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

[RuneSR2]

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:

http://testhmd.com/

https://knob2001.itch.io/testhmd

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

Or zoomed in on the results:

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



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

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)

 

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.  

[RuneSR2]

Btw, maybe a good idea to show Sebastian's results here - which include the Rift-S, but not the CV1:

Source: https://www.youtube.com/watch?v=fvkUtY8ifDs

[ShocksVR]

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 %?

Again, what SS settings are you using for the CV1 ? Oculus or STEAM? It;s read's like you're using Oculus Debug.

Oculus is a squared value, STEAM uses a linear value. I hope you're not comparing Oculus SDK SS of 2.0 to STEAMVR SS of 200%

edit - I think the output render resolution from each headset is a more important number than just comparing '2.0 vs 200%'.

[RuneSR2]

ShocksVR said:

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 %?

Again, what SS settings are you using for the CV1 ? Oculus or STEAM? It;s read's like you're using Oculus Debug.

Oculus is a squared value, STEAM uses a linear value. I hope you're not comparing Oculus SDK SS of 2.0 to STEAMVR SS of 200%

I wrote it last in the post: "For the CV1, I used Oculus Tray Tool to change between ss 1.0 and 2.0."

Index is res 100 % (2016x2240x2) and res 200 % (2868x3168x2). 

It does not make much sense to compare same pixel values. Default for CV1 is ss 1.0, while default for Index is res 100 % - thus I used these values for "baseline". I used CV1 ss 2.0 and Index res 200 % because I think that's the upper limit for both hmds to get optimal image quality - that is, you can go higher, but I don't notice significant gains compared to the very noticeable performance reductions. 

But just get the app and try it yourself - it's only 5 bucks 😉

[DaftnDirect]

RuneSR2 said:

Reading test

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

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

Visual Acuity (Distance Chart)

 

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

These are great tests. Very curious to see where the Rift-S sits with these 2 tests from someone on the forum. Maybe better if someone with multiple headsets does that test rather than me, I've packed away the CV1 and I think it's good to have someone with CV1 and S.. or Index and S, to do the test so there's an overlap with your tests @RuneSR2, any bias towards the S or anomaly would show up better, if you see what I mean.

[RuneSR2]

DaftnDirect said:

These are great tests. Very curious to see where the Rift-S sits with these 2 tests from someone on the forum. Maybe better if someone with multiple headsets does that test rather than me, I've packed away the CV1 and I think it's good to have someone with CV1 and S.. or Index and S, to do the test so there's an overlap with your tests @RuneSR2, any bias towards the S or anomaly would show up better, if you see what I mean.

Great idea - also this isn't a totally exact science, it will depend on your eyes too. I stopped the visual acuity test when I no longer could see the white dot inside the "P" clearly - thus "F" and "P" started to be impossible to tell from each other. 

Btw, fun thing I didn't mention, but Index has gotten a lot of criticism for the glare, but trying the glare test I'd swear the CV1 had *much* more glare (God rays) than Index - Index really has close to none, it was very surprising. Tilting my head, Index could get more glare, but looking straight at the large white letters "GLARE TEST" on the black background, glare was much less using Index than CV1. Maybe I need to clean my CV1 lenses, lol - and that was a joke, my lenses are extremely clean. 

[Anonymous]

I think something like God Rays can vary from device to device.

[pyroth309]

If I do it that way and I'll retest after rebooting my CPU:

On my CV1 I get 88 HFOV and 114 VFOV but I don't have the stock faceplate anymore and I have a VRCover with the pleather that's kinda plush. Could be affecting my VFOV possibly.

On O+ I get 104 HFOV and 134 VFOV with my hand on the front pressing inward both dots fall off at same time here so it's a good number. Where I normally wear the O+ I get 124 VFOV after 1 dot falls off,, 126 for both to fall off. HFOV is same

On Snellin Test - Only did the O+ cause it's not apples to apples to compare pixel density 2.0 to 200%. Reading Line 8. Also I used to have 20/10 vision but nowadays it's somewhere around 20/20 so may be a little better than a normal 20/20 idk.

100% SS after 2.5 meters it starts becoming blurry but I can make out the F and P at 3 meters

200% SS After 3.5 meters it starts getting quite hard to read so I'll just call it that.

[pyroth309]

Forgot to Add - Glare Test on O+ I see none when looking straight on at the dots and the text but if I turn my head 45-90 degrees I get a couple strong god rays that streak across my lens but it doesn't come into my eyes.

Glare results on CV1 -

That about sums it up lol.

I went back and did Snellen Test on CV1 since I had to plug it in to do glare test. At 2.0 I can read out to about 3.75 meters. I tested 1.6 for fun since my O+ is in between 1.5 and 1.6 on pixel count at 200% and I can see out to about 3.5 meters. Reflects my initial findings with the O+ when I first got it in cockpits. Despite the lack of SDE and smooth image, it doesn't increase text legibility. Look forward to repeating these with a G2.

[parsecn]

This was posted in alternate forums (by me) a couple of years ago. TestHMD result in relation to VRCover kits and CV1:

I received the long interface kit from VRCover last week and while it makes wearing glasses in VR much more comfortable, the reduction in FOV is a deal-breaker (for me). The long kit eliminates pressure on my nose by allowing room for the glasses, and I can again feel the facial interface against my face but can't get past the FOV. I know this is subjective and specific to each person, so not having a dig Ser Torvin, just observation.

I suspect I am "looking-for" FOV, like being hyper-aware of it at trying the new interface. It's like looking through two circles and reminds me of daydream or cardboard FOV. I've heard others refer to this as the periscope effect; not sure if it's the correct term to use here.

At any rate, on a positive note, the experience brought me to an outstanding app called TestHMD where I am able to compare both hFOV and vFOV.

Result:
• Oculus CV1 stock foam interface vFOV 116° / hFOV 90° which is reflected in the common result for CV1 users.
• VRCover short interface vFOV 116° / hFOV 88° was surprised to see a reduction from stock Oculus foam albeit very minimal at only 2°; certainly unnoticeable unless the user is using testing software such as TestHMD
• VRCover long interface vFOV 98° / hFOV 80°

for a loss of vFOV 18°/ hFOV 10° respectively

TestHMD also has an eye chart and distance measurement. Very helpful.

In all of my various testing, it's allowed me to conclude:
• Yes, I can see better in VR if wearing glasses. I have 20/20 vision from 3m when wearing glasses
• Nose pain with glasses and short interface; can't do it
• Long interface presents reduced FOV; distracting can't do it
• Have gone back to short interface no glasses with SS 1.8 and "live with" things being a bit blurry.
• Moving to Index in January – this process has encouraged the purchase of prescription lens adapters

No affil with TestHMD.