British and US tank sights vs the Germans sights

Discussion on the tanks and other armoured fighting vehicles, which participated in World War 2.
wo.kelly
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British and US tank sights vs the Germans sights

Postby wo.kelly » Mon Apr 06, 2009 3:42 am

I originally posted this in the other thread but frankly I have seen on many different forums this general lack of understanding of optics on WWII tanks, so I figure it deserves its own post since I spent a bit of time writing it.

Telescopic sights is something most people don't know a huge amount about or there are lots of myths about. One of the big ones I hear and is that allied sights were inferior in magnification to German ones. Allied optics for the most part were not inferior in magnification to German ones. Originally the British 2 pounder gun and associated tanks had a 1.9x magnified sight, which was somewhat inferior to the 2.4x magnified German sights on tanks, which may be the cause of this myth. However American and British tank sights (6 pounder, 75mm, 17 pounder etc) had a 3x magnified sight which was slightly superior in zoom to the 2.4x magnified German sight on more of their common tanks such as the Mark III and Mark IV.

Only certain German tanks had the fancy adjustable optics that had both a 2.5x magnified and 5x magnified option for the sight, mainly on the late production Tigers (originally had 2.4x) and Panthers, and probably other late war ones. The StuG Assault gun series had a 5x magnified direct fire sight it retained but it was not adjustable. However several allied tanks had high powered optics as well. The Sherman Firefly was equipped with a 6x magnified sight, but whether this was adjustable or had to replace the standard 3x magnified optic I am unsure of. The Shermans with the 76mm gun also had a 5x magnified optic while standard shermans had a 3x magnified optic.

So why the notion that German optics were better than allied ones? It has more to do with other factors besides the simple magnification. The 2.4x magnified German sight on Mark IIIs, Mark IVs, and early tigers had a wide 25 degree field of view. In comparison allied 3x magnified optics had only a 13 degree field of view. The adjustable German 2.5x and 5x optics also had an wide FOV compared to allied optics. The 2.5x sight had a 28 degree field of view, while the 5x optics were 14 degree FOV. In short German 5x optics had slightly better FOV than allied 3x, and German 2.4x and 2.5x optics had roughly double the FOV. The high powered 6x sight for the Firefly had a 9 degree field of view which is rather limited. The only allied optic that compared to german sights in magnification and FOV was the 5x optic put in the Sherman 76 series, which had a 13 degree FOV, similar to the 5x mag 14 degree FOV of the German adjustable optics. The StuG was something of an exception, with only an 8 degree FOV for its 5x mag optic, which means it was inferior in that respect to allied optics of similar or even better magnification. What this meant in practice is that German gunners had an easier time acquiring targets their commander assigned for them, as the larger field of view allowed them to see more than allied ones did.

Another advantage of the German optics was their design which created a 'Mili-radian' sight. If you have ever seen one you will see a lot of triangles, but there is a purpose. The triangles utilized a mils that, combined with some math skill taught to panzer crews and a rough idea of tanks size (not hard when your enemies has focused production of a few types of tanks exclusively), allowed the gunner to calculate a rough range of the tank without even having to take a ranging shot. This allowed German gunners to have a high chance of getting first shot hits, and combined with the high velocity guns and powerful guns they had access to from the middle of the war onwards on their tanks, this often meant a kill on the enemy tank before they could react. They were adjustable with a dial around the edges of the optics that let the gunner know what range was dialed in.

Its rather complex but if you are interested you can find a guide here http://www.75thguards.com/ww2online/dow ... _Guide.pdf

American optics were rather primitive in comparison, simply a line down the middle with crossing lines representing 400 yard intervals. They were totally nonadjustable and it must have been rather infuriating trying to land a second shot since the lay of the gun and sight would be thrown off with the recoil and with so many lines you could forget which of those many lines you had lined up on the enemy tank. I know from playing WWIIOL and using those optics that they are not particularly easy to use. British optics on their post 2 pounder armed tanks were similar to the American optics in that they had all the ranges listed in the sight, but it was adjustable so at least you didnt have the problem with the US optics. Whether the british put their own optics in the lend lease Shermans or not I do not know. Still allied tanks lacked this clever triangle system and would have had to rely more on ranging shots which put them at a disadvantage though modern american optics do have a triangle system though not the same design.

So in conclusion allied optics were not inferior to German optics because of magnification, for the most part they had similarly powered optics to the German ones, and standard allied tanks had a relatively adequate 3x zoom on them. However German optics were superior in field of view to similarly magnified allied optics, perhaps this is why the German optic industry had such a higher reputation than any other at the time. Also the German optic design allowed for panzer crews to estimate accurately the range of allied tanks without needed to fire a ranging shot, thus allowing for a higher percentage of first shot hits, and with the large amount of high powered guns they had as the war went on, often first shot kills.

There are books and people who claim the quality of German optics were superior, that they were clearer or something. I cant comment on that and it is mostly claims and impossible to measure. I am sure that during the dark days for the British and Russians some sub-par optics made their way into tank mounts, but again we will not know for sure. As tank optics are quite rare now, and they are 60 years old we will probably never know. However everything above is based on what can be seen, and that is documents that detailed magnification and Field of View, as well as pictures and drawings of the design of each sight.

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Re: British and US tank sights vs the Germans sights

Postby Hoosier » Mon Apr 06, 2009 2:38 pm

'Best explanation I've read.
Thanks for sharing 'Kelly.
;)
Tim

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Re: British and US tank sights vs the Germans sights

Postby Notmi » Tue Apr 07, 2009 7:21 pm

One other things that separates good optics from superb optics. It is its ability to collect and transmit enough light in order to have a bright enough image. Amount of light is not a problem at broad daylight during the summer but early mornings / late evenings or otherwise adverse conditions (smoke, rain) separates good from the best. Anti-reflective coatings help here a lot. Without AR-coating, there is about 4 % loss of light in every glass-air boundary. And every lens has atleast two surfaces (not all glass-air boundaries) and optical instrument usually have several lenses. This 4 % loss quicly adds up.


German optical industry got a decent jump-start at the later parts of 1800's because of three reasons: Ernst Abbe, Carl Zeiss and Otto Schott.
Abbe was a professor at university of Jena, he worked in optics.
Otto Schott was a glass chemist who is considered the father of modern glass industry. Schott, Zeiss and Abbe founded a world leading optical glass manufacturer, Schott AG in Jena.
Carl Zeiss was a very famous optician. He and his company (Carl Zeiss AG) is famous for their high quality lenses for microscopes and other optical instruments. His company was also founded in Jena.

I had a privilege to visit Jena last summer, I was attending a special optical design course in University of Applied Sciences Jena. There is still a large Schott factory located in Jena, among many other optics companies. We visited Schott museum which had a nice exhibition about Otto Schott, Schott AG and its products. Museum was located at Schott factory premises. We also visited Optical Museum Jena which has a large collection of optical instruments from eight centuries. Many of those instruments from last two centuries were products of Zeiss AG. Unfortunately there was no tank optics if I remember correct.

http://en.wikipedia.org/wiki/Ernst_Abbe
http://en.wikipedia.org/wiki/Carl_Zeiss
http://en.wikipedia.org/wiki/Otto_Schott

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Re: British and US tank sights vs the Germans sights

Postby Hoosier » Tue Apr 07, 2009 7:25 pm

Then there was that Steiner fellow...

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Re: British and US tank sights vs the Germans sights

Postby FNG » Fri Apr 10, 2009 6:12 pm

what dictated a sights FOV?

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Re: British and US tank sights vs the Germans sights

Postby Christian Ankerstjerne » Wed Apr 15, 2009 8:14 am

Thanks for that very interesting piece, wo.kelly!


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