Pentax PF-100ED?telescope
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It’s big, it’s bulky … but it’s worth it. That was my rapidly reached conclusion while testing Pentax’s PF-100ED telescope, which has been on the market for the last four years but, along with its smaller PF-80ED cousin and the more recently launched PF-65ED, has been largely overlooked by birders.
With the body alone weighing 2,600 g, it is certainly not for the faint-hearted and, when you consider the demand for a sturdy tripod to support it effectively, the resultant load falls only slightly short of a body-builder’s starter pack! When you have become accustomed to the weight, however, the advantages of having that enormous 100 mm lens at the end of the scope become clear.
This straight-bodied telescope is constructed using a lightweight magnesium alloy, with smooth rubber armour encasing the prism-housing at the eyepiece attachment end. It features a tripod mount with an easily operated eight-point click-stop rotation mechanism so that it can be fitted with a camera, using Pentax’s PF-CA35 35 mm SLR camera adapter, which allows the user to alternate quickly between landscape and portrait shots.
With so much combined weight slung over the shoulder, or simply carried around by the tripod legs, it would make good sense to fit a tripod adapter, such as the 200USS manufactured by Manfrotto. The latter bolts on to the telescope’s foot to increase stability and to reduce the inevitable strain placed on the single ¼ inch bolt, which normally forms the only means of attachment between a telescope and the tripod supporting it.
All the weight is concentrated at the objective lens end of the scope body, so I found that, when there is no counterbalance such as a camera or a heavy zoom eyepiece to compensate, the scope body frequently pitched forward. This meant I had to keep the tripod tilt mechanism constantly tightened, especially when changing eyepieces.
I tested two eyepieces, one zoom and one fixed magnification, both of which are renowned for their high-quality design and construction. Both feature ED glass and are fully multi-coated. The XL 8-24 zoom eyepiece is impressive. Close to the size of a can of soup, it weighs in at 550 g and, like the XW20 32x wide-angle eyepiece I also tested, it is quickly married with the scope body by sliding it in, twisting it and then locking it with a single external screw ring. The zoom indicates a scale of 20-60x magnification, and indeed this scale is reflected when used with an 80 mm objective lens, but using it with the 100 mm objective means that the magnification is ramped up to a powerful 26-78x.
Smooth-action focusing is easily achieved via a broadly milled single knob, offset to the right of centre on the distal end of the prism housing.
Because the zoom eyepiece features a solid screw-out eyecup I found it easier to use than the fixed magnification wide-angle eyepiece, which does not. Considering the diameter of the lens in each eyepiece (the XW20 is larger) and the overall diameter of the eyepieces themselves, achieving a comfortable fit to the eye takes some mastering – particularly in terms of eliminating reflected backlight. Once this has been achieved, however, the results are excellent.
The zoom performs very well indeed, producing a clean, crisp image, and even toward the higher end of the magnification range the results are still very pleasing. The contrast is good, the edge of the field is virtually undistorted and sharp, there is negligible colour fringing and the image remains relatively bright – no doubt aided considerably by the light-gathering capacity of that large objective.
But this is only half the story. Compared with the zoom, the 32x fixed magnification wide-angle eyepiece was truly amazing. In the very poor light conditions which are the legacy of storm clouds and driving rain, I found the difference in brightness between the two eyepieces substantial at the same level of magnification.
The fixed magnification XW20 performed outstandingly, with distant gulls huddled on a muddy island, facing into the rain, appearing artificially illuminated. The whole image also took on a less ‘cramped’ appearance as the 70 0 apparent field of view seemed to inject a new dimension into it. I cannot envisage a brighter image through any other scope under these conditions. If I had one criticism of the XW20, it would be that the eyecup is not deep enough to allow its edges to rest comfortably against your eye socket, which leaves the lens open to stray side light and the eye exposed to the wind.
The PF-100ED is supplied complete with a vinyl stay-on case, which offers more than adequate protection against the elements and is sufficient to prevent superficial damage.
With the recent popularity of high-quality small objective scopes having gained momentum, and angled-bodied scopes now generally outselling their straight-bodied counterparts by five to one, it is difficult to envisage this model ever becoming anything but the preserve of the discerning few who are willing to put image quality before price and portability.
Price: £1,189.99 (body only)
Eyepieces: XW20 (32x magnification) £249.99; 26-78x zoom £319.99
Size: 510x134x117 mm
Weight: body 2,600 g; XW20 355 g;
26-78x zoom 550 g
Field of view: (m at 1,000 m) XW20 32x, 38 m; 24x, 47 m; 26-78x zoom, 26-14 m
Gas-filled: yes
Waterproof: yes
Guarantee: 10 years
With the body alone weighing 2,600 g, it is certainly not for the faint-hearted and, when you consider the demand for a sturdy tripod to support it effectively, the resultant load falls only slightly short of a body-builder’s starter pack! When you have become accustomed to the weight, however, the advantages of having that enormous 100 mm lens at the end of the scope become clear.
This straight-bodied telescope is constructed using a lightweight magnesium alloy, with smooth rubber armour encasing the prism-housing at the eyepiece attachment end. It features a tripod mount with an easily operated eight-point click-stop rotation mechanism so that it can be fitted with a camera, using Pentax’s PF-CA35 35 mm SLR camera adapter, which allows the user to alternate quickly between landscape and portrait shots.
With so much combined weight slung over the shoulder, or simply carried around by the tripod legs, it would make good sense to fit a tripod adapter, such as the 200USS manufactured by Manfrotto. The latter bolts on to the telescope’s foot to increase stability and to reduce the inevitable strain placed on the single ¼ inch bolt, which normally forms the only means of attachment between a telescope and the tripod supporting it.
All the weight is concentrated at the objective lens end of the scope body, so I found that, when there is no counterbalance such as a camera or a heavy zoom eyepiece to compensate, the scope body frequently pitched forward. This meant I had to keep the tripod tilt mechanism constantly tightened, especially when changing eyepieces.
I tested two eyepieces, one zoom and one fixed magnification, both of which are renowned for their high-quality design and construction. Both feature ED glass and are fully multi-coated. The XL 8-24 zoom eyepiece is impressive. Close to the size of a can of soup, it weighs in at 550 g and, like the XW20 32x wide-angle eyepiece I also tested, it is quickly married with the scope body by sliding it in, twisting it and then locking it with a single external screw ring. The zoom indicates a scale of 20-60x magnification, and indeed this scale is reflected when used with an 80 mm objective lens, but using it with the 100 mm objective means that the magnification is ramped up to a powerful 26-78x.
Smooth-action focusing is easily achieved via a broadly milled single knob, offset to the right of centre on the distal end of the prism housing.
Because the zoom eyepiece features a solid screw-out eyecup I found it easier to use than the fixed magnification wide-angle eyepiece, which does not. Considering the diameter of the lens in each eyepiece (the XW20 is larger) and the overall diameter of the eyepieces themselves, achieving a comfortable fit to the eye takes some mastering – particularly in terms of eliminating reflected backlight. Once this has been achieved, however, the results are excellent.
The zoom performs very well indeed, producing a clean, crisp image, and even toward the higher end of the magnification range the results are still very pleasing. The contrast is good, the edge of the field is virtually undistorted and sharp, there is negligible colour fringing and the image remains relatively bright – no doubt aided considerably by the light-gathering capacity of that large objective.
But this is only half the story. Compared with the zoom, the 32x fixed magnification wide-angle eyepiece was truly amazing. In the very poor light conditions which are the legacy of storm clouds and driving rain, I found the difference in brightness between the two eyepieces substantial at the same level of magnification.
The fixed magnification XW20 performed outstandingly, with distant gulls huddled on a muddy island, facing into the rain, appearing artificially illuminated. The whole image also took on a less ‘cramped’ appearance as the 70 0 apparent field of view seemed to inject a new dimension into it. I cannot envisage a brighter image through any other scope under these conditions. If I had one criticism of the XW20, it would be that the eyecup is not deep enough to allow its edges to rest comfortably against your eye socket, which leaves the lens open to stray side light and the eye exposed to the wind.
The PF-100ED is supplied complete with a vinyl stay-on case, which offers more than adequate protection against the elements and is sufficient to prevent superficial damage.
With the recent popularity of high-quality small objective scopes having gained momentum, and angled-bodied scopes now generally outselling their straight-bodied counterparts by five to one, it is difficult to envisage this model ever becoming anything but the preserve of the discerning few who are willing to put image quality before price and portability.
Price: £1,189.99 (body only)
Eyepieces: XW20 (32x magnification) £249.99; 26-78x zoom £319.99
Size: 510x134x117 mm
Weight: body 2,600 g; XW20 355 g;
26-78x zoom 550 g
Field of view: (m at 1,000 m) XW20 32x, 38 m; 24x, 47 m; 26-78x zoom, 26-14 m
Gas-filled: yes
Waterproof: yes
Guarantee: 10 years
