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Re: [OM] WTB: Lens hood/shade for Zuiko 28-48 zoom

Subject: Re: [OM] WTB: Lens hood/shade for Zuiko 28-48 zoom
From: Pschings@xxxxxxx
Date: Wed, 23 Apr 2003 12:08:28 -0400
In a message dated 4/23/2003 10:03:09 AM Eastern Standard Time, 
jeffreyrkeller@xxxxxxxxxxx writes:

> I believe a lens will vignette at wide apertures first - large format
> cameras always specify what aperture is used to cover a 
> given image
> circle.

I think what you are referring to here would more properly be called light 
falloff, and not vignetting. Vignetting occurs when something is blocking the 
light path, like a lens hood, and is more prominent with smaller apertures, I 
believe. Falloff is an optical property of the lens, and IIRC there is a 
theoretical minimum of falloff for any lens that is a function of cos^4 of the 
angle the light is entering the lens, or something like that. Falloff is more 
prominent at wider apertures, I believe.

Of course, I've been known to be wrong in the past. :-)

Back to the original question, I have a 28-48 with the original hood, and I 
also have the 24/2 hood. I'll take a look at them and see how they compare. 
I'll also check to see if the 35-70/4 slip on hood will fit the 28-48 (never 
tried it).

Paul Schings

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