Fw-190 Bar.. once and for all...

[IvanK]

How the revi works ... I thought it was a collimated display therefore reticle size would not vary as distance from the combining glass changes. That is a basic reason for the the reflector gunsights very existence. You will with most reflector sights have view angle limitations but reticle size should not vary with eye to glass distance.

There is something not quite right with this video. I suspect the optics in this sight are not original.

[Feuerfalke]

I noticed that, too. Especially with the building in the background you can see the gunsight changes size pretty much when moving back and forth. I doubt it was like that in the real thing or guessing distances really was pure guessing.

[GF_Mastiff]

nah its just like a sniper scope if you pull back your head and look through it the object looks larger.

it actual stays the same size, it's just the reflection grows as you get farther away.

try it with a pair of high scoped binoculars you will see.

[Feuerfalke]

Originally Posted by GF_Mastiff

nah its just like a sniper scope if you pull back your head and look through it the object looks larger.

it actual stays the same size, it's just the reflection grows as you get farther away.

try it with a pair of high scoped binoculars you will see.

Hm, I compared the size to that building in the background. To me it seemed to vary compared to that and I don't know if it is supposed to. But I must admit I didn't spend much time watching the video that closely and I never saw it working in reality either. It just surprised me, to see it working like that.

[IvanK]

No Mastiff thats the point, any reflector gunsight or HUD works on the collimated principal of a projected image. Its nothing like a Sniper scope or high powered binoculars. The Reflector gunsights principal reason for invention was to present a constant sized reticle image independent of the pilots head position. the Reticle (by the process of collimation) is focused at infinity therefore its angular dimension is independent of the shooters eye position.

Unlike a Ring and bead where the Angular dimension of the Ring is directly proportional to the distance between the eye and the ring. In fact A Ring and Bead gunsight is only accurate at one fixed Eye to ring distance.... thats why there was a need for the reflector gunsight.

What I think is happening in the video clip is that the apperrance of the pilots eye getting closer to the sight is in fact the zoom of the video camera. The camera itself is moreless at a fixed distance from the sight but the zoom control gives the illusion that the eye is getting closer to the sight when in fact its not. So the Zoom magnification has in effect two differrent focal distances the sight body itself and the reticle which is (by definition) at infinity. The net result is that this camera zoom does not replicate the effect of the pilot moving his head closer to the sight.

[GF_Mastiff]

it's exactly like a sniper scope with the red dot in the middle, if you have ever used one. I have and that's what the red dot does, when I look in to the scope from a distance it looks larger than it really is. The lense in the scope causes it to look as if it is getting larger when it really isnt.

[IvanK]

Yep I am a rifle shooter as well The principals are totally different. In a rifle scope the image of the sighting reference be it a dot or cross hair is magnified, therefore there is an associated focal length. In these sights the aiming refrence and your eye are seperated by a lens. Therfore any time you change the distance between your eye and the scope the amount of magnification changes as does the aiming refrence (dot or cross hair) size.

With a reflector sight there is no magnification whatsoever on the displayed reticle. There is no lens between your eye and the projected reticle. The reticle is displayed at infinity. I have used slightly more advanced gyro reflector sights in real life ... Ferranti Isis and CSF97K and HUDs,though more modern than the Revis the basic principals are the same. The symbology size does not change as you move your eyes closer or further from the combining glass. If it did than any form of angular range finding (stadimetric) would not be possible.

[Bobb4]

Originally Posted by IvanK

Yep I am a rifle shooter as well
With a reflector sight there is no magnification whatsoever on the displayed reticle. There is no lens between your eye and the projected reticle. The reticle is displayed at infinity. I have used slightly more advanced gyro reflector sights in real life ... Ferranti Isis and CSF97K and HUDs,though more modern than the Revis the basic principals are the same. The symbology size does not change as you move your eyes closer or further from the combining glass. If it did than any form of angular range finding (stadimetric) would not be possible.

I see from the photo's that the sight was inline with the right eye. I am assuming US and British planes had it centrally placed. Would this have made much difference?
And if it did, one hopes SOW models this...

[Avimimus]

Originally Posted by IvanK

What I think is happening in the video clip is that the apperrance of the pilots eye getting closer to the sight is in fact the zoom of the video camera.

Zoom lense video cameras apparently existed since the 1930s (I didn't know that)

[zapatista]

Originally Posted by Avimimus

Zoom lense video cameras apparently existed since the 1930s (I didn't know that)

its an old gunsight mounted in somebody's living room, recording the image with a modern camera