Simple Pinhole for SLR Camera

Ever felt your SLR takes too high quality images? Long for the simpler days? Here is a very simple way to make a high quality, easy to use pinhole to replace your SLR lens.

Step 1: The raw materials

You need just three things for this pinhole "lens":
1. A body cap for your camera (I got a spare one for £1 on ebay)
2. Some thin metal (eg. foil, the side of a drinks can)
3. Tape

The trick of this method is using the body cap as the support for the pinhole. It is a perfect fit for the camera, has no light leaks, is easy to fit and remove (with no chance of causing damage to the camera) and is easy to modify. The thin metal will be used to make the actual pinhole, any piece of thin and soft metal (aluminium is ideal) will do.

Comments

[Lokisgodhi]

A. J. Fricko Co. used to or still does(can't find a listing) market a pinhole camera lens like this. They used a col-lens glued on the front to sharpen the picture.

They used to be available through Wathers.com A model railroad wholesaler/retailer. Not seeing them on their website

Following their lead and trying a co-lens mounted on the front might improve this lens.

[spark master]

can you put a pinhole in front of a lens ?

[Zephyris]

In short no, that has a very different effect. Have a search for bokeh filters...

[The nerdling]

did you give this cap to someone?

[The nerdling]

if you did that guy you gave it to was some one i know.
the reason i asked is because it is exactly like the one i have

[Zephyris]

Nope, not me :) I still have this pinhole nestled in with my DSLR...

[dwerg85]

Nice Instructable, but saying that the images will always be blurry is pretty erroneous. Blurred images are a result of either too big or too small a hole.

Check attached image for an example of how sharp you can get them by just doing it by hand without calculating anything. With proper calculations and preciser drilling of the hole you can get a dead sharp image.
(image is from a pinhole camera using photographic paper. principle is the same tho)

[Zephyris]

Optimum pinhole size is a function of a lot of factors, this website has a very handy calculator.
http://www.stanford.edu/~cpatton/phcalc3.htm

The long and the short of it is that the longer the focal length and the larger the sensor/photographic film the sharper the image can be. For a DSLR with a short focal length (~3 cm in my case) the optimum pinhole size would be about 0.18mm. At this size diffraction effects would be significantly blurring the image forcing me to use a pinhole size of closer to 0.3mm.

To calculate the resolution think about two rays of light coming from a point at infinity (so the rays are parallel). The maximum separation of the rays once they hit the sensor is the same as the size of the pinhole, 0.3mm. My DSLR sensor is ~1.7cm accross therefore the blur due to the pinhole is going to be 0.3/170*100=1.8% of the image frame.

Using much larger focal lengths and sensor sizes can reduce the blur (as a percent of the image frame) - the example above is probably using a pinhole of ~0.3mm and a sensor (photographic paper size) of ~10cm, therefore the blur is 0.03% of the image frame.

[dwerg85]

Ever thought about using zoneplates instead of pinholes? I don't use them but, from how i remember how they work, couldn't they help with the sharpness issues? Or i guess you'll have to resort to what i'm probably going to do when "converting" my slr. Use an extention tube to extend the focal length.

[Zephyris]

I have never tried building a zone plate (though I want to try!). The focus will probably be similar, possibly slightly better with a zone plate... The exposure time is the key thing - a pinhole on a DSLR is very tough to use without a tripod, with a zone plate the exposuresrequired will be far more manageable.

[92033]

You can make an easy tripod base for use on the camera. Use a piece of 1/4" thick plywood or plastic. Drill a 1/4 inch hole in the center. Use double-face carpet tape or layer of rubber cement on face of the wood/plastic base and layer on bottom of camera. Stick together for a permanent bond. Screw your tripos screw into the hole and you're all set. Want 'simpler'? Lightly duct-tape it to tripod. Removes easily. Idea is to hold the camera still and level..this'll do the trick. Great Instructable mind-refresher for me...have been in photography all my lifetime...'1200 Year Old Highlander Immortal', y'know. :-) Which reminds me...Do you know what Jesus said to the Apostles at The Last Supper? "All you guys who want your picture taken, sit on this side of the table with Me". Moses was The First Photographer. He used a Pinhole Camera and Bolt Of Lightning for the FLASH. Came out pretty good, eh?REPLY [flag][delete].

[Marble of Doom]

Nice spy-camera

[92033]

"SPY CAMERA"? I don't think so. :-) The exposures are lonnng...seconds, not split seconds. Even 'minutes' at dark times...can't handhold or conceal like a 'spy camera'. Jest thot I'd letcha know. :-) (The phonetic spelling is intentional. I do it all the time with eMail friends...drives 'em crazy).

[AndyGadget]

I've made one and found the only colour in the garden at the moment.  I really love the diffuse soft focus effect.
With the way I've got things set up I had to use a fairly long telephoto setting to get the whole frame.  I'll re-hash it so I can go wider.
I was using a 3.5" exposure at full aperture and some of my shots had a blur as the tripod hadn't fully settled, but these are the best ones.

[Zephyris]

Nicely done :)

[AndyGadget]

Please do post outdoor pictures once the weather improves.  I'd go and try this now but the weather is somewhat inclement here as well.  (And it's dark ;¬)