How to make a pinhole, which will give good quality image
Many people, who started to make own pinhole cameras are looking for perfect pinhole aperture. Buying a professional laser drilled pinhole is an option, but you can also make it yourself and your pinhole will be really good.
Key Factors for High-Quality Pinhole Images
Before you start to make own pinholes for your cameras is good to know what factors determines pinhole good quality.
First factor is metal sheet thickness
This is is very important. Laser drilled pinholes are made in very thin copper foil. Thickness of foil is around 0,05mm and it’s really hard to find something somilar. Other thing- it’s also really hard to drill a hole mechanical way, because copper foil is is soft and fragile. Easiest source of thin metal are beverage/beer cans. Average thickness of tin can is 0,1mm and this is enough for pinhole making. Cans are made from steel or aluminium. Both are suitable for making pinhole apertures, however aluminium ones are softer and edges of pinhole must be cleaned much exactly after sanding. You can also try to get 0,1mm brass sheets, which are available in stores for model makers.
Why thickness of metal sheet is important, when you making a pinhole? Pinhole made in too thick metal sheet will give strong vignetting and light fall off at the edges.
4×5 inch pinhole photography on photographic paper. Pinhole drilled in thick metal sheet.
Second factor is pinhole diameter (and shape)
General rule is that small pinholes gives sharper pinhole picture. Pinholes, which are large gives more unsharp nad blurry images. I was really happy when i developed my first film exposed using pinhole camera and saw few not so sharp pictures. I also quickly discovered that after small internet research, that smaller pinhole giver much sharper images.
Is that shape of the pinhole matter? The truth is that any pinhole will give some image. Pinhole just punched in metal sheet, with irregural shape and edges will give low contrast and low sharpness image. But ideal rounded pinhole with sharp edges will give much better quality pinhole picture.
Sample shot- taken using pinhole aperture made in thin sheet, but with irregular edges
Third factor is optimal size of pinhole
Shortly- properly chosen diameter for focal length given may produces better image than just very small pinhole. If you don’t like the math, you cn use online calculator like Mr. Pinhole or download Pinhole designer from www.pinhole.cz I use czech version- it is very easy – to get result is only required to enter focal length and sesitive material size.
If you want to calculate optimal pinhole size yourself, here is formula:
d = c × √(f × λ)
d is optimal pinhole size
c -constant different sources provides different values 1,5 1,8 or 1,9
λ- wave length. For this equation wavelenth of green-yellow light- (0,00055mm)
will be correct λ value
6×6 pinhole picture. Pinhole size is too large.
How to Make a Pinhole: Step-by-Step Guide
What you will need?
- thin metal sheet or beverage can
- thin sewing needle or better numbered micro drill bits
- sanding paper gradation 400 and 600
- compressed air
Place a piece of metal sheet on a stable, hard surface. If might be plastic or wooden cutting board. You can mark a squares with scissors or knife and mark place for hole with marker. Remember that beverage can is covered from both sides. Outside with paint, inside with clear protective coat. You have to remove them that using sanding paper with 360- 400 gradation.
To make pinhole using sewing needle you need only punch a sheet of metal on a board. Don’t push the needle deep. After that sand both sides, back side first with smooth sanding paper 500 or 600 gradation. After that clean the hole using top of the needle as drill. Don’t use a force. It’s good also to use compressed air and spray it into a hole.
This method is easiest, but it’s hard too control pinhole diameter. Better way is to use precission micro drills. Sets of tungsten micro drills are available on Amazon. You can also buy them from stores for model makers. Drills from Amazon are quite cheap, but very fragile. So, it’s better to order box with few sets, in case that drill be broken after few uses.
Micro drill are numbered from 0,1mm. You can use them with hand vice or better with Dremel or similar tool.After drilling a hole you should sand the pinhole area vertically and horizontally, the same way as made by needle. After sanding you should put manually the drill into the hole and make some turns to clean it. Compressed air will help to remove metal particles from the pinhole.
Read also: How to take photos with a pinholecamera?
Radar Meadow in Astronomical Observatory Ondrejov. Sample of optimal pinhole size and correct sheet thickness
Exploring Professional Options at Vermeer Camera Store
Find out more about cameras offered in Vermeer camera store. They have insrtalled high quality pinholes. AApertures are made using precise micro drills in 0,04mm steel sheet. Every single pinhole is inspected under microscope before is mounted.