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TestHMD - FOV, SDE, Res, Super Sampling - The Rift(s) against everything else! :-)

RuneSR2
Grand Champion

Couldn't find any thread about this great app that Sebastian (MRTV - https://www.youtube.com/channel/UC2mgZjuHRDW02mx_ok4wfPw ) lately used to measure FOV on HP Reverb G2 and many more hmds. Here's an intro to TestHMD:


According to the dev, current HMDs have these specs, especially when it comes to FOV (Field of View):

83n2uun3yp82.jpg
 

Or zoomed in on the results:

wutu3vdmh8rq.jpg


Note that when you're inside the app, the above results are seen on a wall, like this:

0oo7i35wk0g1.jpg

Comparing my own Valve Index and CV1, and spending some time double and triple checking my results, I got the exact same results as the above - that is for the Rift CV1 I got 88 degrees horizontal fov and 116 degrees vertical fov. And even using glasses - but Norm from Tested also could dial in the lenses all the way using glasses - I got 108 degrees horizontal fov and 132 degrees vertical for the Valve Index. It does take some practice to do these measurements correctly. I've defined the upper limit as where you no longer can see the stimulus material, for example when going from 114 to 116 using CV1, you can sense the last movement, but none when going from 116 to 118 or above. This takes some practice - and for horizontal fov you may have to look left to best see what's moving to the right, might seem counter-intuitive, but has to do with how our eyes are constructed. 

At least I can confirm the results shown inside TestHMD for CV1 and Index, and my IPD is 63.94 mm (right: 31.23 mm, left 32.71). I don't know how much IPD can or will affect these results. Interestingly MRTV (Sebastian) got quite different results for some HMDs, if he was too fast and forgot to triple check his results or if his IPD caused different results, I have no idea. 

Measured as a square, Valve Index (108 x 132) would have 40% larger fov the Rift CV1 (88 x116), which closely fits my subjective experience. 

Fov isn't the only interesting subject that can be examined and measured using TestHMD - I found the reading and vision tests to be just as important:

Reading test
em3c9hwaxkss.jpg


This test was kind of an eye-opener to me - because it's a great way to test super sampling and compare different HMDs - like CV1 and Index. How much better is CV1 using 1.0 super sampling (ss) compared to Index using SteamVR resolution 100 %? Or CV1 ss 2.0 vs. Index res 200 %? In the reading test you just focus on the text and move backwards until you just barely can read the text. On the floor you can see how many meters you can stand from the text and still be able to read it. My results were somewhat surprising:

Rift CV1:
Ss 1.0 = 4 meters
Ss 2.0 = 6 meters

Valve Index:
Res 100 % = 4.5 meters
Res 200 % = 6.5 meters

Note that the ruler on the floor only goes to 5 meters, but I'm confident I'm not very mistaken for the results beyond 5 meters. 

I've spent a lot of time checking these results, but they are what I observed. Index res 200% looks a lot better, but I can't zoom out much more than CV1 ss 2.0. Also it helps moving your head slightly using CV1, because it removes/reduces the SDE, while you don't have to do that using Index. Index res 200 % is a total of 18 mill pixels per image, it's quite massive, so very surprising I can't zoom out a lot more... Also note that the TestHMD worked much better through SteamVR, where I could easily use Index res 200 %, but forcing CV1 ss 2.0 was so incredibly gpu demanding that the app once crashed - might be some driver bug (I used the regular version of TestHMD). 

Another interesting vision test is this one, where I went for the red line, namely normal 20/20 vision:

Visual Acuity (Distance Chart)
xj8u4xiunmlv.jpg 


In this test you measure the  ability to identify each letter, especially separating the F from the P - and I got:

Rift CV1:
Ss 1.0 = 2 meters
Ss 2.0 = 3.5 meters

Valve Index:
Res 100 % = 2.25 meters
Res 200 % = 3.25 meters

I just wrote down the numbers after each test, but strange that I got a better number for the Rift ss 2.0 here than Index res 200%. Important factors could be better contrast due to oled making black text easier to read, and also I've got the Index lenses all dialed-in, so the pixel sizes may not be very different. That said, the Index looks a lot better due to no SDE and much larger fov. Again CV1 profited from moving my head slightly to remove the SDE, while you don't need to do that with the Index. 

I'm slightly baffled by these results - I would have thought that I could zoom out much more with the Index, but that's not the results I got. I was quite amazed with the CV1's image quality, especially for the readability. Comparing ss 1.0 with 2.0 it's easy to see the large impact of super sampling. This goes for both hmds. Also SteamVR res 100 % may correspond more the "ss 1.4", so it's not fully apples to apples, but I do consider CV1 ss 2.0 and Index res 200% for close to the best image quality you can get with these hmds - further increasing ss does not result in large gains. 

Now it could be really interesting to test Reverb G1 and/or G2 for visual acuity! Or if the above results can be confirmed. Note that I used the SteamVR default settings for antialiasing and everything else - to change res I only used the SteamVR res slider. For the CV1, I used Oculus Tray Tool to change between ss 1.0 and 2.0. Index used 90 Hz and lenses all dialed-in.  

Oculus Rift CV1, Valve Index & PSVR2, Asus Strix OC RTX™ 3090, i9-10900K (5.3Ghz), 32GB 3200MHz, 16TB SSD
"Ask not what VR can do for you, but what you can do for VR"

50 REPLIES 50

pyroth309
Visionary
I wonder if those quest numbers listed are with a thin faceplate. I've seen people report that they increased their FoV by as much as 15% by changing out the stock interface. While I definitely get more FoV on my Quest than my Rift CV1 don't think it's 104%. I'll see if I can get my Quest to try.

pyroth309
Visionary
After reading @parsecn post I went back in with my CV1 without a face shield on with my eye lashes touching the screen and I get 90HVOF and 122VFOV. So yea, facial interface is huge.

saami81
Rising Star
I tested Rift S. Fov was 88/118 for me. Without glasses and as close as it goes without pushing with hand.

I was surprised how much super sampling helped. With 1.0 i could read green underline text from 4.5m and with 1.5ss around 7m. Difference was actually huge. I wanted to try 2.0ss, but couldnt with my underpowered computer without crashing.

lensmandave
Superstar
Rift S, Snellen test, red line 20/20 vision readable at 5 metres with SS at 2.0
Intel Core i7 6700K @ 4.5GHz. Asus-Z170-PRO MB - Nvidia RTX 3080 ti - 16GB DDR4 2666MHZ HYPERX SAVAGE.

saami81
Rising Star
I tested red underline text too. 3meters with 1.0ss and 4.25m with ss1.5.

pyroth309
Visionary
Very nice, I'm not surprised by the rift S seeing significantly farther. I can still make out most of the letters at 5 meters with my O+ at 210SS but I wouldn't say it's clear and I would struggle if I just walked in blind and tried to read it without knowing the letters. Why I said 3.5m. At 3.5m I can still make them all out np. I was actually shocked that Rune couldn't see as far with Index though. When I had an Index it was clearer than my O+ for text.

@RuneSR2 - My O+ pixel wise is somewhere between 326% and 328% for a comparable performance hit to CV1 2.0. Why don't you try bumping up your Index to that for fun and see what you get. I know it won't be the same because of how the Index lenses work but I'm curious if it increases your text legibility.

*Edit*
Went back in for fun and set it to 330% I can
read it at 4.25m. It's not sharp but I can make out everything and see
the loop still on the P. I find that interesting because the overall
image is a bit softer/blurrier but yet the text is clearer.
Also tried 500% but it looks worse than 330%. 300% looks a bit better than 330% also but I couldn't see any farther than 4.25m.

Also only reason I listed me pushing on my O+ vs without if you haven't read that other thread is because the halo design is crap on it. It doesn't sit against my face snug when I wear it comfortably. Losing several degrees of VFOV because of that bad design. If I wasn't getting a reverb in a month or 2, I would mod it with velcro like others have done to stop light bleed.




RuneSR2
Grand Champion
Trying to sum up - reading line 8 (20/20):

dzwvh5tm99kr.png


Ss 1.0 = 2 meters (Rune CV1)
Ss 1.0 = 2.5 meters (Saami Rift-S*)
Ss 2.0 = 3.5 meters (Rune CV1)
Ss 2.0 = 3.75 meters (Pyroth CV1)
Ss 2.0 = 5 meters (Lensmandave Rift-S)

Res 100 % = 2.25 meters (Rune Index)
Res 200 % = 3.25 meters (Rune Index
Res 200 % = 3.50 meters (Pyroth Odyssey+)
Res 330 % = 4.25 meters (Pyroth Odyssey+)

(Ss 1.5 = 3 meters - Saami Rift-S*)

*Updated using Saami's post from August 6. 

Looks like I need to eat my words that 200 % is optimal, lol.

The impact of these findings are quite mind-blowing - at least I've heard many times that super sampling does not matter compared to real res - that only true physical res matters. But these results seem to state the opposite - you don't need to care that much for real res if you can super sample high enough. Still Index looks a lot better with no SDE and big fov, but I think I'll appreciate my good old CV1 a bit more when I wear it the next time  B)

I'll check later with Index res 300+ % - feels like I'm late to the show today, but I had to go to work and make some food for the family, sigh  😞   😉

Hmmm, can't let that Rift-S win, even if I have to use drugs!

Itone Eye Drops Review  Its composition Uses and side effects


Oculus Rift CV1, Valve Index & PSVR2, Asus Strix OC RTX™ 3090, i9-10900K (5.3Ghz), 32GB 3200MHz, 16TB SSD
"Ask not what VR can do for you, but what you can do for VR"

RuneSR2
Grand Champion
Just saw this - does make sense, so Rift SS 2.0 is pushing a similar amount of pixels as Index res 200 % (18 mill pixels) - which explains quite a lot:

Rift CV1


Source: https://forum.il2sturmovik.com/topic/30436-pixel-density-supersampling-at-steamvr-oculustraytool-and...

So if Rift-S is set to "Quality" instead of "Performance" (see https://uploadvr.com/rift-s-hidden-resolution-setting/ ), then Rift-S ss 1.0 is 1648×1776 and ss 2.0 is 23,414,784 pixels? - Or close to ss 2.3 using CV1... 

Oculus Rift CV1, Valve Index & PSVR2, Asus Strix OC RTX™ 3090, i9-10900K (5.3Ghz), 32GB 3200MHz, 16TB SSD
"Ask not what VR can do for you, but what you can do for VR"

RuneSR2
Grand Champion

RuneSR2 said:

Trying to sum up - reading line 8 (20/20):

dzwvh5tm99kr.png


I'm starting to see the problems with this test, because even focusing on line 8, we need to adhere to extremely strict rules to be able to compare. Depending on my focus, I get values from 3.5 to 4.25 meters. 

To me the easiest and most secure measurement is focusing on the P. At some point you can no longer tell which one of these two Ps you're watching:

yg2hbqhaaicv.jpg
When you're no longer 100 % sure which P you see, you've reached your maximum distance. Using Index, and after carefully moving my HMD around to get best possible clarity, I'd say my max is 3.75 meters - and that's using res 200 %, 300 % and 400 %.

In the reading test, maybe I was more like 7 meters away at res 300 % than 6.5 using res 200 %, but that test feels more prone to some variance and subjectivity. Not really sure 300 % added anything compared to 200 %. Maybe one should choose a distance for the reading test, where you're comfortable reading the text aloud for friends and colleagues - so no stuttering or being at the very edge of letter recognition, lol. 

Oculus Rift CV1, Valve Index & PSVR2, Asus Strix OC RTX™ 3090, i9-10900K (5.3Ghz), 32GB 3200MHz, 16TB SSD
"Ask not what VR can do for you, but what you can do for VR"

pyroth309
Visionary

RuneSR2 said:

Just saw this - does make sense, so Rift SS 2.0 is pushing a similar amount of pixels as Index res 200 % (18 mill pixels) - which explains quite a lot:

Rift CV1


Source: https://forum.il2sturmovik.com/topic/30436-pixel-density-supersampling-at-steamvr-oculustraytool-and...

So if Rift-S is set to "Quality" instead of "Performance" (see https://uploadvr.com/rift-s-hidden-resolution-setting/ ), then Rift-S ss 1.0 is 1648×1776 and ss 2.0 is 23,414,784 pixels? - Or close to ss 2.3 using CV1... 


I remember reading somewhere when Index came out that because of how the index lenses are spreading things that Rift-S actually has more in the center for text reading. I’m not sure how true that is but it was said on the Internet so of course it’s true.