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02/06/2011 09:41:35 AM · #1 |
I need help!!! Oh wait, you already know that... I mean, I need help with a flash or two. :)
I'm still trying to learn how to use a flash/multiple flashes. I understand how to use them when I'm working with available light and flash.
I'm completely lost when trying to use them as my main/only light source. I can set the camera on program mode, and it does it for me, but I can't adjust my depth of field.
So I'm trying to work in Manual mode. Since I'm working in a dark room, with minimal or no incandescent light, I can't figure out what the metering should be, so I'm just guessing and chimping to see if I'm close. Really bad idea. I'd like to know how to do it correctly.
How am I supposed to have any clue as to the settings when using flash as my only light source? Can anyone help? Please? Pretty please?
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02/06/2011 12:23:11 PM · #2 |
I'm thinking you'd need a light meter. Otherwise, your only real option is the ol' chimp-er-ooo. A wise man once told me "start at max sync, F/16, half-power on your flash and adjust from there." It's worked for me.
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02/06/2011 01:08:59 PM · #3 |
Manual mode, aperture where you want it, shutter speed 1/250, and let E-TTL take care of the rest. The flash will shut itself off when illumination is "correct". This will underexpose the heck out of the ambient light.
If you set camera in aperture priority, aperture will stay where you want it, flash exposure will be the same, but shutter will stay open long enough to expose for the ambient light, which presumably is not what you want.
If you want SOME glow-through of ambient but not full exposure, set the camera in manual mode, choose your aperture, and then set shutter speed to underexpose by 2 stops (or 1, or 3, depending what you want) and the flash will take care of the rest.
That's my old-school approach. There may be a more modern one :-)
R.
Message edited by author 2011-02-06 13:09:27. |
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02/06/2011 01:16:45 PM · #4 |
I usually only have a general idea when I get started. I just experiment and adjust the locations, power and light modifiers, chimping to see if I'm getting close to what I want. Over time, my initial guesses get better.
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02/06/2011 01:25:20 PM · #5 |
First you need to know the Guide Number for your flash. Then you can adjust the guide number for the various ISO settings you use the most per this table.
ISO Factor
100 1
200 1.44
400 2.07
800 2.99
1600 4.30
3200 6.19
Then you can use the equation below to determine your f-stop at full power. Don't worry about the shutter speed, as the flash is faster than any max sync speed you have. However, you will need to remember that the slower the shutter speed, the more of the ambient light will show in the background. This website has some good information Link.
f/stop = guide number/flash-to-subject distance
Now you need to balance your flash strength to the actual f/stop you want. This little calculator will help with that Link.
I actually made a table of f-stop to distance for each ISO value that I keep in my camera bag. I also have a length of rope marked with permanent marker every 1 foot to help when I set up my lights.
Hope this helps a little.
Tim
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02/06/2011 02:34:29 PM · #6 |
It depends on what you're trying to shoot.
For most event type settings, I usually "drag the shutter" to let the ambient light give context to the subject lit by the flash. The simplest way to do this I've found is to get an idea of what exposure you'd have without the flash and set the camera to that shutter speed/aperture/ISO combination with the camera in "M" then I set the flash to E-TTL and shoot away. If you want to make the ambient illuminated areas darker, use a faster shutter speed. Lighter? use a slower shutter speed. To make the flash illuminated areas lighter/darker, I use +/- flash compensation.
You can set the flash to "M", and adjust the flash illumination by setting the power of the flash, however, doing so also means that you also have to adjust the flash power for light to subject distance as well. If that's a constant, this is OK, however if you're in a situation where the distance to your subject is changing often, this approach is kind of a PITA.
I think ETTL generally works well enough to just let it take care of adjusting the flash output.
Now, balancing the color of the flash to to color of the ambient light is a different matter. In a typical indoor situation, the ambient light will be primarily incandescent. The flash, of course, is roughly the same color as daylight. The easiest way to balance the two is to use a CTO gel over the flash. This makes the flash output roughly the same color as the ambient light. Then set the camera's WB to incandescent and shoot. You can do a custom WB too. If you want to make the background warmer in color, you can use 1/4 CTO or 1/2 CTO gels.
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02/06/2011 05:26:42 PM · #7 |
Originally posted by vawendy:
I'm completely lost when trying to use them as my main/only light source. I can set the camera on program mode, and it does it for me, but I can't adjust my depth of field.
So I'm trying to work in Manual mode. Since I'm working in a dark room, with minimal or no incandescent light, I can't figure out what the metering should be, so I'm just guessing and chimping to see if I'm close. Really bad idea. I'd like to know how to do it correctly.
How am I supposed to have any clue as to the settings when using flash as my only light source? Can anyone help? Please? Pretty please? |
Since you are shooting in M mode, you can ignore the metering. Your settings will not change from shot to shot, so there is no reason to have the camera in any auto or semi-auto mode.
You are trying to eliminate the ambient light (pro-tip, you don't need to work in the dark, see below). Set your camera to it's flash sync speed, and your aperture to your preferred setting (I start a f/8, as that is my default aperture). Set your flash to 1/4 as a starting point so you can adjust it up or down as needed.
When you are working with flash as your only lighting in the picture, if you want to know if the ambient light will be a problem, take a meter reading on what you'll be shooting with the ambient lights on. If you are 3 stops or more underexposed, then the ambient lighting will not contribute to the shot, and you don't need to work in the dark.
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02/06/2011 09:41:38 PM · #8 |
wow... I never understand the 1/4 flash & 1/2 flash. It seems like I don't get nearly enough power out of the flash. That, not only do I need it at full power, but am frequently doing a +1 to +3 flash exposure adjustment!
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02/06/2011 10:30:39 PM · #9 |
Originally posted by vawendy:
wow... I never understand the 1/4 flash & 1/2 flash. It seems like I don't get nearly enough power out of the flash. That, not only do I need it at full power, but am frequently doing a +1 to +3 flash exposure adjustment! |
How far from your subject do you have your flash? What are you shooting? Do you have some example pictures where full power is not enough?
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02/06/2011 10:37:40 PM · #10 |
Originally posted by vawendy:
wow... I never understand the 1/4 flash & 1/2 flash. It seems like I don't get nearly enough power out of the flash. That, not only do I need it at full power, but am frequently doing a +1 to +3 flash exposure adjustment! |
If that is the case you need to raise your ISO. There is only so much available light from a flash. If you are firing at full power all the time lower your shutter speed and raise your iso.
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02/06/2011 11:00:38 PM · #11 |
| OOOOH THANK YOU Wendy for starting this ... Like you I am soo lost with my flash. I've just got one little Sigma EF-530 ... and WHATS A GEL??? |
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02/06/2011 11:15:54 PM · #12 |
Originally posted by littlemav:
and WHATS A GEL??? |
Gels are used to change the color of your flash.
Flashes are daylight balanced, so to get them to match other color temperatures, you put a gel on the flash. CTO (Color Temperature Orange) to match with tungsten/incandescent, Window Green or Plus Green to balance for florescent. You can also add various colored gels for creative effect.
//strobist.blogspot.com/2006/03/lighting-101-using-gels-to-correct.html
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02/06/2011 11:18:50 PM · #13 |
Originally posted by MattO:
Originally posted by vawendy:
wow... I never understand the 1/4 flash & 1/2 flash. It seems like I don't get nearly enough power out of the flash. That, not only do I need it at full power, but am frequently doing a +1 to +3 flash exposure adjustment! |
If that is the case you need to raise your ISO. There is only so much available light from a flash. If you are firing at full power all the time lower your shutter speed and raise your iso. |
Shutter speed is not going to help with the flash power.
Aperture, ISO, flash power and distance will affect how 'powerful' the flash is. Since the OP is trying to overpower ambient, there is no point to changing the shutter speed. You don't need to worry about shutter speed until you get to balancing ambient with flash.
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02/06/2011 11:33:12 PM · #14 |
OMG  alohadave Thank you soo much for that link.. (all florescent lights are not the same color temperature. And, depending on which part of the 60hz electric sine wave cycle your shutter happens to grab from the florescent ambient lights, they will color shift on you, too. ) I thought I was nutz or my camera was going nuts because I've had this problem A LOT! was doing some with Big window light, flash, daylight balanced bulbs and a overhead florrisant and kept getting different lighting. Holy Buckets theres a lot to think about!
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02/07/2011 12:16:15 AM · #15 |
Originally posted by alohadave:
Originally posted by MattO:
Originally posted by vawendy:
wow... I never understand the 1/4 flash & 1/2 flash. It seems like I don't get nearly enough power out of the flash. That, not only do I need it at full power, but am frequently doing a +1 to +3 flash exposure adjustment! |
If that is the case you need to raise your ISO. There is only so much available light from a flash. If you are firing at full power all the time lower your shutter speed and raise your iso. |
Shutter speed is not going to help with the flash power.
Aperture, ISO, flash power and distance will affect how 'powerful' the flash is. Since the OP is trying to overpower ambient, there is no point to changing the shutter speed. You don't need to worry about shutter speed until you get to balancing ambient with flash. |
I don't see in her post where she says she is using this off camera, or that she is overpowering ambient. Just that it is her only external light source. Unless I missed something.
Lowering shutter speed will allow her to let some ambient in so the flash doesn't have to fire at 1:1 ratio. Unless she goes lower then 1/60th or is trying to stop water drops or something like that it will help. Flash still fires at 1/1000 or so and will stop motion of most people.
Raising the ISO or opening up her lens are also options since she says she doesn't have enough flash power. |
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