Telescope Reviews: Small Binoculars

Just a few notes from using these various binocs

none of the recent purchases were found to need collimation. several were tested and found to hold collimation at a variety of IPDs from about 57mm to 67mm, about as wide a range as I can see.

Fujinon BFL 8x42 - no false color at all, no field curvature at all, very light and comfortable, although it would be nice if eye relief were about 2mm longer.

GO Apo Roof 8x42 - used for a day at a football game, including watched several skydivers, no false color at all, bright image, one eyecup constantly changed position needed to reset it every time I used it. No pincushion at all. Focus from 40 yds to 200 yds is apprx 15-20° movement of the focus dial.

Oberwerk 8x42 Roof - considerably darker than most of the other 8x42s. Of course the more recent discovery that the exit pupil measures only 4.2mm explains a lot of that.

Oberwerk 8x56 at 5.7° has the narrowest Tfov (and Afov = 46°) of all 8x or 7x binocs in this group. Viewing M45 with moon about 10° away, these picked up a full image ghost reflection of the moon!!! Not just a reflection down the inside of the barrel, but a full image reflection in the fov.

GO 10x50 Genesis - picks up reflections down the inside of the barrel when bright star or planet is just outside the fov.

GO Gemini 8x45 - fov actually measures 7.3° nearly a full degree smaller than specified. Most difficult to focus to a fine point in resolution tests resulted in this one being among the worst in boosted resolution. But still, 1x res and hand held res was right in the middle of the averages.

Oberwerk 10x50 - field stop is blurry, cannot see a clear field stop no matter where eye placement is. Outer 5%-10% fov can still be seen, but it is a dark blur. Front prism protrudes into light path and causes ~5%-7% blockage that can easily be seen as a dark chord across the exit pupil.

Oberwerk Mariner 8x40 - right eye cannot focus to as fine a point as left eye. R is one step lower then L in resolution. However, it still rated as one of the best in hand held resolution. And it rates as the widest sharp fov (7°) of all the binoculars in the entire group.

None of the 10x binoculars have a sharp fov wider than 5°. Most are in the range of 4° to 4.5°

Two of the most comfortable to carry around are the Fujinon BFL 8x42 and the Garrett Apo Roof 8x42.

Although I have not rated any binocular as having less than 60% sharp fov, the Nikon Action VII 8x40 has the worst (least wide % sharp) fov of all the binoculars tested. It shows a significant loss of transmission in the outer 30-40% of the field of view. It also has one of the poorest 6x boosted resolution values.

Not only do these following four share the best on-axis resoluton but also they hold up to show some of the best 6x boosted resolution AND they exhibit some of the best outer field sharpness: Fujinon BFL 8x42, Pentax PCF WP II 8x40, Oberwerk Mariner 7x50, William Optic 7x50 ED

All thoughts and impressions reserved right to potentially change upon more use and additional binoculars added to group tests.

edz

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Edited by EdZ (10/03/07 01:03 PM)

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