Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon EOS dSLR

Reply
 
Thread Tools Search this Thread
Old Apr 1, 2007, 6:35 PM   #1
Senior Member
 
Join Date: Dec 2005
Posts: 185
Default

on page 72 of the manual it says that when using flash with a-dep the desired depth of field will not be obtained. i am referring to the rebel xti. can somebody please tell me why? thanks
camerageak is offline   Reply With Quote
Sponsored Links
Old Apr 7, 2007, 1:41 PM   #2
Senior Member
 
Michi's Avatar
 
Join Date: Jul 2003
Posts: 176
Default

I don't own the XTi, but I would guess that A-DEP and flash photography don't really go together. With a single flash unit, only something at a certain distance will be exposed properly, the rest will be under or over exposed. So while everything between two certain distances may be in focus (probably using a pretty small aperture), most of that will not be exposed properly.

I'm guessing that Canon programmed the camera so that it will override the A-DEP function in order to achieve proper exposure.

If you still need a certain depth of field, you will probably have to set the speed and aperture in M, and then play with the flash settings.
Michi is offline   Reply With Quote
Old Apr 8, 2007, 8:09 PM   #3
Senior Member
 
Join Date: Dec 2005
Posts: 185
Default

i called canon and they told me pretty much what you said . they told me a flash may not cover the range for the d.o.f so the a-dep is disabled when a flash is attached.
camerageak is offline   Reply With Quote
Old Apr 8, 2007, 9:22 PM   #4
Senior Member
 
Join Date: Sep 2005
Posts: 734
Default

In a group shot, A-DEP is to get a all the subjects sharp, basically it selects an appropriate aperture to acheive that, at the same time it refers to that aperture to select the shutter speed, if you have less than perfect lighting, you need to increase the ISO in order for the camera tochoose a fast enough shutterspeed for you.The same as you take picture of a bunch of flowers, all the flowers will be sharp. In a bunch of flowers, you can see in the viewfinder info it stops down the lens alot such as f11, so the shutter speed can be very low, often at 1/30 sec,with ISO 400in heavy cloudy late afternoon, you need to increase the ISO more, unless you have bright sunshine.

It's like A-DEP does half the job for you instead of guessing in M mode or Av mode, all you have to do is to choose the ISO.

That's why when you select A-DEP while in one point focus, A-DEP will swicth to 9 point focus automatically, those activated focus points will pick up any subject within that diamond shape.When you get out ofA-DEP by switchingto any other mode as M mode, the one point focuswill returnback.
coldshot 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 4:12 AM.