As promised in my recent “Digiscoping with a DSLR Camera” entry, I have news to report regarding lens effectiveness for digiscoping using the Canon EOS 40D DSLR camera and Swarovski’s UCA. When we last left off, I had noted that the Canon EF 35mm f/2.0 lens might hold some promise as possibly being a lens with a completely internal focusing mechanism, thus making it a contender for a suitable lens for close positioning to the spotting scope’s eyepiece. Sadly, the promised was dashed when, thanks to the great patience of the staff at Pro Photo Supply, I was able to examine the combination in person and discover that the 35mm is not in fact an internal focusing lens.
However, all the news is not bad, as while at Pro Photo Supply. I was also able to test another theory I had – that being the possible usefulness of different Canon lens, the EF-S 60mm f/2.8 Macro USM. This lens, quite a popular multi-purpose one likely already to be found in the camera bag of many a nature photographer, combines the right amount of focal length to remove vignetting from the image, a physical dimension superbly compatible with the Swarovski UCA’s platform, and a completely internal focusing mechanism to allow for either manual or auto-focus modes to be employed while positioned closely to the spotting scope’s eyepeice. The added benefit of using this lens for DSLR digiscoping is that its macro and portrait properties make it an great lens to have mounted on the camera body for close and mid-range work while at the same time being ready at a moment’s notice to slip onto the UCA for higher magnification photos to be captured through digiscoping.
I have also been making inquiries to some of the prominent after-market lens manufacturers to see what models in their own lines might be suitable for this purpose. They were quite amenable to working with me in this matter and I hope in the not to distant future to have more to report in this area of inquiry.
October 1, 2009 @ 06:42
John
I have been trying my Canon 40d with the EF-S 60mm macro lens using the UCA on my ATS 80 HD with 20 – 60 zoom eyepiece. Results are very frustrating I’m afraid as vignetting is a serious problem, even at 20 magnification alignment of the camera is very critical and at anything more than 20 mag it appears to be vitually unusable. Unfortunately the EF-S 60mm is the only short prime lens that I have.
How have you found the 50mm 1.8 ? now bad is the vignetting is it usable at magnitications higher than 20 ? Is perhaps the Swaro 25 – 50 zoom a better eyepiece to use for digiscoping ? Am i expecting too much ?
October 1, 2009 @ 07:08
Hello Ian. I tried the EF-S 60 macro with the Swarovski 25-50x W and it worked like a charm; no vignetting at all and still room to spare between the eyepiece and the front of the lens. I use two different eyepieces with my ATS80 HD scope, the 25-50x W and the 30x W – both offer a more generous eye relief distance than the original 20-60x model. As for the 50mm 1.8, there is no vignetting with the 25-50x W eyepiece; the only challenge is that as the lens extends when it focuses, you must keep it on manual and use the spotting scope’s focus mechanism exclusively.
October 1, 2009 @ 08:29
John
Many thanks, I feared you may say that, I tried the 25-50 at the British Birdwatching Fair and must say I was very impressed, the FOV is just great. Best part of £600 in the UK though !!! Oh well maybe have to flex the plastic some more.