Carl Zeiss Protalinse VII serial number question

[koh303]

I am trying to figure out the SN/Date of this lens but all the charts i found online start at 173XXX -1912.
Is there any chart or reference for older lenses? Mine has SN 120XXX

[Roger Hesketh]

I take it I am correct in assuming it was you who bought the B&J 5x7. Nice outfit.Congratulations on your new baby.

[koh303]

Scratch that question - i found there was a gap in numbers between 1909 and 1912, but that number falls in that segment.

Does anyone know the image circle of this lens?

[Steven Tribe]

Without access to the CJ numbers here, I would guess this is part of the series "given" to the US Carl Zeiss Organisation. They were assigned to US engraved lenses for quite a few years and there is no record of the serial numbers and dates.

[Louis Pacilla]

Does anyone know the image circle of this lens?

Not sure you posted the size (#) of the Protar VIIa your checking on so Here's the spec sheet from the 1920 B&L and in my experience you can add a couple of degrees coverage to what B&L shows.

[koh303]

Looks like this would cover 5X7 according to the list, it is a 35cm.
Both front and rear cell have the same markings, and i read in a couple of places here and photo.net that these are some type of convertible/double lenses which produce a different focal length with each combination. Can someone explain this or verify as it is relevant to this lens? Both elements are 35cm.

[peter k.]

Yes it is meant for a 5x7, but use it on my Pacemaker 4x5.. Both on, or front only.. my bellows is not long enough for having just the back one on.
Here is the relivent info you need.. p36 shows what you have using examples of the lens combinations..

http://www.cameraeccentric.com/html/info/zeiss_4.html

[koh303]

This chart shows the 350mm as 8X10 plate lens, but only lists the "front cell" in the chart...?

[Roger Hesketh]

This chart shows the 350mm as 8X10 plate lens, but only lists the "front cell" in the chart...?

The lens is double convertible it is made up of two 35cm cells, which can be used individually or combined. When used singly the lens has a focal length of 350mm when used combined the focal length is 200mm. Used combined the complete lens will cover 5x7. The single cells may cover 8x10