Struggling with 580EX

RedTele

RedTele

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Kaz
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Hi, I'm a flash noob.

I bought a 580EX (my first flash) for my Canon 40D recently and I'm struggling to get to grips with it. I just can't get it to consistently get it right through ETTL. I'm shooting in aperture priority, shutter speed 1/250 and ISO 100. The results are all over the place, just as likely to grossly over/under expose the image as it is to get it right :'(

The camera also doesn't think the flash is compatible when I try to set it up in camera menu. Does this mean the flash is faulty?
 
Bit of a very big question.....and an even bigger answer! I m sure someone more knowledegable will be along shortly.

Depends what you are trying to shoot, initially I would suggest you try some test shots, same subject distance and ambient light. Put the flash in Ettl and the camera in auto. Take a few shots with the flash pointed directly and bounced. Then set camera to TV on say 125, I think thats the max synch speed anyway, the camera will now set the apeture. Remember that shutter speed does not control exposure...only flash power apeture and ISO. More test shots....
Then you try setting the camera in manual say 1/60 and F4 and adjusting the flash power. The simplest way is to press the centre button and the display flashes, turn the dial and you will see the EV change up or down. Try a few shots and adjust the Flash Ev to suit and see how it affects the exposure.
You can also set the flash power my changing the flash mode to manual and shoting in manual.
Experiment!!

Dunc
 
If you are indoors put the camera to manual SS 1/200( sync speed or below) or below,aperture f5.6 is ISO 200/400.Put the flash in ETTL point the flash head at the ceiling( assuming its white-ish) and shoot away.Ignore the in camera meter-it will probably show underexposed.
The SS is controlling the amount of ambient light so a slower shutter lets in more ambient and the aperture is controlling DOF,the flash is acting as the main light.
 
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Are you trying to control the flash from the menu screens on your 40d?
If so, you're out of luck :( you'll need the 580ex II or the 430ex II to do that.

eTTl will quite often get it wrong, if the subject is static i'd always use manual anyway.
 
Did you buy it used, without a handbook? You'll struggle without one - the 580EX is very capable and has a lot of different setting options. It's quite easy to get confused.

You don't give us much to go on, but just to make sure you're not running out of power (are you bouncing it?) bump up the ISO to 400 at least, and avoid high f/numbers until you know where the limits are.

1/250sec is fine for your camera, but if you're on Av the normal default will drop the shutter speed in line with the ambient, which suggests maybe you're doing something wrong?

Stick with it. E-TTL is good and very controllable, once you know how ;) If you're getting inconsistent exposures, maybe it's because you need to use the FEL* button. Handbook explains.
 
When a camera is in AV or TV mode it will use the flash for fill only and not as a main light source. When shooting indoors, switch to M mode and set the aperture to F5.6 as a starting point. Adjust the shutter speed to control the ambient light (faster shutter = less ambient light and slow shutter = more ambient light). If it’s really dark (night club dark), use very slow shutter speed (something like 1/25 or 1/40). Don’t worry about camera shake or motion blur, the flash will freeze any motion.
 
Also remember that your metering mode needs to be correct for the subject you are shooting and that you need to meter for the most important part of the scene or subject.

For instance, (I'm using portraits as an example but I think it works the same for all genres), if you are using spot metering it will take a reading from the centre focus spot, if that centre spot is pointing at something dark it will try to bring it back to medium grey! which will more than likely blow out the main subject! And vies versa.

If on the other hand you are using evaluative metering and the scene is predominately bright it will more than likely under expose the subject. and again vies versa.

Remember like computers these modern camera's and flashes are very clever but they are equally dumb! They don't know what you are aiming to achieve and they have no idea about the style you are wanting to portray, so you have to tell it! that's where your knowledge of what your camera is going to do for each scenario comes in to it's own.
 
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