How do you know how much power to add to a flash in manual mode?

jonneymendoza · 17 Apr 2013 at 18:42

Hi.

as the title states. How do you?

Do yo simply take a few test shots and guess or do you know a genuine way to calculate teh correct flash power to apply to a given scene to make sure the flash does not overexpose the subject or underexpose?

Thanks

jonneymendoza · 17 Apr 2013 at 19:42

PistolPete said:
I've very little experience in this areaso this is a genuine question.... but how is trial and error quicker. Surely the point of a light meter is "pop, read the settings, put them into the camera".... or am I missing something here?

This what i am thinking?

jonneymendoza · 17 Apr 2013 at 21:03

-|ScottFree|- said:
If you use the Sekonic L-758DR and your triggers fire using 433 MHz, you can simply take an incident reading from your subject and press a button on your light meter and fire the strobe. You will get an instant reading for correct exposure. Yongnuo 622 Pocket wizards will work perfectly with this system.

A light meter should be one of the first purchases you make when you are a photographer using flashes. The workflow is rapid, the guess work is gone.. You nail exposure every time. Chimping is far more time consuming. The other benefit of having a meter is knowing the precise point of 18% grey. 2.5 stop above correct exposure is white, and 4 stops below is black. This will allow you to completely take control of the light in your image, and have detail in the shadows.

That cost same amount as a 600ex canon flash!

jonneymendoza · 18 Apr 2013 at 16:34

RussD said:
Why spend All that cash on a lightmeter...Silly, unless you be a Pro.
You be using Digital, so it cost you NOTHING to take three shots..One shot at 1/200 or 1/250 at f8 the other at f11 should give you what you want. If it is a bit darker then go down to 1/125 or 1/60 at same appertures. Easy Peasy..

It can cost time taking 3 shots and readjusting your flashes or camera each time

jonneymendoza · 21 Apr 2013 at 00:36

On my 430ex2, the power settings goes from 1/64, 1/32 .....1/1 being the highest.

So my question is, how do i get the relivent figure about with this formulae: GN / metres = aperture

say i know wroughly the distance between flash and subject, say 10m to keep it simple and apparture is f10. what is the formulae?

10/10(distance / apparture) = 1? and 1 being 1/1 to dial in my flash?

say if its f 10/5 = 0.5 im guessing 1/50 on my flash settings?

Also: just found out that some flashes have a build in light meter!