Binoculars

Binoculars

Superb build quality, excellent optical performance and the most trusted name in the sports optics market. Leica equipment has a reputation that most optical companies envy. They have achieved the market leaders position by never offering poor quality or even just satisfactory products. Their binoculars and spotting scopes are the best in the terrestrial optics market, and everybody knows the reputation of their cameras. All very well, but we astronomers like to think we 'really' know our optics, as opposed to the birders who 'think' they know (that should put the cat amongst the pigeons). It is very difficult to tell whether an optic is suffering from mild astigmatism, or exhibits minor undercorrection of lower order spherical aberration by looking at a Slavonian Grebe. A good optic must pass the astronomy test before it's true quality can be established. This is OK for a telescope that can be assessed at 50X per inch of aperture, but what about a hand-held binocular that is commonly used at around 5X per inch of aperture? The same principles apply to when judging the low power in-focus performance of a small refractor. How pleasing are the star images? How sharp is the moon? How well do some of the brighter Messier objects stand out against the background sky, and what faint fuzzies are visible?

January 2003. Fieldview Guesthouse. One of the venues for a weekend of allnighters, attended regularly by some of us hypothermia-seeking masochists (usually members of the Loughton Astro Soc. et.al., and yours truly). An ideal opportunity to test equipment. On this occasion, three pairs of binoculars kindly loaned by Leica Camera Ltd. UK. Trinovid 10X50, Trinovid 12X50 and Minox 10X58ED. Those who expressed a wish to be Guinea Pigs included Tim Jones, Martin Hopewell, Charles Munton, and Andrew 'The French Maid' Robertson. The following was generally agreed. Trinovid 10X50 and 12X50 - Excellent pin-point star images, no internal light reflections or scatter. Darker than usual background sky (a feature of all small binoculars that provide high contrast images), and easily discernable planetary shapes (Saturn was particularly impressive with the 12X50 with virtually no smearing of the image, a very common problem with binoculars that are produced in greater numbers than Leicas). Generally the view was that the 10X50 was the better overall binocular for astronomy. It was slightly easier to hold steady, gave more satisfying wide field views, and was the right balance between aperture/magnification/dark adapted pupil size. The shape of M42 was obvious, M31 stood out in bold contrast and M81 & 82 were easy targets. Further tests carried out back at home revealed healthy circular discs of extra-focal star images at centre-field with slight elongation toward the field edge. The vast majority of small binoculars (even many expensive models) often exhibit astigmatic star images, it was nice to find a binocular that could collapse and expand a star image symmetrically. The moon was clean and very crisp in both Trinovids, although the 12X50 has the edge in visible lunar detail. Some make-shift Astrosolar filters fitted to the 12X50 provided beautifully crisp solar images with sunspots in bold contrast. Overall verdict - High class luxury binoculars. Solid, well engineered and comfortable to hold and use. Excellent astronomical performance. The best generally available 50mm binoculars.

Leica Binoculars Mag Aperture Exit Pupil Linear Field Close Focus Dimensions Weight Trinovid 10x50BN 10x 50mm 5mm 115m/1000m 3.35m approx. 178x135x63mm 1150g Trinovid 12x50BN 12x 50mm 4.2mm 100m/1000m 3.25m approx. 182x135x63mm 1050g Please contact Chris at chris@brayimaging.co.uk or 01525 219100 for latest prices.

10x58ED

The star of the test and the real surprise was the Minox 10X58ED. I had expected them to be similar to most mid-priced roof prism binoculars, with satisfactory optical performance but generally uninspiring. I was wrong. They are now my firm favourite medium size hand held astro binocular. Although larger and heavier than the Leicas, the Minox was still comfortable, and easy to focus when wearing gloves. For spectacle wearers, the viewing comfort is superb, even better than the Leicas. I can't think of a binocular that has had such an immediate positive impression with every viewer. Shouts of 'b***dy hell these are good' confirmed that this binocular was not just a personal 'like'. Eye relief is outstanding, with none of the problems associated with some wide-field eyepieces, such as over-critical eye positioning. Binoculars belonging to other observers were compared to the Minox in order to set a 'known' benchmark, including a Fuji and a Canon Stabilized. None performed as satisfactorily as the Minox in overall image quality, some of this I think is due to an ideal exit pupil diameter with the Minox of 5.8mm, coupled with a manageable 10X magnification for hand held use. If this combination is allied to excellent quality optics, then there are very few, if any, hand held binoculars that will outperform a binocular like the Minox for astronomy. Everything about them is so immediately usable. I found myself preferring to use them over extended periods rather than spend time at the telescope. (I can only imagine what the Minox would be like if they included an internal stabilization system). I must admit, I was actively looking for ways to delay handing them back to Leica after the weekend. The term 'ED' used on the Minox denotes 'extra low dispersion' referring to superior correction for chromatic aberration. On test however, there was little difference in lack of chromatic aberration on the moon or during the day between the Minox and Leicas. I suspect that if normal Krown and Flint elements were used in the Minox OG, chromatic aberration would be more noticeable. As it is, any chromatic aberration is far from objectionable with the Minox. Deep sky fuzzies within the grasp of 58mm aperture were all visible, although as the transparency came and went, so did the visibility of fainter galaxies and planetaries. M31 was the best I've seen it in a hand held binocular for many years, and M42 was superb, surprisingly, even better than the low power view with my 60mm Tak. (using two eyes makes such a difference). As with the Leicas, the use of nebula filters has not been thought of when designing these binoculars, however, I am in no doubt that a way will be found to attach them. Astronomers are very useful for manufacturing home made add-ons. Back at home, the moon was clear and crisp and although the Leicas just nosed ahead for image sharpnesson the moon, I still admit to preferring the Minox as providing a more 'immediately' satisfying view, again the Minox eyepieces provide this benefit. Extra focal star images were symmetrical over most of the apparent field (something that was lacking in a pair of 15X58 Minox I tried earlier). The 58mm Minox binoculars are available in 8X58ED, 10X58ED and 15X58ED. On test, the 10X58ED was notably superior in all areas important for astronomy. There is no wasted aperture because the power/aperture ratio is too low, and the usable field is greater than the higher power Minox. All 58mm Minox binoculars are offered in a luxury foam lined case, a welcome addition for the gadget presentation freaks amongst us, and tripod mounting is possible with all models. Overall verdict. I can't think of a hand held binocular that I would rather own. Now, if Leica UK could only find it in their hearts to loan a pair for me to take to the Texas Star Party this year.

MINOX BD 10x58 ED BR Magnification: 10x Aperture: 58 mm Exit pupil: 5.8 mm Field of view: 6.2° Eye relief: 19mm Close focus: 4,9m Over run: > 4 dpt Diopter adjustment: >2 dpt Operating temperature: -10° to +45° Water resistant: up to 5 m Height, width, depth: 225x159x69 mm Weight: 1485g Includes aluminium case and neoprene strap. Please contact Chris at chris@brayimaging.co.uk or 01525 219100 for latest prices.