• Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.

    Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
Feel the intensity, not your equipment. Maximum image quality. Minimum weight. The new ZEISS SFL, up to 30% less weight than comparable competitors.

Using a camera wildlife lens as a spotting scope? (1 Viewer)


Well-known member

Three things make me wonder about the possibilities of using a camera lens as a spotting scope.
(1) When the combined weight of carrying both a camera lens and a spotting scope can be significant, and when one's interested in wildlife photography + wildlife watching. Not to mention the cost of owning both.
(2) The relatively poorer (or should I say much poorer?) quality of digiscoped spotting scope images when compared to a dedicated camera lens at a similar or even lower price points (e.g., Kowa 663M vs. Tamron 150-600 G2. To be honest, digiscoped images from $3K spotting scopes do not look great either. I find scopes to be fantastic for wildlife watching, not photography. )
(3) And posts like this on lens2scope attachments: Lens to eyepiece adapters - Turn your Lens into a Telescope - Bob Atkins Photography

I am am considering trying this possibility before splurging on a high end scope. Has anyone tried these third party attachments? Would love to hear your experience! Why aren't camera companies pushing their own lens2scope versions? For instance, both Canon and Nikons have their right angle viewfinder attachments for their DSLR cameras; and their wildlife lens quality is fantastic! So I am confused ...



Forum member

I am am considering trying this possibility before splurging on a high end scope. Has anyone tried these third party attachments? Would love to hear your experience!

Years ago, I used an (angled) Lens2Scope with a Sigma 50-500 "Bigma" zoom lens, as well as some other, smaller photo lenses. Image quality wasn't so good, and after comparing it to a Zeiss scope in the field, I went ahead and bought a proper scope. I think I wasn't too enthusiastic to take the lens off my Sony Alpha 700 back then, after finding it was really susceptible to dirt and hard to clean. No idea if that's still an issue with today's (mirrorless) SLRs, it was really a long time ago.

(I also tried an older Minolta straight view adapter on older Minolta lenses. This wasn't very good at all.)




Well-known member
The Minolta telescope lens adapter has short eye relief.
I prefer the Vivitar TLA-1 and clones.

I have numerous lens to telescope adapters, including very unusual fittings.
Also 4 Kenko adapters that I don't like. The ones I have have dirt inside from new and small AFOV, although long eye relief.

I must have tried several hundred photographic lenses with these adapters.

Few lenses are of good enough quality to make good spotting scopes.

However, some mirror lenses work well.

The Pentax own make mirror scope is just a 500mm Pentax mirror lens with their own angled adapter.
Both scopes I have are not that good.
However, the back end accepts 24.5mm fit eyepieces with a bit of play and fits any T2 mount lens.

There are several other own make spotting scopes based on mirror lenses.

The Vivitar Series1 600mm f/8 solid cat lens is excellent with a 2x teleconverter at 120x and very good at 180x with a 3x teleconverter. It easily splits both components.of Epsilon Lyrae with space between the double stars at less than 2.5 arcsecond separation.

The Optomax 500mm f/8 and similar Canon, Minolta two types, Nikon mirror lenses are excellent with a lens converter.
Also the Nikon 500mm f/5 mirror lens.

I recently saw Porroprism adapters for Canon, Nikon and T2 mount lenses. I'll try to find the name of these as they should be better than roof prism adapters.

The Nikon own make converter is good.
The only one I don't have is the Leica one, although I have an old Leica Galilean adapter.

The Tamron 90 degree adapter 18mm fl is good.

The Tewe 600m f/5 Petzval lens and Ross 50 inch f/8 telephoto are both excellent with lens adapters.

Last edited:


Well-known member
I usually use 1.5x or 2x teleconverters with photo lenses, as the telescope adapters don't like fast lenses.

The Sigma 500mm f/4 complex mirror lens is particularly poor with excessive CA except at one distance setting.

Photo lenses optical surface finish is usually poor compared to a normal spotting scope.
Spotting scopes are usually poorer than high quality astro refractors.

There were a few very high quality survey lenses like the 1930s Zeiss 75cm f/6.3 Telikon and Zeiss 120cm f/7 Cooke triplet lens that are of near astro quality.
They were used with black and white film.

The 2000mm f/14 Den Oude Delft Maksutov Cassegrain military lens is superb with a lens adapter.
Saturn at 200x was as good as any view I have seen with this size optics.

The 2000mm f/14 Zoomar odd design mirror movie lens is dreadful.
The Zoomar 500mm f/5.6 mirror lens is good, with and without its 2x teleconverter.

The Celestron mirror lenses generally were not very good. SCT or Maksutov.


Alexis Powell

Natural history enthusiast
United States
Three reasons for scopes and digiscoping:

1. The magnification of a camera lens, even a long one, is quite modest compared to scope magnifications used in birding. Digiscoping takes advantage of the magnification of the scope since images are taken through the eyepiece. The camera sees, roughly, what the eye sees.

2. The quality of the real-time view (in terms of e.g. response time, contrast/tonal range, and resolution) when viewing through a camera, is much inferior, no matter whether it is on ground glass in an SLR or via an EVF display. The only way to see full camera resolution (which may be inferior to eye) is afterward, during playback view. That is not satisfying for birders who prefer to watch birds in real time rather than pictures of birds. Also, one generally ends up seeing fewer birds since so much time is spent looking at images on the screen on the camera rather than at the bird or landscape and thus possibly noticing other birds around it. So camera birding is not good for effective traditional birding.

3. The quality of digiscoped images can be absolutely superb. Most images are not so good simply because of sloppy technique or because of physical limitations e.g. those inherent to any system trying to get a clear image over the distances, in unstable air, that are typical in scoping as compared to the relatively short-range photography that is typical with long lenses. With the same attention to what can and can't be done, and to what it takes to do well what can be done, digiscoping delivers.



Well-known member
Further to the above.

It is, I am told, fairly easy to design camera lenses with diffraction limited views on axis.

But this is deliberately sacrificed to improve the off axis performance that is required for good overall images with a camera.

The actual design of camera lenses is done using aberrations rather than wavefronts.

This is may be why the only near astro quality visual images I have had with camera lenses is either simple doublets like the Astro Berlin 600mm f/5 and 600mm f/5.6 (actually the same lens with different iris stops), or some Petzvals.

There are old Leica Telyts, can't remember spelling, that are simple astro doublets.
Also the 2,000mm f/10 and 2,000mm f/11 Astro Berlin lenses. One is a doublet, one a triplet and both two metres long. Used as movie lenses.

There are a few other simple doublet camera lenses, usually German makes.

Also high quality mirror lenses, but these have central obstructions. These are highly favoured as military lenses.


Users who are viewing this thread