AGFA Optima Vorsatzlinse lens??

[marcusverger]

I have a 'close up?' lens/filter - Agfa Optima Vorsatzline, (35.5mm thread) to be used on my Agfa Silette.
What is the correct distance or focus to use when using this extra lens??

Has anyone used this lens, if so, what are your results?

Thanks, Marcus

 

[macfred]

Those diopter lenses were made to be used with an AGFA Proximeter. The Proximeter was designed to be attached in front of the rangefinder window, to obtain focused and a parallax-free image in the viewfinder.
Mike Butkus has the manual for it https://www.cameramanuals.org/agfa_ansco/agfa_proximeter.pdf
AGFA did several Proximeters for the Optima, the Karat and maybe the Silette. I guess there are a few on ebay.

 

[AgX]

It is a lens. In spite of the fact that close-up lenses were typically offered by filter manufacturers and also listed under filters.


The term "diopter" lens is misleading. First, here in Europe diopter is not a lens, but a metrological unit. Second, in America the term diopter is used for an eypiece, a diopter lens thus is a correcting lens for an eyepiece.

 

[AgX]

What is the correct distance or focus to use when using this extra lens??

It is to project an image of the subject into infinity (thus yielding parallel rays). The taking lens is set to infinity and then a sharp image is projected onto the film, when the subject is at the focal length of the close-up lens.
This is the concept behind close-up lenses.

The focal distance typically is indicated on such lens by means of the unit diopter (reverse of focal length in meters), sometimes in coding or maybe even not at all as seemingly in your case.
To then establish its focal length the easiest way is to project an image of the sun as a sharp point onto something heat-resistant. The necessary distance is the focal length of the close-up lens.

When setting the camera at shorter focusing distances with a close-up lens mounted, the focusing distances for the close-up lens become shorter. You can find them at tables.

The focusing distance for a close-up lens is always related to the position of the close-up lens, not to the film!
(Unless explicetely stated otherwise.)

With this in mind you should be able to use your Agfa lens without even further means.

 

[macfred]

The term "diopter" lens is misleading. First, here in Europe diopter is not a lens, but a metrological unit.

AgX is right - when I said diopter lens (and I guess I'm not the only one here ... ) I'm talking about close-up lenses.
For the sake of completness : https://www.lindseyoptics.com/blog/what-is-a-diopter/

 

[AgX]

Well, as close-up lenses got their focal length indicated in diopters... from this point of view "diopter-lens" might not even be that wrong... maybe it should be "diopters-lens"...

 

[macfred]

^ A gentlemen's agreement ...

After a quick research I found a few pics with the Silette's close-up attachements - obviously there were the Proximeter and the Natar attachement to work with the Sillete's close-up filters.
https://www.udospickmann.de/agfa-silette https://www.udospickmann.de/agfa-silette?lightbox=dataItem-jlew8put

 

[marcusverger]

Thanks, Guys! This has been very useful indeed.

Thanks Again !!

 

[AgX]

To use such close-up lens without dedicated framing device better, one might mount a stick or so to the camera that ends at the necessary distance.

 

[AgX]

In post #4 I said "reverse of focal length in meters"

The right term instead is "reciprocal".

But I think you understood it nonetheless.

 

[marcusverger]

I have ordered/bought (of eBay) an 'Agfa Proximeter' in original case with instructions!. Shouldn't be too long in arriving. All I need now is a Super Silette to go with it.

Will let you all know when it arrives.......