"Charles Kinghorn" <charlesREMOVE@CAPScharking.com> wrote in message news:260jvv0c1v7s7fmt4uuocblku4bidi9p1c@4ax.com...

> I posted this in the Pentax Discussion Group, but I thought someone

> here might have some input:

>

> I discovered recently, on the Mamiya web site, that the Mamiya 645

> Tele-Converter 2x works with their 50mm shift lens as well as their

> telephoto lenses from 150mm to 500mm. This permits a more normal

> perspective when photographing buildings while correcting for the

> verticals, assuming in both cases that one is filling the frame

> (perspective depends on distance). It effectively gives one more

> options when doing architectural photography with a small camera.

>

> My first question concerns the Pentax Rear Converter K T6-2X. Will it

> work with the Pentax 28mm shift lens? I borrowed a second-hand one

> yesterday, and my in-house playing with the two lenses indicates that

> it might. I will be field testing it; but we are expecting snow over

> the next few days, so it could be several days before I can try it

> outside. Has anyone else tried this combination out and with what

> results?

>

> My other question also concerns the Pentax Rear Converter K T6-2X. It

> does not appear to focus at the same distance when used with a lens,

> compared to that lens alone. It "appears" to focus closer on the

> lens's focusing scale. Is this normal?

>

> Any help or feedback on these two questions would be much appreciated.

>

> Regards,

> Charles Kinghorn

On Nikon gear, the 1.4X and 2X converters do work with the

35mm and 28mm PC lenses (and shifts amounts are effectively

multiplied by the TC multiplier, making extreme shifts possible

[horizon line outside the frame]), BUT, shifting the lens decenters

the optics in the system, with bad effects with small stops. With

the Nikkor set, limiting the aperture selection to about f5.6

optimizes things...

--

David Ruether

d_ruether@hotmail.com

http://www.David-Ruether-Photography.com