JimH123 Loc: Morgan Hill, CA

For users of Canon lenses, there is an adpter by Geoptik that attaches to the back of the lens, and allows a CCD to be connected to the other side. Unfortunately, this company only builds these adapters for Canon lenses. And by the way, they charge around $156 for this adapter.

Well, I decided to construct one of my one and as you can see above, it works quite well. First thing I stared with was a rear lens cap. These are all plastic and I bought a bag of them for a few dollars. My intent was to cut a hole through the adapter and to attach necessary adapters to get to a t-thread (42mm 0.75mm pitch). In looking at the lens cap, it had an indented ring on the backside that offered a wonderful attachment point. So I started with a 55mm to 52mm step down ring. The 55mm fit into this indented area and I expoxied it in place. I also took great steps to make sure that the step down ring was absolutely flat so that the lens would not sit at an angle. But 52mm was not useful, so I added another step down to go from 52mm to 42mm (0.75mm pitch). But it had the wrong gender, so had to find a male to male adapter. At this point, I had what I needed and the assembly could now screw directly into the Atik camera. And I find that I can focus a little bit beyond infinity.

I have 3 of these Rokinon/Samyang/Vivitar lenses: 14mm f2.8, 24mm f1.4, and 85mm f1.4

If I consider the 24mm lens, it produces a full frame equivalence of 105.6mm.
And the 85mm an equivalence of 250mm.
And the 14mm an equivalence of 61.6mm.

I find I am unable to use the 0.5x focal reducer since it would require moving the lens even closer to the camera and there is no room to do this.

BOM (Bill of Materials):

42mm male gender changer: http://www.ebay.com/itm/321760773442?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
55mm to 52mm step down ring: http://www.ebay.com/itm/281809543929?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
52mm to 42mm step down ring: http://www.ebay.com/itm/191270081895?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
And here is a rear lens cap. I bought a bag of 10 for $12, here is just one by itself. You can see the indented ring. I had to remove that one plastic barrier to it going all the way around. http://www.ebay.com/itm/1-piece-Rear-lens-cap-cover-for-Sony-Alpha-Minolta-Af-mount-lens-Replacement-/151553738712?hash=item23494e87d8

And the mounting adapter is similar to this. I can't access the same eBay page, I recall that the inside diameter I needed was around 40mm and I had to look at a number to these to find a suitable size. The sellers aren't very good at providing the inner dimension, so you might have to contact them: http://www.ebay.com/itm/Mount-Ring-For-Hasselblad-Lens-Adapter-Metal-Adjustable-Tripod-/271838291023?hash=item3f4ad3244f:g:vDoAAOSwcwhVLK2X

JimH123 Loc: Morgan Hill, CA

Here is an example of using the 24mm Rokinon at f1.4 tonight with the Atik Infinity. The 4 bright stars are the bowl of the Big Dipper with Dubhe as the lower right bright star. There are at least two galaxies showing, although very small since this was only a 24mm lens (acting like a 105mm lens due to the small size of the CCD sensor). It looks like it is working well, although I do see some coma distortion in the corners. But this was at f1.4, and perhaps at f2.0, it would be a little less. This is a stack of 10 shots of 40 sec each for 400 sec total. With the moon out tonight, I was aiming away from that bright beacon in the sky. I have to get up early in the AM for work, so this is all I tried tonight. Used the iOpton tracker since it is so easy to set up.

(Download)

nicolas59

Hello !

I would like to do the same photos with an adaptator between my Canon obj and my Atik Infinity...
Have you got other photos made with this setup ?

Thanks a lot
Nicolas

JimH123 Loc: Morgan Hill, CA

The key to it is finding a rear lens cap that has a suitable surface in which to make a hole the right size to insert the adapters and to epoxy them in place.

But for Canon lenses, there is a commercial adapter available, I think for around $85. The company make one for Canon and another for Nikon. I will try to look it up tonight.

nicolas59

Thank you !
Nicolas

JimH123 Loc: Morgan Hill, CA

Here is a suitable adapter for Canon

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2836_Geoptik-T2-Adaptor-for-CANON-EOS-Lens-with-1-4--Phototripod.html

nicolas59

Thanks

CraigFair Loc: Santa Maria, CA.

Thanks for the links I was able to get the adapters to connect my Nikon lenses to my M42 Camera.
Craig

nicolas59

I have read with this kind of system, we will have much coma with Canon objectives...
I will see...

JimH123 Loc: Morgan Hill, CA

With good glass, there won't be coma. I have examples.

Some lenses my need to be stopped down a bit. Using the camera aperture ring creates ugly spikes. I plan to buy some cheap lens caps and drill out some various sized holes and use this instead of stopping down. This works better.