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Fast lenses are pretty darn expensive these days (take a look at fast prime lenses, like the Sigma 85mm f/1.4 for Canon, which runs almost $1,000, or Nikon’s 85mm f/1.4, a hugely popular lens with wedding and portrait photographers, yet it costs around $1,700). If you bought one of those lenses (or any fast lens, like a zoom that’s f/2.8), you didn’t buy it to shoot it at f/8 or f/11. You paid that money for the f/1.4, so when you pull out that lens, you want to be shooting it at f/1.4. That’s the look, that’s the f-stop, and that’s the effect you paid for when you bought that expensive lens. So, make darn sure you’re getting your money’s worth by shooting it at the f-stop you bought it for.