Pressure-fit Dagor

[Ash]

Thanks to Don Qualls, I received a Polaroid Prontor Press #1 shutter in the post yesterday. I've been playing with it after work, during my evenings, and I have some success!!

That Doppel-Anastigmat Series III/2 180/6,8 from my grandfather, the one in the sunken barrel that I could never really be bothered to use because of its stiff aperture, near-impossibility mounting to a camera etc etc...



Turns out the laziest method works great!

Here's the lens on the camera in its original barrel... http://i2.photobucket.com/albums/y43...d/DSC00124.jpg

Here's the lens:
http://i2.photobucket.com/albums/y43...d/DSC00039.jpg (before i managed to strip the white lettering )
http://i2.photobucket.com/albums/y43...d/DSC00913.jpg
http://i2.photobucket.com/albums/y43...d/DSC00916.jpg

And here's the prototype pressure-fitting, rubbish photo.

I folded masking tape (3-fold, so it is adhesive on both sides, in a slither) and ran it around either element, so that the lens is held by pressure, surprisingly secure, in the shutter.

It's now dark outside so I can't take a nice photo of the camera (with its nasty fibreboard lens panel) nor can I take a couple test photo's

[Ash]

Here's my first shot with the lens!

I'm really pleased. It was shot about 3pm at Lydiard Park, 1/8 at "f/8" on the shutter, which is more like f/16 on the lens. The lens is a 6,8 and the aperture scale is for a 4,5. Metering against my hand, EI-12 for the Kodalith ortho = 1/8 at f/16. Looks about right to me



Not bad for an early lens held in a new-ish shutter with tape

EDIT: forgot to say that's a straight scan, no editing (obvious by the specs in the sky) and no levelling etc.

[Ash]

There's a 100% crop at 720dpi I believe

[Donald Qualls]

That's working pretty well, Ash.

That aperture scale *should* be for f/4.7, on a 127 mm Tessar-type lens, so you'd have to calibrate for other lenses by either measuring the aperture (through the glass) from the front or developing a "correction" by looking at what point on the aperture scale the diaphragm is lost from view from the front, calling that f/6.3 (in the case of the Dagor you're talking about) and applying the same correction over the entire scale from there.

Looks like your Dagor is working pretty well, though, regardless how you arrive at exposure -- so I'd say you've adequately calibrated the combination of that ortho film and that lens/aperture...

[Ash]

Thanks Don. I'm off to bed in a moment (it's 1:30am and I need to be up in time to get your Kalart packed and posted ).

Since I have both the front and rear original threads, I'll be trying to gut all but the thread part, and attach that to the Dagor elements. In this way I can permanently screw the lens elements onto the shutter, but still remove them for shutter/lens cleaning.

If that's not possible, at least I have the template pitch and thread to give to a machinist to make new brackets to attach to the elements. Thanks again Don!