EV and ISO Settings

[petert]

This may seem like a silly question, but I thought I would ask... The math seems right, but I've never tried it.

Here's a suppose-it for you: if you're shooting at ISO 1600 in a rock club (stage lights and no flash). You meter - frame - click... then look at your results and think "good shot, but I don't want all that grain"... is it equivalent to changing down to ISO 800 and add 1EV to get the same sensitivity or the same shot? Will the quality-of-results be the same or better? I'm trying to improve the end result of my low-light shots here and thought this might work.

Thanks in advance...

[chloew]

I'm not sure what you mean by adding 1 EV in this situation. If you change from ISO 1600 to 800 in your example, you need to increase the aperture by one stop (reduce the f stop by 1.4) or double your exposure time, to get the same overall exposure. If you do one of these two things, you will get the same exposure as in the original picture but with less grain. However increasing the aperature will decrease your DOF, while changing your exposure time will affect the amount of motion blur.

Unfortunately in most cases you already have your lens wide open (you can not increase the aperture) and are pushing the exposure to the point that you will get motion blur.