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Old Feb 3, 2004, 2:22 PM   #1
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Default Speedlite 420EX, 10D and Full Auto

Just to add to the flash discussions of late, I sent my non-expert partner with our 10D to a trade show in Vegas. I set the camera up on full auto, since he's not a tinkerer like me. I also told him he might want to use the Speedlite since he would be taking some shots of people from many feet away.

Granted, trade shows are fairly well lit, but I thought the flash would help. Well, with the 10D on auto (green square) and the flash on the green dot, his shots were way off. It picked ISO of 400 and some of the shutter speeds were as low as 1/6!

Needless to say, those shots have quite a bit of streaking from being hand-held. He reshot some images using the bult-in flash and they came out just fine (ISO 100 @ 1/60).

I'm really struggling to learn how to utilize this flash. What can anyone add on top of what I learned from the previous threads?

Thanks.

Alex


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Old Feb 3, 2004, 6:27 PM   #2
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In Auto mode, the camera will provide a flash speed of at least 1/60 sec. If you got some with slower speeds, either he inadvertently moved out of auto into Av mode or the flash didn't fire for whatever reason. Also, the camera doesn't choose ISO, that's a function set by the user.
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Old Feb 3, 2004, 9:11 PM   #3
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Default Re: Speedlite 420EX, 10D and Full Auto

Quote:
Originally Posted by Alex Campuzano
... I also told him he might want to use the Speedlite since he would be taking some shots of people from many feet away... Granted, trade shows are fairly well lit, but I thought the flash would help. Well, with the 10D on auto (green square) and the flash on the green dot, his shots were way off...
When he just turned the flash on for the 1st time, and did not wait for the green ready light, the camera will use a lower speed and only switch to 1/60s when the flash is readied on auto (green square)... Also it could be that he was taking pictures too fast between shots (the people were far away) and the flash had not time to recharge in which case the shutter speed will again default to the slower ambient exposure until the flash has completely recycled and readied again!

BTW ohenry is correct the ISO has nothing to do with flash... and has to be activated manually from a menu selection.
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Old Feb 3, 2004, 9:56 PM   #4
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Oh yeah....I didn't even think about the flash not being ready to flash. Good point, NHL.

Sometimes the obvious stares us right in the face and we don't even notice
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Old Feb 4, 2004, 10:57 AM   #5
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Default Speedlite

Mmmmm, maybe I'm wrong. I just cranked up the 10D and put it in full auto. I hit the drive-iso button, and the only thing I can change is the single shot or the timer - not the ISO. The thumb wheel on the back does not change anything in this mode... for me.

I went back and looked at some of my earlier shots I took in FA and did seem some fluctuation in ISO. Numbers like 125, 200 and 400. I gurantee you my friend wouldn't know the first thing about changing the ISO. The EXIF data tells me he did shot in FA.

I also thought of the flash not being at full strength, so I took 4 shots within 6 sec. with the Speedlite and got perfect exposures at ISO 100. Go figure. Does the EXIF show if an external flash was used in a shot? All I see is "Flash did not fire." but I thought that just meant the built-in flash since the big boy was connected.

Thanks for all your advice!!!

Alex
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Old Feb 4, 2004, 11:12 AM   #6
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Well, a little research goes a long way. The camera does indeed automatically select ISO between 100-400 when in the Basic Auto mode. Learn something new every day. I never put mine in any of the basic modes, so I had to look it up.

EXIF records both the internal and external flash firing.

I have no explaination for the low shutter speeds.
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Old Feb 4, 2004, 11:39 AM   #7
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Quote:
I also thought of the flash not being at full strength, so I took 4 shots within 6 sec. with the Speedlite and got perfect exposures at ISO 100. Go figure. Does the EXIF show if an external flash was used in a shot?
Did you try this is the dark and "far away" subjects? Also at wide angle the GN is less depleting the flash capacity faster... and take the flash longer to recharge: you will see the change to the slower shutter speed between charge. The EXIF will show the flash status, and when it's 1/2 charged, it could still fire but not at full capacity!

The Auto ISO in the Basic zone is kind of interesting though OHenry, good findings... :P
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Old Feb 4, 2004, 1:52 PM   #8
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At full auto mode, the camera will select the synchro speed at 1/60 or faster depending on the lighting condition (at this mode, flash light source will dominate the scene which requires 100% flash coverage), it does the same with ISO setting if ISO was set on auto (prefers to select higher ISO setting at low light). You need to set ISO manually if you donít want the camera to override that. To avoid the under-exposure when flash was not at full charge, do not shoot until you see the flash ready light appears on the viewfinder (press the shutter half way, refer to you manual instructions), or the ready light turns green on the flash unit. The slow synchro mode only happens when you shoot in AV mode, or you intend to set at slow shutter speed in TV mode. If slower shutter speed was selected in full auto mode, your flash was not ready at the time he took the shot; most pictures will result in underexposure. If subject is far away, dark scene, wide-angle shot, which requires the flash to fire at full power, it will take longer time for the flash to recycle, and also depending on the condition of the batteries too.
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Old Feb 4, 2004, 2:24 PM   #9
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Quote:
At full auto mode, the camera will select the synchro speed at 1/60 or faster depending on the lighting condition...
tuanokc

Do this in a darkened room on Auto mode (green square)... 1/60s is only selected when the flash is fully charged! Press the test button on the external flash to discharge the unit manually, the camera will switch to a lower shutter speed until the flash is recharged -> if anyone takes a picture before the flash is readied the shutter speed is defaulted to the ambient lighting, ie lower than 1/60s if the room is dark enough even with the external flash remaining on, ie the picture will be exposed properly but with streak because of camera shake and incomplete flash!
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Old Feb 4, 2004, 4:11 PM   #10
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NHL

I'm saying the same thing you said, that why I do not recommend to shoot when the flash is not fully charge, to verify this, the photographer has to confirm the flash ready light is on in the viewfinder or on the flash unit. and yes, the camera will swicth back to is ambient metering mode if the flash is not fully charge, the only different is: when you shoot, the flash will go off even it's not ready, and therefore result in underexposure...
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