The Pinhole

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Pinhole Tabby!

The history of photography dates back before the development of the chemicals, negatives, and photographic paper. It all started with the Pinhole concept that is called “Camera Obscura”. This is the act of viewing, or projecting, a view of the world into your eye or into a darkened chamber.

The concept is intrinsically very simple and that is the beauty of it. You pierce a hole in a thin sheath, and you have a lens. Apply that lens to either a darkened chamber for viewing, or permanently onto a negative or device capable of capturing the scene and you have Pinhole photography!

I am not going to go into great detail on how to make your own Pinhole lens for your camera. I do, however, want to share some of my observations and tips I have learnt through making my own. The basics are very well documented online as a quick search through Google will demonstrate. I will provide a few links to the sites you can visit and read the basics there.

Final Pinhole & Materials
This article is specifically directed at Digital Pinhole Photography. A few of the links below will take you to Film Pinholes either for interest sake or if that is your goal. The technique is essentially the same for any kind of Pinhole so don’t be put off by the brand names or references to Film versus Digital.

The exposure times for Pinhole Photography are too long for hand held shots. You must use a Tripod or at very least set your camera down on a stable surface. I use a remote shutter control to reduce shake. You can also just use the timer system to delay the exposure till you have let go of the camera thus avoiding shaky exposures.

Alternatively, skip this whole article and buy a laser cut, precisely engineered, pre-made Pinhole cap for your particular camera. Honestly, I will eventually buy a set from a certain manufacturer but I strongly suggest people make their own first. It can be a little frustrating but ultimately rather rewarding to make one yourself.

Pinhole test on my drill!
What follows is what I learnt from trying to make a few Pinholes so far which have progressively gotten better. Firstly, size DOES Count! The smaller the hole (up to a point… excuse the pun), the sharper the image will be. I first tried drilling with my smallest drill bit into the plastic of the Body Cap. At 1mm it is too big and produces a very vague, blurry image.

I then followed the steps in most online tutorials and drilled a larger hole in the Camera Body Cap and applied my Pinhole to an aluminium sheath gotten from an aluminium, well-known drinks can. The smaller and more perfect I got the hole, the sharper the results were.

If you want the best possible results you really need to use as fine a needle as possible. A sewing needle works quite well because, unlike a nail or a pin, it has a long slender point which gives you more control over the hole you puncture.

Now, I must warn you that thin aluminium cans are VERY sharp razor blades when cut open. Please be very careful. It is relatively easy to cut the aluminium with a pair of heavier crafts scissors. A can will give you lots of aluminium to experiment with. I cut around the top and bottom and then straight down the remaining tube side to give me a square of stubbornly curly aluminium sheeting.

I suggest cutting the right sized discs first. See that it fits neatly inside your Body Cap. Once you’ve got that done then move onto the delicate art of the Pin Prick!

While you might think that that the aluminium sheet is already pretty thin, it isn’t good enough for a good Pinhole. For clarity sake let me compare the actual hole in the sheet to a tube. The longer the tube, the more the light bounces around in it causing aberrations in the exposure. This is the reason why the better tutorials advise you to sand down the surface even thinner.

There are two approaches to making the hole together with the sanding process.  The one method is to literally make the pinhole first but also dimple the sheet so that you are sanding down the small area from behind and thereby thinning the material only around the actual hole. I found that this is problematic. You can accidentally sand down too much and make a much larger hole than expected.

The second method is to first sand the metal right down in the centre where the Pinhole will go and THEN make the tiny Pin Prick through the delicate metal.

Personally I actually found a combination of the two to be ideal. So make the tiniest Pin Prick you possible can and dimple the material very slightly. Then start sanding down the side of the dimple. Gently keep sanding and you will feel the metal gradually become more like tin foil than the original aluminium can. If you are careful to only sand in the middle, the disc will still retain a fair stiffness and structure.

Test on wild cherries.
As you are sanding down the aluminium, keep very gently poking the needle into the hole and rotating it to clear the aperture of barbs. Then sand some more. Keep repeating the process as it will give you the thinnest material and the smoothest, roundest Pinhole possible. You can also poke the needle through from both sides and sand down both sides of the aluminium too.

A good way to keep checking the size and smoothness of the hole is to periodically hold it up to your eye and view it against a lit scene. Since you will be holding it up very close to your eye, make sure to blow off all dust beforehand. The hole should be tiny and the edge very smooth. If you hold it up close to your eye you will actually experience the Pinhole effect.

The size of the Pinhole should be roughly in line with the sizes you find on the net for the best results. I have no real way of measuring but my final one looked to be around 0.3-0.5mm in diameter. Without machinery that is probably about as good as one can get it.

This is not an exact science. It is about practice. If you get a decent enough Pinhole rather set it aside and start a new one to improve upon. You will regret ruining your less than perfect product when it becomes worse. Make notes of which one is which so you can keep track of what works best. I put a number on the edge of each aluminium disc where it is concealed behind the plastic Cap.

Also keep testing it on your camera (remember to dust it all off first) and view it on your PC to compare the different lenses you make. You are looking for sharpness that you simply cannot tell on such a small LCD display.

Accidental effect with Sun’s rays
I did use a black magic marker to blacken out the inside of the aluminium. I waited for it to dry and gently inserted the needle and turned it to make sure the hole was still circular and not odd shaped from the ink.

I still have not actually glued the aluminium to the Body Cap. The reason being is that I am still not finished with it and I don’t want to throw away the Cap and start with another one. It is not a cheap exercise!

My aluminium discs fit very snuggly inside the Cap body so the light is sealed off well enough for the tests. This is why I advised you to first cut neat disc shapes. I’ve also found some dense black foam (used in expansion joints in construction) and I intend to cut discs with a hole in the middle from this foam to use as a stopper inside my cap. This will hold the aluminium in place and block any possibility of light leaking in around the edges.

With any parts of the Pinhole lens it is important to take note that you do not want to cast shadows or create a vignette effect in your construction. As you can see in my Pinhole assembly I drilled the hole in the Cap substantially larger and tried to bevel it from the outside to minimise the tunnel effect. Similarly you want to avoid that on the internal side too if you use the black foam stopper as I mentioned above. Cut an adequate hole in the centre to allow the light to pass through and fall neatly on the sensor without hitting a “Tunnel”.

Taking Pinhole photographs takes patience. You will most likely not be able to see anything through your viewfinder at all. That is quite normal! If you take photographs outdoors in bright light the “Live View” on the camera should display your scene quite well.

Indoors you will probably be shooting blindly. Shoot, check the photograph and turn your tripod to aim more accurately and repeat the process. Tap foot while waiting and pray your subject doesn’t get up and walk away mid exposure. Get yourself a lazy cat!

Your exposures outdoors on a sunny day will probably be between 1-5 seconds. In the shade it might be more towards 5-10 seconds. Indoors you are looking at 15-30 seconds. The larger the Pinhole, the shorter the exposure times but at a cost in sharpness.

Extension Macro Tubes
On an interesting note, while a Pinhole has no depth of field, you can create a “zooming” effect by moving the Pinhole further away from the camera. This you can achieve by either using “Tube” extenders used for Macro photography or make your own. See the link under the “Film & Misc Links” section how to make an economical version!

For more photographs and experiments I’ve made with my Pinhole please go to… http://www.slickpic.com/u/JoRodrigues/ and look under the section called “Digital Pinhole”.

On a last word of advice, do not be disappointed if your results are not as sharp as a razor. As it is said; “If you want sharp, put some glass on the end of your camera!”

This is an art, not a science. Have fun!

http://www.jorodrigues.com/ | https://www.facebook.com/JoRoderickAuthor

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