What film for looong pinhole exposure

Hello. I am new to this forum and am unsure if this question has

been posted. But here goes anyway. I have a piholga. I want to take

a long 4-5-6hr exposure in the woods/forrest showing the sun as it

passes across the sky. I was thinking of using Illford Pan F maybe

with a red filter(?) Maybe a ND filter? The info on the camera

is:Pinhole size = .0079" or 0.2010 mm

Equivalent to approx a 40 mm focal Length and an f stop of f/215

Thanks in advance for any help you can offer.

Fuji Neopan Acros is a great film for very long exposures but I have never taken a exposure even close to that long.

I think it's just going to take some experimenting to see.

 

If I'm figuring right, without factoring in reciprocity failure, you need about 7 seconds for a "normal" exposure in daylight with 25 ISO film. So 4 hours is about 11 stops overexposed. You need a combination of film reciprocity failure and ND filters to make up roughly 11 stops.

 

Of course, high reciprocity failure also means high contrast. If the sun is IN the picture, that area will be overexposed no matter what. You could very well wind up with a light stripe where it's overexposed and the rest of the image pitch black.

 

If you haven't taken other shots with the sun in the shot, I would suggest doing so just to see if you have any issues with flare or get a big "fireball" or other effects that show they're going to ruin the shot.

4 to 6 hours pointed into the sun is a lot to ask.

 

Fuji Acros is the best p-hole film I have found because of lack of reciprocity

failure. But I think you want reciprocity failure, to allow an exposure of that

duration.

 

A red 25 will darken your sky (maybe not after six hours) but the forest will be

black.

 

The only way I have found to get a decent image out of a really demanding

situation with the pinhole is to bracket. Which means . . .build more cameras!

hello dave,

here is a link to a photo i took using a pinhole camera. it is of the moon, but it is giving the results you are looking for. http://www.f295.org/Pinholeforum/forum/Blah.pl?m-1142871822/s-1/highlight-moon/#num1

surf around the f295 site as there is plenty of info available to you. you may need some filtration if you want the sun in the shot, maybe a few ND filters.....AH! but would it be a lensless photo after you shoot it through glass? har har har! anyway another option you may consider is to use a paper negative. photo paper is about asa 6 or less. you do not need to figure reciprocity either! also this site http://www.pinhole.cz/ may be of help. it has all kinds of great info and includes reciprocity info for you. e mail me if i can help further.

 

eddie

Wow! Thank-you all. Some good advice. I got this idea after seeing a simaler photo in Eric Renner's excellent book on pinhole. I don't recall the tech info on the shot and have since had the book "aquired" by a friend so I can no longer reference it. But The post about using a paper neg w/ asa 6 seems logical. Also, a mind-meld with other pinhole gods has come to this conclusion as far as if I use filters will it still be considered "lensless": 'If the filters are held on with gaffers tape or better yet duct tape the process will be pure.' Again thanks to all.

 

Dave