Lens Sweet Spot

Aaarhus seen from my kitchen window today.

During the hollidays I'd like my DSLR pictures to be sharp from the foreground to infinity. Most lenses has a sweet spot, where pictures are better. When you've found that it's a matter of point and shoot.

Some rules of thumb if you want a sharp picture from foreground to infinity. 

When in doubt, try F8 - else try:

• 24mm ~ >= f11 <= f16.
• 35mm ~ f16 (street photo, 2m -> infinity sharp).
• 50mm ~ >= f22 (2m -> infinity sharp).
• > 80mm (no sharp foreground) f5.6 (from 100 m. -> infinity).

For most lenses the general rule is low f-stop + 2. 

• e.g. 1.8/50 ~ f4.

If you want to find the real sweet spot for a lens, try settings as above. Shoot several pictures, and compare the sharpness on the PC. For every new picture add an f-stop. 

Source, see this article.

A nice calculator is found here. Here is the result of the hyperfocal calculator:

From: http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm 

Hyperfocal Distance

On Wikipedia you can see the formula for hyperfocal distance:

"In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an "acceptable" focus." (from: Wikipedia)

In theory we could create an app for the calculations, but ... in the field you just need something that works. I guess the rules of thumb will do the trick.

Sony a58
Change the autofocus area to 1/3 (probably it's in the center). Then you  should have the correct focus, provided that the f-stop is on the sweet spot. Set aperture between >= 8 and <= 11, and set ISO to auto. Then it's a matter of "point-and-shoot". That would be a good street or landscape setting.


Tamron B018S
Look at this site for specifications.

There's a video with a german photographer using apertures ranging from 5 - 11, but more than often 5 or 8. 

Tip: 

• Try manual focus.
• Use A on your camera's settings ring.