Wildlife photographers often wish they owned a longer lens of 500mm or so to taking close ups of birds and other smaller creatures. And often they may  already have such a lens in the form of a spotting scope. By attaching the camera to the rear end of the spotting scope you create a lens with a similar  magnification to that of around 800mm
This technique is referred to as digiscoping.

You need to buy an adaptor to attach the camera to your spotting scope. These are often specific to the spotting scope and with the exception of a few

camera brand adaptors, they usually all have a T2 mount thread at the camera end. So you buy the adaptor, attach it to the scope and then screw in a T2  adaptor that’s specific to your camera mount. We have the T2 camera mounts here at PhotographyAttic

Camera specific scopes such as the Pentax PF80D need the PF-CA35 which has a direct camera mount.
The Nikon Fieldscope range including the EDIII A need the FSA-L1. Nikon also produce the FSA-L2 for exclusive use on EDG Fieldscopes

Opticron have a wide range of scopes and several adaptor combinations all requiring a T2 mount at the camera end.  See the Opticron Telephotography and Digi-scoping page for more details

Swarovski also have a range of scopes and a really informative page on digiscoping: Equipment – spotting scopes, cameras, etc.  You need a T2 mount with their systems

Barr & Stroud supply a spotting scope adaptor for their Sahara and Bresser Safari spotting scopes. T2 mount required. This adaptor also fits some Helios, Bresser,  Meade and Praktica spotting scopes.

Leica’s DSLR Photo-adaptor allows T2 mounted SLRs to be attached to the Leica Spotting scopes

T2 adaptors do not have any form of electrical contacts so you have to use your camera’s manual or aperture-priority mode.  As the spotting scope doesn’t  have apertures you just point and shoot and the camera will set the correct shutter speed. You could use the ISO setting to adjust shutter speed and increase the ISO for a faster shutter speed.

Focusing is manual. Focus the scope like you normally would but take more care on accurate point as the lack of depth of field will mean you have to be spot on to get a sharp photo. Also the increased magnification will make it difficult to hand hold so it’s better to use a tripod.

Further reading
Peta Pixel have an interesting article comparing the use of a Spotting scope against a Canon Super telephoto

In this occasional series we’ll take a look at design concepts that have tried to revolutionize the way we take photos. The first in the series looks at digibinos. A hybrid product combining binoculars with a digital camera.  Pentax came up with the innovation announcing their DB-100 model in March 2002.

Having a camera combined with binoculars wasn’t a new thing. Tasco produced a 110 film version back in the early 80s. It wasn’t a success, and neither was the Pentax .

What the Pentax had was interesting – a pair of 7x magnification binoculars and a digital camera with a focal length of 280mm (on a 35mm camera). What let it down was the low resolution of the camera at just 0.8Mp and the build quality. For £300 it felt like you were getting a cheap digital camera with a budget pair of binoculars that didn’t have the flexibility of normal compact binoculars. You could adjust the size for different width eyes by push pulling the case, but they didn’t feel as comfortable as ordinary binoculars.

The LCD viewing screen was also smaller than digital cameras at the time.

I was taking photos remotely the other day and used binoculars to view the distant scene. It made me think that having a camera built in would be a good thing…but I’d want the clarity and depth seen through the binoculars to be recorded by the camera. I still believe there’s a future for this kind of hybrid technology, but it has to be smarter than the previous attempt.

Pentax DIGIBINO DB-100 Announced – New Story