I have devised a way of using the very popular Rokinon 8mm F2.8 fisheye lens that comes under several other branded names including; Samyang and Bower. The photo included is of no great interest. In fact it’s just a photo taken at the rear of a house. But, the significance of the actual image lies in the fact that it is an infrared photograph taken by using a 8mm fisheye lens on an unconverted Fujifilm X-Pro1.
Surely a filter cannot be fitted onto the front of the 8mm fisheye lens? So how did I do it, I hear you ask? The answer is after the jump, but lets just say that, this is going to be one of those try-it-at-your-own-risk kind of posts :)
The short answer is, I didn’t fit a filter to the front end of the lens at all. What I actually did was fit the filter to the rear of the lens! keep on reading to find our how.
I purchased a cheap 37mm circular R72 infrared filter I bought online for just under 8 GBP, a 39mm R720 IR filter would have been more of an ideal fit, but I couldn’t find any for sale). Now came the only real tricky part as I had to remove the IR filter glass from the filter ring. To do this you need a very small slotted screwdriver, (like the ones used for tightening frames of spectacles), or similar tool.
Now if you look closely at the filter you will see one or two cut-out notches. Lay your filter onto a flat surface and wear a stout glove on the hand you will not be holding your screwdriver in. This is in case the screwdriver slips and you end up stabbing yourself in the hand! Position the tip of your screwdriver into one of the notches on the filter ring and apply gentle pressure in an anti-clockwise direction until you feel it rotating. Keep doing this until it comes all the way loose. When lifting the actual piece of circular glass from the filter ring please ensure you do not smear it in any way.
Take the rear cap off your 8mm Fisheye lens and carefully set the now removed R72 piece of circular glass onto the rear of the lens. Couple the lens to your camera by placing the camera over the top of the lens, in order that the added piece of glass does not fall out. Switch on your camera, set the lens to the settings I’ve previously mentioned here, and you are good to go. Enjoy!
Ordinarily, (when not shooting infrared), but using the 8mm fisheye on my X-Pro1, I would stop the lens down to an aperture of F8 and set focus to 0.40m (1 foot, 4 inches). This gives me a field of focus somewhere in the region of 20cm, (8 inches), to infinity. But these settings changed dramatically in my attempts at infrared usage. I now found that I had to stop the lens down further, (to F16 to be precise), and set focus to 0.3m (1 foot). I found that keeping the lens to F8 for infrared photography resulted in very soft images. So through trial and error I found F16 produced the sharpest photos in return.
While this is only a prototype it does work and proved the concept, now lets see a manufacturer pick it up…