What is the depth of field at 50mm f/1.8 on full frame?
At 50mm, f/1.8, on full frame, focused at 2.5 meters, total depth of field is roughly 25.5cm — running from about 2.38m to 2.63m from the camera. That's enough margin to keep a subject's whole face sharp even at a slight angle, though a full-body pose at this distance would still show real background separation.
Why 50mm f/1.8 Feels Different From 85mm f/1.4
50mm's shorter real focal length than 85mm produces meaningfully more depth of field at a comparable subject distance, even at a similarly fast relative aperture — this is the same focal-length effect that drives every depth-of-field comparison on this site, independent of the roughly one-stop aperture difference between f/1.8 and f/1.4. It's a large part of why 50mm f/1.8 lenses have such a strong reputation as versatile, forgiving primes: fast enough for real background blur, controlled enough that focus errors are less punishing than they are on a longer portrait lens.
What Changes This Number
Stopping down to f/4 more than doubles the total depth of field at the same distance, to roughly 57cm — a real, useful adjustment for a two-person portrait where both faces need to sit reliably within the sharp zone. Moving the subject further from the camera widens the sharp zone further still, at any fixed aperture.
Check the exact figure for your own distance and aperture in the DoF & Hyperfocal Calculator, pre-filled with 50mm f/1.8 at 2.5 meters.
Frequently Asked Questions
Is 50mm f/1.8 wide enough for genuine background blur?
Yes, at typical portrait distances the background separation is real and visible, though it's noticeably more moderate than an 85mm or 135mm lens produces at the same f-number, since depth of field narrows with longer real focal length at a fixed distance.
Why is 50mm f/1.8 often called a forgiving lens for beginners?
Its depth of field at typical shooting distances is generous enough that a small focus miss is less likely to ruin a shot than it would on a longer, faster lens like an 85mm f/1.4, while still delivering real, visible background separation.