Could someone look in the photoes section under TL 120 interior shots
and look at the photo labeled F22. Does your camera at F22 have about
the same aperture opening? My camera came with mismatched apertures
so I took a lens off and matched the apertures and the markings of the
aperture rings to the viewfinder lens's ring. But I am not positive
that the matched apertures are now appropriately sized at F22. The
apertures of the lenses when not linked can be closed down further
than F22 and opened up wider than F 2.8 Some shots have been off
exposure wise, while others are spot on. I just wanted to eliminate
my lens openings as one of the variables.

Dale Yingst

--- In MF3D-group@yahoogroups.com, "Dale Yingst" wrote:

>
> Could someone look in the photoes section under TL 120 interior shots
> and look at the photo labeled F22.

I don't see the photos posted. Were there any problems loading them?
Send them to me if there's a problem, and I'll post them.

Sam

> I don't see the photos posted. Were there any problems loading them?
> Send them to me if there's a problem, and I'll post them.
>
> Sam

I just looked and it's there. Photos section- Tl 120 interior shots
folder- F22 picture

Dale Yingst

Found it. I was looking for a F-22 directory, and your "sampson17112"
ID didn't help. They look pretty close to my cameras at f:22

Sam

--- In MF3D-group@yahoogroups.com, "Dale Yingst" wrote:
>
>
> > I don't see the photos posted. Were there any problems loading them?
> > Send them to me if there's a problem, and I'll post them.
> >
> > Sam
>
>
> I just looked and it's there. Photos section- Tl 120 interior shots
> folder- F22 picture
>
> Dale Yingst
>

Dale Yingst wrote:

> . . . I am not positive
> that the matched apertures are now appropriately sized at F22.

Do you have a mechanism by which to simply measure the
aperture? I'm able set my shutter on B and backlight the
open back. Then I can hold my caliper in front of the lens
and get a purty-good idea of what it measures in mm.

Since the "f" in f/stop is the focal length of the lens and
we know the lenses are supposed to be 85mm. By the power of
division, we can determine that for an 85mm lens, the
aperture diameters are:

Diameter
f/2.8 30.4mm
f/3.2 26.6mm
f/3.5 24.3mm
f/4.0 21.3mm
f/4.5 18.9mm
f/5.0 17.0mm
f/5.6 15.2mm
f/6.3 13.5mm
f/7.0 12.1mm
f/8.0 10.6mm
f/9.0 9.4mm
f/10.0 8.5mm
f/11.0 7.7mm
f/12.0 7.1mm
f/14.0 6.1mm
f/16.0 5.3mm
f/18.0 4.7mm
f/20.0 4.3mm
f/22.0 3.9mm

Does yours come anywhere near those numbers?

________________________________________
John Thurston
Juneau, Alaska
http://stereo.thurstons.us

John Thurston wrote:

> Since the "f" in f/stop is the focal length of the lens and
> we know the lenses are supposed to be 85mm.

Arrgh.

I apologize. . the TL120 doesn't have 85mm lenses. As Don
has politely pointed out to me they are actually 80mm (which
would have been obvious to me if I had opened my eyes).
Disregard my earlier B.S.

Diameter
2.8 28.6
3.2 25.0
3.5 22.9
4.0 20.0
4.5 17.8
5.0 16.0
5.6 14.3
6.3 12.7
7.0 11.4
8.0 10.0
9.0 8.9
10.0 8.0
11.0 7.3
12.0 6.7
14.0 5.7
16.0 5.0
18.0 4.4
20.0 4.0
22.0 3.6
________________________________________
John Thurston
Juneau, Alaska
http://stereo.thurstons.us