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Re: [OM] So here's the deal...

Subject: Re: [OM] So here's the deal...
From: Jan Steinman <Jan@xxxxxxxxxxxxxx>
Date: Thu, 16 Dec 2010 09:30:01 -0800
> From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
> 
> ... exposure adjustments for magnification when shooting macro... The 
> effective aperture is reduced and the image becomes dimmer.

Ah, but does the resulting "effective aperture" effect depth-of-field, or is 
DOF still strictly the result of reproduction factor and true focal ratio (as 
opposed to light transmission)?

I suspect the answer is "no, DOF is independent of extension light fall-off" 
just as slapping a neutral density filter on the end doesn't increase DOF.

I've often wondered briefly about that, but I've been too lazy to fully 
research it and puzzle it through.

----------------
An American is a person who demonstrates against a new power plant, then goes 
home and flips on all the lights, turns up the air conditioner, puts a tape in 
the stereo, opens the refrigerator door, plugs in the coffee maker and sits 
down to see if the television cameras caught him protesting. -- Wendell Trogdon
:::: Jan Steinman, EcoReality Co-op ::::

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