Know your lim­its

The ex­po­sure set­tings you use will also be dic­tated by what you’re happy to ac­cept in terms of blur, noise and so on…

NPhoto - - Nikopedia -

■ If you do this for a living, you soon learn what re­sults you can ac­cept in terms of mo­tion blur, depth of field and noise – and what you can’t. Even if you don’t, it’s worth de­cid­ing what you’re able to live with for the three set­tings. But (and this is where auto-ex­po­sure and auto-ISO fail to de­liver), there are vari­ables, even within each set­ting. Here are five cru­cial ques­tions, the an­swers to which it’s worth work­ing out be­fore you go out shoot­ing:

How slow can you shoot hand-held?

It de­pends on how steady you are, which is some­thing you can work on to im­prove, but also on the fo­cal length of the lens. It’s eas­ier to hold steady with a wide-an­gle lens than with a telephoto, be­cause the telephoto mag­ni­fies ev­ery­thing, in­clud­ing your twitches. 1/30 sec with a stan­dard fo­cal length of 50mm should be re­li­ably sharp. In ad­di­tion, Nikon’s vi­bra­tion re­duc­tion sys­tem in some lenses will give you per­haps a two-step im­prove­ment, so that’d be 1/8 sec in the case of a 50mm lens – but of course that will only ad­dress cam­era shake, not sub­ject move­ment.

What shut­ter speed freezes what move­ment?

There are so many vari­ables here, from how fast some­thing is ac­tu­ally mov­ing to how fast it’s mov­ing across the frame (this de­pends on the fo­cal length, its dis­tance from you, and on whether it is mov­ing to­wards you or cross­ing in front of you). You need to get used to think­ing in terms of speed across the frame.

What aper­ture gives just-rea­son­able depth of field?

Take a regular sub­ject in a regular crop, such as two peo­ple talk­ing a few me­tres from the cam­era and framed with a stan­dard lens so that they fill a third or half of the frame. How much needs to be sharply fo­cused and how much can be blurred? An aper­ture of f/5.6 is a usu­ally a good start­ing point.

How much depth from the small­est aper­ture?

When you’re aim­ing for deep fo­cus, it’s more usual to think of it the other way round. Know­ing that you want full depth of field, it’s usual prac­tice to start with your lens stopped down, to f/16 or f/22, and then find the cam­era po­si­tion that al­lows front-to-back sharp­ness. Know­ing roughly what this will be from ex­pe­ri­ence saves time.

How much noise can you tol­er­ate?

Even here there are vari­ables, be­cause noise is at its most vis­i­ble on very smooth mid- and mid-to-dark-toned ar­eas. If it’s a de­tailed scene, you will be able to tol­er­ate more noise than if you’re shoot­ing a clear sky, smooth skin or a blank wall. And if you dis­play the im­age small, that too will hide the noise.

1/30 sec at f/2, ISO1250 I wanted to use se­lec­tive fo­cus­ing here. An aper­ture of f/2 en­sured sharp fo­cus on the statue. I knew from ex­pe­ri­ence that at 1/30 sec I’m safe from cam­era shake. That left just the ISO for ad­just­ment.

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