Re: Cokin vs. Jessops P size filters in the UK

["Des Crawley" <d.crawley@xxxxxxxxxx>]

Hi,

I am in the realm of conjecture but perhaps the following might assist you:

The vignetting is likely to come from the filter mounting holder rather
than from the filter itself. The "P" series filter ought to be large enough
to avoid  vignetting with a 52mm filter size lens. .  So, to see if this is
so  conduct a test with the filter mount in place but the filter off the
camera. Under reasonably bright light conditions-camera on a tripod for
ease of handling- adjust your lens until it is focussed on target object
and with lens at the wide end (28mm) of the zoom point .   Then use your
depth of preview button to stop the lens down at each aperture. If the
filter mount is the problem you should pick up the vigneting in the
viewfinder.  This approach will need some patience and willingness to
really examine the darkened image in the vewfinder for sufficient time to
allow your eyes to become accustomed to the dim view-particularly at small
apertures.

If my suspicions are correct the vignetting will appear at the wide angle 
end of the scale only. 

What to do about it ? Well, if it is the filter  mount accessory it might
be possible to trim back its front or leading edge which I recall is
designed to carry  two-three filters all up. Trim back the two (?) filter
slots that are really redundant  so that the mount   now only takes the one
filter dedicated to your (mine too ) passion for IR. Your filter mount will
now not intrude or extend so far out in front of the lens element and thus
not be "seen" 

Incidentally, because I am essentially a lazy sod I have sometimes simply
used the Cokin red filter) P series) with HIE-135 by just holding it in
place taking care to use just finger tips and with hand behind the front
element alignment of the lens. It works-but no doubt will upset the
sensibilities of some friends who read this site.  This  approach might
allow you to avoid vignetting unless of course you end up with superb IR
shots of your fingers, instead !
Regards from the Land of Oz- a country specifically designed for IR
photography

Des
- ----------
> From: JL <jql7285@xxxxxxxxxxx>
> To: infrared@xxxxx
> Subject: Re: Cokin vs. Jessops P size filters in the UK
> Date: Tuesday, March 31, 1998 7:53
> 
> > On 30 Mar 98 at 19:19, Spearmint wrote:
> > 
> > > Just a quick FYI for anyone in the UK who uses P series filters . . .
> > >
> > > Jessops now do their range of filters in P series sizes at
considerably
> > > cheaper prices than you'd pay for their Cokin equivalents.  I just
> > > purchased a graduated orange sunset filter, similar to Cokin 198 for
> > > 8.99, compared to Cokin's price of 17.99.
> 
> Speaking of Cokin filters, the last time I used them, I was disappointed
> to find "vignetting" around all the corners of my photos, and have shied
> away from then since. I have a red filter that I'd like to use for IR,
> but am afraid of this problem again. Any ideas on how to avoid it? I was
> using a 52 mm on a 28-70 zoom lens with a Nikon.
> 
> Thanks,
> 
> jackie
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