Wikipedia is not a very reliable source. It is constantly getting editing and is filled with conflicting information everywhere. However, for example US testing of the t-34 noted that the optics of the t-34 were superior to anything they had. And the US like i said were rather critical of the t-34, even tho some of the flaws they noticed was because they did not know how to handle the vehicle properly.
In the same article wikipedia claims that the t-34 is the best tank in the world, then goes on rambling how horrible the t-34 actually was :/
And that the reason why the t-34s acted in a disorganized fashion and very slow to find targets can be atributted to the 2 man turret, poor coordination and crews or perhaps vision, not gun optics and cam pretty much be only contributed to the very early versions of the t-34.
If the t-34 was so crappy, then why did the germans base their panther on the t-34? Why did the germans value captured t-34s and used them to great effect?
Because most USF and also some british optics were actually even worse than the T34 optics. There is so much information about the optics subject that I can't believe people are still spreading misinformation. German tank optics provided more FOV than their counterparts. The fact that german tank crews were very well trained in distance calculation and so on provided them with the very high chance to get "first shot hits" without having to fire ranging shots. This was due to the design of the german optics. Now pair this with a high velocity gun, and you are hitting far away targets before they even get a chance to react. Carl Zeiss optics, to this day, belong to the best in the world.
This is out of the Tigerfibel. You can clearly see the triangle system the germans used in their optics. Exactly this made judging distances very easy for the german crews since they mostly knew the size of the opposing tanks out of their head.