FOV

Post by **Znith** » Thu Oct 18, 2007 3:56 pm

What is the actual FOV of your visors? Please be specific in degrees.

I looked on the TDVision site but all it says is a 72" screen 10 feet away.

Thanks

Post by **crim3** » Mon Oct 22, 2007 4:30 am

If I'm not wrong, trigonometry says 33.4 degrees
And if I'm wrong... shame on me

Post by **eschur** » Mon Oct 22, 2007 9:26 am

That is exactly correct. The TDVisor-SD with its Diagonal Screen size of 72" and 4:3 aspect ratio at 10 feet has a 33.4 degree FOV.

The TDVisor-HD with the 108" Diagonal screen size and 16:9 aspect ratio at 10 feet has a FOV of 48.45 degrees

Post by **decoril** » Tue Oct 23, 2007 12:43 pm

eschur wrote:That is exactly correct. The TDVisor-SD with its Diagonal Screen size of 72" and 4:3 aspect ratio at 10 feet has a 33.4 degree FOV.

The TDVisor-HD with the 108" Diagonal screen size and 16:9 aspect ratio at 10 feet has a FOV of 48.45 degrees

In the viewing angle calculator of this page: http://www.myhometheater.homestead.com/ ... lator.html you will get the espectacular cypher of 48.45 degrees only if the 108" at 10 feet and 16:9 are 108" of screen Width, and a not so espectacular one of 42.8 for 108" of diagonal screen size, that seems to be the TDvisor. How can you make such a mistake?

Post by **eschur** » Wed Oct 24, 2007 11:39 am

Thanks Decoril! I did the calculation by hand and I used the diagonal screen size as the horizontal. The correct FOV for the TDVisor-HD is 42.8 degrees.

Post by **crim3** » Sat Oct 27, 2007 1:43 pm

Anyway, it is diagonal FOV what use to be listed at the features of HMDs, not horizontal FOV, in the same way that diagonal length and not height x width is used to describe a display dimensions.

So, more than 33 degrees of diagonal FOV for tdvisor sd and more than 48 degrees of diagonal FOV for tdvisor hd seems to be the correct numbers.

Of course, corresponding horizontal and vertical FOVs can be calculated if interested.

Post by **decoril** » Sun Oct 28, 2007 6:03 am

Hi crim3, i?ve tryed searching for calculating for myself but havent finded how to; can you kindly post it?
I have very much interest on knowing what the horizontal an vertical FOVs are

Post by **crim3** » Tue Oct 30, 2007 11:14 am

Yes, sure.
Hope this is clear enough. If not, just ask.

Post by **Jahun** » Tue Oct 30, 2007 6:08 pm

hehe nice one.

I wonder if it helps for someone to understand it clearer now

Post by **crim3** » Wed Oct 31, 2007 1:55 am

o_O!

Well, the key is the arctangent (atan), that gives the angle associated to the relation between half the size of the display and the distance to the display (the two cathetus of the triangle). That's the angle alpha in the first figure (I should have numbered them). Double this angle and you have the FOV.

For the horizontal FOV, the problem is that we don't know the width of the display, but we know the relation between the sides, 16:9, and the diagonal lenght (108"). The arctangent of 9/16 is the angle between the diagonal and the width (angle beta). With this angle, the diagonal lenght and the cosine definition, we have the width (the sine gives the height). Knowing the width we can, finally, do the same that with the diagonal: the arctangent of the relation between half the widht and the distance to the display. Double the result and you have the FOV.

Vertical FOV would be double of the arctangent of the relation between halft the height and the distance to the screen.

Of course, all distances must be in the same unit, so I converted them to meters.

Post by **DevilMaster** » Mon Apr 28, 2008 2:35 am

decoril wrote:In the viewing angle calculator of this page: http://www.myhometheater.homestead.com/ ... lator.html you will get the espectacular cypher of 48.45 degrees only if the 108" at 10 feet and 16:9 are 108" of screen Width, and a not so espectacular one of 42.8 for 108" of diagonal screen size, that seems to be the TDvisor. How can you make such a mistake?

I just noticed this topic, so I want to make a consideration. TDVision compares their visors to watching a 72 inches TV at 10 feet. In the page you link, by setting "Distance to main viewing location" as 10 feet and "Diagonal Size" as 72 inches, I get a current viewing angle of 27 degrees, much less than the viewing angles mentioned in this topic!

Post by **genetic** » Thu May 08, 2008 10:50 pm

To eschur,

Just curious if there would be a way to get a 60 degree or larger FOV at the loss of over all picture quality. Maybe an attachment lens or something.

As things stand now, I WILL Buy the top of the line TDvisor once headtracking is implemented.

The increase in picture quality is great but to be honest, after so many hundreds of hours of HMD use, FOV is far far more important to me.

Post by **crim3** » Fri May 09, 2008 11:34 am

DevilMaster wrote:I just noticed this topic, so I want to make a consideration. TDVision compares their visors to watching a 72 inches TV at 10 feet. In the page you link, by setting "Distance to main viewing location" as 10 feet and "Diagonal Size" as 72 inches, I get a current viewing angle of 27 degrees, much less than the viewing angles mentioned in this topic!

I haven't calculated it, but it looks like it's giving the horizontal field of view, which is shorter than the diagonal FOV. In the end, that's the number that really matters.

FOV

FOV

FOV Size

FOV Correction