"In photography, bokeh is the aesthetic quality of the blur produced in the out-of-focus parts of an image produced by a lens. Bokeh has been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations and aperture shape cause some lens designs to blur the image in a way that is pleasing to the eye, while others produce blurring that is unpleasant or distracting—"good" and "bad" bokeh, respectively. Bokeh occurs for parts of the scene that lie outside the depth of field. Photographers sometimes deliberately use a shallow focus technique to create images with prominent out-of-focus regions." (obtained from https://en.wikipedia.org/wiki/Bokeh)

Bokeh is a really cool effect when used properly and something that most photographers have tried or actively use and is especially popular with photography enthusiasts all over the world.

One neat side effect from this technique is that if you have light on the background these will get blurred into into big circles of light (all credits for the included bokeh photo go to user SumbO, over at http://7-themes.com/6870065-bokeh-photography-wal... but you are not restricted to that shape. Those big circles are circles due to the shape of the lens, which is circular, so if you restrict the light coming in and force it to take another shape, then a correctly made bokeh photo with lights on the background will have that shape, enter the bokeh kit.

I've seen several bokeh kits for sale and some diy ones, but none of those was very appealing, I really didn't want to use rubber bands on top of piece of cardboard it just seems to cumbersome, what I wanted was bokeh kit that I could easily clip-on the lens with a single hand, something that was sturdy enough for repeated use and something I could easily create new shapes for.

Well I have a 3D printer and I know how to make 3D models so it was time to design something. I went with Fusion 360 for this design so that I could take advantage of the parametric design, this should allow me to easily to scale the model to different lens sizes and in fact I did just that, I modeled this for a 52mm lens and afterwards scaled up for a 55mm lens and I only had to change to drawings, how awesome is that :).

P.S. This was quite a learning experience as this was only the second time that I modeled something in Fusion 360.

Step 1: Basic Shape

First things, first, dimensions, I wanted something to clip over the lens, so I measured the lens I had, a 52mm, and after adding a 0.4mm to ensure a snug but not overly tight fit, I had 54.60mm, which I then offset by 1.7mm, this was simply eyeballed, I just need something thick enough to be solid and you could probably get away with less.

I extruded the outer circle 10mm and then extruded the inner one by 5.5mm thus cut that piece of the bigger cylinder, once again I just eyeballed it.

Step 2: Lens Openning

Next it was time to open a path for the light to enter the lens, so I opened a 35mm hole on the center of the design by sketching it and then extruding it out.

Step 3: Clip-on Shapes

I could simply have made the shapes that I wanted on the design I already had, but I decided I wanted something modular that wouldn't take much space in the bag, so I decided to create a clip-on design for the shapes also, something that could be easily printed and made by anyone, even if they didn't knew how model.

The measurements provided in the pictures were once again roughly made, I just went on to sketching on the surface of the design for a shape that could easily be clipped on the bokeh kit, when that was done I extruded that shape out by 2.5mm. At this point I was considering a collection of different shapes so I need a clip-on shape that was really thin to maximize the number of shapes that I could make and carry and minimize the plastic I would have to spend.

Step 4: Making the Slot

I had the space for the clip-on shapes, I now had to make a slot through which they would slide into the design, so I offset the space I had just make, by 0.8mm and then extruded out that shape by 1.18mm (you guessed eyeballed it again :) ). I now had a slot, but also had a tricky overhang and I hate those, so chamfer to the rescue, I chamfered the overhang by 0.8 to coincide with the 0.8mm offset from before and the slot was done, I could easily be printed and I had roughly a 1mm thickness for the clip-on shapes.

Step 5: Cliping the Bokeh to the Lens

Before continuing I really needed to solve my main problem, how to clip the bokeh to the lens securely? I already had a couple of bokeh kits using small screws but wasn't happy with that design, metallic screws could damage the lens plastic one didn't last long so I need something else. I went with two side clips, these have a small lever for you to press which is more than enough to open the clips thus allowing for quick and easy removal/installation, and as this is printed in a single piece, there's no need for finicky assembly.

So I sketched this design on the bottom of the design, but I still need to cut a bit of space for the clips to extend and grab the lens, so I made a 11mm height rectangle that I then extruded out of the design by 5mm, I then proceeded to extrude the clips joining them to the kit by 10mm

Step 6: Perfecting the Clip

At this point I decided to add a chamfer to the piece that was actually going to grab the lens. This step is probably useless, but my reasoning was that at the top of that piece any support generated by the slicer would be hell to remove, so if I can minimize that I will.

Step 7: Perfecting the Kit and Making the Clip-on

At this point the model looked almost finished but I wasn't happy with the entrance to the channel that the clip-on shapes would have enter. I opted to cut out a bit of top of it to make it both easier to print and easier to insert the shapes.
Next were the clip-on shapes, I already had the basic shape, the one that I offset by 0.8mm before, so I offset it again this time by 0.2mm to the inside. Then I proceeded to create a small handle that would protrude slightly from the kit to make it easily removable and to ensure that it wouldn't brake I applied a fillet to the base and to of it thus making it stronger and less harsh to your fingers.

I could have left design it like this and the print tolerances should ensure that the clip would have worked but I wasn't if with repeated use this was going to fail, so I opted to incorporate a small spring to make it sturdier. I simply cut a slot on the sides with a 1mm thickness and added a 1mm half circle to the outside of the clip, this provided the springiness to ensure that clip-on would stay on.

So with the shaped sketched out all that was needed was a 1mm extruded and the base design for the clip-on shape was done.

Step 8: Getting Creative

The design was now done, all I had left to do was to make some cool shapes and start taking pictures. I already had a bunch of shapes ready from my other attempts at a bokeh kit, a couple of them were made in inkscape the others were from taken from fonts like Wingdings and its variants, or Font Awesome. I simply imported the drawings, centered and extruded them out of the clip-on shape and it was done. Now I need to print this and test it.

Step 9: Printing and Testing

I printed the bokeh kit with PLA, at 220ºC (this is BQ PLA and this is the recommend temperature), 0.2mm layer height, 3 perimeters, 15% infill and supports. I don't like needing supports, but I was really out of ideas trying to avoid it, in the end I just caved in they are there to be used if we need them and this design needs it.

The clip on shapes were printed with the exact same settings and overall it took roughly two hours to print the whole kit.

At this point I had a small problem, I still hadn't bought a DSLR :P, but I had an old SLR so I checked that dimensions were spot on. Next beta testing, I still hadn't access to a DSLR but I knew someone that had so I gave it to a friend that tested it and confirmed that it worked, in fact he liked so much that I made a couple of extra shapes for him. So Christmas comes and low and behold I now have access to a DSLR, it's not mine but I can play with it (thanks sis ;) ), it's at that moment that I see the it does not fit, but why? Easy the lens are 55mm not 52mm dohh, so parametric design to the rescue simply add 3mm extra to initial design, move the clips 3mm, export the design and print it.

So give you an example of what you can achieve with this check the included picture (done by user Mk82 over at:

https://www.dpreview.com/forums/post/56474177).

So for your bokeh kit needs here are the designs, one for 52mm and the other for 55mm.

52mm