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DIY Pinhole Lens Process - Found some problems - for 6X24 Wine bottle Box Camera

Mustafa Umut Sarac

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Finally , I bought a 35X12X10CMS Wine bottle box with middle lock and protections at corners to make my 6X24 Pinhole Camera. Box will be at my hand wednesday.

Its a curved plane camera with calculated 0.39mm - 85mm focal lenght.

I asked to experienced people to make the pinhole and they said make a bump at the thin metal foil with a needle and than sandpaper this bump to open your pinhole.

I thought this bumb can cause vignetting at the camera and I am thinking to scan the hole than make calculations to find the diameter. And I found experimenters with this method dont care about the diameter .

For exact 0.39mm diameter and no vignetting of bumb , what do you advise ?
 
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Mustafa Umut Sarac

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Willy T said:
Laser cutting?
Click to expand...

For laser cutting , kerf of the laser - diameter of laser beam - should be lower than the cut hole. Turkish laser kerf is 1.mm or 1.5mm , you can find 0.3 at germany. I cant import , I am looking for a bright idea.
 

blee1996

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Earliest is to buy from RealitySoSubtle from France, he has several diameter laser cut pinholes to choose from. Excellent quality at reasonable prices.

Laser drilled ‘Pinholes’. – RealitySoSubtle

Precision, top quality laser drilled pinhole apertures mounted in 20mm vinyl discs. These pinholes are perfectly round and fault free. The pinholes are 50 microns thick, that's 0.002", or 0.05mm - extremely thin. The thinner the better when it comes to image quality! These are the pinholes used...
realitysosubtle.fr

I have done DIY myself, the best come out from those mini hand drill bits which has different sizes.
 

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Mustafa Umut Sarac

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Thank you very much , Its impossible to import good from abroad because of Turkish Customs , I have to pass above and best possible option is to learning using needle and thin metal foil while not creating least possible vignette. I need to learn the shortways.

Umut
 

blee1996

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I have used both sewing needles and those micro drill bits, on aluminum soda or beer cans.

With needle, you have to find the thinnest possible, and make lots of holes with different force. After sanding, you will find the holes are all of different sizes. But you can experiment and achieve the size you want.

With micro drill bits, it is much more consistent and the hole is more rounded. You still need to do some sanding, but not as much as with needle.
 
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Mustafa Umut Sarac

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Hello Blee , Can you tell me is there a vignetting risk at drill and sand method ? How do you measure the diameter ? Thanks,

Umut
 

blee1996

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You will try to make the thin sheet metal as flat as possible, especially around the pinhole. You can use a hardwood under the thin sheet metal, when you do the needle piercing or micro drill. When you gently sand it, it will also help to make the sheet metal flat (n addition to make the hole rounder).

Pinhole photos will always vignette, unless you do a perfectlly spherical film plane. This is part of the effect and charm of pinhole photograhy.

For pinhole size measurement, I use an Epson V700 scanner at highest resolution and do the measurement in photoshop.
 

Dan Fromm

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Hmm. 85 mm focal length. 6x24, which probably means 56 mm x 240 mm, diagonal ~ 246 mm. Angle covered, ~ 110 degrees. Corner illumination ~ 3.3 stops down from center; this is what cos^4 implies.

I think the OP has been worried about mechanical vignetting by the bump in his sheet of foil caused by forcing a needle through it. As has already been mentioned sanding the foil can remove the bump. Nothing, however, can be done about cos^4, i.e., optical vignetting.

OP, stop worrying. Use a micrometer to measure the diameter of needles you might use. If you don't have a micrometer, find a friendly machinist. Choose a needle that's more-or-less 0.39 mm in diameter. Don't worry if it isn't exactly that size. Puncture a sheet of aluminum foil or beverage can. Don't worry if it isn't perfect. Go take pictures.
 

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For thin metal such as that used in a little tea candle, which is what I use, take a no 10 or 11 size sewing needle. These points are very fine.

Take a pencil with an eraser at the end, insert the eye part of the sewing needle into it. Carefully, to not bend or damage the needle.

Cut the bit of metal into a small square.
Sit this on top of a soft material like some cork.
Carefully twirl the pencil with point of the needle into the bit of metal until it breaks through.

Take a small fine nail file, an emery board, and gently smooth BOTH SIDES of the metal around the very tiny hole.

Take a good magnifying glass or loupe to look & see if the edges are getting smooth & fine.

Make several this way & experiment with them.

I've been making my pinholes for over ten years this way for all sorts of supports - plastic film cannisters, folding cameras, 4x5 lens boards, coffee cans and so on.
 

mcfitz

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These are some of the results in a converted 6x9 folding camera with a pinhole made this way.
 

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Mustafa Umut Sarac

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Blee , Thank you very much , my friend have a Epson V700 and is there anything we should know to see the magnified scan at real magnified lifesize at the screen. We dont have photoshop or gimp and I want to do the measurement while on epson software.
By the way thinner the metal , smaller the hole , is that true ? I will check the shop for thinnest metal , does metal foil works ? You say , vignette is normal but when I see the photographs of curved plane 6X24 pinhole cameras , there is no way vignette.
 
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Mustafa Umut Sarac

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Hello, Do you measure the pinholes diameters or do you try the pinhole and reach a agreement ? I want to make exact focal lenght. BOTH SIDES smoothing is very important tip. Thank you very much.
 

mcfitz

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Mustafa Umut Sarac said:
Hello, Do you measure the pinholes diameters or do you try the pinhole and reach a agreement ? I want to make exact focal lenght. BOTH SIDES smoothing is very important tip. Thank you very much.
Click to expand...

A little bit of both, it is tricky. I have a loupe with a micro scale in it & look at the pinhole on a light box. Then make the calculation & set the pinhole into the support. From there it is experimentation.

Good luck, the other thing I would say is try & enjoy the entire process. Pinhole is wonderful and for me every step is worthwhile as I ALWAYS learn something, and cannot predict the results. Letting go of expectations opens up so many possibilities.
 
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Mustafa Umut Sarac

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Thank you very much.
 

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Mustafa Umut Sarac said:
my friend have a Epson V700 and is there anything we should know to see the magnified scan at real magnified lifesize at the screen
Click to expand...


2400 DPI


  • Millimeters per dot (pixel):
    25.4÷2400=0.0105825.4 \div 2400 = 0.0105825.4÷2400=0.01058 mm ≈ 0.0106 mm
 

MattKing

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I have friends who use either a slide projector or an enlarger set for high magnification to measure the size of the pinholes they make.
To do this, you need a pinhole of accurately known size to serve as a comparison.
Project/enlarge and measure the image of the known pinhole to first calculate the magnification.
Then project/enlarge the image from the one you are trying to determine the size of, measure the image, then factor out the magnification.
This will also give you a chance to check how clean and close to circular your pinhole actually is.
 
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Mustafa Umut Sarac

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Hello Matt , We have multigrade enlarger 35mm and a 6x6 film enlarger but no reference pinhole at the hand. Do you think pixel counting on a jpeg compressed image works or not ?
 

MattKing

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Mustafa Umut Sarac said:
Hello Matt , We have multigrade enlarger 35mm and a 6x6 film enlarger but no reference pinhole at the hand. Do you think pixel counting on a jpeg compressed image works or not ?
Click to expand...

I'm not the one to ask Umut - I'm the one who is more likely to pull out the slide projector and borrow one of my friend's previously measured ones to use as a reference instead!
 
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