I Think Firmware .255 Reduced Vertical FOV for the "Large" Setting

I’ve been using the .180 beta version of Pitools since I got my Pimax 5k XR and just updated to Pitools .253 (which means flashing to firmware .255).

Right away I noticed that I could now see the borders on the top and bottom of the image with FOV set to “Large” where as before I could only see the bottom one. I’ve tried readjusting the headset angle, tightening the straps, etc–but it’s definitely a change with the optics themselves–either in the firmware itself or in Pitools.

I tried going down to Pitools .249 (which is still using that .255 firmware) but this made no difference. So I’m thinking that maybe the reduced vertical FOV was introduced in the .255 firmware itself–the same firmware that introduced the “Potato” FOV mode.

Before I flashed to .255 I’d spent many hours trying different depths of padding, shifting the headset, tightening straps, etc, trying to maximize FOV, so I had a really clear idea of what “Large” could look like on my headset and I know for a fact I can see the top border now no matter what I do, where as before I could adjust things so that it wasn’t visible.

Maybe if I hadn’t been paying such close attention to it before I wouldn’t have noticed, but I’m still surprised no one else seems to have commented on this FOV reduction. Since FOV is the main selling point for Pimax, this seems like kind of a big deal? Or at least it is to me …

1 Like

I cannot comment on that because I am stuck at v132 PiTool, but you may try hmdq tool (https://github.com/risa2000/hmdq). It will dump rendered FOV(s) in OpenVR for particular mode.


Check your refresh rate. At 120hz large FOV is limited like you say. Going back to 90hz may well fix it.

1 Like

I got similar experience after flashing, but then I figured “Hidden area mask” was on. Check this.
I can not tell for sure is it smaller then before, as after first impression I was soon deep in gaming, not able to recognize changes any more.

1 Like

Thanks! I’ll try to figure out how to use this.

Thanks for responding, but this doesn’t have anything to do with “Hidden area mask.” I know this because I’ve always had that setting on, I had it on with the .180 version of Pitools, before Pimax shrunk the FOV “Large” setting vertically. So I don’t see why it would have a different impact with newer Pitools or firmware.

As for your being too involved in gaming to notice the reduced FOV anymore–that’s great for you, but I still notice it and am not happy to see it reduced from what it was when I bought my Pimax. Whatever advantage is gained from shrinking it–less distortion?–I would prefer to have the choice to keep the greater FOV. Now whenever I use my Pimax I can’t help but notice the bottom and top borders of the image, which is exactly the kind of immersion-breaking effect I bought my Pimax to avoid.

I would like to get the FOV I paid for back again. I love my Pimax and this is the first time I’ve felt let down by the experience of using it.

Now when you said about having before hidden mask, I didn’t got before some big difference with or without it. Now it is big. I think now option “with” is changed, and covers much bigger area. Try without it.
I changed default pimax picture with some prety ladies :slight_smile: I can see whole picture as before, from edge until edge. Left and right edges are changed more, maybe reduced a bit (1-2 pixels) and rounded.But changes are so small, not worth talking about.
ps: I also like big fov, I bought it big, and I use it. I do not want any reducing, at any cost.

Okay, I tried disabling Hidden Mask, and you are right–it does make the “Large” setting slightly bigger. But not as big as it was in the .180 beta version of Pitools, and disabling Hidden Mask Area should decrease performance since it just means the card will have to fill in pixels you don’t actually see.

I’m glad you feel the same way I do about FOV. This is why I don’t want to lose any FOV that we already had.

1 Like

Thanks for the suggestion, but unfortunately I can’t go any higher than 80hz anyway, because I have an XR headset, with an OLED that can’t go any higher. I wonder if that might have something to do with it–could the software or firmware that enabled 120hz be shrinking “Large” FOV on my headset because it I’m running at the highest res for my headset? Like maybe that’s just automatic now or something?

I have noticed this as well. I see bits of black screen at the top and bottom of the left and right parts of the display which were never there before. I have it set to wide and 90HZ. Definitely a smaller FOV than there used to be.

Could you record the headset geometry by using the hmdq tool (as I posted above) and send me the file?

I have had this feel of reduced fov too when I have updated to test the 110Hz on a 202 5K+ after a long time not upgrading the driver/fw (I was with pitool and fw before updating).

As I was focusing on trying the 110Hz mode I haven’t investigated further about this feeling of reduced fov.

Now this makes me think about the idea to have a vertical fov reduction setting in pitool in addition to the horizontal fov setting.

Reducing the vertical fov should brings better performance gains per degree of reduced FOV than reducing the FOV horizontally, as there are more pixels horizontally then vertically.

For games where horizontal FOV is important, like racing games for which it allows better awareness of surrounding cars, better visibility in curves, and better sense of speed, the trade-off of losing some vertical fov to be able to keep the maximum horizontal fov (large instead of normal, or normal instead of small for heavy games / weak graphic cards) may be well worth it !

I really would like to give this a try !