Sunny f??

A situation came up recently where I had a Canon G9 in my hand and wanted to manually set a "Sunny f16" exposure. Alas, what we have for f stop values on this compact camers is 2.8, 3.2, 3.5, 4.0, 4.5, 4.8, 5.0, 5.6, 6.3, 7.1 and 8.0. Can someone tell me which of these compact camera f stops would equate to f16 on a dslr? Is there a "not too hairy" formula to calculate f stop equivalencies?

Thanks

If it won't go all the way to f/16, then you need to set it at f/8 and use the old equivalence formula to set the shutter speed to further reduce light to the right level. An equivalent exposure for f/16 @ 1/125 and 125 ISO would be f/8 @ 1/500 and 125 ISO. Said another way, since f/8 is 2 stops more open than f/16, you would need 2 stops faster shutter speed for equivalent exposures. At 200/250 ISO equiavalent sunny 16 exposure shooting at f/8 will require a shutter speed two stops faster than at f/16, so you would shoot at 1/1000. For 400 ISO the new shutter speed will be 1/2000 at f/8.

Thanks Hank. Of course that's right! I think I had a duhhh moment. Meanwhile, I've order a copy of the book "Math For Dummies". Thanks again.

Here's an equivalent to the sunny 16 rule.

In bright sun, at f5.6, add a zero to your ISO to determine the shutter speed.

For example, with your aperture set to f5.6 and ISO at 100, you shutter speed would be 1/1000. With the sunny 16 rule, ISO 100 at f16 would require a shutter speed of 1/100, or on older mechanical cameras, 1/125; which is an equivalent exposure to f5.6 at 1/1000.