First pinhole - need help

[ABrosig]

OK. I started pretty redneck on my first pinhole experiment - disassembled a spare Holga lens, replaced main element with a piece of soda can with a sewing needle pinhole and, voila. Or so I thought. Very limited experiment and, as you can see, I got images and exposure looks pretty good. But, focus sucks!



As I said, a very limited experiment (I had three frames remaining on a roll of HP5+ and decided to try it for a purely exposure/does anything come out test).
Obviously, the shutter assembly of the holga (120CFN) is causing the framing. Kinda liking it, so that's not necessarily an issue. But I'm wondering what my focus problem is. Lens was screwed all the way in to the mountain/infinity setting and, it appears, the only thing in focus in the image is the lower left-hand corner of the shutter assembly, which would be about 2-inches in front of the film. (??????) Figured my focal length at about 2-1/8 inches, measured, and used a calculator I found on the web for pinhole diameter and exposure. (I don't have a micrometer/caliper so diameter was something of a guess.)

Any recommendations/suggestions/ideas on what I can try next? The Kodak website on pinhole photography recommended a #10 sewing needle to make the aperture for a focal length of about 3 inches and I think I was pretty close. Do I want a longer focal length? I'm planning on building my first, wooden pinhole from scratch, so won't have the shutter assembly issue and can set focal length to, realistically, anything I want. Planning on 1/4 inch either oak of lauan plywood. I do have some woodworking experience, so the actual construction should be a snap.

Thanks in advance for any help/input forthcoming.

 

[Jani_from_Finland]

You just must ask my fellow citizen "mablo" he is genious in this (as well in all photographic essens). Check out his Holga pinholes and the super sharpness in them.

 

[alienmeatsack]

My first suggestion would be to try the hole again and make it as tiny as possible.

When I did them using a sewing needle, I literally spun the needle between my fingers against the soda can material until it started to dent the can and as soon as it punched through I stopped. I then very carefully sanded both sides down and put the needle gently through the other side just barely piercing the metal to clean the hole up. I got pretty decent results from the shots I did with that.

I finally invested in a pin vise and some micro bits to make cleaner holes for my project pinhole camera I am working on. I don't have results from them to show.

But, I think you are on the right path. It's really a matter of playing with hole sizes to get the focus you want... and making sure the edges of the hole are as clean and sharp as possible as they will make the image fuzzier as a result.

 

[charjohncarter]

Why just the main element (?), I don't know anything about Holgas, but usually your just have the soda can piece (not other elements) and a pinhole. At least you are using a camera with a format that is good for pinholes. My experience is the larger the format the better.

If by 'main element' you meant the only element forget this post. By the way, my pinholes are 400 muc (which in English is very very very small).

Here is one in almost the same format:

 

[ABrosig]

Chose the holga as a starter because, frankly, I was sitting around last night, bored, with an old holga and a can of soda in my hand 🙂 But, I agree, the format is perfect. I found plans for a 4X5 pinhole, but that calls for a much larger investment, in negative holders, developing frames, film holders, etc, than I'm willing to go for at this point.

On a side note, I'm thinking about using the guts of the volunteer holga, which gave up its life for the pinhole, for the film transport in my next (first) pinhole build adventure. I've searched the interwebs thingy and can't seem to find any references beyond the couple I've already accessed.

I did go out today and splurge on smaller sewing needles AND (wonder of wonders) found an old set of pocket calipers that belonged to my dad. The new needles I've got go down to .5 mm, at least as close as I can tell by eye on the scale. I'll try one of those and see where it gets me. I'm also thinking shoot a whole roll (rather than one or two frames at the end of another) to give it a full test. I'll post some results following the next run. Thanks for your help.

 

[Dwig]

...

When I did them using a sewing needle, I literally spun the needle between my fingers against the soda can material until it started to dent the can and as soon as it punched through I stopped. I then very carefully sanded both sides down and put the needle gently through the other side just barely piercing the metal to clean the hole up. I got pretty decent results from the shots I did with that. ...

+1, this is a good method.

Piercing thin aluminum (soda can, aluminum foil, ...) usually results in a tear that leaves ragged edges. These are very, very undesirable. Brass and copper sheets work much better.

The "create a dimple and sand off the bump to leave a round hole" is an excellent approach. However you make the hole, examine it carefully with a high power lupe (25mm or shorter FL camera lens works well for this) to see that it is round. If not, try again.

 

[charjohncarter]

+1, this is a good method.

Piercing thin aluminum (soda can, aluminum foil, ...) usually results in a tear that leaves ragged edges. These are very, very undesirable. Brass and copper sheets work much better.

The "create a dimple and sand off the bump to leave a round hole" is an excellent approach. However you make the hole, examine it carefully with a high power lupe (25mm or shorter FL camera lens works well for this) to see that it is round. If not, try again.

But keep it small. Read Mr. Pinhole on the web.

 

[oftheherd]

You might want to look at this: http://www.mrpinhole.com/calcpinh.php for pinhole size. They actually make hand drills with some drills about the size of a human hair. But while not as durable over the long run, tin foil punched between two pieces of cardboard is relatively easy to make and use.

 

[ABrosig]

Well, after three unsuccessful but improving attempts, the fourth time was a charm! Kept getting smaller and smaller on the pinhole and I finally hit on this:



This is the modified Holga; removed the lens completely, glued the aperture on the back of the lens mount, in front of the shutter, then had to glue the whole thing together because I'd had it apart so many times, the screws stripped out. But I'm pretty happy with the results for a first test of this configuration. Now, working on exposure, etc., before the next project, which is building a larger, roll-film pinhole from scratch. (Yikes!)

Thanks to all for the input. Let me know what you think.

 

[rtphotos]

Hi ABrosig,

I was going to comment that you must remove the lens element(s) and just use the pinhole alone, but it seems that you have that sorted out. 🙂

Your last image of the church (?) is very nice and quite sharp!

Modifying a commercially made medium-format camera, like the Holga or Isolette is a great way to enter the world of pinholes.

Regarding pinholes - after making my pinholes with thin (0.002") brass shim and a fine sewing needle ("dimple and sand method"), I use a scanner to scan the pinhole (1000dpi or greater). I open up the image in Photoshop to examine its roundness and to measure the size of the pinhole.

As charjohncarter alludes to, there is a sweet spot pinhole size for every focal length. If optimal sharpness is your intent, select the size of the hole wisely. A smaller pinhole does not necessarily equate to a sharper image!

Here's my trusty modified Pinholga - 24mm focal length, 0.18mm pinhole, and f/133 [click on it for more details]:



And for whatever it's worth in case someone is contemplating doing something similar, here is a short YouTube video on how I did this Pinholga conversion:

http://www.youtube.com/watch?v=z-1dNpXbky0

Best of luck on your next pinhole camera-making project! 🙂

ross 🙂

 

[pvdhaar]

Not only does the size of the hole matter (a smaller size gives higher resolution up to a certain point), but also the shape. If the edges are not smooth, you'll get more diffraction that softens the image.