Flash exposure - Am I missing something??
Discussion
I'm using a Canon 450D with a 580EXII flash. Is there a setting to tell it not to expose for the background?
If I put it in aperture priority, I get shots ruined because it's staying open for ages to capture the background.
If I put it in shutter priority, I can force the time of the exposure, but then it shoots everything wide open.
The only way I can get a shot properly exposed on my subject at high speed without it trying to expose for the background is to run everything on manual using trial and error which, it seems to me, rather defeats the whole point of eTTL and all that.
If I put it in aperture priority, I get shots ruined because it's staying open for ages to capture the background.
If I put it in shutter priority, I can force the time of the exposure, but then it shoots everything wide open.
The only way I can get a shot properly exposed on my subject at high speed without it trying to expose for the background is to run everything on manual using trial and error which, it seems to me, rather defeats the whole point of eTTL and all that.
Simpo Two said:
What are you trying to choot?
(I mean shoot, duh)
It's a general question, really. Could be an insect, could be the kids, could be people at a party. Just anything where I'm only bothered about properly lighting the subject and their immediate surroundings, and couldn't care less about the background which is probably just clutter anyway.(I mean shoot, duh)
Edited by Simpo Two on Friday 2nd April 09:58
Ah, I wondered if the background was very dark.
I use fill flash (iTTL in Nikonspeak which I think is the same as your eTTL) and apart from using a little flash compensation now and then, it works very well.
Wild hunch - are you using spot metering? On a Nikon this disables fill flash. Time to check all your settings and menus possibly. High ISO can also lead to raging overexposure.
I use fill flash (iTTL in Nikonspeak which I think is the same as your eTTL) and apart from using a little flash compensation now and then, it works very well.
Wild hunch - are you using spot metering? On a Nikon this disables fill flash. Time to check all your settings and menus possibly. High ISO can also lead to raging overexposure.
Edited by Simpo Two on Friday 2nd April 10:06
On my 5D there is a custom function which lets you set the shutter speed set by the camera when shooting with a Speedlite in Av mode. I don't know if there something similar on a 450D, but RTFM about the custom functions and check. (I'd expect it to have it - I think that custom function has been on every EOS I've used ever since the EOS10 35mm camera.) Incidentally, E-TTL should work fine in Manual exposure mode - the actual shutter exposure shouldn't affect the flash exposure. As you are discovering, it will only affect the background.
FWIW ...
My primary flash experience goes back a few decades using a Metz unit that exposed according to the settings you dialled into it (usually the same as the camera unless bouncing) and 35mm bodies with no eTTL type functionality to speak of. Never had much of a problem with the exposures unless I forgot to set the correct settings.
A couple of years ago I rented a 580 EX II for a weekend and attempted to work out how to use it on a 400D. Then I found the manual on line and attempted to read and absorb that. The I found myself fumbling around in the dark (outdoor night shoot) wondering why some shots worked, more or less, and other just did not, for what seemed like a variety of different reasons.
I conclude that other than leaving everything, including the camera, on fully auto the only sensible thing to do was set aside a couple of weeks to get to grips with what the programmes in both parts of the system can offer. Since eTTL by its nature cannot always produce what you hoped to get if you seek something special from the composition knowing how to 'tune' it becomes a vital skill.
At least with digital you can see how adjustments change things and correct before ending up with a totally wasted shoot. Providing you have passed the degree level course for using the 580 EX that is ....
My primary flash experience goes back a few decades using a Metz unit that exposed according to the settings you dialled into it (usually the same as the camera unless bouncing) and 35mm bodies with no eTTL type functionality to speak of. Never had much of a problem with the exposures unless I forgot to set the correct settings.
A couple of years ago I rented a 580 EX II for a weekend and attempted to work out how to use it on a 400D. Then I found the manual on line and attempted to read and absorb that. The I found myself fumbling around in the dark (outdoor night shoot) wondering why some shots worked, more or less, and other just did not, for what seemed like a variety of different reasons.
I conclude that other than leaving everything, including the camera, on fully auto the only sensible thing to do was set aside a couple of weeks to get to grips with what the programmes in both parts of the system can offer. Since eTTL by its nature cannot always produce what you hoped to get if you seek something special from the composition knowing how to 'tune' it becomes a vital skill.
At least with digital you can see how adjustments change things and correct before ending up with a totally wasted shoot. Providing you have passed the degree level course for using the 580 EX that is ....
Edited by LongQ on Friday 2nd April 18:12
speedlights, due to ettl will always expose for ambient light, if the background is lit more than flash can deliver it will give fill flash, if its darker it will act as primary.
You can set the speedlight into manual mode and automatically adjust the output. Other options are to use the [P] zone which will always force a shutter speed no less than 1/60th.
Things to consider are this expose for your primary area, adjust ISO speed to suit. On your camera you have creative zones so use them the [face] one is for people priority too. You can increase/decrease both camera and flash exposure seperately when out of creative zones. My advice is try manual mode, set your Av and Tv settings manually and the flash will not control the camera but will adjust its power output (if you want to keep eTTL on). I suggest setting flash exposure compensation to -1/3rd of a stop.
Speedlights are great but can take a lot of practice, if you need a quick and sure hit then use [P] to force the 1/60th max setting.
You can set the speedlight into manual mode and automatically adjust the output. Other options are to use the [P] zone which will always force a shutter speed no less than 1/60th.
Things to consider are this expose for your primary area, adjust ISO speed to suit. On your camera you have creative zones so use them the [face] one is for people priority too. You can increase/decrease both camera and flash exposure seperately when out of creative zones. My advice is try manual mode, set your Av and Tv settings manually and the flash will not control the camera but will adjust its power output (if you want to keep eTTL on). I suggest setting flash exposure compensation to -1/3rd of a stop.
Speedlights are great but can take a lot of practice, if you need a quick and sure hit then use [P] to force the 1/60th max setting.
I find that for quick snaps P mode works pretty well.
There seems to be an art to flash with the Canon Speedlites
I've found this site gives a good explanation of how it works.
http://photonotes.org/articles/eos-flash/
There seems to be an art to flash with the Canon Speedlites
I've found this site gives a good explanation of how it works.
http://photonotes.org/articles/eos-flash/
Kermit power said:
I'm using a Canon 450D with a 580EXII flash. Is there a setting to tell it not to expose for the background?
Set to manual and make sure that the settings will underexpose if shot without the flash used to be fairly reliable for me on a 400d. I never did get a solution to make it give me what I was after in AV - manual was the way to go.stigmundfreud said:
My advice is try manual mode, set your Av and Tv settings manually and the flash will not control the camera but will adjust its power output (if you want to keep eTTL on).
I didn't know that bit! Sounds like that might be the answer, so long as it doesn't mean it over-exposes the subject. I'll give it a try.look up FEL, you can tell the flash to automatically underexpose its (not the camera) exposure or over expose it. Likewise when out of M mode you can tell the camera to over/under expose by 2 stops EV.
To give an example I did a test in the house. I set to AV and let everything take its course. It took 3 seconds. Changed to M, set my Av and Tv manually, nothing else changed. perfectly exposed indoors at 1/200th at f8 but the flash batteries take a hammering. Thats just an example and not always going to be the case. a 430 or 580 has enough guide to fill a typical house room on its own
To give an example I did a test in the house. I set to AV and let everything take its course. It took 3 seconds. Changed to M, set my Av and Tv manually, nothing else changed. perfectly exposed indoors at 1/200th at f8 but the flash batteries take a hammering. Thats just an example and not always going to be the case. a 430 or 580 has enough guide to fill a typical house room on its own
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