Even though there is no ‘official’ sweet spot for lenses we can look at examples to see what looks to be the best.
On the Canon 50mm f/1.8 STM lens (aka the ‘nifty fifty’) the sweet spot for aperture seems to be about f/5.6.
This is where the image seems to have the least amount of aberrations and the highest amount of sharpness.
How Do I Find My Lens’ Sweet Spot?
If you want to check for yourself the best way to do this is to either take a bunch of pictures of the same subject at different apertures.
The best way to do this is to print out a test chart and take pictures of that, but you could also use something like a newspaper.
You can find a test chart at the link below:
Then you would zoom in on the picture in different parts of the image to see which image has the most sharpness and least aberrations
You could also use the link below where there are sample images for the 50mm lens at different apertures.
Change the aperture so you can compare the images at different f-stop values.
When doing this you can see that the sharpest range of apertures is from about f/4 to f/11 but the sweet spot for the f-stop seems to be about f/5.6.
At What Aperture Is The 50mm 1.8 Sharpest?
Personally, I find the 50mm to be sharpest at f/5.6, but in the range of f/4 to f/11 the lens still performs brilliantly.
This doesn’t mean you should avoid other apertures though.
Sometimes you need to be using a wider aperture to achieve a shallow depth of field and a lot of the time you can mitigate aberrations in post-production.
You can also increase sharpness in post-production too.
The sweet spot for the nifty fifty Canon lens is around f/5.6.
If you want to find out more about the Canon 50mm f/1.8 then check out the video below.