Why f2 or f2.8 is the sweet spot for photography

When you shoot a portrait, you might think hey I paid a lot for this f1.4 super duper lens. I'm going to take my portraits at f1.4 !!!

Uhm no.

You have to remember that you want a slice of reality to be in focus from about a foot in front of your models eyes, and a foot or two behind. Standing 6-10 feet away, this will nearly always mean f2.8.  If you are closer, then f2. If you are at great distance, like 20 yards, then f3.5 or even f4 is what you want.

This is one of the biggest mistakes I made starting out and one that took the longest time to get into my head.

Remember also that sharpness improves as you step down two or three clicks from maximum. A few rare GOD lenses achieve 95% of best sharpness from the widest aperture. But that's rare.

Take the 50mm 1.2 nikkor.  At 1.2, its barely sharp. But click once to F2 and its nicely sharp. But click once more to 2.8 and its TACK SHARP.  Most lenses that are crappy can't compare until they hit either 5.6 or f8.  Which is what you get with all those zoom lenses shot on Auto. And that's a boring picture.

So I hang on some "zestier" sites which have nude shots by semi pro photogs. And almost always the biggest error is you don't get a blurred out background. They are shooting at f8. It's what their camera has told them is correct. And in a way that camera is right. It's going to get a lot in focus for you, except that's not what you want.

You want to strike that complex medium. You want ALL of your models face and body (esp for NUDES the BODY!) i focus. But to focus the picture on that you have to decide if you want that OR NOT.

IF you are bettina Rheims and shoot in lavish french apartments with 500 year old furniture, you take pictures of your nudes at f8.

But if all you have behind you is a black cloth, Or if you are outside and want the background to fall away into creamy bokey, Then f2.8 is your friend.  If you are REALLY close (and you shouldnt be to take a full body nude but maybe you can't help yourself!) then f4 is what you are after.

Working with Flash makes this even more annoying. Since flash can make any aperture bright enough, your camera will again say "Oh ok f8 it is" and you say Freak You camera, I'm going to manual mode! And then you get the shot.

30 years of this. trust me. Try it.