Re: [APML]: Bobby's M31

[Wil Milan <wmilan@airdigital.com>]

Philip Perkins wrote:

> First of all congratulations on your new page layout. It looks fine and I
> think you have some fine images. I was particularly interested in your M31
> shot taken with the Sigma 400mm f/5.6 wide open.  This is an extremely sharp
> photo and the quality is as fine as I've seen from any lens.  It appears to
> be almost a full negative scan and as far as I can see there is no sign of
> chromatic aberration and the stars are pin sharp to the edge of the frame.
>
> Would others concur?

I certainly do. Excellent image, Bobby, both technically and aesthetically
pleasing. Great work.

> Wil, if you are tuned in, would you expect similar
> performance from the Tamron 400mm f/4 wide open?  You may see the image at:
> http://www.webwide.net/~bobbym/m-31.jpg

I've had similarly excellent results with the Tamron 400mm f/4. For an example
of a full-frame shot taken with the 400 f/4, see my shot of the M42 & Horsehead
region (see URL below). That shot is just about a full-frame shot, cropped only
slightly along the long edge. I've been very pleased with the images from this
lens, which I always shoot wide open. The URL is:

http://www.psn.net/~airdigital/Horsehead_and_M42_Tamron_400mm_f4_PJM_40min_26_Oct_1997_Table_mesa.JPG

(I apologize for the long file name; it's how I keep track of exactly which file
is which. I also apologize for the @#%! film scratches; I wish I could find a
color lab which doesn't use roller processors.)

FYI: Benjamin Gomes-Casseres has done some controlled comparisons of this lens
vs. an AP Traveler and a few other lenses and scopes, with the tests yielding
excellent results from the 400 f/4. (Ben, if you have a chance you might post
the test results you sent me -- thanks.)

> I am currently scouting around for a lens in the 400mm range. I would prefer
> something faster than f/5.6, but for this sort of quality I might be
> prepared to compromise!  My ideal choice might be a Nikon 400mm f/2.8,
> however I baulk at paying the sort of money that could buy me a whole new
> scope! :8  The Tamron 400mm f/4 looks very interesting but is hard to find.

The Tamron 400 f/4 is indeed hard to find. It's now discontinued, and it never
sold in great numbers. A Tamron rep told me it wasn't a big seller for two
primary reasons: its high price (well over US$2000), and that most photographers
went for the faster (but less sharp) 300 f/2.8. According to the rep many 300
f/2.8 buyers figure to use a 1.4x teleconverter to cover 400mm, but that
combination is *not* as sharp as the "native" 400mm f/4.

Wil Milan
--
"When I consider your heavens, the work of your fingers, the moon and the stars
which You have set in place, what is Man that you are
mindful of him, or the son of Man that you care for him?"  -- Psalm 8