I really need help with Flash

Iron Flatline · Jan 2, 2007

Hi all.

I am having a very hard time with Flash. I have read a lot of threads about Flash, but have yet to come to grips with the underlying math. I'm pretty competent when it comes to available light, but augmenting it or creating my own has been an exercise in frustration.

Basically, I need a short-cut so I can kick-start my flash education. I really like to understand the technical aspects, but I prefer to learn off shots that I get right. As of now, I'm just getting them wrong.

I use a Canon 5D with Speedlight 550EX and a LumiQuest diffuser, all set to E-TTL. I'm usually pretty close to the subject, using a 24-70mm lens. On some of them the flash is in the other hand, being triggered by a little remote. I never got the manual for the Flash (good price on eBay for it though) so I haven't really had a chance to understand the settings.

A party photographer offered me the following advice: shoot as slow as possible. Don't shoot faster than 1/60th, preferably even 1/50th or 1/40th to get as much info in the background of the subject. I've also been shooting relatively open apertures (around f5.6) but have gone smaller (f8 up to f11) if warranted. I've been shooting at ISO 50 or 100, but forget to reset in the heat of fun shots.

Now, a lot has to do with the environment, and sometimes all I need is fill (no problem) but lighting with Flash is not working for me.

I'm not happy. To wit:

1/60th at f6.3, ISO 50, flash on the camera. Almost no detail in the back. No idea what to do here...

2006%2012%20New%20Year%27s%20Eve%2016.jpg

1/60th at 2.8, ISO 200, flash on the camera. This one is pretty good:

1/60th at f4, ISO 400 (too high), flash on the camera. Not bad, but too brightly filled. ISO too high?

1/60th at f2.8, ISO 100, flash in the hand (bad lighting angle). He's over-exposed, but the background came out ok. Should I have shot faster? A smaller aperture?

1/60th at f9, ISO 100. This one is quite good, I'm pleased with it. Is it the smaller aperture that helped me get this right?

Ok, here's two that show why I currently prefer to shoot with available light:

1/50th at f7.1, ISO 100, flash in the hand way below the camera. Discounting the poor lighting angle, she is still way too bright, and there's no detail in the background....

1/60th at f1.4, ISO 400. Maybe these kind of shots will always be better without flash...

Help. How can I get better Flash images?

Big Mike · Jan 2, 2007

If you haven't read it yet...this is often called the EOS Flash Bible

I've read countless posts about Canon E-TTL...it can be hard to figure out what the camera/flash are doing. I still use an 'auto' flash and shoot in manual mode...usually with some guess and test to get it right.

I think the trick is to meter for the ambient light...and then use your FEC to control the exposure of the subject. If you can get some sort of balance...that's the key. Obviously, you can't expect to expose a very dark background at the same time that you flash your subject...but with enough ambient light and a slow shutter speed...you should be able to pull it off.

Iron Flatline · Jan 2, 2007

Hmm... that's quite a lot of info. Thanks, I will dig into that.

Yes, I have the camera in manual mode when I use the Flash. Heck, I don't even know yet what E-TTL means.

Sw1tchFX · Jan 2, 2007

When you're inside, and the ceiling is bright, BOUNCE IT. You can fit a bounce card in the flash too to reflect more light back into the subjects eye sockets.

Also, in a dark area (like a bar) bump up your ISO well past 50, becuase if you still shoot at 1/60th, you'll get more detail in from those shadows. LIke the third one for example, if that was shot at ISO 800 the background would have been much brighter. Also, don't worry about the flash overexposing when you change the ISO. The flash SHOULD adjust for it and if it doesn't than Canon really screwed up.

Jazz · Jan 2, 2007

Iron Flatline - One of my New Years resolutions is to improve with handheld flash. I hear you. I try to always think of it as two separate exposures, one for the background (camera) and one for the foreground (flash).

So, for the ones (1 and 6) with dark backgrounds, I'd open the aperture from 6.3 and 7.1 to say, f4, and/or raise the iso (you probably don't really need iso 50).

Then for the foregrounds that are too bright, turn the flash down, either through flash compensation OR put the flash on manual and turn down the power.

This last technique is what I've decided to do, as it is hard to always know what the heck the chip's logic will do. I have Nikon stuff, but it doesn't matter. In a similar situation as your shots, I'm at iso 800, at f4, 1/60 with flash on manual at 1/64 power. I want to see if I can just learn what that's gonna do and when I get used to it, then I'll vary it. I'm hoping it's easier than predicting the chip's logic. (which is my b.s. way of saying I'm sick of reading the nikon flash manual

).

ksmattfish · Jan 2, 2007

You will probably learn quicker if you set your flash and camera to manual control. Most of what I say below assumes the camera is in manual exposure mode, and can't change aperture, shutter, or ISO on it's own.

Photo #1: To increase background ambient light exposure decrease shutter speed, increase ISO, or open the aperture (although when using the flash in manual mode aperture and flash power are used to control flash exposure, so adjusting aperture may not be the best option).

Photo #2: Dark scene. Flash is overcompensating. Reduce aperture size or flash power if in manual. Dial in flash exposure compensation of -1 in ETTL/TTL.

Photo #3: Same thing as #2. Lowering the ISO in manual would decrease exposure for both the subject and the background. Lowering the ISO in ETTL/TTL would lower the exposure of the background, but probably not change the amount of flash on the subject, because the ETTL will just adjust the flash to counter your ISO change.

Photo #4: Same as #2 and #3. Combinaion of dark background and a close subject when in ETTL/TTL needs flash exposure compensation dialed down.

Photo #5: If you were in manual flash mode then a smaller aperture would reduce flash exposure of the subject. If you were in ETTL/TTL mode it's probably that the fairly light colored background (similar in tone to the subject) was less tricky for the camera/flash to figure out.

Photo #6: She's not too bright; background is too dark. See #1.

Photo #7: You gotta love available light, at least compared to frontal lighting. If you want to use a flash to lighten up the shadow on her face a bit in ETTL dial in -2 flash exposure compensation. If you are in manual flash mode set the flash power to 2 stops lower than normal for the aperture and subject distance. See how it looks; adjust flash power/compensation to increase or decrease fill flash to your liking.

Familiarize yourself with the inverse square law. Everytime you double your flash to subject distance, you reduce the amount of light by a factor of 4, or 2 stops (assuming the same flash power).