Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old May 13, 2009, 12:10 PM   #1
Senior Member
 
Join Date: Jun 2004
Posts: 629
Default av or tv priority

When shooting outdoors with subjects that are not on the move, am I better off shooting with av priority or tv priority?

I know the ultimate answer is probably "Neither" and go to full program mode on my Canon XSi. But my skill set as a photographer isn't there yet.

I'm shooting with either a 24-70 2.8 lens or a 70-200 2.8 lens.

Thanks
FaithfulPastor is offline   Reply With Quote
Sponsored Links
Old May 13, 2009, 12:34 PM   #2
Senior Member
 
rjseeney's Avatar
 
Join Date: Dec 2004
Location: Taylor Mill, Kentucky
Posts: 2,398
Default

I rarely shoot on shutter priority. Shooting on AV allows you to control depth of field, and more importantly control the amount of light entering the camera. You'll immediately see if the shutter speed is too slow to freeze the action and you can then raise the iso if necessary. Shooting in shutter priority, it's too easy to get underexposures, as the camera will select the largest aperture available which may or may not result in the correct exposure. Some camera's will tell you the the exposure is correct, but for me, just shooting in aperture priority is easier and more intuitive.

Shooting in bright light makes the option a little less clear, as it's easier to get correct exposures with fast shutter speeds, but i'd still rather have direct control over DOF.
rjseeney is offline   Reply With Quote
Old May 13, 2009, 12:47 PM   #3
Moderator
 
Join Date: Aug 2004
Posts: 8,529
Default

I agree - for the same reasons rjseeney mentioned. The only time I ever use shutter priority is when I want a shot that shows motion blur (prop of an airplane for instance).
Remember though if you're shooting portrait type work outdoors, flash is still a critical instrument. Your external flash should have high speed synch - this is it's purpose - so you can shoot at shutter speeds above synch speed and still be able to use the flash for fill.
JohnG is offline   Reply With Quote
Old May 13, 2009, 12:51 PM   #4
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

There really isn't much difference. In Av, you use the Main Dial to select the aperture, and the autoexposure system picks the shutter speed. In Tv, you use the Main Dial to select the shutter speed, and the autoexposure system picks the aperture. The result is the same. In practice, the only difference is which indicator has the Main Dial pointer.
TCav is offline   Reply With Quote
Old May 13, 2009, 1:56 PM   #5
Moderator
 
Join Date: Aug 2004
Posts: 8,529
Default

Quote:
Originally Posted by TCav View Post
In Tv, you use the Main Dial to select the shutter speed, and the autoexposure system picks the aperture. The result is the same. In practice, the only difference is which indicator has the Main Dial pointer.
I guess I disagree. It's possible to get to the same answer in all three modes but "the results are the same" assumes you started from the same place.

For example, let's say you're in TV mode and dial in 1/500 and the camera selects f5.6 as the aperture.

You only get that same result in AV mode if you start at f5.6.

And, for that matter, let's assume you do start out that way. You then take 3 photos as your subject re-positions themselves. Each time their pose is 1 stop less exposure.
2nd shot in TV mode is 1/500 f4.0
2nd shot in AVMODE IS 1/250 f5.6
3rd shot in TV mode is 1/500 f2.8
3rd shot in AV mode is 1/125 f5.6

Same exposures in each pairing but Completely different photos.

AV and TV mode assume you only care about 1 of the 2 variables.
JohnG is offline   Reply With Quote
Old May 13, 2009, 2:47 PM   #6
Senior Member
 
rjseeney's Avatar
 
Join Date: Dec 2004
Location: Taylor Mill, Kentucky
Posts: 2,398
Default

Quote:
Originally Posted by TCav View Post
There really isn't much difference. In Av, you use the Main Dial to select the aperture, and the autoexposure system picks the shutter speed. In Tv, you use the Main Dial to select the shutter speed, and the autoexposure system picks the aperture. The result is the same. In practice, the only difference is which indicator has the Main Dial pointer.
The problem is, you'll typically want more control over DOF. Say you're shooting a group. You'll want greater DOF to make sure everyone is in focus. Why play around with adjusting shutter speeds to get the aperture you want when you can select it directly and if necessary adjust the iso. Same thing for a portrait or landscape....it's more intuitive to start with aperture and change Iso as needed, than to start with shutter, then changing it to get the correct aperture, and possibly still needing to adjust ISO. Even when shooting moving objects, especially in lower light, just selecting shutter speed could easily result in underexposures because even if there is not enough light, the camera will still just select the largest aperture.
rjseeney is offline   Reply With Quote
Old May 13, 2009, 2:51 PM   #7
Senior Member
 
Join Date: Jun 2004
Posts: 629
Default

Part of the reason I'm asking this is because I posted some photos (People section: My bride and my mother in law) and I was hoping you guys would take a look at those (I also posted the exif info) and tell me why my bride looks so washed out.

Can you help me out?
FaithfulPastor is offline   Reply With Quote
Old May 13, 2009, 3:44 PM   #8
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

Quote:
Originally Posted by JohnG View Post
I guess I disagree. It's possible to get to the same answer in all three modes but "the results are the same" assumes you started from the same place.

For example, let's say you're in TV mode and dial in 1/500 and the camera selects f5.6 as the aperture.

You only get that same result in AV mode if you start at f5.6.

And, for that matter, let's assume you do start out that way. You then take 3 photos as your subject re-positions themselves. Each time their pose is 1 stop less exposure.
2nd shot in TV mode is 1/500 f4.0
2nd shot in AVMODE IS 1/250 f5.6
3rd shot in TV mode is 1/500 f2.8
3rd shot in AV mode is 1/125 f5.6

Same exposures in each pairing but Completely different photos.

AV and TV mode assume you only care about 1 of the 2 variables.
I'll concede that. Thank you.
TCav is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 9:16 AM.