January 24, 2022

HoloLens FOV: Why Some Are Bigger, Others Are Smaller?



Here we are again.

You know what I mean by that, but I promise every time I bring up the topic of FOV with HoloLens, I have new information in hand. You can check the link at bottom of this post to verify that. This time no exceptions.

Check out this video first.

Can you see the a problem with FOV in the video? No. Many would agree that if the real device can be like this, there is no worry about FOV.

Now it’s my discoveries: 1. FOV in the above video is pretty good. 2. FOV in January prototype try out is good too. 3. FOV in the semi-final prototype is very small. Why is that? I don’t know. Lets ask a better question: What the hell is the difference between the three? I don’t know either, but the last question is something I can work on. Lets get on to it.


Case 1: The above video. The video was created live by a special HoloLens worn by a camera, which means if you are wearing a HoloLens like that, you can see the whole room full of holograms. The FOV is very good indeed. The above two picture was screen shots from the latest Minecraft demo, which uses the same technique as in the above video for capturing live mixed reality video.  Notice in the above two pictures: “A” looks a lot like the lenses on HoloLens, “B” looks like a PC.

Case 2: January 21 live try out by a group of reporters. That was lab level HoloLens that doesn’t look HoloLens at all. There were a lot of tangling wires and it was driven by a laptop. That FOV may not be as great as Case 1, but sufficiently good.

Case 3: The close to final HoloLens shown at Build Conference and E3. The FOV is very small and insufficient.

We have two things to work on: the CPU/GPU and the light engine/light projection. It’s either or both of them. In any case, it’s likely not able to get the light to human eyes fast enough, therefore, dizzy effect for the Case 3, so they have to limit the FOV to get the speed.

But, what exactly is it? I have to leave it to Microsoft. I need answers too.

The bright side is: a large FOV is possible if you don’t worry about carrying something big. I believe there are many use cases where you don’t mind carry something big. Remember a tethered or even wired solution are desirable too (use your imagination). Again, we need some confirmation.


HoloLens: Field of View (FOV) Collections

Also, there is a collection of FOV related links from HoloLensFov.