16 July, 2017

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. 


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

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