Queen & Co. "E. Francais" conversion lens set help

[tmcsweeney]

I recently got lucky and was able to find a set of brass lenses at a garage sale. They are labeled Queen & co. Philadelphia with the signature "E. Francais" on them. The glass is in perfect shape and the only part I see missing is the flange and lens board which I can have made. The problem is that I can find very little information on the lenses and what combinations of lenses will cover what formats and focal lengths. Any help would be great. Thanks

[Steven Tribe]

Francais had a serious success with his range of casket aplanats!

A close-up photo of the copy of the guide to usage/coverage/focal lengths would help as there are

3 versions of the the no.1 set
3 versions of the no.2
1 version of the no.3!

Serial number would also help.

191808

[tmcsweeney]

Francais had a serious success with his range of casket aplanats!

A close of the guide to usage/coverage/focal lengths would help as there are

3 versions of the the no.1 set
3 versions of the no.2
1 version of the no.3!

Serial number would also help.

191808
The serial number is 19040
and underneath it has inscribed Trousse #3.

[Steven Tribe]

So that makes it easy!

The table gives combination of lenses 2 to 7 - in pairs or single.
Note that the last combination is is with 3 lenses!
Made for a ulf camera ( 24x30cm) but coverage for some combinations is larger.
Made from about 1893 for a decade or so.
There is a lot of detail in the J.F. Eder book.

If you are a one-time visitor - don't ask us the value of this!
Casket sets are not popular, however!

[tmcsweeney]

Nah not visiting..... starting to get out of digital and back into analog processes. I’ve been pretty lucky actually I just picked up a Voigtländer Heliar 480mm 4.5 and a stenopeika plate holder for next to nothing. Thanks for the information.

[Steven Tribe]

Your welcome!

I have been lucky with a Heliar too - a 30cm first series Heliar Universal - without the Universal engraving.
Being lucky with large/ultra large lens purchases gets expensive in the long term - think cameras and materials!

[tmcsweeney]

Which book? I would love to read it. I just purchased a wet plate holder from Europe.... this can get expensive..lol

[tmcsweeney]

I am looking to start using this lens for some wet plate photos but am having difficulty determining F stop. Trying to convert the scale on the lens from mm to F stop. I know there are numerous threads on the forum, but I was wondering if there was an easy conversion table? The markings on the lens show the actual diameter of the iris opening not an actual F stop.

[tmcsweeney]

Here is a picture of the hand written card that was pinned on the inside lid of the box the lens came in. Not sure if this information is useful in determining F stop. I find it funny that the card has "Size of head" written on it.193298

[Steven Tribe]

The first thing to do is to work out the focal lengths of each of the single lenses and the various combinations.
You can check the results against the cm. values in post #4 for the casket set number 3. Your casket set is a #3 bis, which usually means the same physical dimensions as #3, but with longer focal lengths. I don't think anyone has information about the the #3 bis set!

The iris scale is in mm (the actual diameter inside the lens) which is common in convertible lenses and casket sets. You just devide the focal length of the lens combination mounted by the F value wanted. For instance, a combination of 14.5 inches focal length and a F value of 8 wanted. The iris diameter must be 1.8" or 45mm. Obviously, many of the faster values will be impossible for many/most combinations as the iris has a restricted maximum value.

This is only an approximation as it is the optical aperture size which determines the F value, not the physical diameter.