[LargeFormat] Re: Center filters vs Gray grads vs. Neutral density filters for 4x5

[Jim Brick]

I own a couple of center filters for my wide angle lenses. But I don't have 
a densitometer. If I did, I would measure the density in the middle, the 
density at the edge, and measure the distance from the middle to the edge. 
But alas... I cannot.

All I know is that they do the job that they are supposed to do. I get 
evenly exposed photographs, from corner to corner, using a center filter.

Jim


At 05:47 AM 7/19/2002 -0400, Guy Glorieux wrote:
>On the subject of ND filters, can anyone provide information on center
>filters used to reduce vignetting with very-wide angle lenses.  In
>particular, how quickly does the density decline from center to edges?
>Thanks,
>Guy
>----- Original Message -----
>From: "Jim Brick"
>
> > A graduated ND is used to balance a bright sky with a dark foreground.
> > That's why it is graduated. A ND filter is used to reduce the total
>amount
> > of light reaching the film, usually so you can use a wider f/stop
>(reduce
> > DOF) or for a longer shutter speed (to make water look silky.) ND
>grads and
> > ND filters are different and used for completely different purposes.
> >
> > Jim