This blog is my attempt to keep track of some of the things I learn along the way, with my Canon 7D, G12 and accessories. All images copyright Brad Calkins, not to be used without permission (or purchase). I do not attempt to monetize my blog, other than to promote my stock photo portfolio on Dreamstime.

Wednesday, December 23, 2009

Do we need a new Sunny 16 rule?

Many photographers who have been around for a while will be familiar with the 'Sunny 16' rule. On a sunny day you set the aperture to f/16, and the shutter speed to 1/(ISO). If you camera is set to ISO 100 you'd use 1/125, or 1/90 as the shutter speed. Rules are useful, as far as they go, and as cameras have had meters added it becomes less useful.

People do still like to shoot in manual, though, and it is still relevant to have a place to start for exposure - especially for white or black subjects which you'd have to compensate for if you used the meter. I'd like to suggest, however, that the rule needs an update - shooting at f/16 just isn't a good idea with today's digital sensors. Most sensors these days (APS-C or micro 4/3, anyways) start to hit the limits of diffraction by f/16. It is better to shoot at f/8, or even f/5.6. On a digital compact like the G10 you don't even have f/16 as an option! Note that I'm talking about using f/5.6 or f/8 as a starting point - there are good reason to use f/16, even with diffraction...

So here is my new 'Sunny 8' rule:

On a sunny day, set the aperture to f/8 and the shutter to twice the ISO speed.

Note that these days shutter speed are displayed as their reciprocal (at least on my 40D's top LCD and in the viewfinder), so why not lose the 'one over' part and just tell it like you set it!

Off to give it a try :)

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