ISO question

[Badcast]

I read on a post not to use the inbetween ISO settings like 250 500 is there a reason for this or is this not correct.

Randy

[Steaphany]

The only reason I would see for avoiding the in between ISO settings is it complicates the math.

If you have the ISO set to 200 and the meter yields a combination of f/8 aperture at a 1/200th shutter, you can alter the ISO to 400 and then it's a simple selection of f/8 aperture at 1/400th shutter or f/11 aperture at 1/200th to have the same exposure.

Now if you set the ISO to 250 or 500, you no longer have an obvious relationship to maintain the exposure.