View Full Version : shutter speed with flash question
31st of October 2005 (Mon), 19:24
I have just wrecked some good haloween photo's in my living room and need some input. With my 18-135mm lens apature at 4.5 ( one stop less than full open) and the ISO at 400 and the built in flash the shutter speed is like 1/15 to 1/8 and they all look like complete garbage. My question is this on full auto the shutter speed goes to 1/60 or 1/40 how is it dong that ? I have the same flash and almost the same apature how high will the camera put the ISO in auto? I ordered a 430 EX flash today is this thing going to help me get much better shutter speeds and what do you find to be a decent hand held protrat or snapshot shutter speed? Another question even my built n flash glares of things in photos (like the green couch or walls) with the larger flash will this be much worse or better? Thanks in advance
Signed frustrated !!!
31st of October 2005 (Mon), 19:47
It sounds like you are using the flash in AV mode to get such a slow shutter speed. In this mode the camera will set the shutter speed based on getting a correct exposure based on the background lighting levels. This is useful say if you want to get a picture of someone standing in front of a city-scape at night.
Flash photography is a little different to conventional photography. When using a flash the camera will try and deliver the correct amount of light from the flash regardless of what shutter speed, aperture, or ISO is selected. This may not be possible given the limitations on how much light the flash can give off. When you put the camera into Full Auto or "P" mode, the camera will select a nominal shutter speed usually between 1/60 and 1/200 (or 1/250 depending on the camera).
You should follow the usual rules for shutter speed when using a flash i.e. minimum of 1 / focal length to ensure no camera shake, and a speed based on the movement of the subject to prevent motion blur (i.e. faster motion shorter shutter speed). As the shutter speed increased and the aperture changes the flash will increase the amount of light output to compensate. What you will notice is that the background will become darker.
I usually use manual mode when using flash. Typical settings are around shutter: 1/100 - 1/200 and aperture f5.6 - f8ish. There is a good sticky under the flash area of the forum which will give you good information on flash photography with the EOS system. It would certainly be worth a read.
Hope this helps....
31st of October 2005 (Mon), 19:57
Flash photography is hard, and can take a while to learn. If the photo's not of people you'd probably be better off using a tripod and no flash. With people it would depend on the scene you're trying to capture, using an on-camera flash you'd usually get the "dear in the headlights" look. If you post a sample photo, even if it's bad, we could probably give you better advice.
31st of October 2005 (Mon), 21:33
I would say that the 430EX flash you ordered will vastly improve your flash photography. If nothing more than allowing bounce you will be better off but the power increase will be dramatic. Getting off auto and getting control of the camera back would help too IMO.
I have moved to shooting portraits in M. Shutter speed and f-stop dependent on background, subject, etc.
31st of October 2005 (Mon), 21:49
If I put the flash on TTC mode and use the AV mode on the camera will he flash correct for what apature I select with in reason(not like f20) and change the output of the flash to composate and with the flash on will the shutter speed increase when I meter it or will the camera still give me speed based on the ambient light? do the camera and the flash comunicate and and sink together or do I have to do it?
31st of October 2005 (Mon), 22:09
The flash doesn't have a TTC mode. It has an ETTL mode, and that's it's only mode, if it's the internal flash.
Av mode is usually used with FEC of -1 or so, when there's enough light on the background but not on the person in the foreground. Other times, when the flash is the main/only light, put the camera in M mode, choose whatever aperture you like, set the shutter to 1/200th (but experiement with this), and shoot away. The flash will go about the right brightness.
1st of November 2005 (Tue), 18:30
You are not alone. Many people (myself included) have had some problems adapting to flash on a DSLR. When I was shooting with a Canon G3, there was a setting to limit the shutter speed in AV mode so that it would never fall lower than 1/60. I suspect many of us would turn this mode on when shooting our kids outdoors (using fill flash with a 550ex) where a shutter speed might want to be 1/500 in sun and 1/30 in the shade. (Nikon has this shutter speed floor on the D70s (CF21) - and probably others.) It took me a couple of days to realize that was why I wasn't getting the results I expected.
I agree with the advice given on this thread so far - i.e. manual mode will give you the best results when used properly. The word PROPERLY is the real trick, however.
I'm not the super-experienced photographer some of the other folks are. I admit it: When using fill flash outside, I'll still go to the <<gasp>> "P" mode when the action is in-and-out of shadow too fast for me to keep up with in "M" mode.
And I believe the 430EX will become your friend.
1st of November 2005 (Tue), 20:32
When using fill flash outside, I'll still go to the <<gasp>> "P" mode when the action is in-and-out of shadow too fast for me to keep up with in "M" mode.Another option would be Tv mode with the shutter at flash-sync speed (1/200 or 1/250 depending on your camera). Change your ISO to get the aperture into a reasonable range.
1st of November 2005 (Tue), 20:54
Also a good idea, Curtis!
I've been experimenting with this: Setting it at 1/250 inside or shade and back to auto otherwise. It works well when I pay attention; horribly overexposes when I don't and I wind up shooting 1/250 in full sun. :o
My priorities seem to be:
1) Enjoy the moment (when it's a "family" thing)
2) Try to orchestrate (location of me or the subjects), frame, and fire
3) Watch the viewfinder data or chimp
Someday #3 will become part of #2 [I hope - I really, really hope]
dbiggs, if you can concentrate better than me, Curtis has a good solution.
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