Measuring for close focusing with folders.

Helge · Aug 10, 2021

ciniframe said:
Yes, they had a fixed focus model Tourist with a single element meniscus lens, 86mm working at f12.5 and a front mounted aperture that will stop down to f32, all mounted in a single speed 1/50sec shutter with T and B settings also.
The interesting thing about the Tourist was that the flange where the lens clipped on has been the same distance to the film in every one I’ve measured so that you can clip on a lens from a different model, although the shutter linkage won’t align so you usually have to use a cable release.

I believe something similar was sold as "folding Brownie". Still beats a Holga. ;-)

Danielle_B · Aug 10, 2021

Helge said:
I believe something similar was sold as "folding Brownie". Still beats a Holga. ;-)

I think you're right. considering it's limitations it doesn't do too awful. Some Pan F 50 on a sunny day and the Kodet lens can actually pull off something nice.

pbromaghin · Aug 13, 2021

With regard to the original question, like any good programmer I finally resorted to reading the instructions.

The Voigtlander Bessa 1 Instructions for Use, say to measure from the front of the lens. HOWEVER, it only specifically mentions measuring from the front of an attached Focar lens. Apparently Voigtlander offered a pair of magnifying lenses to be attached to the front of the lens via push-on mount. These allowed photographing as closely as 13-1/2 inches! That's 34.29mm for our Metric friends.

With the F1 lens the infinity setting adjusted to 31-1/2' (80cm) and the 5ft became 20-3/4' (52.7cm).
With The F2 lens the infinity setting adjusted to 17-1/2' (44.45cm) and the 5ft became 13-1/2' (34.3cm).

At those distances, the starting point will really make a difference!

Danielle_B · Aug 13, 2021

pbromaghin said:
With regard to the original question, like any good programmer I finally resorted to reading the instructions.

The Voigtlander Bessa 1 Instructions for Use, say to measure from the front of the lens. HOWEVER, it only specifically mentions measuring from the front of an attached Focar lens. Apparently Voigtlander offered a pair of magnifying lenses to be attached to the front of the lens via push-on mount. These allowed photographing as closely as 13-1/2 inches! That's 34.29mm for our Metric friends.

With the F1 lens the infinity setting adjusted to 31-1/2' (80cm) and the 5ft became 20-3/4' (52.7cm).
With The F2 lens the infinity setting adjusted to 17-1/2' (44.45cm) and the 5ft became 13-1/2' (34.3cm).

At those distances, the starting point will really make a difference!

If it's anything like the Kodak Tourist cameras it would still be measured from the front of the lens. when I use the diopters on my Tourist cameras I measure from the front of the original lens and it seems to be working fine for me.

pbromaghin · Aug 17, 2021

Yesterday I tried the scotch tape method on the Bessa I 6x9 and the image was clear and easy to see. However, the results varied wildly, both longer and shorter than measured distances. There were even differences on multiple measurements from the same position! It came down to 3 mistakes.

1) I applied the tape across the 9cm opening, 2) the frame members at either end are about 2mm closer to the lens than are the transport pins and the upper and lower members that determine the actual film plane and sometimes the tape stuck to that, and 3) tape can curl, skewing the results and 9cm made that to easy to happen.

Next time the tape will go vertically across the 6cm dimension and will be taped to the frame that guides the edges of the film.

Donald Qualls · Aug 18, 2021

What I've done in the past was to cut a piece of CD jewel box cover to fit across the film rollers and rails, then put frosted tape on one side. The taped side goes toward the lens, obviously. This gives a surface about as flat as well-managed film and is both easy to handle and reasonably durable -- but much cheaper and less fragile than actual ground glass.

Helge · Aug 18, 2021

pbromaghin said:
Yesterday I tried the scotch method on the Bessa I 6x9 and the image was clear and easy to see. However, the results varied wildly, both longer and shorter than measured distances. There were even differences on multiple measurements from the same position! It came down to 3 mistakes.

1) I applied the tape across the 9cm opening, 2) the frame members at either end are about 2mm closer to the lens than are the transport pins and the upper and lower members that determine the actual film plane and sometimes the tape stuck to that, and 3) tape can curl, skewing the results and 9cm made that to easy to happen.

Next time the tape will go vertically across the 6cm dimension and will be taped to the frame that guides the edges of the film.

Here is the zen micro koan of the day:

Tape the pressure plate.

Look through the lens of an SLR camera looking at a clear, flat, high contrast target, the same thickness as film and backing paper taped to the pressure plate of the folder.

Jim Jones · Aug 18, 2021

Some CD jewel boxes are awfully flimsy. Perhaps one can find thicker and more rigid plastic somewhere around the house. I prefer glass cut to size and with the sharp edges dulled with a coarse whetstone. Once I have glass, it seems worthwhile to grind one surface with appropriate material rather than using Scotch Magic Tape. A side by side test under a 15X loupe of ground glass and Magic Tape indicates that they are about equal in practical focusing ability. I can make a flawless ground glass, but a flawless Magic Tape application is more elusive.

Nicholas Lindan · Aug 18, 2021

I use microscope slides & scotch tape. Easier than cutting up window panes. I tape the slide against the rails; for some cameras getting the slide to sit against the rails is a problem so I shim the slide with thin card so it sits on the aperture at the level of the rails.

Measuring for close focusing with folders.

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