DIY Fisheye lens filter

I want a fisheye lens, but I don't want to spend 500$ on a real fisheye unit. What to do?
I saw this cool post: http://photojojo.com/content/diy/make-your-own-fisheye-lens/
And decided that I could do one better: I would go to an eyeglasses shop and get the highest prescription lens-blank they had. 

Items needed:
A digital camera (SLR or point-and-shoot)
If it's an SLR, you also need an 18-55 lens, stock with most cameras.
Very thick, uncut eyeglass-lens. ($15)

Step 1 Buying the lens

Buy a blank, uncut lens from an optician.they come in either +sizes, which are convex and will do the opposite, and -size concave lenses, which make the magic happen. I am using a -8.00 hi-index lens. Don't buy the compressed plastic kind either, you want super-size coke bottles

Comments

[QueenQuill]

Awesome idea! Have you ever used a door peep hole for a fisheye lens? I've seen it a few places online (like here: http://www.popsci.com/video/2007-08/5-minute-project-video-peephole-fisheye-lens ).  I wonder how the effects would differ between the peep hole method, and your method....hmm...now I wanna try them both!  If only I weren't so poor. =/  Ah well, if anyone tries both methods, let me know how it turns out!

[danlance]

I suppose I don't have the required minimal focal distance on my lenses. 35mm and 50mm are too big for getting it in focus. From your posted images I see your photo lens is an ultra wide one (17 or 18mm+). I guess this is the problem.

[mycombs]

 Yes, the lens is a 18-55 zoom lens. I tried with my 55mm fixed, and it didn't work! You can try this trick with a simple pint-and-shoot, and set the focus to "macro" and it works, too.

[zainalalieff]

What should I ask to the optician to request for the lens?

[mycombs]

 Hi, sorry I took so long to respond!
Ask the optician for the highest prescription they have, plastic lenses are cheaper and thicker than glass, I think. Show them the photo above, or write down the measurements shown! Index 1.60

[PseudoJunk]

I bought a fisheye lens for my Holga for about $20.
Not only do I use it on my Holga, but I'm constantly experimenting with it with my other cameras by taping it to the end of my lenses.
Every time I go out and take pictures people give me these odd glances because I have this DSLR with a cheap lens attached to my regular one :)

Anyway, I really like your idea!

[danlance]

Hi !
I tried an -6 lens over a Canon 35-135mm lens and a fixed 50mm lens. I was'nt able to focus with both of them no matter how I hold and at any distance the prescription lens in front of the photo lenses. Please any idea how to handle this? Thanks.

[BobS]

I built a fish-eye adapter (prototype) from a strong negative lens in front (probably over -10), and a magnifying glass from a 'third hands' unit about 30 mm behind it.

This way, the out of focus image is compensated back into focus. It is now the same optical system as if looking the wrong way through binoculars.

The color shift can be corrected in photoshop with a one time calibration test:

Every channel (RGB) has a slightly different size. Make a pic at night at minimum zoom (maximum fish eye), with a point light source in a corner (far away streetlight, or the planet Venus). 
Zoom in (in photoshop) to make the light source a pixelated colored line. Now go to the red and blue channel, and find out by trial and error how much the image size has to be changed (probably something like 99.8 and 100.3 %) to position itself at the same spot as in the green channel.  Write down these percentages, preferably with a permanent marker on the monitor (I mean, don't loose the numbers, or you'll have to recalibrate!).

From now on you can get a picture almost free from color edges by quickly resizing the red and blue channels with the percentages found.

I'm sure this can also be done with another good image program, as long as it can resize per channel by fractions of a %.

[danlance]

Please forgive my English :)

[vr360]

 amazing solution!!! thanks for sharing!! :)