Old G. Rodenstock Elkonar triple convertible

[MIke Sherck]

I have come across a very old G. Rodenstock Munchen Elkonar Anastigmatsatzlinse triple lens set in a nice lined wooden box. The lens is in an old Compur shutter. The lens has three elements: 29.0 cm f/12,5 in the front of the shutter, an 18.1 cm f/12,5 in the rear of the shutter and a 21.3 cm f/12.5 in the box. Also in the box is a yellow filter. If anyone has any information on this, I'd appreciate it. I'm hoping to sell it and will list it here once its been identified properly.

Thanks!

Mike

[Dan Fromm]

The VM says that the Eikonar (EI, not EL) series III was sold as a set of three lenses. Individual lenses f/12.5, pairs f/6.3. It doesn't say what the pairs' focal lengths are, does say that they cover 70 degrees wide open and 90 degrees stopped down. The single elements should do the same.

[Louis Pacilla]

Pretty sure this was a four glued element per cell where each cell is corrected for use alone or shorter and faster focal lengths when used in pairs.
Probably a copy of the Protar VIIa. The yellow filter was probably for use with single cells to help with focus shift.

[john wilton]

VM: "Eikonar Casket Set Symmetrical Anastigmats, 3+3 type 110-180mm. An early example reported in Sweden
was a f5.4/24cm at Nr110,01x, in a mahogany tailboard camera. See below for an f6.8 series: there may be
parallel production of two 3+3 symmetrical anastigmats at two apertures."

Later series:
"Eikonar Lenses. There seem to have been a group of products here at different apertures and possibly with
different designs. The trade name seems to have been allowed to lapse, possibly in the early 1930's, as they
were not noticed in the adverts, even though some of the products may have been continued under new
names, possibly in modified forms.Eikonar Series 11 f5.4 This was listed in 1925.
Eikonar Series 111 f6.3 This was listed in 1925. An f6.8 Eikonar was sold as a set for 2 or 3 foci, with
accessories, possibly filters. H&D gives 11-18cm as the range of foci. It seems to be new in 1913-1914, and
offered in f6.3 up to 37cm and then f6.8 to 51cm and then f7.5 to 60cm. Frerk suggest 18cm for a 13x18cm
plate, or 12cm at f9 for 10x15cm. Single cells are used at f12.5. It covers 70-90°, the latter stopped down.
Eikonar f4.5 for 60-80° These were discontinued by 1926. (The f4.5 may be the Series 1
missing from the list.)
f5.4 for 70-90° same.
Eikonar Series 1V f12 90-200mm This seems to be a symmetrical anastigmat 3 + 3 glass probably
of Q11 (Kollinear) type from the reflexions. It is a real wide angle, the 15cm illuminating 10x8in and covering
1/1plate sharply and probably 10x8in if it is stopped down. (This was confirmed by a professional user who
had applied the lens on 10x8in and spoke well of the results.) It was seen as an f12.5/15cm lens at No148,66x
made perhaps about 1914 as it uses old stop markings from f12.5 to f50. Here the mount is heavy and really
impressively solid- but finished in very dull matt and gloss black. This Eikonar may have been a predecessor
of the Perigon, but of different design.
Frerk notes that Rodenstock lenses were good value as the price was not too high and the quality really good
and this seems an excellent example. It was listed in B.J.A. 1925, p744.
Fig 016 022 Rodenstock Eikonar wide angle f12/15cm No148,665."