Flashguns the basics

Flashguns can be a scary bit of kit to get to grips with, but with a little bit of knowledge and practice they can be one of the most important tools you have. First you need to understand the flashguns anatomy, what the buttons and flashing lights actually do. 

As flash guns varry in design layout i will be talking about my SB700 a lot of the features are interchangeable with other makes and modes the method is likely to be different.

Modes 

The SB-700 has a handy mode slider on the side of the screen the remote and master are deslected ont he no off button.

ITTL - Intelligent through the lens, in this mode the camera meters the image through the lens to determine the power of the flash. The benefit its you do not have to think about your setting its automatic. The down side is it will quite often over power the flash, resulting in you batteriesdying faster and the recharge rate being longer. This mode is useful in situation you need to think fast or you have varying light. there is also a flash exposure compensation allowing you to quickly adjust the power output with a range for +1 to -3 stops this helps ensure the flash is not too harsh.

Manual -  This setting allows you to input the power output. the power is rated in fractions with each stop halving the intensity of light (The SB700 alters the stops in increments of 1/3 allowing you to really fine tune the power). This is the mode i use most it allows me to know what the flash is doing exactly and control it.

GN mode - you set the subjects distance with in the flashgun to determine the power. This is a feature I have not used.


Master and Remote- The master mode allows you to trigger 3 separate flashes independently controlling there power output, the receiving flash guns are set to remote mode and can be run in manual or TTL. 
This is a fairly complex triggering method having 3 channels to allow 3 different sets of masters and remote to work in the same area with out triggering each other. The master flash can be triggered before the shutter removing it form the image.
I have not used the master mode on the flash but my D610 allows the pop up flash to be the master flash. the benitfit of this was not having to carry any extra triggers and batteries, the draw back is the flash has to have a line of sight with the remote meaning its likely to be in your image.

Zoom.
Flash head zoom refers to the spread of light. this can have a large effect on your images appearance even thought it dose not change the flashes out put. 24mm is the widest on the SB700 this will give you a large spread of light giving a soft glow. where as at 120mm the light is focused in to a smaller area giving a harsh light. I like to this of this as a running tap at 120mm and the same tap with a shower head attached at 24mm, its the same rate of water but just spread out, if you put your hand under the shower you'll get damp but if you put it under the tap you'll get wet.

The best way to understand these features is to play about with them see what works and how.