Until recently, I had resisted the temptation to buy a zoom eyepiece for my, now ageing, Leica APO Televid telescope. For four years I used 20x and 32x wide angle lenses, inter-changing them when necessary. I had been put off zooms through previous experiences that showed that the angle of view and optical quality of a fixed magnification eyepiece was superior than the (then) currently available zooms. Things were soon to change.
Throughout July and August, I sat watching gulls at my local roost, many of them so distant that I either hoped that they might fly closer or simply put up with the poor views. It taught me a lot, and through experience with closer gulls, I managed to get a feel for these distant birds. It reached a point where I could have a ‘gut-feeling’ about their identity, sometimes confirmed by the bird flying closer, but also sometimes left unsubstantiated. However, recently a friend watched the roost with me: he had the new Leica 20-60x eyepiece on his APO Televid. I found a distant ‘juvenile Yellow-legged Gull’; a ‘gut-feeling’ through my 32x was transformed into a ‘definite’ through the zoom set at 60x. The clarity and brightness of the image was excellent, and despite the obviously less bright view, the features confirming its identity were clearly visible.
It was incredible, a revelation if you like, and I determined then that I would get one. Now, after a frustrating period waiting for the eyepiece to arrive at my local shop and having had one for a few weeks, I offer my considered opinion about its optical quality and whether it replaces the fixed magnification eyepieces.
Like the other eyepieces for the Leica telescopes it is a sizeable object, with its large eye-relief looking big enough to drink coffee out of. It has, unlike my old eyepieces, a screw out eye lens shield and a normal bayonet mount. At times my eyepiece is a touch loose, when I zoom in the whole things turns a little (actually worst on colder days when the lubrication stiffens), a bit annoying, but more than compensated for by the quality.
At 20x the image is bright, clean, sharp, and neutral in colour - this last feature is something that sets Leica apart from many telescope producers, which have blue or yellow casts to their images. There is a slight fall off in quality towards the edge. In comparison my fixed 20x eyepiece offers an incredible angle of view (almost twice that available on the zoom) and is sharp right to the edge, even if you have to adjust the focus slightly to make sure. With the fixed 20x though, probably an optical illusion caused by the massive angle of view, things seem further away.
The joy of the zoom is the ability to get a higher magnification without changing eyepieces. To do this you turn the eyepiece anticlockwise. The image does tend to go out of focus a touch as you zoom in (but not always when you zoom out). At 32x the image is still very sharp and this quality continues right up to 60x. All those friends who have looked through my ‘scope have all commented on its quality and brilliance of image. At 40x it is way above the quality of the fixed magnification lens, which is small and rather like peering through a knot in fence.
One aspect of my birding is the use of a digital camera through the ‘scope, and again I had some concerns that the quality of the image might be less than that through my 20x. This has proven to be unfounded and the image is if anything sharper – maybe more to do with age rather than optics. There is now the opportunity and added benefit of zooming to a higher magnification image without changing eyepieces – the results can be seen by looking at the video-grabs of juvenile Caspian Gull and Richard’s Pipit at the photo page. The only drawback is that with my fixed 20x I can use the camera fully zoomed out as well as the normal fully zoomed in, giving images at 20x instead of 200x.
I can honestly say that it has not been taken off my telescope since it arrived and I am wondering what to do with the fixed magnification eyepieces. The new zoom eyepiece offers an excellent image, quality to be expected of the best manufacturer of birding optics, and for one am a convert.
Brian Small
September 2000
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