Crop sensor, 50mm equivalent, portraits at f/2. On the camera screen everything looks tack sharp. On a 27 inch monitor at 100 percent the eyes are just slightly soft — not motion blur, more like the focus landed on the eyelashes or the cheek instead. Shutter is 1/250 or faster and I am using single point AF. What is going on?
Also check your viewing habits. 100 percent on a 27 inch monitor is looking at a print about a metre wide from 40 centimetres away. Almost nothing is sharp at that magnification, and photographers torture themselves over softness nobody will ever see. Zoom to fit and ask whether it is sharp at the size it will actually be viewed.
True, but it is still a useful diagnostic. Just do not treat 100 percent as the standard your work has to pass.
Whatever test you run, run it at two different distances before you adjust anything in the camera. I calibrated against a target at a metre and a half once, was delighted for a week, and then worked out I had made everything at five metres worse.
1/250 is not always fast enough for a person breathing at f/2 up close. A centimetre of subject sway is enough to move you off the eye when the depth of field is two centimetres. Going to 1/500 for close portraits made a chunk of my soft shots disappear.
Check your sharpening pipeline too. Camera JPEGs get sharpening baked in and the raw file looks soft next to them until you apply capture sharpening. If you switched to raw recently, that alone accounts for a visible difference.
I did switch to raw about two months ago, which lines up suspiciously well.
Fast primes are always soft wide open. Stop down to f/4 and stop worrying about it.
Modern fast primes are pretty good wide open. The softness people blame on the lens is usually missed focus, and a tripod test separates the two in ten minutes.
@chalkbag_chen · 6mo ago · 3 replies
Two separate things are happening and both are normal. The back screen is a 3 inch display showing a downsampled image, so almost anything looks sharp on it and it is not evidence of anything. The real issue is that at f/2 on a 50 at two metres your depth of field is a couple of centimetres, which means the eyelashes and the cheek genuinely are at different distances and the camera picking either is plausible. Use eye detect AF if the body has it, and if you are focusing and recomposing, stop — swinging the camera after focus moves the plane by more than your depth of field. Then shoot a ruler at 45 degrees on a tripod at f/4 and you will see immediately whether it is technique or a front/back focus problem with the lens.
Reply
Report
@goldenhour_glen · 6mo ago
Ruler test shows focus landing about 3cm behind the target. So the lens then?
Reply
Report
@chalkbag_chen · 6mo ago
Consistently behind across distances means back focus, and most bodies have a micro-adjustment for it, or you can send body and lens in as a pair for calibration. If it only misses at close range, that is a different and more annoying problem.
Reply
Report