What to take into account as a pinhole newbie?

[perminna]

I bought a 6x12 Noon Pinhole camera yesterday, the most beautiful piece of crafting I've seen. It should arrive in a week or so. What should I take into account when I start taking my first pinhole photos? The focal length of the camera is 60mm and the aperture is f/207.

I develop my own film and I'm going to use either Ilford FP4+ or Fomapan 100 as a test roll. I have a tripod and a spirit-level to get the camera steady and straight. I know the final image will be a mirror image of the actual scene.

Do I need to take something else than normal aperture + exposure time + film ISO into account? The aperture of the pinhole is f/207 so it's about 9.5 stops from f/8. Do I just extend the exposure times by 9.5 stops (if I meter at f/8) and get good results?

[rst]

Do I need to take something else than normal aperture + exposure time + film ISO into account? The aperture of the pinhole is f/207 so it's about 9.5 stops from f/8. Do I just extend the exposure times by 9.5 stops (if I meter at f/8) and get good results?

You should also take into account long exposure reciprocity. Short: The longer your exposure time gets the less sensitive your film is. Depending on the exposure time that can be another few stops, especially with Foma 100.

Here is an interesting read about Reciprocity failure: Click!

Cheers
Ruediger

[perminna]

Okay, thank you Ruediger!


Which films you guys recommend to be used with pinhole cameras? I've been thinking of T-Max 100 in addition to FP4+ and Fomapan 100. In color I've been using for example Fuji Reala 100 and Kodak Portra 160VC with 120 (and 135) cameras. Do these all work (if the reciprocity failure is compensated with extended exposure time)? How about a slower film, like Rollei Pan 25?

/Minna

[xxloverxx]

How about a slower film, like Rollei Pan 25?
/Minna

That would make your exposure time go into multiple hours — if that's what you're looking for, go for it.

[perminna]

Um, that's not what I want for now. I don't have the patience to take a long exposure like that.

Let me get my math straight. If I use sunny 16 rule on a sunny day, I'd get f/16 and 1/125s with ISO100 film. f/16 is 7.5 stops away from f/207 which would convert exposure time to (roughly) 2 seconds. And taking reciprocity failure into account, the correct exposure would be 8 or maybe 16 seconds (2 or 3 stops). On a cloudy day exposure time would be 16 or 32 seconds. You need to use 30 min exposure times during night time, right? That would give about 2 h exposure time with ISO25 film.

I think I start googling example pictures with proper descriptions.

[rst]

You do not have that much of reciprocity failure for times around 2 seconds. So even with Foma 100 that only ends in the 5 seconds range.

Using times which already have reciprocity correction and then go to a different film speed does not help. You have to change the measured time and then do reciprocity correction. Reciprocity correction is not simply a factor which you multiply your measured time with.

Example HP5:
Your measured time is 1/2@f8 which translates into around 7 minutes for f207. Add reciprocity will leave you at around 40 minutes.

Now take a film which is two stops slower and assume it has the same reciprocity behavior as HP5:

Now your measured time is 2 seconds @ f8 which translates into 28 minutes @ f207 and with reciprocity you end at around 5 hours and 30 minutes. Which is different from the 2 hours you would get if you calculate for the slower speed and start from the already corrected time of 40 minutes.

And then there is the fact, that different films have different reciprocity behavior.

Just to have a fun start I would recommend Fuji Neopan Acros which has nearly no reciprocity failure up to 120 seconds. And up to 1 hour it is less than a stop.

Cheers
Ruediger

[edp]

Acros 100 needs hardly any reciprocity corrections up to exposures of several minutes, which is just one reason why it's good for pinholes.

[bsdunek]

Allow me to introduce you to Mr. Pinhole http://www.mrpinhole.com/index.php Go to the exposure guide and enter your f-stop.
A quick reciprocity table is at http://oak.cats.ohiou.edu/~schneidw/...rrections.html
I have searched out several articles on the web of exposure and reciprocity and have made my own charts which I keep in my camera bag. With a little adjusting I can hit the exposure most every time.
If you use negative film (FP4, HP5, etc.) then you print just like any photo. Works great and is a lot of fun!

[Pinholemaster]

A Black Cat Exposure calculator is a handy tool to have when working with pinhole cameras. Makes adjusting your exposure time from what your meter tells you to the new time for your pinhole aperture a simple turn of a wheel.

http://www.blackcatphotoproducts.com/

[SMBooth]

Download and run Pinhole Designer ( http://www.pinhole.cz/en/pinholedesigner/ ), has a neat exposure calculator where you can select film type and it will give exposure with reciprocity factored in.
Fuji ACROS has no reciprocity up to around 2min even more so its a good B&W pinhole film.