Re: [APML]: 2X converter

[Space Boy <astro@cu-online.com>]

The Astro-Photography Mailing List
------------------------------------

Greg Mueller wrote:
> 
> I have the 4" focuser. The 2x converter I was referring to is the one
> Pentax sells for use between their lenses and the camera body. I figure,
> if it doesn't create any optical problems it would attach quite nicely
> as the field flattener has the "rear end" of a Pentax lens built onto
> it. All you'd have to do is unhitch the body put in the 2x converter and
> hook the body back on.
> 

 I forgot to mention this.

 I think it would be better to try the 1.4x, since it is "less radical"
than a 2x.  Generally speaking, 1.4x's perform better than 2x. 
(However, note that there are some really GOOD 2x TCs out there).  Plus,
your f-ratio would be more "manageable" at f9.8 (vs f12!).

  I read somewhere, that David Muench (well known landscape
photographer) went to Alaska, took only a couple P6x7 lenses and a TC
(forgot which one, probably the 1.4x).  This kinda implies he's
satisfied with the Pentax TC, quality-wise.


Space Boy