The German sights are actually the best optics in the game. The main triangle is the apparent size of a 2m target at 1000m. The smaller triangles are the apparent size of a 1m target. Using this, you can mathematically calculate the range of a target of a known size based on the ratio of the apparent size of the target relative to the size of the triangle.
Google "Zeiss Panzer sight" its the first hit.
Yes indeed. The German sights are the best in the game, no doubt. It is good to see that HTC modeled the quality of the optics and not just the sight reticule. Truthfully though, I think HTC has given the other countries too much credit especially the US tanks. Once you learn the "Mili-Radian" formula, and are able to compute it in your head without looking up the dimensions of the enemy tank in the sights, at the worst your second shot will be on target. I took the time to look up each GV's dimension in AH and made a spread sheet. I used to have to look up each tank (if I had the time), but now I know the basics and like I said... usually at worst the second shot is on target. Doesnt mean I get the kill, it just means I have the enemy tank zeroed in.

You can use the length, width, or height to compute the ranges. The height is the most difficult to use in AH to gauge distance so I usually use the length/width or the ratios when they are facing me at an angle other than perfectly parallel or perpendicular.
For instance, if *any* of the M4's or T34's are directly facing you and they are half as big as the base on the big triangle (or they fill up the base of a small triangle), that tank is 1500 yards away give or take 75 yards. If the enemy tank is a Panther and it is "2 mils wide" (half the base of the large triangle or the full length of the base of a small triangle), then it is roughly 1875 yards away give or take a few yards. When the Tiger is "2 mils" wide it is roughly 2000 yards away. If the M8 is "2 mils" wide, it is just shy of 1400 yards out. Again, these are all enemy gv's facing you perfectly parallel.
Be able to identify the enemy tank, know the dimensions of the enemy tank (or be able to look them up quickly, this is where spreadsheets are good), gauge the size of it as close as possible in the "Mili-Radian" sight, dial it in and then send your love down range.