Failed Pin Hole Attempt - DPChallenge Forums

Canon EF 16-35mm f/2.8L USM

01/28/2005 01:16:57 PM · #1

Hello guys, and good morning from this spot in the world.

I tried last night to do some pinhole photography with my camera (300D). What I basically did was drill a hole in the body cap and glued a small piece of acrylic in front of it to prevent dust to get to the sensor, tried diferent ISOs and exposure times, but everytime I just got a blury image. I also tried positioning myself at different distances from the subject, and covering the hole with a cardboard and making a smaller hole on it with the same results.

I read somewhere in the forums that this was possible, also some company sells a body cap pre-drilled to work with this technic. Am I doing something wrong, or all that you get is a blurry image. Someone in this site shared a link to a "pin hole time calculator", tried the results it gave me, but it was either a totally white image or black.

Anyone tried this recently?

Thanks guys.

thatcloudthere

Canon EOS-1D

01/28/2005 02:01:01 PM · #2

What size drill bit? I'd think that with the sensor so close to the opening, you'd need a pinhole sized pinhole...one that you would need a really small bit for.

01/28/2005 02:04:01 PM · #3

I think it is like 1mm, but when i covered that hole with the card board id did the hole wiht the a clothes pin, so it was really small, and the results were exaclty the same.

hyperfocal

Nikon D7000

Nikon MF 105mm f/2.5 AIS

01/28/2005 02:04:26 PM · #4

If all you got was a blurry image and the exposure was enough to register an image then probably your "hole" is too large. Try a small sewing needle punched into a thin brass shim glued over the hole in the cap. Don't worry about the dust isssue, because is hole should be too small for that to ba an issue.

Good Luck.

P.S. If your really looking to get into pinhole photography get the $20 kit from bender photo (the same people who make the DIY large format kits). It iscules a pinhole primer as well as several brass shimsetc.

01/28/2005 02:27:42 PM · #5

I guess I am going to try that, I thought the hole I made was small, but I don't think I can go smaller than that.

Thanks for all your help.

kirbic

Canon EOS R5

Canon RF 24-70 f2.8 L IS

01/28/2005 02:40:10 PM · #6

The best hole diameter should be about 0.3mm. You can buy a drill bit that small, but it's a specialty item. The edges of the hole need to be clean and smooth, and the material should be as thin as possible.
The results you get with even the best quality pinhole will still not be perfectly sharp, that's just the nature of pinhole photography.

01/28/2005 03:00:21 PM · #7

I know I can not expect sharpness, that's what I like about pinhole, but really, this was very very blured.

Spork99

Canon EOS M6 Mk II

Canon EF-M 22mm STM Lens

01/28/2005 03:02:11 PM · #8

You need a good pinhole. The method you describe is not going to give good results.

radiman

Sony 16-50mm f/3.5-5.6 E-mount

01/28/2005 03:18:49 PM · #9

Maybe if you tried to use some tinfoil. That may be thin enough to get a really small hole in.

jmsetzler

Sony Alpha a6000

01/28/2005 03:46:29 PM · #10

I bought the Finney pinhole cap (f/180) to play with on my 10d. It works about as well as I expected.

ANY bit of dust on your sensor becomes a big black blob on the photo. The photos are also incredibly soft...

hyperfocal

Nikon D7000

Nikon MF 105mm f/2.5 AIS

01/28/2005 04:42:20 PM · #11

follow up..

Also use extension tubes to increase focal length. This also will increase sharpness slightly due to less defraction effects since the light rays don't bend as much to cover the sensor.

01/28/2005 05:09:20 PM · #12

Thanks a lot guys.

I was planning to get the kenko extension tubes on my next trip to the camera store, I will try to find the cap you mention. I will get back tou you as soon as I try them out, and maybe enter some pictures in one of the challenges :)

Thanks again for all your help.

scottwilson

Canon EOS-350D Rebel XT

Canon EF 28mm f/2.8

01/28/2005 05:13:39 PM · #13

The blur from the pin hole will of course be about the size of the pin hole. The blur from diffraction will be the wavelength of light, say 450 nm, divided by the pin hole size then multiplied by the distance the pin hole is from the sensor. In practical terms this means too large a pin hole and you get a blurry photo due to that, too small and it is diffraction that will blur the image. For a pin hole that is 50mm from the sensor the optimum pin hole is about 0.15 mm. At this point you will have a blur spot of a little over .2 mm, for a 22.5 mm sensor we will get about 110 usable pixels, pretty low resolution.

If you move the pin hole closer you can make it smaller but the gains here are not great, the possible resolution goes as the square root of the inverse of the distance between the pin hole and the sensor, and this begins to breakdown when the pin hole is about as close to the sensor as the sensor is wide.

The only good way to get a higher resolution image from a pin hole camera is to use a very large sensor, like an 8 by 10 piece of film.

Because of their small sensors digital camera are not at all well suited to pin hole photography.

01/28/2005 05:34:03 PM · #14

So Mr. Scott, if I understood right, using the extension tubes as suggested by Steven will help regardless of my current pinhole size. This is because I dont think I will be able to make the hole smaller with the tools I have available right now.

I understand the sensor size vs. the regular pin hole camera film, did a lot of tests with 8x10 and 4x5 paper back in college, and the 8x10 gave the best results by far. I guess it is only a trial and error kinda thing doing it in the DSLR, but at least I will try to get some artsy shots just to play around.

Thanks

scottwilson

Canon EOS-350D Rebel XT

Canon EF 28mm f/2.8

01/28/2005 05:44:57 PM · #15

Originally posted by eruelas:

The extension tubes will make the photo a bit blurrier. However you will also get more magnification so you will see more of the detail of what you are photographing, but the field of view is reduced. If the pin hole is on the order of 1mm then you would have to get it a long ways from the camera before diffraction would be a problem, but pulling it away from the camera will increase the effects of diffraction not reduce them.