I took this shot of jazz great Peter Appleyard, the wizard of the vibraphone, back in 2009:

So how did I do this – what was behind my decisions?

Here’s my thinking and execution:

• This called for a “situational” portrait; an environmental portrait showing him at work, as it were.
• I therefore used a 24mm lens on a full frame camera (in fact it was the 16-35 f/2.8L set to 24). 24mm is nice and wide, but not so wide I get crazy distortion in the subject (provided the subject is small in the image).
• I bounced my flash behind me to the left, off the ceiling.
• Since the venue was dark, and I wanted a lighter background, I used not my normal “400-40-4” settings, but 400-30-2.8 – ie a stop and a third lighter in the background. 400 ISO, 1/30th second. f/2.8.  (Since I am using a wide lens, f/2.8 gives me enough DOF. Since I am freezing the subject with flash, 1/30th second is fast enough).
• I used “off-centre” composition (using the Rule of Thirds).
• I focused on Mr Appleyard, using one focus point, then recomposing.
• I stayed ou t of the way of the audience as much as possible.

This is the thinking that goes though a photographer’s mind quickly. Practice the same – think about things like lens, light, exposure, and composition. You will see you will get quick at this just by asking the right questions.