Need Grubb Lens Expertise

[Steven Tribe]

Well done. In all modesty, you forgot to mention that you also found the sizes for the aplanatic doublet (which Grubb claimed was purloined by Dallmeyer re. the RR!) which appears to be very rare.
But I don't understand why all the Grubb aplanatics we have found, have such low numbers if they were still available in the 1880's?

The new "A", c/o Peterloy, looks like the same size (proportions) as my "A".

A bit more information about Grubb is that the original London agent for Grubb at the start of the 1860's was (Israel) Joseph Solomon of Russell Square who ceased trading around 1872. Perhaps Watson took over the agency at this time?

[CCHarrison]

In trying to crack the Grubb code, I ran across references to Grubb's telescopes.... I found an 1888 Grubb Telescope catalogue with plenty of references to "Class B" and "Class C" telescopes. And then references to Specifications "A" and "B" which appear to relate to build quality... Please see this link to an 1888 Grubb Catalogue.. I am now thinking the letters on the photo lenses have to do with max aperture size of the lens or stops supplied?

Dan

PS - it references Grubb's swith to Watsons as agent too...

[Steven Tribe]

Tempting to think of A,B and C as quality gradings - a great shock for B and C owners!
I don't think it can be correct as there are, at least, E's around (5 quality grades seems unlikely).
If it is aperture size, then there should be more As than Bs etc.?

[CCHarrison]

I think it has to do with aperture size. Remember Grubb's lens was touted as using faster apertures than similiar landscape lenses of the day. Given Grubb's focus on aperture - it must relate to that...

Dan

[Steven Tribe]

I have found a mention of the Grubb code system in an 1861 photographic note!
Just a passing remark, but it means that C coded lenses are designed for 10x8" coverage. So A and B are for smaller formats. I would imagine that the numeral indicates the maximum speed of the lens.

[Steven Tribe]

Here is a very basic list of Grubb serial numbers which I have gathered during the last few days.
There is an advert in a British Journal in the late 1850's which I yet to get hold of.
The sizes which dominate are A (1/2 plate?), B (full plate plate? and C (10x8"). I have a seen a source which mentions A to E sizes, but have only seen a single D size. Additional "Digits" are only sometimes present. I have seen : 0, X, 2 and 3.

The size marking didn't start until after serial number 546, but was in operation by at least 756.

The Grubb models seen were:

- Ordinary Petzvals.

- Patent Petzvals. These had a bayonnet type flange mounting, which allowed some turn of the barrel. It is uncertain as to whether the patent referrs to the mounting, or whether the Petzval employs the patent "aplanatic" lens as a front achromat!

- A heavy duty Landscape Patent Aplanatic lens, where a very visible screw-in system with a single aperture opening cause change in the F values. This apparently has a scale system marked - but doesn't correpond to any known f scale.

- A neat pill-box style Aplanatic landscape meniscus. The system is an obvious development of the above model, but with only two positions. There is the usual system of various sized washer stops for the pill box. This, by far, the commonest model found. It is regularly offered incomplete, where the front section has been removed. It is easily recognised as there are pairs of screws in the side of the barrel.

- A late landscape model (new engraving style without A,B,C etc) giving size of plate covered. Aperture control is by wheel stops - similar to Dallmeyer's landscape series.

Serial Numbers.

264 patent aplanatic auction 2018
359 1/4 plate Petzval
483 patent 18"
509 patent helicoid aplanatic
546 patent helicoid aplanatic
647 patent (helicoid?) aplantic - Science Museum/South Kensington London
696
756! patent helicoid aplanatic
756 C Error?
790 Petzval ebay july 2018
870 landscape
879 landscape

Introduction of A, B, C etc. sizing engravings?

986 A2 petzval - the "A2" has a different style engraving.
993 A2 petzval
1066 A3
1449 A2 small Petzval
1539 C landscape 43cm
1554 C
1686 A
2071 A3 Petzval 140mm
2241 A
2409 D aplanatic
2410 D aplanatic
2719 C
2795 C
2890 B
3147 Ao
3510 D
3631 Ax

ANCD sizing given up? 2409/10 stereo pair engraved both D, suggest that D was used for stereo pairs. 2409/2410 aplanatics are quite small!

5046 Watson engraved double celled aplanatic
5204
5218
5308 New engraving style "10x8". Wheel stop aplanatic.

I will update this list when I can add more flesh to the bones!

[Willeica]

I am based in Dublin and have written this article about Grubb family and their later lens making relationship with the Parsons family.

http://macfilos.com/photo/2017/4/9/g...iants?rq=Grubb

I am also the proud owner of the following Grubb lenses

509 mentioned and pictured in the article but not on Steven's list
3631 which is on Steven's list

In addition I know that 879 is now in the hands of a Grubb relative.

Grubb addressed the Royal Dublin Society about his lens design on March 26th 1858. I have a copy of what is said to be his address but they look more a printed version of speaking notes



I am a member of the Royal Dublin Society (RDS) and tomorrow a group from the RDS will go to view the Grubb Telescope at Dunsink Observatory near Dublin.

To finish off my introduction, I am a collector of mainly small format cameras such as Leicas and a keen amateur photographer, but my growing interest in Grubb, because of the Dublin connection, is stimulating my interest in larger formats.

William

[pgk]

This link adds another lens to the list: https://collection.sciencemuseum.org...bb-camera-lens unfortunately no photo but they state that lens number 647 was a patent aplanat and that it was made in 1857 - I wonder if an email would produce more info and perhaps a photo?

[Steven Tribe]

I had added this patent aplanatic to the list. It will be the early version with helicoid front.

[pgk]

Thanks. Do you think that their dating is correct?