Protar IIa? Huh?

[Kevin Crisp]

I thought I knew protar lenses but now I am stumped. The auction site now has a Protar "IIa" lens for sale. I have never heard of one, but the photo clears shows this B&L lens marked IIa. It isn't a typo as, apparently, some of the series VIII lenses might have been. I've seen no such thing in old or newer B&L literature. What's more, the combined focal length of the lens is marked as 10" on the rim of the front cell. This is also usual, since the individual cell focal length is the usual marking on old and newer lenses, no the combined focal length. You can't see how the back cell is marked.

Anybody know what a IIa protar was? The focal length (apparently for the combined lens) is given as f:8. Thanks and have a safe New Years' Eve.

[Ole Tjugen]

Protar IIa's are not convertible, that's why there's only the one focal length. Apart from that, I can't tell you more until I get home in a week or so.

[Bernard Kaye]

I saw this. It is not a Protar VII or VIIa; I think Ole will clear this up but remember favorable comments about earlier "single Protars" No, I am only in my 80s, not 100s but do read. Bernie

[CP Goerz]

CZ did make a Series IIa Protar, its an F8 semi sharp lens which has a bit lower than normal contrast, average sized image circle for the given focal length. Its not convertible BTW.

[Jason Greenberg Motamedi]

From the VadeMecum:

Series IIa Anastigmat Protar f8.0 2 + 3 glasses (Layout Zei 008) To cover 75 or 80°
This was made in focal lengths of 90, 110, 136, 167, 205, 244, 295, 350, 433mm.
This was one of the last of the Anastigmats to be introduced, and the 3-glass rear component was used to
allow improved spherical correction with a critically flat field. In fact, it has the typical advantages of sharpness and contrast with a really good angle covered. Customers would have compared this anastigmat with an RR, and found real advantages in a lens of similar size and without too great an increase in cost compared with either an RR or a Series V. But it must have always lived in the shadow of Symmetrical Anastigmats such as the Series VI and similar lenses, where the main reason that the Series IIa sold was probably that it was about half the price.
Today it does not seem to be easy to find, but does occur. Curiously, both those seen were 110mm, and this
may be due to its use on several Stereo cameras, where the moderate size, cost and weight resulted in their
use. One very attractive version noted was in an aluminium mount with a copper or bronze iris ring at
No34,14x, and a stereo camera by Billieni of Nancy is shown with lenses like these by FBB as Fig E'. This
option of an alloy mount was offered by Zeiss in 1901 for most if not all lenses, but no other example has been seen of this type. Later alloy was used more freely for lens cells. The focal length used can be seen from this Table, derived from the Zeiss one. Focus Film size Film size Image mm overed at covered at diameter
f8.0 f12.5 mm

110 6x8cm 9x12 170
136 9x12 12x15 210
167 12x15 13x18 260