Double Gauss

[FluffPuppy]

Of interest:

http://en.wikipedia.org/wiki/Double-Gauss_lens

[danfromm]

Even more interesting that TTH isn't mentioned at all.

[FluffPuppy]

[danfromm]

Taylor, Taylor & Hobson. They were the leading exponents of 6/4 double Gauss lenses between the World Wars. Schneider's original Xenon and Leitz' early 6/4 double Gauss lenses were made under license from TTH. For some reason German and German-influenced sources ignore TTH's double Gauss lenses.

Among TTH's better-known double Gauss trade names are OPIC (that's the first fast one, 4"/2, and the first successful one, the original Planar was a flop), Panchro, Speed Panchro. I have one of their post-WWII 6/4 double Gauss types, engraved Taylor Hobson Anastigmat 4" f/2 (2 1/4 x 2 1/4). It was made for the Vinten F95 and Williamson F134 and F139 (an F134 with the clockwork drive replaced by an electric motor), all aerial cameras that shot 6x6 on 70 mm film. The 4"/2 is somewhat of a cult lens, as are Speed Panchros. I use mine on a 2x3 Speed Graphic, it actually covers 2x3 and is a very fine lens.

[indianadinos]

[FluffPuppy]

[sichko]

[danfromm]

Fluffy, thanks for the correction.

My only excuse, and it is a very weak one, is that the text you cited was buried in the fine print.

[danfromm]

[iangreenhalgh1]

You neglected to mention the Cooke Triplet, that was a British design, nothing to do with Zeiss or Germany.

[danfromm]

Thanks for the suggestion, Ian. The Cooke triplet was invented by Dennis Taylor of T. Cooke & Sons. That firm's principal product was microscopes; T. Cooke & Sons last traded as Cooke, Troughton & Sims.

According to the VM, CZJ made some triplets before 1890 but these, unlike the Cooke triplet, weren't anastigmats.

[scsambrook]

Thomas Cooke & Sons of York, England, were a interesting company. Their core activities were astronomical telescopes and surveying instruments, neither of which really let them prosper. Although we think of them as an "optical" company now, one of their strengths was in precision engineering, especially gear cutting. The armaments firm of Vickers bought a substantial interest in the limited company before World War I to fill a gap in their own range of skills.

H Dennis Taylor is one of the under-estimated greats in late 19th century in optical design. Apart from his own work with telescope objectives (for which he was acknowledged in his own time as one the world's best) and the famous "Cooke Triplet", he had some not inconsiderable dealings with Zeiss and its associated Schott glassworks. It was Taylor who actually proposed the characteristics of some of the "new glasses" which Schott successfully formulated and manufactured in the 1890s. And, although it's now generally forgotten, he was successful in chemically applying lens coatings in the early years of the 20th century. Sadly, Cooke's failed to invest in the research needed to produce a commercially practical system of applying the coatings and Taylor abandonned the work. Despite his importance to Cooke's, he remained no more than a salaried employee there, with no executive power whatsoever.

Cooke's were better engineers than businessmen. They saw no future in Taylor's anastigmatic triplet and were quite happy to see him do a deal with Taylor, Taylor and Hobson for its manufacture, out of which they made very little money. Despite the name, there was no connection between H Dennis Taylor and TTH. Relations between Taylor and Cooke's deteriorated so much that at one point he resigned and took himself off the Leicester to work for TTH. Cooke's seemingly realised the error of their ways in letting him go and subsequently persuaded him to return to York.

Vickers supported Cooke's after the end of WWI, largely to retain capability in rangefinder and fire-control instrumentation. Eventually they integrated Barr & Stroud products into their systems and let Cooke's go into receivership by withdrawing their support. And then, in a typically Vickers stroke, as major creditors, they bought the company back from the receiver for a nominal sum, reformed it and sustained it in peacetime making microscopes, survey equipment and - of course - specialised naval and military optics.

There's a short history of the firm by Anita McConnell called "Instrument Makers to the World" which gives a useful introduction to it. But being a short account, there's no deep exploration of Taylor's importance in photo lens design, or the interaction he had with both Zeiss and TTH.

[iangreenhalgh1]

I live near the main Vickers works at Barrow so I find this very interesting.

It is widely written that WW1-era british rangefinder equipment was inferior to German and this was an issue at the Battle of Jutland.

There was a lot of cross-pollination of ideas between the British and German firms in the pre-WW1 era.

One example of how true attribution of the origins of things is trick is the Ross Xpress. Ross were making Tessars under licence from Zeiss then when they took over the Zeiss works in the UK they introduced the Xpress which was a 4-element design too but had the cemented doublet in a different position to the Tessar. Many used to say the Xpress was better than the Tessar and Xenar.

[danfromm]

Qouth iangreenhalgh1:

[scsambrook]

[scsambrook]

[iangreenhalgh1]

The real problem at Jutland with British Gunnery was three-fold, firstly the shells were defective and tended to break up on impact rather than penetrate, this was corrected before war's end, many German ships were peppered and if the British had had effective ammunition, they would probably have been able to sink several German ships, as it was, they just turned them into charnel houses. Secondly, not all of the fleet (Beatty's battlecruiser squadron especially) had sacrificed accuracy for rate of fire in their drills, this led to disaster and the loss of three battlecruisers as they ignored and circumvented the safety measures to prevent flash travelling to the magazines, they stored cordite charges in stupid positions and even removed anti-flash doors on the shell and powder hoists. Thirdly, gunnery training was lacking among much of the British Fleet leading to bad shooting, not least the mis-reporting of shell splashes between ships. Jutland was a close run affair though and Jellicoe came within an ace of winning the war that day, it was only Scheer's emergency U-turn and Jellicoe's fear of mines and submarines that saved the German fleet from disaster.

But getting back to optics, the problem with the Ross Xpress is they sold several different designs with the Xpress name:

[scsambrook]

Ian wrote - The real problem at Jutland with British Gunnery ...
Ian, anyone interested in the Battle of Jutland might find Jon Sumida's "In Defense of Naval Supremacy" an interesting read relative to gunnery there. Sumida did a great deal of archival reseach into the question of fire-control in the Royal Navy before and during the Great War. He certainly considers himself to be the leading expert on the subject, although he virtually ignores the signifcance of optical instruments in such systems. Still, he had his reasons. Sort of.

A riposte to the Sumida book is John Brooks' "Dreadnought Gunnery and the Battle of Jutland". Brooks disagrees with some important themes in Sumida's book . . . and got a thoroughly vitriolic review by Sumida in the academic comic Journal of Military History See “Gunnery, Procurement, and Strategy in the Dreadnought Era,” a review of Dreadnought Gunnery and the Battle of Jutland by John Brooks, Journal of Military History, 69 (October 2005): 1179-87. Sumida's comment were so adversely critical that Brooks appealed for, and got, the right to reply in a subsequent issue. Pretty much the sort of written brawl seen on some other internet photo forums from time to time If you fancy digging deeper, your local library will be able to get hold of both books, and the Sumida review.

Apologies to anyone who feels this drifting off-topic, but the companies who were involved in making this gear were pretty much always involved in making photographic equipment in one form or another. And the significance of cross-fertilization from military instruments to civilian products (and vice-versa) is something it pays us to be aware of.

[Excalibur]

***Apologies to anyone who feels this drifting off-topic***

Carry on, I'm interested in WW1

[danfromm]

No need to apologize, threads always drift.

To get us a little, but not much, closer to the original topic, does anyone here know why TTH decided to stop supplying lenses for aerial cameras to Vinten and AGI?

[cooltouch]

Wow, a great history lesson.

Hey, I was looking at the original link and clicked on the image showing the formulas for double Gauss designs, 1978-2010, and spotted an optic that's the subject of a current thread here: the Voigtlander 25mm f/0.95. Bottom right corner. Lots of glass in that puppy.