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Hi Kenny,

When I asked Kowa why the Highlander distortion-free zone (i.e. sweet area) was offset up in the field, they replied that it was due to the prisms. Maybe someone else in the forum would know why prisms could cause this.

Milt

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Milt,

I think Holger has given the most plausible answer to this. It is what I have alluded to in the past. I have seen this off center sharpness in a number of binoculars.

Another test that I have done in the past will show the same result. That test is fully explained in the thread on vignette. Place a glass over the objective lens. using a target laser,(a laser collimator with a cross hairs and bulls eye target) shine the laser thru the objective lens. Direct the back end of the binocular towards a white wall several inches away. Move the laser around in front of the objective lens, keeping it perfectly perpendicular to the objective and observe the exit pupil image. You will be able to see that the maximum exit pupil is off-center in all of the these binoculars. I believe this is showning tilted prisms, a testament to the suggestion that the prisms can be tilted yet the images can be merged.

Oberwerk 22x100
Orion 15x63 minigiant
Garrett Gemini 20x80
Oberwerk 8x56
WO 7x50 ED

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