So when we consider the fov, do we imagine the plane is outside of sphere? or inside of the sphere? How do we project?

[cremtty]

So viewspeed v2 formula was this

sin(f2v/2)/sin(f1v/2)   

and inside of f1v , f2v   it should be computed as f2v= 2* arctan(9/16*tan(f2h/2))                 f2h=fov2 horizontal

However If you imagine the (virtual) sphere that you consider when you imagine focal length

and if you consider the physical screen inside of that sphere ( cut sphere with hyperplane)    (screen does not one point contact to the sphere!  imagine it is inside of sphere)

then viewspeed v2 is just getting the radius of sphere.

 

Then It should be independent to the ratio, but it's not

That's because of the definition of sphere ( or fov)

If fov is calculated as the plane inside of sphere

then it's horizontal - vertical formula should be f2v= 2* arcsin(9/16*sin(f2h/2)) 

and in that case it does not depend on the ratio.

 

So the point is how do we define fov? How do we project the screen?  Do we imagine screen outside of sphere? or inside of sphere?

viewspeed v2 depends on this fov definition, hence it might be mathmatically (scientifically) wrong.

 

after i calculate zs=1/n(limit(arcsin(r*sin(f1/2))/arcsin(r*sin(f2/2)),r=0,dir='+')) 

it seems like the definition of fov is tangent base... hence it seems viewspeed v2 is just arbitrary (has no meaning)

 

 

 

I'm not english speaker. sorry for my english.

 

ps. I still don't think zoom ratio is perfect. It has a point but we are human.  There might be better hueristic way. Besides,  0mm theoratically respect the pixel (infinitly near) at crosshair. It has pros and cons too.

In my opinion maybe we should try to multiply some function to the focal length.

Edited May 12, 2022 by cremtty

[cremtty]

So today i finally understand the meaning of view speed v2. yeah actually it has some meaning.

"focal ratio at some point on monitor"

and now i understand why the original developer use 9/16. However you can use another value 3/4, 1/2 , ... etc, if you understand what it will mean.

 

The original developer just want to use the point of boundary of largest square in physical display. I hope admin of this site make a option about it.

If you forget about the aspect ratio, then viewspeed at different number (3/4,1/2, 9/10, etc) is focal ratio at 75% , 50% , 90% of monitor horizontal distance.

So don't be obssesed with aspect ratio.

e.g.)

If you usually focus on 50% of your monitor horizontally, then try 1/2. 

 

 

viewspeed with different value might be another option for mdh.

 

By the way, most of the people will use 16:9

and if you change the monitor, then just remake the muscle memory for that monitor. If you just pick one method on this site to change the fov then you will recover like in 2 days.

For example what if you change your desk? what if you move to another house? What you can do is just make a new muscle memory but if you use similar cm/360 for the default fov (eg 103)

and use sens in another fov by the fixed method, you will get through that.