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Photography Question 
Donna L. Jones
BetterPhoto Member Since: 4/22/2002
 

Flash


I have a Canon D30 and a Canon Speedlite 580EX. When I set it to TTL and auto on the camera everything comes out underexposed at wide or normal but well exposed if I zoom in . I'm on my way tomorrow to photo a reception in Colorado so I went to the local camera store. They say it's just the way it is because the flash tries to read the ambient light and I have to always zoom in close. WHAT? That can't be true with a $500.00 flash...can it? We changed the white balance to auto from flash and that helped a little. Set 400 ISO..Still underexposes...Can anyone help me???? Thanks, Donna Jones


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12/30/2008 5:26:08 PM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  First, make sure the LCD panel on the 580EX has "ETTL" in the upper left, and not "TTL". I think it should automatically set for E-TTL when mounted to your camera, but if it has been changed to TTL via the mode button, or if it is not making a good connection with all the contacts in the hotshoe, then the flash exposure will be wrong.

Also make sure that the 580EX's custom function C.Fn03 = 0 for E-TTL operation. If set to 1 (TTL).

Just for clarification, D30 (circa 2000-2002) or 30D (c. 2006-2007)? If D30, that camera has an early implimentation of E-TTL auto flash exposure for digital. Because of the limited dynamic range of the sensor, it goes out of its way to avoid overblown highlights, so if there are bright reflections or lights in the frame it will fire the flash at a lower output than many users expect or like. The camera might be seeing these "hot spots" in a scene when zoomed wide, but zooming in elimates them. Similar with brides in white dresses. Solution is to apply Flash Exposure Compensation (FEC), set either on the D30 (works only in P, Av, Tv, M modes) or on the 580EX.

If 30D, this camera has the improved E-TTL II auto flash metering, which is better but still can be fooled. The 30D includes a custom function, C.Fn-14, that can change the flash metering from E-TTL to Average which is less sensitive to avoiding highlights.


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12/31/2008 8:16:38 AM

 
Donna L. Jones
BetterPhoto Member Since: 4/22/2002
  Thanks for the tips Jon. I do have the 30D and I made the custom function change you mentioned on the flash. Also made the change to CFn14 on the 30D. The flash still won't put out enough light. It's amazing. I could stand 10 feet away at the wedding and get a badly underexposed print of a group but zoom in to one person at 200mm and it's perfectly exposed. I have the Tamron VC 18-270 lense....I have a job doing a school function Jan. 24 but may have to have them get someone else. I just cannot get it to work. I don't recall having this problem in the past...I'm at a loss and the local camera shop is too..any other ideas?


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1/6/2009 10:24:35 PM

 
Jon Close
BetterPhoto Member Since: 5/18/2000
  Weird. Do you have samples? One wide of the group that's underexposed and another zoomed in on one person in that group where the exposure is right? Incl. ISO, aperture and shutter speed.

In the meantime, as a workaround the problem, try zooming in on the one person, do Flash Exposure Lock, then zoom out to take the shot. For this to work you'll probably have to fix the 580EX's zoom setting to 28mm so that it (and the power output) doesn't change with the lens zoom.


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1/7/2009 6:45:10 AM

 
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