June Pinhole SC sign up thread - DPChallenge Forums

Canon EF 100mm f/2.8L Macro IS USM

05/28/2010 01:38:19 AM · #51

Originally posted by JustCaree:

Originally posted by bvy:

Originally posted by JustCaree:
This stuff is coool looking but I have no idea what it is.

//en.wikipedia.org/wiki/Pinhole_camera

so if I am understanding this right... you basically cover your entire lens except for a small hole? set the shutter speed real slow and shoot?

no lens at all - just a hole in front of film/digital sensor

tehben

Canon EF 24-105mm f/4.0L IS

05/28/2010 01:57:01 AM · #52

Originally posted by JustCaree:

mmhm

oh yeah but no lens...

Message edited by author 2010-05-28 01:57:39.

JustCaree

Canon EOS-1000D Rebel XS

Canon EF-S 18-55mm f/3.5-5.6 IS

05/28/2010 03:19:47 PM · #53

oh so my camera since i cant remove my lens cant do it.. well poop

tehben

Canon EF 24-105mm f/4.0L IS

05/28/2010 03:54:08 PM · #54

Originally posted by JustCaree:

oh so my camera since i cant remove my lens cant do it.. well poop

Ya, pretty much...

05/29/2010 11:07:52 AM · #55

Anybody making a new pinhole this weekend?

bvy

Sigma DP1x

05/29/2010 12:25:22 PM · #56

Originally posted by bspurgeon:

Anybody making a new pinhole this weekend?

You are! How's it going?

tehben

Canon EF 24-105mm f/4.0L IS

05/29/2010 12:55:58 PM · #57

Did this one last weekend.

05/29/2010 01:31:54 PM · #58

Originally posted by bvy:

Originally posted by bspurgeon:
Anybody making a new pinhole this weekend?

You are! How's it going?

Great! Just looking for a thin needle. I have a 0.58mm beading needle which obviously will work, but there are smaller needles out there! I've got the oatmeal box ready. I'm also looking for very thin Velcro so I can swap out pinhole plates.

Message edited by author 2010-05-29 13:34:08.

bvy

Sigma DP1x

05/29/2010 01:37:49 PM · #59

Originally posted by bspurgeon:

Originally posted by bvy:

Originally posted by bspurgeon:
Anybody making a new pinhole this weekend?

You are! How's it going?

Yes, just looking for a thin needle. I have a 0.58mm beading needle which obviously will work, but there are smaller needles out there! I've got the oatmeal box ready. I'm also looking for very thin Velcro so I can swap out pinhole plates.

Velcro's a great idea. I can even see using it as a shutter of sorts. My current shutter is an improvised bit of business made with black electrical tape and a rubber band. Don't ask.

Do you have a scanner? For making pinholes, I just use any old sewing needle. Poke, spin the metal, sand, then scan. If you know your DPI, it's easy to count pixels and get a rough calculation of the diameter of your pinhole. I repeat the process gradually until I get the size I want. Just an idea.

05/29/2010 02:19:21 PM · #60

Great tip Brian. Yes, I have a scanner. So you then use this information to calculate aperture, then exposure time/shutter speed?

Pinhole Calc

bvy

Sigma DP1x

05/29/2010 02:39:45 PM · #61

Originally posted by bspurgeon:

Great tip Brian. Yes, I have a scanner. So you then use this information to calculate aperture, then exposure time/shutter speed?

Pinhole Calc

It's an art as much as a science. There's probably a good range of pinhole diameters that will deliver good results for a given focal length (or camera depth or pinhole-to-film distance to satisfy the purists). The idea is the shorter the focal length, the smaller the hole (aperture) -- but it's not a linear relationship. (I think it's a log function, but I'll spare you the math.)

That calculator is a good tool. So is this one which tells you to use a smaller hole. I believe there are different formulas, so anything in the neighborhood of what these tools tell you should work fine. (My own Quaker Oats pinhole is 0.42mm or ~f/226).

Exposure is trial and error. These calculators will give you an idea where to start, but every homemade camera is so different from the next one that you'll end up devising your own system. For me, bright sun in snow or sand is about 15 seconds, bright sun is 30 to 40 seconds, hazy sun or early or late day sun is 45 to 60 seconds, bright overcast 60 to 90 seconds, etc. The good thing about measuring exposure in tens of seconds versus fractional seconds is that you have a lot of wiggle room. And if you're under, you can always push the development a bit in the darkroom. (Pulling if over doesn't work as well in my experience.)

Don't know if I'm helping or muddying the waters...

05/30/2010 02:59:57 AM · #62

First from my freshly minted oatmeal box. Good times!