55-200mm zoom with a minimum f-stop of 3.5-4.8 As you zoom through the lens, it cannot be open as much. Only the $1000+ lenses have zoom above 200mm and maintain an f-stop of 2.8 all the way through.

May 12th, 2009, 08:53 PM	#1
Gary Douglas Regular Crew Join Date: Feb 2008 Location: Lancashire Posts: 40	Any difference between tv and aperture? When I use TV, if I magnify to the cameras capacity the f stop changes from 1.8 to 2.8. Other than not being able to control the f stop doing this is there any fundamental difference between the TV and Ae mode? and also If exp + is adding gain, what is exp - doing? Closing the iris? Thus changing the shutter speed value right? Sometimes it seems the camera is bringing the shutter speed down as opposed to adding sensor gain aswell, is this correct?

May 12th, 2009, 11:27 PM	#2
Gary Douglas Regular Crew Join Date: Feb 2008 Location: Lancashire Posts: 40	Another thing Does cinemode stay consistant. I set the exposure but when zooming in and out the shutter speed and f stop are constantly changing.

May 13th, 2009, 12:00 AM	#3
Alan Craven Major Player Join Date: May 2003 Location: York, England Posts: 518	Using "Tv mode", which is better described as shutter priority, you set the desired shutter speed, the camera selects an appropriate aperture for correct exposure. It will also increase gain in poor light. Using Av mode, which is better described as aperture priority, you select the desired aperture, and the camera then selects an appropriate shutter speed for correct exposure. The camera also rotates a variable neutral density filter in the light path to avoid extremes of aperture in Tv, or shutter speed in Av. If you have an SD card in the camera, half pressing the PHOTO button with exposure lock selected via the joystick will show you what the selected aperture and shutter speed are.

May 13th, 2009, 11:46 PM	#5
Gary Douglas Regular Crew Join Date: Feb 2008 Location: Lancashire Posts: 40	aRghh this camera is a nightmare. Whats the deal with me setting f2.8 it adding 9db without me even touching gain and then me filming in the exact same conditions a day later and it filming with 0db? Another thing. If I have exp set on, the gain levels won't change, the image will stay consistantly at the same settings right?

May 18th, 2009, 11:51 AM	#6
Nick Gordon Regular Crew Join Date: Mar 2008 Location: Milton Keynes, UK Posts: 166	The camera defaults to auto, and takes its best guess at what's needed to get the best exposure. If you fix shutter and aperture, it will move gain around to try to get it right. Check the manual - there is a way to fix everything - gain, shutter, aperture. Can't remember what it is. It's a consumer camera; slightly illogically, you generally have to pay more money to get a camera that makes you do it all yourself.