How to Make a Fish Eye Lens for a Nikon D-90 Digital SLR for $16





Introduction: How to Make a Fish Eye Lens for a Nikon D-90 Digital SLR for $16

I got the inspiration to do this Instructable while reading another Instructable that accomplished the same "fish-eye" effect using a PVC reduction pipe and an entry door viewer.

There was concern in the prior Instructable about around scratching the lens so I wanted to solve that problem in my easy to build fish eye lens as well as make a version which is easy to use, remove, etc.

I decided to modify the design by using an existing camera attachment which would easily mount to the camera and comes with most Nikon lenses.

The secret to my design is to use the lens shield as the attachment platform which allows the fish eye lens to be easily attached and removed from standard lenses while enabling a hands free experience.

The lens that I am using in the shot below is a Nikon 18-105mm VR lens. It came with the kit when I bought my camera.

Step 1: Prepare the Materials

The only thing that I had to buy was the door entry viewer which was $15 and some change so I rounded to $16.

In addition to that you will need:

- 1 Entry Door Viewer - The one shown below is a 160 degree large diameter version.
- 1 scrap particle board. 3" X 3" square
- 1 scrap particle board 1.5" X 1.5" square
- The old handy duct tape approx 10" in length
- Spare Lens shield - I never use one on this lens anyway so I'm using the one that came with it.

Step 2: Assembly Instructions

1. Place the lens shield on the 3"X3" square particle board to trace the circle diameter. (Make sure you use the end that is opposite of the camera connection.)

2. Find the center of the particle board and drill a 1" hole or as required by the instruction in your entry viewer.

3. Using the 1.5" X 1.5" square particle board piece, find the center and cut a 1" hole or as required by the instruction in your entry viewer.

4. Round off the corners of the 3" X 3" square to make a circle which matches the outside facing section of the lens shield.

5. Thread the entry viewer in the holes in both the small and the larger particle board pieces. (See 1st picture below)

6. Using the duct tape, carefully wrap a piece around both the large particle board piece and the lens shield to connect the two together. (See second picture below)

Step 3: Enjoy Your New Fish-eye Lens!

Have fun!

I built this in about 1/2 hour (most of the time was used in cutting out a circle. I used a drill press to lob of the corners with a drill since I didn't have a scroll or jig-saw handy.)

I think the pics came out pretty good for a quick project. :)

One note: Use the highest setting as you can on image quality and size since all of the shots below needed to be cropped significantly. (There is a lot of black space to crop out. See last photo for an example)



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    59 Discussions

    Love the front door photo :D
    Fantastic job! This makes me almost wish I hadn't spend $100+ on my fisheye =x

    8 replies

    Where can you buy a fisheye for a dslr for only 100+? Where I live it's more like 600+...

     Damn, just looking at this instructable makes me shiver. I mean why get a proper camera and then rape it with a crap quality lens? Just save some money, get a job.

    I'm curious as to why you are here at all, as your comment can apply to 99% of the instructables here.

    the point is it works, and works well. a better question is why spend $600+ when it can be done for $16

    'Fraggotmode' has a point. While it's a nifty little trick, it has no control over aperture, no way to focus it, and aberrations ruin the photo...being the owner of both real fisheyes and those inexpensive fisheye converters, I do happen to know what I'm talking about. His comment doesn't apply to 99% of instructables, that's a gross miscalculation.

    Why spend $600? Because stopped down to f/4 on my Tokina, I can do 100% crops and still have tons of sharp detail. Try that with this, and tell me how it goes. It CANNOT be done for $16 on the same level as a real fisheye. Don't compare a $300 junker to a Bugatti.

     agree!  This can also be done to point and shoots, (my section).

    rather than buying a peep hole thing, use a the lenses in the view finder thing from a disposable camera. just turn one of the lenses around and it turns it into a fish eye.

    2 replies

    great idea dude ,, tell me exctly how do u turn a l\nikon lens into a fisheye simply by inverting one lens in it

    wow! i never knew that! i just tore one apart now, gonna make the cheapest fisheye cam ever! thx! :D

     how close does the door view finder have to be to the lens and i seem to have alot of camera glare is their anyway of getting rid of this?? thanks, andy.

     it will work on ANY camera, just shrink the size of the tube to fit the diameter of your camera barrel! 

    Agreed that this was more work than was needed. I made one many years ago, long before Instructables was even an idea on the net, using the same peep-hole optics for my very first digital camera. Using just a cap from a butane-refill can as the holder to slide it over the lens barrel. It was just the right diameter to fit the camera's lens housing lightly but snuggly enough to hold it in place. As others have said, it can also be mounted in an inexpensive lens-cap. These work exceptionally well on smaller P&S cameras with a 3X or greater zoom lens on it. As the exit pupil of the peep-hole matches the entrance pupil of the smaller diameter lens on most smaller P&S cameras. You need about at least a 3X zoom to be able to zoom into the smaller circular image in the center of your field of view, getting the full circle to fill the camera's frame from edge to edge--making use of as many pixels as possible for the greatest detail and resolution.

    Now here's for the important bit., and why I logged in to leave this comment: The strongly negative lenses in these peep-hole devices, as well as being so inexpensive, are not blackened properly on the edges so you get that light grayish framing around the outside of your images as well as producing much lower contrast and lens flares from bright lights. (This lightness also makes it difficult to mask out later when you want a completely black circular mask for prints or displaying the image.)

    Take the front of the peep-hole apart (the front ring unscrews from the main barrel) where the flat lens faces toward your subject. You will find two identical strongly negative lenses there, touching inside-face to inside-face. Use a good black magic-marker or sharpie to completely blacken the sides of the two negative-lens elements (they are both identical so there's no need to keep track of which goes in front or back). Being careful, of course, to not get any magic-marker on the polished faces of the lenses. Try to not get any dust or fingerprints (or magic-marker) on the polished lens areas. If you do, carefully clean those surfaces without destroying your intended blackening job. You might want to take the time to use some flat-black paint or marker to blacken any other internal surfaces in the barrel of the lens-housing. Reassemble. Your images will improve greatly.

    If you have a "chromatic aberration" filter in your photo-editing software, you can then use it to remove the small amount of CA that these inexpensive lenses impart in your images. PTLens being a good plugin for this, but there's also some good freeware plugins for freeware editors like Irfanview and FastStone, a free plugin called CAFree by Tom Fiddaman works very well, Google for it.  With these inexpensive lenses and a little editing you can get faux fish-eye images that rival some of the $2500 fish-eye Nikkor lenses for SLRs. I was amazed what kind of image quality could come from such an inexpensive lens design, especially when the lens elements aren't even achromats. This shouldn't be possible, but it is. (For the naysayers, don't knock it till you've tried it and compared the two.)

    But be sure to blacken the unpolished areas of those optics inside. You'll be surprised how much the images improve.

     Talk about the hard and expensive way (lens hoods are expensive) to do something simple! Just glue one to the front of a cheap lens cap that can be found on eBay. Us geezers were doing that over 40 years ago. 

    Quick, he lives at 20711, it's the gray house, let's get him! :)

    Anyways, nice instructable, might just have a cheap xmas gift for my friend with photography skills (and as tight a budget as mine)

     Awesome idea!
    The crop is pretty bad though...
    Maybe if I can find some nice "detective lens" to replace it...