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12-20-2010, 02:21 PM   #1

Join Date: Feb 2010
Location: Blunsdon,Wiltshire, UK
Posts: 959
Sigma 600mm f/8 mirror

Looking at the manual that came with a Sigma 600mm f/8 mirror lens that I aquired the other day it says that if you use the Neutral density filter of 4X in place of the normal one it reduces the effective aperture to f/16.
The weather is bad here at the moment so I have not had a chance to try it.
Has anyone used this filter and noticed any change in DOF?

12-20-2010, 03:02 PM   #2
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Join Date: Sep 2006
Location: Mississippi, USA
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Posts: 572
Like any ND filter all it will do is block the light and let you use a slower shutter speed. It won't change the aperture size. I've played around with the filters on mine and no dof change has been noted.

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