Product Review

The shape of things to come? OceanWanderers reviews the new TD-1 telescope/digital camera combination from Kowa.

Our good friends at Kowa Optimed Inc. recently provided with a sample of their new 'super telephoto digital camera scope', better known as the TD-1. Who could say 'no' to a hot new product from one of the world's leaders in birding optics, especially when the marketing brochure promised the chance to "enter the world of amazement, impact and surprise"! This review is written with the typical birdwatcher in mind, however, the instrument will undoubtedly find many other uses such as general wildlife viewing (elephants to dragonflies).

FIRST IMPRESSIONS: OK, I confess this is a cooool looking scope!! The crisp metallic finish and squat, muscular design gives the new TD-1 digital-telescope a very modern and appealing look. Oddly, when you lift it for the first time it is hard not to feel disorientated by the weight, or rather the lack of weight. The chunky metal design (no plastic here) gives the impression that the unit is going to weigh a ton but in fact it's a manageable2.3 kilos (5.1 lbs).

Figs. 2 & 3. At 39 cm (15.4 inches) long, the TD-1 (bottom or left) is more compact than other high-end Kowa scopes. Compared here with the Kowa's classic TSN-4 Prominar (center) and its replacement the TSN-824 Prominar (top or right).

For many field birders, an important feature of telescope design is that it should be compact, ideally short enough to fit easily in your carry-on luggage or a day pack. It is notable that Kowa’s main rival Swarovski has adopted this manta in the design of the new ATS 80 and ATS 65 scopes, which are tiny in comparison to their enormous but outstanding predecessor, the ST80 HD. The Kowa TD-1 is not too far off the mark here and I sincerely hope that neither the length or weight increases much in future, more powerful, incarnations.

The accessories included with the scope are lens caps, a remote control for the camera, USB and video cables, CD-ROM with image downloading software and a diopter seal. A soft carrying case (C-TD1, US$146), AC adapter (TD1-AD ~US$54) and threaded 67mm UV filter adapter ring (TD1-FA, US$47) must be bought separately.

Fig. 4. American Oystercatcher photographed through the TD-1 using manual exposure..

USING THE TELESCOPE: The telescope itself does not require battery power and can be used independently of the camera unit. Thus you do not need to turn the unit on to make full use of the scope itself. This is a God-send if your batteries run out in the field! The image is reasonably bright and quite useable at both ends of the zoom range. 10x is fine for scanning through flocks of birds, where upon you can crank up to 30x to study something carefully. Of course, it would be nice to be able to zoom higher (e.g. 40-50x) to look closely at plumage details or very distant birds but this is a compromise users can live with. After all, many birders already favor fixed magnification lens, finding the wide field of view more useful than extreme magnification power. Compared to the TSN-824 with zoom eye-piece, I found a noticeable narrowing of the depth of field and one has to adust the focuse more when studying groups of birds. I imagine this is a comprise associated with adapting the lenses for use with the in-built camera.

You use the scope in the same way as any other. For frequent telescope users, aiming quickly becomes intuitive but for newbies, a pair of small aiming sights are included on the top of the eyepiece barrel. The diopter adjustment ring, allows you to calibrate the eyepiece to your own vision. You simply turn the ring until two fine lines etched on the glass come into sharp focus.

Fig. 5. The color liquid crystal display (LCD) is positioned below the eyepiece and surrounded by the camera controls. The camera is turned on by holding down the green button at bottom left. A thumb wheel allows this to be locked to prevent the camera turning on during transport. Three menu buttons (Display, Menu and Timer/Delete) allow a limited degree of manual control over the camera, stored images and the LCD display.

Fig. 6. With conventional digiscoping, locating the subject with the camera in place is often tricky because of the difficulty in seeing the camera's LCD screen and the shallow depth of field. Usually it is necessary to pre focus the scope on the bird and then lift or screw the digital camera into place against the eye piece. With the TD-1, you can aim the telescope at a subject or pan around in just the same way you would use a conventional telescope and then snap a photograph without taking your eye off the subject. No wonder Kowa's marketing catch phrase is, "Find & Shoot!"

FEATURES: Most spotting scopes use the eyepiece to zoom, however in the TD-1 zooming is done using the objective lens so that the 'apparent field of view' remains constant. There are two focusing rings on the barrel, the closer one is for the zoom (10-30x) and the more distant is for fine focus. For those used to taking photographs with conventional 35mm format cameras, the 10-30X zoom of the TD-1 is equivalent to using 450 to 1350mm lens. At 10X, the lens manages a respectable apperture of f2.8 but this falls to f4 at 30X. Consequently having enough light can become a significant problem. Adding to the woes, the maximum ISO equivalent is 200, so there is no way to crank things up (ideally ISO 400-800) on overcast days to get that valuable but grainy record shot of a rarity.

Fig. 7. The mode selector wheel is a prominent feature on the left hand side of the TD-1. This switches the camera between Auto Focus (AF) and Manual Focus (MF) modes. Two additional settings switch between Play Back mode (PLAY) allowing you to review saved images on the LCD and a camera Menu mode (SET UP). The latter two work in conjunction with the 4-way cross selector button on the handle grip. The wheel turns easily, so much so that it often shifts when you carry the scope around, so you have to get into the habit of checking it periodically. A lock device similar to the power control would be a plus here. An unobstrusive flap just to the right of the mode selector wheel gives access to ports for USB and video cable connections as well as the plug-in for the optional AC adapter unit.

Power is supplied from four AA batteries. A tiny green LED lamp reminds you when the power is on, even when the screen is dark. These drain pretty quickly when using autofocus but last much longer if you do your focusing with the manual setting and don't spend too much time reviewing images. [As a rule I rarely discard image in the field, except for obviously hopeless ones of course. I find it preferable to examine the images on a computer screen where I can better judge the sharpness and exposure.] An AC adapter (TD1-AD ~US$54) is sold separately that allows the scope to be powered from a standard wall outlet. This would make sense if you are transferring images to a computer or television and I'm actually surprised this does not come as an accessory with the scope.

Fig. 8. The hatch for the battery and memory chip compartment is on the underside of the handle grip, and opens with a simple sliding lever. I've not had problems with this opening unexpectedly but found that gravity worked against me when trying to change batteries in the field with the scope sitting on a tripod.

IMAGE CAPTURE: For me at least, it is much easier to focus looking through the eyepiece, rather than squinting at the tiny screen. I will confess that I have not used the tiny infra-red remote control unit. In theory, this should help minimize camera shake although in practice, holding the telescope very firmly as you smoothly depress the shutter should help to reduce wind vibration. The shutter button is on the top and front of the handgrip, much like a conventional SLR camera, and allows you to maintain a firm hold to minimize shake. When you depress the shutter button, there is an audible 'clunk' as a mirror tilts, allowing light to shine on the camera sensor rather than pass up into the eyepiece. The detector for the infra-red signal is located below the LCD screen and the remote unit requires a CR2025 watch battery.

For wildlife photography, rapid camera response is critical. This is a problem with many digital cameras, even some of the more expensive digital SLRs such as the very popular Canon 10D (up to 2 secs delay). I got the impression that the TD-1 is no slower than the Nikon Coolpix series which dominate the digiscoping market. That said, I found the camera power button annoyingly temperamental and it would not always respond as quickly as it should. Perhaps a better 'click on/click off' switch could be employed? In the field, I prefer to hold the button down firmly until the screen comes to life, rather than simply punching the button once and getting ready to shoot.

One very irritating feature is that the focus resets (even in manual focus mode) as soon as the power comes back on. This means that the focusing has to be repeated and perhaps the shot missed. When digiscoping, it is important to be able to prefocus the telescope on a roosting bird or perhaps a nesting hole and wait for the right moment to get a good shot. To minimize the drain on the battery, it makes sense to let the camera unit drop into sleep mode, especially if the wait period is likely to be more than a few minutes. Having to refocus as well as wake the camera up adds an excessive delay and therefore greatly increases the likelihood of missing the desired shot. Any camera designed for wildlife or sports shooting needs to wake up almost instantly.

Images are saved onto a SD memory card. The TD-1 comes with a paltry 32 Mb card and leaves me wondering if giving away tiny and essentially useless memory cards is an inside joke for the digital camera industry. You need to immediately buy yourself at least one 128 or 256 Mb card before venturing into the wilds. Without giving the reason, the instruction book states that larger cards cannot be used with this camera. 512 megabyte and 1 gigabyte cards are quite affordable nowadays and would be more appropriate. As yet, I've not put my skepticism to the test by forking out for a larger card. In each shooting session, a directory (folder) is created on the card and images are saved sequentially as KOWA0001.jpg, KOWA0002.jpg etc.

Fig. 9. A Sanderling pauses on a Long Island beach to take on fuel before its long flight to the high arctic nesting grounds. In the late afternoon light, the shutter speed struggles to capture crisp images, presumably due to unavoidable shake of the tripod-mounted telescope.

IMAGE QUALITY: The camera's sensor (charged-coupled device or CCD) can capture 3.14 million camera effective pixels and right off the bat, I can say that this is way too few! Eight to twelve million pixels would be more appropriate.

Fig. 10. An endangered Piping Plover bathed in late afternoon sunlight.

What about the color reproduction? I found that some of the images taken in bright sunlight showed a noticeable blue cast (see the Sharp-tailed Sparrow and Mute Swan below). Switching between the two white balance modes 'auto' or 'cloudy' did not make much difference.

Fig. 11. A inquisitive Saltmarsh Sharp-tailed Sparrow pops up from the vegetation in response to some gentle spishes. Note how the browns and oranges are quite good but the white underparts and the green vegetation show a strong blue tinge. Fig. 12. The same effect is seen in this image of a swimming Mute Swan. On white birds, getting the exposure right can be quite a challenge, evidenced here by the over-exposure on the wings and back. The feather detail is better on the neck and head but marred by the same blue tint .

IMAGE HANDLING: Downloading images is simple. You can either slip the SD card into a card reader attached to your computer or connect the telescope directly using a USB connector cord (included).

EYEPIECES: At present, the eyepiece is not interchangeable but I don't see this as a problem given the quality of the zoom and relatively wide field of view.

Fig. 13. Digiscoping is not only for the birds. Large insects, such as this dragonfly, also make good subjects. This individual was photographed in sunlight at less than full zoom using the manual focus option. For some reason, the TD-1 camera tended to over-expose the images, blowing out the detail slightly. I'm not sure why this is but wonder if the shiny surfaces of the exoskeleton might be part of the reason? With a minimal focusing distance of about 20 meters, the autofocus function could not cope at all.


Kowa has given us an exciting glimpse into the future and I'm confident that within the next 3-5 years, birders all over the world will be marching around with digital cameras built into their optical gear. Needless to say, telescopes will be first items where this becomes the norm but I suspect binoculars will not be too far behind. The implications are tremendously exciting. Puzzling birds can be photographed at will and compared to reference books later on or alternatively posted on the web for instant expert feedback. The possibilities are endless and one can even imagine 'camerascopes' with built in wireless connections allowing users to beam their fresh images around the world. The lives of local recorders and bird records committees will also become easier with more and more photodocumentation. We have already seen a major leap in documentation with the revolution in digiscoping and all-in-one optical units will propel this further. The TD-1 from Kowa marks an important new landmark on the road to this brave new world.

As the review above makes clear, a number of major improvements need to be incorporated before this combination scope/camera really catches on with serious birders. Here are the four most pressing issues:

Overall, I think the engineers at KOWA are to be congratulated for taking this bold leap into the future. As a first effort, the TD-1 is really quite impressive but there remains plenty of room for improvement, notably in the sensitivity of the sensor. The requirements to convert this pioneering model into a true 'birding digiscope' seem straightforward, at least in concept but presumably more tricky at the manufacturing level. I have read arguments about the problems with combining the current lens system with better CDDs but frankly this is all Greek to me! However, I have sufficient confidence in the inventiveness and skills of the electrical and optical engineers back in Japan to believe they will overcome the technical hurdles. Indeed, I can hardly wait to see future revisions of the TD (assuming of course there are some!) and "enter the world of amazement, impact and surprise".


A quick survey of the web indicates that the TD-1 retails for approximately $1,900 (US) or £1,499 (UK) and €2,170 (rest of Europe).


Objective Lens: 55mm ED Lens
10-30 x
Real Field of View: 3.94 x 2.95-1.31 x 0.98 degrees
Apparent Field of View: 39.4 x 29.5 degrees
Exit Pupil: 2.7-1.8mm
Relative brightness: 7.3 3.2
Eye Relief: 20mm
Field of View at 1000m: 68.8 x 51.5-22.9 x 17.1m
3.14 million camera effective pixels (1/2.5-inch CCD)
Image Size: Two options, 2048 x 1536 (large)or 1024 x 768 (small)
Lens: 3x Zoom ED Lens f=75-225, F/2.8-4 (450-1350mm 35mm equivalent).
Auto Focus Mechanism: contrast detection system
Auto Focus Area: Middle
Minimum Focus Distance: Manual focus, 5m-infinity, Auto focus, 20m-infinity.
Dipoter correction: -5 to +5m
Visual field ratio: 85%
LCD Monitor: 1.8-inch low-temperature polysilicon TFT liquid crystal
Recording system: Saves images as JPEG (Exif Ver.2.2)
Image quality modes: HQ/SQ (High Quality/Standard Quality)
Recording media: SD Memory Card
Photographing functions: Single-frame, serial frames, and self-timer. Note the camera automatically switches to the 1024 x 768 (SQ) image size when in serial photography mode.
Photometry system: Central photometry
Exposure synchronization: EV4-15.5 (Wide Angle), EV5-15.5 (Telephoto Angle) on ISO100 basis
Photometry system: ISO100-200 Automatic adjustment
White Balance: Two options, Auto or Cloudy
Self-Timer: Approx. 3 seconds
Play Back Mode: 1 Frame, 4 Frames, 9 Frames, enlarged 2x, 3x, and 4x.
Delete Function: Delete single picture, all pictures or reformat entire card.
Computer Interface: USB Interface (Camera side Mini B)
Video Output: (NTSC/PAL), DC Input
Power: 4 AA batteries (alkaline, nickel manganese, lithium, nickel cadmium, nickel hydride)
Recommended Operating Conditions: Temp: 0-40 degrees C, Humidity: Less than 85%
Size & Weight: L385 x W130 x H125, 2.3 kg

You can learn more about the TD-1 and other superb products from Kowa Optimed Inc. by visiting their website (

Fig. 14. The TD-1 Prominar ED from Kowa Optimed Inc.

Page layout and photographs copyright of Angus Wilson© 2005, All rights reserved.
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