Fs and light metering

[Sara Anderson]

Hi,
I am not a pro in studio photography but recently I've been getting many clients that are interested in studio shoots. I use a set of 3 strobes of neewer (each of 300 watts) n use my flash guns occasionally if I need lights from different directions.
All this time I've been working with the trial n error approach. However all the training videos I see ask me to use light meters n adjust each light at different f levels. I understand I need to adjust my aperture according to the reading of the meter if the meter was placed on my subjects face to get the perfect lightings. I however don't understand how to set different lights at different levels of f! There's only one f at the camera!
Are there any tutorials online that can teach me the basics or give me an idea at least? Also, I heard there are many iPhone apps that work as a lightmeter. Can anyone suggest? Not sure if I'm ready to invest in an expensive meter at this stage
Thanks.

 

[bryan elliott]

You should dictate to the light what apperture you are working at and not be dictated by the light to your working apperture

 

[Garry Edwards]

It's a form of shorthand. I'll try to translate...
"Set the keylight to f/11, set the fill light to f/8 and set the background light to f/16"
means "set the keylight so that the meter gives a reading of f/11, and set f/11 on your camera"
By the same token, the fill light will, with exactly the same modifier and at exactly the same distance, be set to produce exactly 1 stop less light than the keylight. And the background, all things being equal again, will be set to produce exactly twice as much light, or 1 stop more light, than the key light.

AFAIK the various phone apps can only meter continuous light (to some extent). They can't measure flash