revised tank gunsight optics

[RTHolmes]

something about the new gunsight optics seems a bit weird to me - the way the different magnifications are represented. check these out:

M3/75


M4/75


M4/76


HT explained the idea behind it:

Zoom/power and FOV do not exactly make sense when translated to a computer screen because moving your head closer and farther away changes zoom.

When dealing with a computer screen you really only have a field of view because lowering the field of view effectively zooms in.

Hence we choose the best zoom/fov ratio and use that as a base to have a circle touch the top and bottom of the screen.

After which sights will the same power will be the same size on the screen, but as the sights FOV decreases the circle will become smaller.

So the objects on the screen will be the same size for any 6 power sight. But the circle size will vary with the sights FOV.

HiTech

... which I said I understood, but thinking more about it I dont think its right.

If you look at the 75 vs the 76, they both show the same FOV in mils which isnt right if the 76 has 2x the magnification of the 75.

What I'm requesting is that the virtual image for all the sights be the same size. Ive mocked up a M4/75 example below together with the current M4/76 so that you can see what I mean:

M4/75


M4/76


this is how I'd expect the optics to look, and how RL optics work (telescopes, binoculars, cameras etc.)


edit: btw the tiger's optics already work this way, when you toggle between the 2 magnifications, the FOV changes, not the size of the virtual image ...

[CrosFire]

A buddie of mine has a sherman telescope aiming reticule and it adjusts. The you turn this band on the top to the left and the plus goes down with the range markers unlike in this game.

[hitech]

A buddie of mine has a sherman telescope aiming reticule and it adjusts. The you turn this band on the top to the left and the plus goes down with the range markers unlike in this game.

You might wish to check the make and model of the sight you speak of.

HiTech

[tf15pin]

If you look at the 75 vs the 76, they both show the same FOV in mils which isnt right if the 76 has 2x the magnification of the 75.

For a single scope with two power setting you would expect the field of view to about decrease by half when doubling the magnification. I think the case for the 75 vs 76 scope is that they are two completely different fixed power scopes, and it is not unreasonable that they have two different magnifications with the same field of view.

The first post in this thread quotes the FOV of the 75 to be 12 deg and the 76 to be 13 deg.
http://bbs.hitechcreations.com/smf/index.php/topic,311037.0.html

Maybe smokinloon can be PMed for his primary source. If it has more information on the optics, or ideally a schematic of each sight, it will be easier to see how the magnification was nearly double while keeping the same FOV.

[RTHolmes]

well the actual magnifications might be different, but I'm not commenting on that. I used 2x difference between the 75/76 optics just for simplicity to show the difference in the way its represented onscreen.

[hitech]

RTHolmes:
Per SmokenLoon. and our data also.

M4-75: 3x w/ 12 degree FOV.
M4-76: 5x w/ 13 degree FOV.

Look at your first screen shots of the M4/75 and the M4/76 which are correct.

Both have close to the same field of view. Notice how the sight in both takes up the same % of the circle. I.E. both circles are close to the same # of mills across the circle.

But the 76's circle uses almost twice the amount of the screen, I.E. twice the power. So take a piece of paper, lay it on the screen and measure 5 mills on both. You will see that the 76 has the correct power as compared to the 75.

Like I said, power and FOV do not exactly make since on a computer screen.

In the computer world power translates to FOV of the overall SCREEN (I.E. size of image on the screen). And FOV translates into circle size.

HiTech

[RTHolmes]

ok thanks I finally got it! I was confusing the apparent FOV and the true FOV.


I'm retiring with a slightly aching brain

[hitech]

I'm retiring with a slightly aching brain

My brain also ached when trying to figure out how to do it.

HiTech

[M0nkey_Man]

  ill just

[SmokinLoon]

The first place I look online for information on a tank or other such vehicle is here:

http://www.tarrif.net/

... from there, I verify some of that information to make sure it is legit, etc.  That website is not without errors, for they have the T34's listed with 5 speed transmissions.  Anyone who considers themselves any sort of a WWII enthusiast should know better then that and have a printed source or two (original sources work best).      

There is a handy comparison tool there as well. 

They have a long list of sources that are highly regarded, be sure and check them out.