Sam, I've been thinking about your Mamiya 55
graft onto the TL120 but I'm wondering what
you're doing for focus?

As I recall, the C330 focused by moving the
entire lens board rather than rotating elements.
Have you incorporated any focus into your
TL120 or are you using your 55 equipped camera
as a fixed focus rig?
--
John Thurston
Juneau Alaska
http://stereo.thurstons.us

John,

It's focus free. Preset to 13 feet. At f22, my primary aperture,
everything is sharply in focus from 6 feet to infinity. Point and
shoot MF3D!

Sam

--- In MF3D-group@yahoogroups.com, John Thurston wrote:
>
> Sam, I've been thinking about your Mamiya 55
> graft onto the TL120 but I'm wondering what
> you're doing for focus?
>
> As I recall, the C330 focused by moving the
> entire lens board rather than rotating elements.
> Have you incorporated any focus into your
> TL120 or are you using your 55 equipped camera
> as a fixed focus rig?
> --
> John Thurston
> Juneau Alaska
> http://stereo.thurstons.us
>

Hi,

At 08:11 PM 6/21/2007, you wrote:

John,

It's focus free. Preset to 13 feet. At f22, my primary aperture,
everything is sharply in focus from 6 feet to infinity. Point and
shoot MF3D!

Sam

Obviously, any subject space with Nears and Fars that fit between 6.5 feet and Infinity will work with f/22 when focused at 13 feet.

If there's insufficient light to shoot at f/22 for the shutter speed you require, here's a chart of some wider apertures you can use with your lens still focused at 13 feet.  Each of them require that you find a subject space that fits within the range of Near and Far specified.  (All distances are in feet.)

f-Number ---- Near ----- Focus ------ Far

22.6 -------- 6.5 ------ 13.0 ------- Infinity
19.3 -------- 7.0 ------ 13.0 ------- 91.0
16.5 -------- 7.5 ------ 13.0 ------- 48.7
14.1 -------- 8.0 ------ 13.0 ------- 34.7
11.9 -------- 8.5 ------ 13.0 ------- 27.7
10.0 -------- 9.0 ------ 13.0 ------- 23.4
 8.3 -------- 9.5 ------ 13.0 ------- 20.6
 6.8 ------- 10.0 ------ 13.0 ------- 18.6
 5.4 ------- 10.5 ------ 13.0 ------- 17.1

Any subject space that fits within the boundaries shown for each f-Number, will look every bit as sharp as the 6-foot to Infinity subject space does when using f/22.  So when the light starts to fade, just look for tighter subject spaces.  The spaces required to fit these wider apertures won't deliver as much OFD in your stereo views, but at least you don't have to put the camera away for lack of sufficient shutter speed at f/22.

Mike Davis

--- In MF3D-group@yahoogroups.com, "Michael K. Davis"
wrote:

>
>
> Hi,
>
> At 08:11 PM 6/21/2007, you wrote:
>
> >John,
> >
> >It's focus free. Preset to 13 feet. At f22, my primary aperture,
> >everything is sharply in focus from 6 feet to infinity. Point and
> >shoot MF3D!
> >
> >Sam
>
> Obviously, any subject space with Nears and Fars that fit between

6.5

> feet and Infinity will work with f/22 when focused at 13 feet.
>
> If there's insufficient light to shoot at f/22 for the shutter

speed

> you require, here's a chart of some wider apertures you can use

with

> your lens still focused at 13 feet. Each of them require that you
> find a subject space that fits within the range of Near and Far
> specified. (All distances are in feet.)
>
> f-Number ---- Near ----- Focus ------ Far
>
> 22.6 -------- 6.5 ------ 13.0 ------- Infinity
> 19.3 -------- 7.0 ------ 13.0 ------- 91.0
> 16.5 -------- 7.5 ------ 13.0 ------- 48.7
> 14.1 -------- 8.0 ------ 13.0 ------- 34.7
> 11.9 -------- 8.5 ------ 13.0 ------- 27.7
> 10.0 -------- 9.0 ------ 13.0 ------- 23.4
> 8.3 -------- 9.5 ------ 13.0 ------- 20.6
> 6.8 ------- 10.0 ------ 13.0 ------- 18.6
> 5.4 ------- 10.5 ------ 13.0 ------- 17.1
>
> Any subject space that fits within the boundaries shown for each
> f-Number, will look every bit as sharp as the 6-foot to Infinity
> subject space does when using f/22. So when the light starts to
> fade, just look for tighter subject spaces. The spaces required

to

> fit these wider apertures won't deliver as much OFD in your stereo
> views, but at least you don't have to put the camera away for lack

of

> sufficient shutter speed at f/22.
>
> Mike Davis

Another solution is to change the focus distance by adding negative
diopter lenses such as 0.25 or 0.50.

Francois