Back to the ultra wide angle. Two pictures from same distance of about 1 foot to demonstrate focal length.
ISO 400 / 39mm / F8 – focus is on the eye…notice the blur on the bow and in the background
The second picture
ISO 400 / 40mm / F22– focus again is on the eye…notice how clear everything is, the big difference is how long the aperture stayed open to get the same picture.
Refer to the chart below to understand why.
- graphic from asmallsnippet.com