Canon 580 EX II Speedlite - I'm confused!
Discussion
I have a 580 EX II speedlite, which I'm using with a 450D, and I'm a little confused as to how it should work on the ETTL.
It just doesn't seem to take the flash into account on setting exposure. Is this right?
If I set it to shutter priority, it sets an exposure length which, as far as I can tell, would be the required length without any flash (eg 1/8th of a second at f/2.8 and ISO 100 in a reasonably well lit room).
If I set it to exposure priority, it automatically sets the aperture to wide open and tells me the shot is going to be under-exposed. It does then actually seem to expose the shot fine, but this is of course bloody annoying if I don't want the shot to be wide open.
If I shoot in Manual, then the flash appears to always fire at the same strength, so dropping a stop on the aperture, for example, will double the exposure of the shot.
Am I doing something wrong? Have I got a problem with the camera and/or flash?
Mu understanding of ETTL was that the flash would automatically fire with enough power to correctly expose the image, but this doesn't seem to be happening?
It just doesn't seem to take the flash into account on setting exposure. Is this right?
If I set it to shutter priority, it sets an exposure length which, as far as I can tell, would be the required length without any flash (eg 1/8th of a second at f/2.8 and ISO 100 in a reasonably well lit room).
If I set it to exposure priority, it automatically sets the aperture to wide open and tells me the shot is going to be under-exposed. It does then actually seem to expose the shot fine, but this is of course bloody annoying if I don't want the shot to be wide open.
If I shoot in Manual, then the flash appears to always fire at the same strength, so dropping a stop on the aperture, for example, will double the exposure of the shot.
Am I doing something wrong? Have I got a problem with the camera and/or flash?
Mu understanding of ETTL was that the flash would automatically fire with enough power to correctly expose the image, but this doesn't seem to be happening?
I usually try to understand all this by thinking that with flash, you are sorta' taking two superimposed shots, one with the camera (background) and one with the flash (subject/foreground).
In Shutter Priority, set the shutter speed at or slower than the sync speed; I think that's 1/250 for the 450D. The camera will then set the aperture ( as best as possible) to expose the background properly. The flash will expose the subject.
In aperture priority the same sort of thing happens, but if it's a relatively dark scene, shutter speeds can be long, requiring a tripod. The "subject" is correctly exposed by the flash.
In manual, set both shutter and aperture to get the background as best exposed as possible, checking in the display. If you can get around -1.0 to -2.0 that's often OK. Again flash exposes the subject.
In all three, adjust flash intensity (where required) using Flash Exposure Compensation (FEL) until it all looks "right". It's all very clever!
Am I understanding it properly?
In Shutter Priority, set the shutter speed at or slower than the sync speed; I think that's 1/250 for the 450D. The camera will then set the aperture ( as best as possible) to expose the background properly. The flash will expose the subject.
In aperture priority the same sort of thing happens, but if it's a relatively dark scene, shutter speeds can be long, requiring a tripod. The "subject" is correctly exposed by the flash.
In manual, set both shutter and aperture to get the background as best exposed as possible, checking in the display. If you can get around -1.0 to -2.0 that's often OK. Again flash exposes the subject.
In all three, adjust flash intensity (where required) using Flash Exposure Compensation (FEL) until it all looks "right". It's all very clever!
Am I understanding it properly?
I've just actually done a very non-male thing and referred back to the manual again! It does indeed seem as though I'm going to need to use manual mode for most of what I'm trying to do.
I've been messing around taking a few pics of the kids, and ideally I'd like to step the lens down to f4, as it is quite a bit sharper than at f2.8. If I do this on Av setting, I do indeed get a very slow exposure time, which is useless for a 1yr old who has just figured out how to walk!
Playing around with manual settings isn't an issue at all (in fact it's rather satisfying), but it would've been nice to have an option to only expose for the subject in this instance, as following the kids round the house often produces messy backgrounds which are too close to be thrown out of focus even at f2.8, so having the background underexposed can actually be a positive benefit.
I've been messing around taking a few pics of the kids, and ideally I'd like to step the lens down to f4, as it is quite a bit sharper than at f2.8. If I do this on Av setting, I do indeed get a very slow exposure time, which is useless for a 1yr old who has just figured out how to walk!
Playing around with manual settings isn't an issue at all (in fact it's rather satisfying), but it would've been nice to have an option to only expose for the subject in this instance, as following the kids round the house often produces messy backgrounds which are too close to be thrown out of focus even at f2.8, so having the background underexposed can actually be a positive benefit.
Here is an excellent site with information about flash in general but has some very specific information on the Canon flash system.
http://photonotes.org/articles/eos-flash/
http://photonotes.org/articles/eos-flash/
Colin RedGriff said:
Here is an excellent site with information about flash in general but has some very specific information on the Canon flash system.
http://photonotes.org/articles/eos-flash/
That looks great, thanks! http://photonotes.org/articles/eos-flash/
in AV or TV the flash is just used for fill so the shutter speed/aperture value won't actually be different from if you used no flash. if you want the flash to light up your subject then you will have to set to manual, P or auto.
if you set it to manual you can set the apeture for your DOF then the shutter speed so that its not too slow, then you can choose the ISO to suit the scene.
for night time shots in my living room I'll normally set the aperture wide open (f2.8) and a shutter speed of 1/30s ISO 800 and I bounce the flash (+0.5-1FEC) off the celing so I get a nice even spread of light. best to play with settings and see what you get
if you set it to manual you can set the apeture for your DOF then the shutter speed so that its not too slow, then you can choose the ISO to suit the scene.
for night time shots in my living room I'll normally set the aperture wide open (f2.8) and a shutter speed of 1/30s ISO 800 and I bounce the flash (+0.5-1FEC) off the celing so I get a nice even spread of light. best to play with settings and see what you get
Gassing Station | Photography & Video | Top of Page | What's New | My Stuff