Re: [APML]: M45 scanned with Nikon LS1000

["Bobby Middleton" <bobbym@webwide.net>]

I've seen many comments regarding the larger opening of the OM-1 compared
to Nikons.
Is it possible this is a contributing factor to the lesser amount of
vignetting that appears in
this shot. If I still had my OM-1 I could have done a "same-scope"
comparison. My
m-45 shot at http://www.webwide.net/~bobbym/m-45.jpg was done with a Nikon
F and it
certainly has much more vignetting. It was done in the same "lens-forward"
position of the GEG.
Its 90 min ex time was double that of Chris's, so that is certainly a
factor.
I've also calculated my true focal lengths acheived by the GEG; they are
close to what you had Philip.
GEG straight through, no reducer:         2800mm.......f/11
Reducer in rear position:                         2032mm.......f/8
Reducer in front:                                 1778mm.......f/7
Reducer in front with 2" extension        1600mm.......f/6.3

Bobby Middleton   
----------
> From: Chris Vedeler
> 
> Yes that shot was taken with the GEG with the lens forward position. 
Whether
> it is truly f/5.5 I don't know, but that is what they advertise.  I'm
pretty
> happy with the small amount of vignetting it produces.  In fact looking
at the
> negative the vignetting is hardly detectable.


> Philip Perkins wrote:
> > settings. This has the effect of greatly lowering the contrast and
hence
> > the degree to which negative defects are visible.
> >
> > Regarding the photo, you said that it is taken at f/5.5. I am
interested if
> > this was at Lumicon's stated f/5.5 (with the lens in the forward
position).
> > If so, your image shows remarkably little vignetting. I