When you’re sifting through your pictures from a shoot, you might have observed different levels of sharpness in images despite the same lens and the scene/light staying more or less the same. One of several reasons for this varied sharpness is the aperture you’ve used. The lens doesn’t maintain the same sharpness all through its aperture range. Almost all lenses have an aperture range in which they capture the sharpest images. This aperture range is a lens’ sweet spot. Here is how you can determine your lens’ sweet spot…
Identify your lens’ mid-range
Most lens work best at their mid-range apertures. Find out the widest aperture of your lens. It’s the aperture setting when your lens is completely zoomed out. The sweet spot is usually two full f-stops from the maximum aperture. For example, for a f/4 lens, the two full f-stops would get us the sweet spot at f/8 or a one f/stop further i.e., f/11. So the mid-range f/8 to f/11 would get us sharper results with an f/4 lens.
Now that you’ve determined the mid-range of your lens, you can find out the exact sweet spot to achieve the crispest images. The sweet spot is different for different lenses. Find your lens’ sweet spot by carrying out a test.
For this, you’ll have to use the Aperture Priority mode while clicking your images.
Why Aperture Priority Mode?
When you use Aperture Priority Mode instead of the Automatic, you can control the aperture setting which affords you more creative freedom. If your ISO is set on Auto, the camera decides the ISO and the shutter speed for you, so choosing the aperture setting manually wouldn’t prove that tough to capture sharp pictures.
f/16 and f/22 apertures are usually best for keeping everything in the frame in focus. However, keeping everything in focus may not render a sharp image. To achieve a sharper result, choose an aperture from the mid-range. Eliminate potential camera shake by using a tripod and releasing the shutter remotely or using the camera’s timer.
How to switch to Aperture Priority
Turn the big Mode dial on your camera to Aperture Priority (Av in Canon, A in Nikon/others) to switch from Automatic. Now move the Main Dial to change the f-stop. When you rotate that dial, you’ll see the changing f-number on your screen.
Test for the sweet spot
Set up your camera on a tripod. Switch to Aperture Priority mode and shoot with different apertures. Begin with the maximum aperture. Then turn the main dial twice towards the right and click another shot. Similarly, take around eight shots. Now view your images on your computer screen with 100% zoom. It’d be easy to spot which aperture setting gets you the sharpest image.
Clicking sharpest images
Choose Aperture Priority Mode and click pictures throughout the mid-range apertures (mostly f/8 through f/11). Use tripod and remote shutter release or camera’s timer to prevent camera shake. This will get you some of your crispest images.
Knowing your lens’ sweet spot doesn’t mean that you stop shooting beyond it. Keep experimenting with aperture for photography is all about getting out of your comfort zone and learning.
~ Aatika HJ, Write Wing Media