Originally Posted by Dallaz

This post is a few days old now but in case your still working on these shots or others like it, you definitely won't need more than a 1000th of a second shutter speed to freeze that bullet, so basically if it's still blurry/out of focus it's just the aperture and focus that now needs to be settled. For the focus just hold something in the water right where you are dropping the item whatever it may be and get a good focus, then just slap the dial over to manual focus so you don't have to mess with it again. also I have to assume your shooting in manual mode and any form of auto ISO is turned off, if not, do both of those.

With your ISO constant at whatever setting you had it, turn your shutter speed down from 1/4000th to 1/1000th saving you 2 stops of exposure to stop down your aperture from f2.8 to f5.6. Your exposure will be exactly the same as it was at 1/4000th but with gained depth of field using the smaller aperture so once the bullet hits the water and possibly shifts to the front or back a little bit from the point of focus you should still be fine. Lenses generally are their sharpest "technically" when stopped down roughly 2-3 stops from wide open so if your shooting with a f2.8 lens instead of stopping down an f.2 or f1.4 lens you will compromising a little sharpness just from shooting wide open, perfect focus or not, just a fact.

With the set up you have and the shots I've seen from you I'm sure you already know most if not all of this but I'm just trying to be helpful, so if you only take away one thing from this, I'm happy


On a side note, I may go as far as 1/750th of a second and f.6...... And seeing if the bullet is still "frozen" at that speed, shooting with the ISO no higher than 800 for something like this where your supposed to be getting exacting detail, you shouldn't have to anyways using those lights