Saturday, July 16, 2011

Super Ultra High Power Telephoto Lens Hack

Last night was a full moon and it happened to be a very clear night. There were a couple stray clouds meandering across the night sky to which my dad alerted me and suggested I grab my camera. I grabbed my shiny new Nikon D3100 and headed out to grab some shots of the moon, but as I only had the kit 18-55mm Nikkor lens, I was not planning on any close ups. This is what I started expecting:

I make it outside just as the clouds are passing but grabbed a few pics anyway, as it was nice out and still looked cool. My dad mentioned how back in the day, people would go out and shoot entire rolls of film of the moon with it in different locations to use later in enhancing other pictures. That seemed pretty cool, but we discussed the miracles of the GIMP and other things with cut and paste editing. Anyway, the idea of actually looking at the moon came up and I mentioned how awesome it looked through my spotting scope. shortly thereafter I made a trip inside and grabbed my Gander Mountain 12-50x scope and a tripod. At 50x, the moon entirely filled the eyepiece of the scope with great detail.

Since the camera was still outside, I decided to see how well it worked if I just put the camera behind the scope and looked through it. It actually worked fantastically well. Though it was very difficult to hold still and keep the moon in the frame, I managed to grab a couple awesome shots such as the one below

Moon Hax

With the great success that that experiment led to, I promptly set about the task of making a more stable lens hack platform. For this platform, I planned on just using a board with some 1/4-20 bolts to hold everything in place and to allow the camera to be positioned up high enough so that it would be on axis with the scope. initially I had only placed a single hole for a bolt for each the scope and camera, but found that I needed to adjust the distance between them more than I had anticipated, so one of the holes became a slot with the help of a 1/4" router bit and the drill press (I was far too impatient to bother setting up the router).

To provide a way to attache the mount to my tripod, I drilled a 3rd hole and counter bored it slightly and pressed a 1/4-20 nut into it. This later proved to not work so well as it was terribly not balanced, so I later adjusted it. When replacing it, I also  filed some notches into the bolt and Guerrilla Glued it into place. Hopefully the notches and expanding action of the glue will keep it snug this time.

When it all gets put together, it looks something like this:

 and can take pictures like these:

mailbox ~300'

Green thing ~90'

Overall, though the image quality is nowhere near fantastic and does not fill the whole sensor, it is still quite excellent for the price. It does not respond well with small apertures as there is major vignetting, which is improved greatly with wider apertures. There also is a lot of chromatic aberration present, especially if the camera and scope are slightly off axis. I believe that CA is still present when using the scope on ts own as it really isn't designed for this use... In the final pic of the moon above, I removed the red and blue channels and desaturated it, to remove large amounts of CA

But yeah, reasonable very long lens for maybe $2 in parts(or entirely scrap if you have a proper basement)? Sounds great to me =]

These few pics are hosted in 14.2MP at my Picasa
also, check out my Flickr... for some more interesting stuff but limited hosting and such...