Tom Lester, November, 2005
Anyone who has spent hours trudging around the bush carrying an 80mm spotting scope and heavy-duty tripod on their shoulder knows how tiring the experience can be and how sore their shoulders can get after awhile. Yet, given the prevailing wisdom, many naturalists still choose to endure the extra weight in favor of the superior optics that 80mm scopes are supposed to provide over the smaller 60-65mm scopes.
Well, things have changed. In recent years several companies have introduced a number of 60-65mm spotting scopes that have superlative optics and more compact, light-weight designs for easier field use.
Now, I'm about to add another one to the current mix of superior, smaller spotting scopes-- the Pentax PF 65mm ED scope and its exceptional line of XW and XF eyepieces.
Comfort, Focus and Handling
The porro-prism Pentax 65mm ED spotting scope features a sleek, compact magnesium-framed body with a black protective rubber coating. At just 37.7 oz., the nitrogen-purged weatherproof scope (JIS Class 6) is very light and easy to carry, particularly when mated with one of the small lightweight video tripods and shoulder slings made by Velbon, Manfrotto and other tripod manufacturers. In fact, this scope/tripod combination is so darn lightweight that sometimes I forget I have it slung over my shoulder!
The scope is available in a straight and angled version. The body is well balanced and the columnar focus is easily adjusted with either hand making targets easy to spot and focus on quickly. It features an extendable rubber lens hood that provides shade to minimize reflective light under extremely bright viewing conditions. The hood also has a sight-line to help with target location and adjustments.
Eye Relief and Field of View
As Steve Ingraham points out in several of his BVD spotting scope articles, the quality of the eyepiece is critical in determining the overall performance of a spotting scope. While a large objective lens can provide lots of light to view an image, it's the eyepiece design and construction that ultimately determines the quality of the image the viewer sees.
Pentax makes two series of compact eyepieces that are compatible with the 65mm ED scope; the world-renowned XW ED (extra low dispersion) telescope eyepieces and the less expensive XF eyepieces.
The XW series eyepieces are waterproof (JIS Class 4) and come in four fixed focal lengths (20mm, 14mm, 10mm and 7mm) which yield a field of view at 1000 meters of 61m, 44m, 31m and 21m, respectively. Each eyepiece in the series has a generous eyerelief of 20mm and an extremely broad 70 degree apparent field of view which provides stunningly panoramic images.
XW eyepieces are available in magnifications of 19x (#XW20), 28x (#XW14), 38x (#XW10) and 58x (#XW 7) and feature the same superlative optics with lanthanum glass elements as found in the BVD's Reference scope, the 80mm Pentax ED spotting scope.
The less expensive XF series are not waterproof and do not have the extra low
dispersion lanthanum glass optics. (Editor's note: According to Pentax on 9/21/2007, the XF eyepieces are indeed JIS Class 4 waterproof and do contain lanthanum ED glass elements, even though their literature makes no mention of those facts.) These eyepieces are available in three focal
lengths (12mm, 8.5mm and a 6.5-19.5mm zoom). The eye relief for the two fixed
focal length XF eyepieces is 18mm while the XF 20x-60x zoom eyepiece eye relief
ranges between 15mm at 20x and 11mm at 60x, resulting in less than desirable
eyerelief for eyeglass wearers when using the zoom.
(**Tip: I've found that in some instances I can offset the problem of limited
eyerelief by using glasses with the new, highly flexible "twist flex"
frames that allow the eyeglass lens to move closer to the viewer's eye when
lightly pressed against the rubber eyepiece ring cap.)
Resolution and Image Quality
When the XW eyepieces are combined with the scope's extra-low dispersion objective lens, the Pentax 65mm scope offers a bright, extremely sharp, high-contrast image with only a nominal amount of chromatic aberration. The image is color neutral to slightly warm and exhibits virtually no curvature (spherical aberration) at the edge when using the standard straight line test at 100 yards.
Indeed, the image quality in the Pentax 65mm ED scope with the XW eyepieces is the equal to any other 65mm scope I have used, particularly when one considers the wide 70 degree field of view the scope provides. Further, with the exception of a small loss in brightness due to the smaller objective lens size, I found the image quality of the 65mm Pentax to be the virtual optical equivalent of my well known, very expensive Austrian-made 80mm scope : ) .
As for the use of the fixed focal eyepieces, some folks might find it a bit inconvenient. However, I found that when I needed to change eyepieces, the "slide and twist" design allowed me to change eyepieces in a matter of seconds without sacrificing the extremely high quality of image provided by the XW series eyepieces.
Cost-wise, two Pentax XW eyepieces (E.g. the 28x and 58x magnification combo) will set you back about the same amount as a 20x-60x variable zoom found in some of the higher priced spotting scopes on the market. Alternatively, one can elect to use just one XW eyepiece for all applications, in which case I suggest using either the 38x (XW10) or the 28x (XW14) eyepiece. I also found it very effective to use the 28x XW as my standard eyepiece and then switch to the XF 20x-60x zoom on the odd occasion when I needed more power to identify a distant shorebird or that darn hawk perched in a tree on the other side of the river.
Don't get me wrong, the Pentax XF 20x-60x zoom and other XF eyepieces while less expensive, still provide a very good image, although not quite as good as the XW eyepieces. The image generated by the XF eyepieces is less bright, somewhat warmer in coloration and has slightly more chromatic and spherical aberration. Yet, despite these minor drawbacks, the XF series eyepieces provide an image quality that will satisfy all but the most discriminating viewer.
Lastly, the Pentax XW and XF eyepieces are compatible with the optional PF CA35 camera adapter. Using this adapter, the Pentax scope can be combined with any one of a number of the Pentax digital and SLR cameras to yield excellent digiscoping results.
Overall Field Impressions
There are times when I would gladly pay a king's ransom to a porter to carry my 80mm scope and heavy-duty tripod, particularly on those long hikes through a marsh or up a steep mountain trail. However, I think now I've stumbled on a more realistic, less expensive option; the Pentax 65mm ED scope.
Granted there are times when having an 80mm scope, particularly at first and last light can make a difference, however, I find that a good quality 65mm scope can provide all the necessary optical quality, brightness and magnification one needs to make 98% of the bird identifications one has to. And, in my opinion, no 65mm scope does it better than the Pentax 65mm ED scope, particularly when mated with the excellent XW eyepieces.
Combining the Pentax 65mm scope with a good light weight tripod such as my Manfrotto 718b or a Velbon Victory tripod, one gets a stable yet eminently transportable viewing platform. Yet, this same combination is so light and maneuverable that it's easily slung over the shoulder and forgotten about as you walk along a narrow path chatting with your friends and birding with your binoculars.
Conclusions:
Pentax has continued its excellent tradition of the superb 80mm ED scope by producing a real winner in its 65 mm ED scope and companion XW and XF eyepieces. This is particularly true given the significant difference in price between the Pentax 65 mm scope and some other higher end 60-65mm spotting scopes on the market.
The XW ED eyepieces are optically equal to any spotting scope eyepieces on the market and offer the viewer an extremely wide image that is bright, sharp, color neutral and full of contrast. For those wishing to spend a little less money on an eyepiece or get the convenience of a zoom, the XF series offers some excellent options.
In closing, the scope's excellent optics, sharp image and broad field of view combined with its lightweight weatherproof construction, balance and field durability make the Pentax 65mm ED scope worthy of serious consideration for any birder, naturalist or hunter looking for a superior spotting scope, regardless of price.
Now, get out there and bird!