How to allign a non-zoom camera phone to the T80ED spotting scope

Bad allignment at 20x zoom

Correct allignment at 20x zoom

bad allignment 80x zoom

Correct allignment at 80x zoom

adaptor tilt and mounting screws

Digiscoping adaptor positioning screws

For alligning a camera to the T80ED spotting scope you would need an adaptor of some sort which keeps your phone at the right spot. The Olivon universal adaptor requires a tripod-mount hole which is present at most compact cameras, but obviously is not there in your phone. So from here some DIY is required that will fix your phone to the adaptor. I first attempted to use the Olivon adaptor as it was, connecting a plywood phone holder to the bracket that contained the tripod-mount screw. Details of this construction can be found here. However I found out that the Olivon adapter is just not sturdy enough to guarantee an optimal allignment when removing / reattaching the adaptor or camera phone. My theory on this is that because the camera phone cannot optically zoom in, allignment is very critical.

So my second Galaxy S phone adaptor only reused the Olivon eyepiece screw-on cilinder and fixing screw ring. The rest was made of plywood, hard wood, metal springs and metal allignment screws. This allowed for a solid, accurately tweak-able phone holder (see pictures).

So once the adaptor is in place the allignment process can begin. The combination of the Samsung Galaxy S phone and the T80ED spotting scope always results in some amount of vignetting. Again, would the phone have some optical zoom, I could just zoom into the picture spot and there would be no vignetting at all. Fortunately, for the maximum zoom of 60x the vignetting is very small, limited to some dark spots in the very corners of the picture. This is the magnification I want to use most, as I want to have as much as zoom as possible. Below 60x magnification I would use mainly for identifying the subject.

In fact I could even allign the phone such that there would be no vignettig at 60x zoom, but I noticed a considerable loss in brigntness (which is seen as dark rings and some reflections appearing in the image) at a certain point. So the very small vignetting is some sort of optimum. In fact I like a very little of vignetting myself, just a personal thing.

If you want no vignetting, simply crop it away using the android app “Reduce phote size”. I used this app, as it was the only one I found that actually crops the image without further resizing or compressing after playing with some settings. I want to keep all my available megapixels, just in case I want to further zoom into details.

To allign the camera I specifically looked at minimal zoom of 20x and maximal zoom of 60x. I aimed the scope a light surface without texture like the clouded sky, or even better indoors on a wall 3-4 m distance with indirect light. You will see a light spot.

1. Allign the picture approximately in the center of the phone screen. This is done with the X & Y positioning screws.
2. Look at 20x at the edges of the round image. They should show soft vignetting and be perfectly round. twist the tilt screws to have the correct agle between the eyepiece and the camera lens of the phone. In my case the right 2 screws need to be turned much mre than the left. I think that the assembly of the camera lens in the phone also has some inaccuracy, as I already compensated for the fact that the backside of the Galaxy S phone is not flat but curved. Most probably to fit the antennas of the Galaxy S phone. For this reason I made a small cut-out in my adaptor mount(s).
3. Tighten all screws such that in 60x zoom only very small vignetting is visible. darker spots will get visible on the phone display in the process. now it is really a matter of tweaking the X, Y and tilt screws. change the magnification of the eye piece to make sure there are no distinct dark spots in any magnification.
4. At some point the tilt screws should be fine. At 80x zoom even very little changes in X and Y change the darker areas on the screen. When satisfied I fix the Y screw. I keep a very little margin on X screw so I can shift the phone a very little in the phone slide in the X direction. I need this as there will be very small changes each time I screw the adaptor on the scope. In fact it is the only thing I have to do after putting the adaptor on the scope and sliding the phone into the wooden slides. It takes 1 second to find the optimum, so it is acceptable.

That’s it, all set for mobile phone digiscoping.

Tagged: 20x, 60x, Allignment, Android, Bauer, Digiscoping, Galaxy S, Olivon, Outdoor club, Reduce photo size, Samsung, T80ED, vignetting, zoom

Posted in: Digiscoping, Projects DIY