CN FORUMS ARCHIVE Telescope Reviews: Nikon Action Extremes eye relief

A question from another thread asks;
I wonder if anyone has any experience using the Nikon Action extremes ... with eyeglasses. How is the effective eye relief? I've read a detailed review of the Orion Ultraviews on the site, and I know from that that they will work well with eyeglasses, even though their stated eye relief (22mm) turns out to be less when actuually measured. Thanks! Brian

The eye relief is listed as 17mm on the 10x50 and 8x40. On the 12x50 it is listed as 16mm.

I measured exactly 17mm on the 10x50 and on the 8x40 and 16mm for the 12x50.

The binocular housing (eyepiece holder, focusing, prism housing) is identical on all three models mentioned here. The 12x50s and 10x50s cannot be told apart from one another without looking for the 10x50 or 12x50 label on the housing. The 8x40 has the identical housing, but just has shorter objective barrels.

Eye relief can be determined easily by pointing the binocular at a bright light source and holding a white card behind the eye lens. as you move the card towards or away from the eye lens you can see the small bright dot projected on the card will enlarge and contract. If the card is either too close or too far away the projected dot will be too large. The dot will reach the smallest and sharpest clearest image when the card is at exactly the proper eye relif distance. this represents the distance where all the light rays are contained within the image of the dot.

With the eyecups turned all the way in, 6mm of the eye relief is used up. The lens is recessed 5.5-6mm below the top of the eye guard when the eye guard is completely closed down. So, usable or effective eye relief in this position is 17-6 = 11mm. With any binocular the most eye relief you get to use is when the eye cups are turnedd down. That is the maximum effective eye relief. It is always less than the stated eye relief.

The eyecups are twist out, semi-hard, with a click notch that holds at 3 extended positions. Each click out adds 3mm extension. When the eye cups are fully extended, the lens is recessed 15mm in from the top of the eye cups. The eye cup full extension adds an additional 9mm recess to the 6mm. I verified that I was easily able to to see the entire FOV in all models without my glasses and with the eye cups extended fully out.

In the Nikon Action EX models, I am able to see 100% of the FOV with my glasses on and the eye cups closed down. In fact, even with the eye cups extended out 1 notch, I was still able to see the entire FOV with my glasses on, in all models.

The Orion Ultraview 10x50 were fine with the eye cups down, but with the eyecups fully extended, would not allow me to see the entire FOV, even without my glasses. About 10-15% of the fov is blocked. The lens recess with the cups down is 3mm and with the cups fully extended 14mm (eye cups fully extended adds an additional 11mm recess).

edz

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