Re: [APML]: 300mm F2.8 lenses..which brand?

["Philip Perkins" <philip@astrocruise.com>]

The Astro-Photography Mailing List
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> To those who responded to my last posting re the Pentax 800/4 lens, thankyou very much 
>for your help and input. Unfortunately, the lens was sold before I had a chance to check 
>out.So to this, I have > 
> I have seen many beautiful images taken with these big 'guns' but which has the 
>flattest field at max.aperture?

Jim 

I have used both Tamron and Nikon 300mm f/2.8 lenses. The Nikon does have
the edge on resolution, especially at the edges, where the Tamron has some
colour fringing.  However I was really surprised by the amount of vignetting
from the Nikon lens, even when stopped down to f/4. I think I would have to
stop it to f/5.6 to reduce vignetting to an acceptable level. I took plenty
of photos with the Tamron at f/4 and saw no sign of vignetting (I did not
try it seriously at f/2.8).  I was not prepared for this vignetting and I do
not recall anyone bringing it up as an issue before I bought mine.

I do not think it is an issue with this particular lens because my Nikon 
400mm f/3.5 vignets in just the same way.

This problem has had me rethinking my plan of investing wholeheartedly 
in Nikon lenses. In fact I may sell the 300mm f/2.8 because it gets used so 
little and it was a very expensive investment. It cost me three times more 
than the Tamron.

The big problem with the Tamron is the slop in the Adaptall mounting
system. This is a potential killer and means that the camera body really
needs mounting too.  In portrait format, this can be a big problem.

So whatever lens replaces the Nikon 300mm, it will have to have a native 
Nikon fit.  I am even thinking of trying the Sigma range, which is highly 
regarded.  They do a 70-200mm f/2.8 zoom which is highly regarded by 
professional photographers over here.  I know that zooms are not considered 
optimum but this one is supposed to be exceptional.  The zoom range would 
give valuable flexibility and in my experience the field coverage of 200mm 
is proving to be more useful than 300mm.  The other potential 300mm targets 
are actually covered better with my 400mm.  It seems that I can cover the 
range better by skipping 300mm and going with 200mm and 400mm.  There is 
only one target I can think of that appears optimum for 300mm, and that is 
the Antares - Rho Ophiuchi region, but I would cover that with 200mm.

Regards
--Philip

Philip Perkins  --  philip@astrocruise.com
51 27'N 1 36'W  --  Wiltshire, UK
43 54'N 5 32'E  --  Luberon, France
Astrocruise     --  http://www.astrocruise.com