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Digiscoping Compared to Long Lenses

A scope is a scope or modern form of telescope, they are often used by those interested in studying birds. They have a single lens like a telescope rather than a pair of binoculars and are used either with a tripod or some type of clamp to provide stability. Most come in two parts a main part (the scope) and an eyepiece, often changing the eye piece changes the magnification, you can also get zoom eyepieces.

Digiscoping is connecting up a camera to look through a scope. Either with a connector or an adaptor on the camera that replaces the scopes eyepiece. There are a range of brackets and adaptors that make the connection of a scope to a camera possible. Digiscoping can be done with anything from a phone camera, through point and shoots up to quality DSLR cameras.

You will find a larger article on digiscoping techniques and equipment, click here to see it.

In this article we want to look at the benefits available when using a DSLR camera from the digiscoping method and compare it with using long lenses.

Looking at what Nikon has to offer we find a Fieldscope digital camera attachment FSA-L1 will connect to the digital SLR cameras, and fits as eyepiece onto a fieldscope. Nikon recommend the scopes that have ED glass for brightness and sharpness. There is a selector on the adaptor that allows the camera to know the information on the scope connected.

The magnification obtained is dependent on the scope used.

Fieldscope Adaptor selector settings F-number Focal length Effective focal length with crop DX sensor
ED82/ED82 A A 13 1,000 1,500
III/III A/II series/I B 13 800 1,200
EDII series/ED
C 13 800 1,200
ED78/ED78 A D 13 1,000 1,500

Fielscope ED50 or ED50A should not be used as they are not strong enough to support the cameras weight.

Metering is done on spot or centre weighted, focusing is manual using the scopes manual focus ring, and with any of the above models, slight vignetting may occur at the periphery of the image, this is the dropping off of brightness towards the edge of the image, or possibly loosing the corners of the image. The camera is best used in either aperture priority or manual, as the aperture is fixed. There are a variety of ways you can fire the camera including a remote, cable release or short self timer setting.

Never point it anywhere towards the sun, or your next purchase may be a white stick!

As the optics operate in a different way to a camera lens, the  fixed F stop listed above is only approximate and will vary between camera models, but the cameras internal meter should be able to cope with this, or you may need to use exposure compensation to get this right.

To use this you will mount the scope on a tripod and ideally should have a stabiliser bar from the tripod to the base of the camera. If you did not use it on a tripod locked up solid you would have to have a stutter speed equal; or higher than the focal length so 1/800 second or faster. Locked up nice and solid, you need enough speed to cope with the movement of your subject, as you would if you were closer using a VR lens giving the same view. We would suggest you use a right angle viewfinder on the camera with its 2X magnification for focusing or use a D300/D3 with Liveview that can be zoomed to check focus.

You donít need an eyepiece, but you may want one so you can use the scope separately from the camera.

Experiences vary, many say that 90% of images taken are unusable,  the reason for this may be in part due to the camera system used, lining up a phone with an eyepiece is unlikely to be as reliable as a proper adaptor. Similarly some point and shoots with digital zooms can be set to get silly magnifications, perhaps 9,000mm equivalent or beyond and this is far more problematic. However a fairly high percentage of non usable shots are likely to be taken due to the following:-

  • Camera shake, caused by your movement, wind, movement in hide, general vibrations.
  • Focus, as you are focusing at the aperture you are taking you have to get it right, maybe taking several shots slightly moving the focus setting.
  • Depth of field, practically nothing, anything you photograph needs to be very near to a flat plane equal distance from your camera.
  • Subject movement, and your speed options being limited.
  • Subject changing position, or leaving before shot is taken, particularly if you use a timer release or mirror flip delay.
  • Atmospherics, heat haze, evaporating water, reflected polarised light and dust and moisture in the air.
  • Vignetting - Images darkening towards edge or missing corners.

You should expect to have to do quite a lot of  work editing the image to get what you want. You may also have to crop the image to cope with vignetting.

So what is the cost:

FSA-L1 Adaptor

Nikon UK price list/recommended


Warehouse express


South west optics


Bristol cameras




Hong Kong eBay supplier ref:330204441712


France eBay supplier ref:330135011806


Scopes (also available angled, price may differ)

Scope Nikon Price Warehouse Express Price
ED82 £899.99 £669  (carry case £70)
EDIII £699.99 £529  (carry case £70)

Eyepieces cost from around £230-£270

So if we used the Warehouse Express prices we get 269.99+669 = £939.99 for a ED82 system, with no eyepiece or case.

This would give me the equivalent of a 1000mm f13 lens.

My initial reaction is that f13 is not very bright for a long lens and therefore there will be limited opportunities to use it. I have  a 1000mm F10 mirror lens and I find it has rarely got used for this reason, however with the faster noise free ISO settings possible with the D300 this year may be better.

Now you can't buy a 1000mm Nikon lens to compare this against.

You can get a cheaper 500mm f8 lens and 2x teleconverter for £127 on eBay or another make at under £100.

There were twenty eight 500mm lens to fit Nikon, including a number of older Nikon lenses at prices under £100 as well as one 500mm f4 ED-IF II lens at £3,500.

The problem is in providing a fair comparison.  The expensive F4 lens and a Nikon teleconvertor would outperform a scope based system in every way but of course be several times as expensive while the cheaper systems are largely unknown makes.

A fairer comparison would be to spend about the same and see what we could get.

We could put on a Nikon 18-200VR and two 2x (non Nikon) converters, or more practically a Nikon AF-D 80-400mm F4-5.6 ED VR lens for £781 with postage and duty included plus a Kenco 2x teleconvertor for £72 incl. postage, a total of £853. We can't use a Nikon teleconverter as they can only be fitted to a limited range of lenses.

Allowing for the teleconverter this would get a 800mm at without about the same light as the scope based solution. You would have to focus manually, and there would be little between them in terms of  ease of operation, requirement to stabilise etc but the lens and converter should not suffer from the vignetting.

In practice we have a 1000mm F10 mirror lens and a zoom that goes to 1300mm, as well as a Tamron lens that zooms to 500mm and a teleconverter to go with it, plus the 80-400VR and teleconverter, so plenty of ways to get to the same length as the scope solution.

Our experience when working at very large distances is that the atmospheric and light play a very important part in the results and that these tend to lack contrast unless well lit. Depth of field and focus is a problem so not all photographs are sharp, but you get some images that would not be possible by other routes.

Given that not everyone has such a selection of lenses, which solution is right for them?

I would suggest that either system would allow possibilities, although I havenít tried the scope solution. The deciding factor is more likely what else you wish to do, if your interest is in birding and you have a need for a scope, then adding an eyepiece, you have a quality scope as well as a way to take photographs, while if your interest is more in photographing wildlife then a shorter lens like the 80-400VR lens and a teleconverter is likely to provide a solution that appeals, as the 80-400VR, being a stabilised lens, is going to allow you to take so very many more photographs hand held up to 400mm and of course you will find that less than 5% of its time you will be using it with a teleconverter connected.

Perhaps over the summer we will try and find someone who has a Nikon scope and adaptor, and arrange to perform a comparative test with them and then give you a follow up on this article complete with examples of what could be contained with both. If you have or know anyone who has such a system then please let us know.

So watch out for a follow up on this article.

See also our other pages:

Digiscoping. What is it, how it works, the challenges it presents and what you should look out for if you decide to invest in this type of photography.

Restrictions on Wildlife Photography  

Nature and Wildlife Calendar

UK Wildlife Parks


By: Keith Park Section: Photography Key:
Page Ref: digiscope_v_lenses Topic: Wildlife Photography  Last Updated: 07/2009

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