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Old Sep 28, 2004, 5:05 AM   #1
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I was wondering if anyone has much experience with the DRebels "A-Dep" mode and if so under what circumstances.

Does it keep with a constant minimum shutter speed (eg. nothing slower than ##) or does it do whatever it takes to get max DOF no matter how slow the shutter? Is focal length a factor?

I am an AV tech and at some of the events I do I would like to get some photos of people both candid and posed. Not meant to be great portraits but more like snapshots of people enjoying themselves (mostly without flash however). Might be used for something like a church scrapbook.

I wonder what kind of results I might get by handing my camera to someone and telling them to start shooting as I am usually too busy at these events to shoot pics myself. What other modes would anyone suggest for this situation?

David
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Old Sep 28, 2004, 1:19 PM   #2
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Amateur wrote:
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Does it keep with a constant minimum shutter speed (eg. nothing slower than ##) or does it do whatever it takes to get max DOF no matter how slow the shutter? Is focal length a factor?
It does not keep the shutter constant!
The last time I tried this indoor it picked f/22 and 30" so yes the picture will be blurry from camera shake. From the 10D manual: "If the camera sets a slow shutter speed, hold the camera steady or use a tripod"

-> If you turn on the flash however it will set 1/60 as minimum all the time
With a more powerful external flash like the 550EX or EF500DG Super more peripheral AF points will lit up (than say the central AF point only when used with the built-in flash)



IMO just put the camera on manual with the shutter @ 1/60 and set the smallest aperture you can get away with. In this mode the camera only uses the central area for metering with its E-TTL flash and will get all exposures correct. If you let the camera pick the AF points based on A-Dep the exposures will vary all over the place depending on where the camera decided to focus on: bright area -> underexpose - dark area -> overexpose!
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Old Sep 28, 2004, 3:34 PM   #3
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IMO just put the camera on manual with the shutter @ 1/60 and set the smallest aperture you can get away with. In this mode the camera only uses the central area for metering with its E-TTL flash and will get all exposures correct. If you let the camera pick the AF points based on A-Dep the exposures will vary all over the place depending on where the camera decided to focus on: bright area -> underexpose - dark area -> overexpose!



NHL - is this your suggestion for both no flash and an external flash? I have a digital rebel with a Sigma 500DG Super and have always used it in P or Tv mode - can I do the above and still leave the flash as ETTL or do I need to change the flash to manual mode as well?
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Old Sep 28, 2004, 3:46 PM   #4
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That's correct!

Even with the camera on manual, the flashes are still on automatic E-TTL -> this way you can adjust both the shutter and the aperture and the exposure still come out correct!
Don't forget to enable the High-Speed Sync when the shutter speed is over 1/250s though :idea:

BTW if you set the lens on manual focus (in Tv or Av), the camera will also default back to central area metering only... You can also press the FEL (Flash Exposure Lock) and it'll do the same thing, but a smaller 9% area, in all other modes



The only time you get into trouble is when you set both the camera and the flash on manual.
-> but then the Sigma will compute the distance for you (from the ISO and aperture it read from the camera):
a) You just have to decrease this distance to match the lens marking
b) Change the aperture and the distance will change
In either case the exposure will be correct as well. Who say manual flash is difficult? :?
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Old Sep 29, 2004, 3:01 AM   #5
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Thanks NHL,

Your suggestions are helpful, I will need to put in some experimentation time to fully understand - I'm not well versed with flash photography. I have the 420EX, but I prefer available light photography.

It seems you're saying that if I get the setup right I can hand the camera to someone unfamiliar with the DR and get back some correct exposures. I don't usually have time to hold school.

David
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