Zeiss DC4 camera eyepiece

Popular with both serious photographers and birders merely wishing to take record shots, digiscoping for the most part has involved holding a digital camera against a telescope eyepiece or using an adapter to position the camera correctly and hold it in place. Now Zeiss has designed a camera eyepiece that is compatible with its range of Diascope telescopes: the DC4. This simple bayonet-fitting, fixed 40x magnification eyepiece, with a fully integrated camera and 50 mm screen, allows the user to capture at will the images viewed through the scope.
I put the DC4 to the test with a Diascope 85 T*FL, using the 85 mm objective to maximise light transmission to the camera unit. Note that the unit’s magnification drops to 30x if it is fitted to the smaller 65 mm Diascope; both scopes were reviewed in Birdwatch 120: 47. Taking to the field armed with the above equipment, I had high expectations of ‘instant imaging’ of a standard to compete with the best. The course of true digiscoping never runs smoothly, however, and I was soon to discover the perfect shot did not come easily. Moreover, the DC4 offers plenty of opportunity for user error and it took me a little while to learn to operate it correctly.
A prerequisite for capturing an image successfully is the initial focusing calibration, which is achieved by looking through the eyepiece and adjusting it to your personal focusing characteristics. All you do is pull up and rotate the eye-cup until two concentric circles of a built-in reticle are brought into sharp focus. There is an incremental scale at the base of the eye-cup against which the setting can be recorded, but no mechanism for locking your setting. This procedure is rather like adjusting the dioptre on a binocular: once set, it does not need to be repeated. From now on, the only focusing necessary is that of the scope to ensure that your subject is sharp.
The unit’s two AA batteries provide 1.5 hours of continuous use, which can be extended by means of the power-off and standby modes. A remote-controlled handset, hardly bigger than the average mobile phone and powered by two AAA batteries, operates the unit, turning it on and off, effecting image capture and providing the means to scroll through an
on-screen menu for camera settings (such as ISO, white balance and exposure compensation) and to view and delete images stored on an SD card. The card is inserted into a slot in the rubber-armoured housing, which also contains ports for USB and video cables.
The remote works well and allows you to capture the image without vibration, but I found it took a little getting used to as I normally use both hands to operate the telescope – one to pan and tilt, the other to steady and focus. It is no easy task to simultaneously follow birds in flight, keep them in focus and operate the remote control, which has to be held in the correct position below the unit’s infra-red receiver! Moreover, I found it difficult to initially locate birds in flight and also passerines at close quarters with the fixed 40x magnification, and a zoom would have been useful in these instances. Use of the latter would, however, result in loss of light to some extent. I compared a Diascope zoom eyepiece, set at 40x, with the DC4 and the image from the latter appeared noticeably brighter.
The only other disadvantage of using the remote is the short time lag associated with image capture. By the time you have located and pressed the button and the signal has been transmitted to activate the unit’s shutter, the bird may have changed position. The camera’s serial capture function, however, helps to negate this by effecting up to five consecutive shutter releases, at 0.3-second intervals, on a single activation. This increases the possibility of capturing an acceptable image as a bird changes its position.
While it is possible to monitor your subject on the screen and decide when to release the shutter, the image never allows you to fully assess how sharp the focus is, even when using the remote’s screen zoom function. You can only do this by viewing a bird through the eyepiece and making the necessary adjustment. Clearly this is one advantage over conventional digiscoping using a camera, which offers no comparable means of sharp focusing beyond looking at an LCD screen.
The playback function on the remote enables you to quickly assess likely picture quality and make adjustments to the camera settings before attempting further shots. Images can be written to the SD card in either TIFF (up to 11.3 MB) or JPEG (0.45-1.8 MB) format, but TIFF files cannot be played back on the screen. Although highly acceptable images may be obtained with the DC4, the camera’s 4-megapixel resolution may be considered quite low by current standards and may limit the quality of reproduction. Notwithstanding this, I was able to obtain a number of very satisfactory images.
In addition to the remote and batteries, accessories supplied with the unit include a 128-MB SD card, a USB cable, a video cable (for TV connection) and a charging set with rechargeable batteries for the main unit. Software updates for the unit can be downloaded from the internet.
Although it has its limitations – principally the fixed 40x magnification and its exclusive use with existing Zeiss equipment – the DC4 does what it says on the box, allowing you to observe and take digital pictures without an additional camera and adapter. What else is currently in the Zeiss development pipeline?

Price: £990
Size: 185x65x105 mm
Weight: 795 g
Magnification: 30x (Diascope 65 T*FL), 40x (Diascope 85 T*FL)
Field of view: 30 m (Diascope 65 T*FL), 40 m (Diascope 85 T*FL) at 1,000 m
Close focus:  4.2 m
Resolution: 4 megapixels
Display: 50 mm TFT colour display, approximately 154,000 pixels
Storage medium: SD memory card
File format: JPEG, TIFF
Shutter speed: 1/200 second to 1/8 second
Waterproof: sealed; water resistant only
Guarantee: 10 years