pinhole size

[TZuboff]

UK needles come in number like for example 3/9 or so, pinhole size tables come in mm. Who knows which numbers correspond to which mm sizes?
Tatjana[/url]

 

[Aurore]

Ooooh, this is easy. I've had this link since I built my own pinhole, 9 months ago.

http://mywebpages.comcast.net/hmpi/Pinhole/Articles/Aperture/pin_aper.htm

I, personally, used a #10 needle and ended up with f/206. Good luck!

Aurore

 

[Rlibersky]

Alright I've search some, but this site is getting hard to read all the posts. Good news for Apug hard to search.

I'm looking for information on the optimum pinhole size for said distance from film plane.

Mainly 13, 14, 15, 16, 17, 18, 19 inches. Or is there a best fstop size. then I could figure out the hole size. I'm picking up my homemade 9.5x20 pinhole camera tomorrow. Can't wait to give it a try this weekend.

 

[PhotoPete]

Alright I've search some, but this site is getting hard to read all the posts. Good news for Apug hard to search.

I'm looking for information on the optimum pinhole size for said distance from film plane.

Mainly 13, 14, 15, 16, 17, 18, 19 inches. Or is there a best fstop size. then I could figure out the hole size. I'm picking up my homemade 9.5x20 pinhole camera tomorrow. Can't wait to give it a try this weekend.

Try:
http://www.wandascott.com/howtomake2.html
or
http://www.stanford.edu/~cpatton/pinholemath.htm
or
http://www.photo.net/pinhole/pinhole

 

[tpersin]

Here's a great online pinhole camera calculator to help you figure out optimal pinhole size"
http://www.mrpinhole.com/calcpinh.php

here are needle numbers converted to mm:
4, .90mm
5, .80mm
6, .73mm
7, .66mm
8, .58mm
9, .51mm
10, .46mm
11, .40mm
12, .35mm
13, .33mm
14, .30mm
16, .25mm

if you're looking for more info, may i suggest the f295 pinhole forum:
http://f295.tompersinger.com


cheers!
Tom

 

[Rlibersky]

Thanks, this should be a good start

 

[Donald Qualls]

FWIW, I use the same needle for all my pinholes, from .15 mm up to about .55 mm so far. Since all the holes are smaller than the needle shaft, I just have to control how deeply I let the needle penetrate.

What I do is make a dimple that just penetrates, then sand off the dimple with a very fine whetstone (nice and flat, stays put, and I can use it with oil if I'm so inclined); measure (eyeball, if it's not close yet) and repeat as needed. I can usually make a hole within .001" (about .025 mm) of the desired size on the first or second try, and the resulting holes are perfectly round, burr free, and have a razor-thin edge. They aren't quite as clean as a Lenox Laser hole, but they're about $18 cheaper...

I use .001" thick brass shim stock, but you could just as easily use the thin aluminum from the side of a beverage can...