Of ambitious photographers, the Smartphone is often ridiculed, but there are areas where the simple cell phone snap of even expensive DSLRs are superior. Digiscoping, so the photography with a spotting scope, the compact design of smartphones is a great advantage.
For nature observers, a good spotting scope is part of the basic equipment for every excursion. It is obvious not only to watch but also for photographic purposes to use the high-quality optics. Shooting with the spotting scope is called Digiscoping (English: Digiscoping). In principle, you can connect each camera. Very easy, it goes with Smartphones.
By their light weight and flat construction without moving out optics can be mounted easily smartphones with simple mechanical adapters at Spektivokulare. Not there optical adapter for smart – phones other than for system cameras -, because the lenses of smartphones are not exchangeable.
Fitting slip-on adapter
However, there are adapters with a bracket for the Smartphone and an attachment to the spotting scope. KOWA allows individual adapters for all common Smartphones (60 Euro, E.g. TSN IP6 / 6s for the iPhone 6) produce. They consist of custom-fit trays for protection for the back of the Smartphone. Included are two interchangeable sleeves with different diameter, which are connected on the eyecups of the eyepiece from KOWA.
The adapter does not have optical elements, it’s a mechanical adapter. Would again be seen, one simply subtracts the adapter from the eyepiece. He can stay on the road all the time on your Smartphone and hindered not its usual use.
This slip-on adapter designed although mechanically very simple, but you can work well with them. Disadvantage: when buying a new smartphone with other dimensions, you need a new adapter.
You must buy a tailored slip-on adapter not expensive. You can even build it with little effort. You need a custom-fit Smartphoneschale, an eyepiece cover and some glue. On eBay there are corresponding Smartphone protection shell for eight euros including shipping. Enter of the exact Smartphonebezeichnung and of the word “Alucover” (example: “Samsung S5 mini Alucover”) leads to the goal. The optics trade, are worried the eyepiece cover (other term: eyepieces, eyepiece protection). This is a simple plastic cover lets you cover the eyepiece when not in use.
In the eyepiece cover drills to a centimeter hole centered and then sticks it to the protector. On the scope to adjust the position of the eyepiece cover using the image preview on the Smartphone screen. This is of course only as long as the adhesive is not yet hardened. 2-component epoxy resin adhesive is recommended for a fixed link such as, for example, UHU plus 2 K (10 euro). This adapter uses one such as an eyepiece cover on the spotting scope and pulls it off with one hand.
You can replace the Eyepiece Cap also through a T2-ring (20 euro). The adapter is safer than an eyepiece cover through the screw connection. Assembly and disassembly of the adapter to the stand requires a handle then but more than.
Flexible universal adapter
Who does not want to commit on a particular Smartphonemodell, should access to an adjustable universal adapter. We have tested the Lens2scope-Butterfly-Smartphone adapter (about 80 Euro) representing this adapter type.
The attachment to the scope via a wide sleeve which is placed over the eyepiece and is clamped with three screws. Traces of use are only a matter of time at the eyepiece. The adapter ring that is attached to the eyepiece can be separated from the other adapter, to facilitate an exchange between observing and photographing.
The concept of the Lens2scope butterfly has not convinced us. The many adjustment options increase the size and weight of the adapter. In addition, the many adjustable parts cause instability. There is a vast variety of such universal adapter in the trade. As far as we can tell, they all suffer from similar problems as the Lens2scope butterfly.
Unavoidable digital zoom
To adjust the image area of the Smartphonekamera, the image circle of the spotting scope you can activate mostly the digital zoom of the Smartphone. Apart from a few exotics like the Samsung zoom do not have Galaxy S4 smartphones optical zoom lenses.
When using the digital zoom, only part of the sensor is used for recording, the Smartphone then extrapolate this scaled down image by interpolation on the nominal size of the sensor. A dual digital zoom reduces to two megapixels, for example, the effective resolution of 8 megapixels. This corresponds to approximately full-HD format.
This is sufficient for many purposes such as social media and for the screen display. At the movies in full HD no significant losses are noticeable through digital zooms up to the magnification factor 2 x with Smartphones with at least 8-MP sensors. A single picture with full HD (1920 x 1080 pixels) has just two megapixels. For this reason, the Smartphone for the HD movies on the spotting scope reflected fairly decent, when photographing but must take swabs in purchase.
Zoom factor in the practice test
We have connected to the Smartphone Samsung Galaxy S5 mini and S7 different scopes, to check what zoom factors to adjust an image without vignetting are necessary. The less the digital zoom is used, that is of course the better for image quality.
The eyepiece of the spotting scope must be set to the lowest zoom level, otherwise the vignetting increases. The used spotting scope has a great influence on the required digital zoom factor.
The KOWA Prominar TSN 883 with factor 1, 5 x needed the least digital zoom on our Samsung S5 mini with us in the test. However the tested combination recorded stronger than at the Zeiss conquest Gavia 85, which is a slightly stronger zoom (1, 6 x) required. The significantly cheaper Vanguard endeavor H82 A delivers a visibly smaller eyepiece image. Here we had to zoom with factor 2, 5 x.
The auto focus of the Smartphone works for Digiscoping, unless the sharpness on the scope was preset in advance roughly. The auto focus of the two Samsung Galaxy smartphones used by us (S5 mini / S7) turned out to be so fast, that it would be sufficient in principle also for moving objects.
Due to the strong tele effect of spotting scopes, it is very difficult to keep moving objects in the image field. Another advantage of the Smartphone is already quite well can be seen much on the display, and it must be removed thus not necessarily, take a look at the subject.
It has more smartphones. By their ease of use and fast working in conjunction with the spotting scope auto focus it well suited for the Digiscoping. Mirrorless DSLRs and high-quality digital compact camera have a better image quality with photos, they are but more complex to manage and disagreeable extra baggage during a field trip.
Special Digiscoping in c’t photography 6/2016
The c’t photography 6/2016 includes a detailed special, which covers all aspects of Digiscoping with Smartphone and compact system camera. Here is explained in detail why the small image sensor by smart cameras on the scope has advantages over the big sensor in a DSLR.
The complete table of contents of the c’t photography 6/2016, an overview of the added material on DVD, previews and editorial found in the heise shop. You now can order – shipping is free of charge up to the 20.11 – output for 9.90 euros or purchase from Monday, October 24, at the kiosk. (sts)