The use of spotting scopes for photography purposes
It is possible to use a spotting scope as a super tele lens. Most of the manufacturers of binoculars and spotting scopes provide us with some tools for this, adaptors and brackets. But, when image quality is your main concern, it is not a favorable option for serious photography. But if you don’t like to carry both a big lens and a spotting scope, there may be some solutions worth considering. I also realize that photography can be an expensive thing. Cutting in optics may seem a solution. But, it comes with a prize, paid with a poorer image quality.
I tested some combinations of spotting scopes with photo adaptors for myself and my findings are explained below. If you are thinking of buying a spotting scope for use as a big lens, read the following carefully and then consider if it is the right solution for your situation.
How does it work?
This slightly depends on the spotting scope you use, but the basic principles are all the same. You’ll have to remove the eyepiece of the spotting scope and replace this with a photo adapter. Depending on the brand of camera (and the type: Manual or Auto focus camera) you will need a conversion ring for the bayonet of your camera. You’ll lose auto focus and have to focus with the focusing wheel of the scope, using the viewfinder of your camera to check focus. On my Nikon F90X an extra focussing help is provided that keeps working on spotting scopes; a < o > marking for out of focus and in focus that appears in the viewfinder. The viewfinder image can be too dark to critically focus, even in conditions that appear to be bright enough. Remember you are focussing through an aperture of at least f10,5.Usually the length of the spotting scope with photo-adapter will be 800mm, for some scopes also 1100mm adaptors are available. With the 800mm on a 80mm front lens spotting scope (such as Swarovski AT80 HD) you get a working aperture of f 11, with the 1100mm this will be about f16. Optolyth manufactures a field scope with a 100mm objective lens and a 1200mm photo adapter.
Most spotting scopes come in two different versions. A ‘basic’ one and a scope with a system of Extra Low Dispersion or APO or High Definition optics. These are lots more expensive but prove their worth when you compare the results between the two of them. They provide a crispier image with better colors. Especially because photographic films are much more sensitive than the human eye these better optics are worth their money for the demanding photographer. Of course the more expensive optics do not matter when you take just pictures as a record of a rare species, for example. This is what most spotting scopes with photo adaptor are mainly used for.
Follow the next guidelines for using a field scope together with your 35mm SLR camera and you’ll take quite satisfying images with your spotting scope.
- Make sure your camera is as
light as possible: the bulkier the body is, the more wacky the
combination will become. Remove battery packs and vertical grips,
flash units and other unnecessary load.
- Use faster films such as ISO
400. Especially color negative films will suit well because they
are more tolerant in exposing than slide films.
- Use the heaviest tripod you
can afford. The load of this thing will become worth it’s
weight in gold when it comes to shooting in even the slightest
wind conditions.
- The tripod head should be
stable. Don’t use small ball heads.
- A bean-bag on top of the telescope
on tripod can improve the stability enormously.
- Use a shutter release or self
timer to make sure the combination is free of any movements and
vibrations.
- The optical quality of spotting scopes is in my opinion not suitable for professional photography. There usually is some or more distortion near the edges and corners. If you only want to use the spotting scope to shoot some pictures, for evidence of a record of a rare bird for example, the benefit of color corrected optics is relatively small. It only provides you with a better image of which the quality isn’t the most important thing.
There are some spotting scopes, however, that perform better then others. The Leica APO Telyt 77 for example, performs better with a camera than its main competitor, the Swarovski Habicht AT80 High Definition. This is because of the bayonet, which does not turn when adjusting the camera position. The viewfinder looks also a bit brighter and this will be proven by the results on film.
The test
I have tested some telescopes with Kodachrome 200 slide film, a critical film that does not tolerate any major under- or overexposure. I set up the scopes on a Slik SL67 tripod with Manfrotto HEX quick release plate attached. The camera was my Nikon F90X (N90s in USA) and I used the self timer, set on 8 seconds, for releasing the shutter.I tested Leica Televid 77 and Leica APO Televid 77;
Swarovski Habicht AT80 and Swarovski Habicht AT80 High Definition;
Kowa TSN 821 and Kowa TSN 823 (The Extra Low Dispersion equivalent of the TSN 821);
Optolyth TBS100ED (the only telescope with 100mm front lens; a 'big gun' in spotting-scope country.
Please note all these scopes, except the Optolyth, have about 80mm front lenses. In consider scopes with smaller front lenses unsuitable for any photography. However they are easy to carry on, the working aperture for photography purposes can reach numbers as high as f22. The viewfinder remains too dark to focus properly, even in bright conditions.
Results
One of the first things that took my attention was the ease of use with the Leica’s. Although the Swarovski scopes are my favorites when just looking through in nature, the Leica’s perform better with a camera attached. The bigger tripod socket seems to offer a more rigid attachment to a tripod. Again I would like to stress the use of a heavy tripod adds more image quality than any other variable.Swarovski’s bayonet has no safety lock so the photo adapter can rotate freely when you (accidentally) move your camera. Ease of use is in my opinion one of the more important aspects. Swarovski revised their scopes in early 2000, adding a bayonet with a safety lock to their eyepiece. When they add this construction to their spotting scopes, there will be no major difference between their and the Leica scopes.
Optically the APO or ED versions performs better and are worth the extra money when photography is a main purpose of use. For determination purposes only it is a very nice bonus, but not necessary.
The full image and 2 details show the performance of the test example of the Leica APO televid 77 with it's photo adapter on tripod and bean bag on top. Images are sharp. Click on an image to see a higher resolution image (opens in a new window). Please realize that it is impossible to judge an image on a monitor. These images are only meant to give an impression.
Test results with photo adapter with 7 popular spottting scopes
Spotting scope Focal length adaptor (mm) Effective F-stop Image quality Ease of use Leica Televid 77 800 10,5 ++ ++ Leica APO Televid 77 800 10,5 +++ ++ Swarovski AT80 800 10,5 ++ + 1100 14,5 + + Swarovski AT80 HD 800 10,5 ++ - (long adaptor) 1100 14,5 + + Kowa TSN 821 1200 results to be published results to be published results to be published Kowa TSN 823 1200 results to be published results to be published results to be published Optolyth TBS 100 ED 1200 results to be published results to be published results to be published
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