Flash exposure

[KaisB]

Hi there,

I want to know how to set my exposure parameters when I need flash. the camera will calculate the exposure based on the ambient light. and the photo will be different when the flash runs.

Camera : NIKON D3100.

Thanks,

[jdepould]

Well the flash changes the amount and character of the light in an image, so it's always going to look different. Beyond that I'm not sure what exactly you're asking. Could you give us some samples images to describe what you're talking about?

[i speak in math]

Typically, a camera will meter for a scene ignoring that any flash is going to take place. With TTL, the flash will emit a pre-flash burst of a predetermined amount of light. It uses this to calculate the correct amount of flash to use. Then takes the image using the camera settings + the calculated flash amount.

[JFSanders]

Originally Posted by KaisB

Hi there,

I want to know how to set my exposure parameters when I need flash. the camera will calculate the exposure based on the ambient light. and the photo will be different when the flash runs.

Camera : NIKON D3100.

Thanks,

If your question is about using on camera pop up flash. Don't use it. Take a bit of time to look at DPS' e-book titles on lighting. Also look at Scott Kelby's books on lighting. It will become apparent to you that pop up flash will not be a choice you would likely make.

[timiroberts]

I speak in math nailed it.
If you're using a camera & flash that will pass along TTL information, you'll be OK. If you're using a manual flash or camera that won't pass TTL to an off-camera flash, you will have to adjust your camera and flash exposure settings individually until you've got a proper exposure.
Alone, your camera will meter the scene "as is" without the assistance of the flash.

[Randy Orton]

Flash photography is essential to learn if you take photos outdoors in the environment, particularly if you photograph people. The lighting is never perfect so you have to modify it to suit your requirements. Here are 4 essential basics to help you get more out of your flash.

[KaisB]

Hi professionals,

thanks for the reply.

Actually to reformulate my question, I'm using M mode and with my D3100 I adjust my settings based on the exposure

-2 | | | -1 | | | 0 | | | +1 | | | +2

when it is zero I know that the needed object is properly exposed and I can make the photo.

well, I don’t like the flash because the shadow gives me bad feeling of no uniform light’s image (any way )

So I'm not professional but I expect to make my image less exposed so that it will be compensated by the flash's light!

May be I didn’t understand the concept, if you can explain me + this TTL mechanism.

I guess also the distance to the subject should be valid to get best result?

Thanks ALL !

[JFSanders]

Yes, flash is only good for a certain amount of distance. Light falls off at the square of distance to the subject. The pop up flash is almost useless if you ask me as it creates harsh frontal light which flattens out your subject. And it is weak to boot. TTL means through the lens. Your camera uses it to determine exposure in any mode except Manual. In manual it will give you a reading but will not make adjustments to aperture or shutter speed. And it can be fooled by choosing the wrong metering mode. Jim

[conor5150]

Can I piggy back on this question?

I just got the SB-600 speedlight and have only been playing around with it in the house at night mostly.

Nikon D60 with 35mm f/1.8G lens ......so in P mode I get a correct exposure at say f/4 and 1/30 sec......the meter reads dead center......yet when I put the flash in the hotshoe it now reads as way overexposed , and no amount of tweaking on the dial will get the meter to read as a correct exposure......why is that?

[JFSanders]

What mode do you have set on the sb-600? I use ttl-BL when in p mode. Also, have you made a photograph even though it reads as overexposed? Just to see what you get. Also, P mode will give you alternate combinations, did you see a *P in the corner of your screen? If so, you can wheel back to the standard combos or go to another mode and return to P and it will be reset to the defaults.