Another note on primes…

“Why should I buy a prime lens”, I am asked often. The answer is always the same: sharp, small, fast, and consistent. Oh – and fun.

Look at this photo:

A typical prime shot: 50mm lens on a crop camera (meaning a “real” 80mm). In available light, I used the following settings:

  • Manual exposure mode.
  • 800 ISO
  • 1/80th second shutter speed
  • f/1.6 aperture.

Let’s say I had used a consumer lens: f/5.6 at 50mm. That’s almost four stops slower, so I would have had to use either:

  • A slower shutter, like 1/6th second; meaning a shaky picture;
  • Or 12,000 ISO, meaning a grainy picture;
  • Or a combination, meaning a little of both.

And the background would not have been nice and blurry, and simple.

Even an f/2.8 zoom lens would have meant 1/25th second or 3200 ISO, or a combination. And again, less blurriness.

So in real life available light situations, a fast prime can be invaluable. So you can document everyday moments and tell everyday stories, which are often the best. Here, the storytelling is done by the simple composition, the leaving out of the face, and the fork hovering expectantly.



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