(This is the 2nd part of a 3 part series. If you missed the first post, you can find it here)
Now that your camera is dialed in, let’s talk about that lens you have stuck to the front end. Not all lenses are equally sharp. The same is true for aperture values and focal lengths. As you should know by now, a smaller aperture gives you more depth of field. And the greater your depth of field, the easier it is to get pictures that appear sharp. But that’s not why you bought your 50mm 1.8. You also don’t lust over Canon’s 85mm 1.2 because you care about how it looks at f8. But you have to realize that every lens you have is not its sharpest when shot wide open. Your 50 1.8 is sharper at f2.8 and sharper still at f4. This is also true for zoom lenses. The mighty 70-200mm 2.8 is sharper at f4 then it is at 2.8. And speaking of zooms, this brings us to yet another point: Zoom lenses, especially telephotos, tend to get softer as you approach their maximum focal length.
All lenses have a performance sweet spot. With zoom lenses, it is usually toward the middle of the zoom range, and with both zooms and primes, it is usually 1 or 2 stops slower than the maximum aperture.
Now if you have made it this far and you think I’m suggesting that you not shoot wide open or at your maximum focal length, you might miss the whole point of this conversation. More on this in part 3.
Naturally, higher end lenses are usually sharper, especially at the maximum aperture, and have a sweet spot that covers a greater percentage of the zoom or aperture range and higher end cameras have better ISO performance. Spending more money, however, isn’t the solution because there is so much room for human error.
That’s what we will cover next time: shooting technique.