Perfect Pinhole Exposure Times

[@stuartgraham5055]

As a total newcomer to Pinhole photography this video was both much needed and appreciated. Needless to say I will be watching more if not all your videos on Pinhole photography. thank you so much!!!

[@BurningtunaDC]

Super helpful video presented in an easy to understand way. On a few occasions I paused your video, pulled out a calculator, and performed the math using the formulas you presented just to make sure I understood what you were doing. Thanks for shooting and sharing.

[@robertdungan6848]

I found the math very interesting. I haven't done math like that since I graduated from college in 1975. I went to Mr. Pinhole and generated a table that gives you the exposure for F16. I then copied it and kept the parts I would use. From 1/1000 to a few seconds that yields a exposure time of 15 minutes. I know I won't wait for more than 15 minutes for a exposure. I printed this out and glued it to the side of the camera. To use, I meter using the ISO get the exposure for F16 look up the exposure on the chart. I find it works well for photo paper negatives. When I used film (Foma 100) I did the same except I added time for reciprocity failure to the chart. Makes it pretty simple in the field.

[@tgchism]

Absolutely stretched my brain a bit but in the end it made sense and I'll be making a field notebook like you did in the next video! Thanks for taking the time to share this with us!

[@charliemcdarris6403]

This was very helpful. Thank you. I’ve been using the Pinhole Assistant App for the iPhone and was wondering if it was giving me the most accurate exposures. After watching your video 2x and understanding how the formulas work, I understand the concept. Also, I was able to confirm that the Pinhole App was spot on but has to be set up correctly. For anyone using that app, be sure to go into the menu to make sure under “Utilities” you select a specific film under the “Set Film Reciprocity”. It is somewhat hidden but must be selected to work properly.

[@alanwilliams9842]

I followed your system and it seems to work quite well. I did find that applying the Ilford reciprocity factor did give me a slightly overexposed negative.

[@TheScienceofPhotography]

As long as the highlights aren't completely blown out I prefer my black and white negatives to have about 1 stop of overexposure. Glad the system was able to get you close. Keep on testing!

[@bodudas8346]

Yes, thank you for presenting pinhole exposure in a logical understandable manner. Yes it appears daunting, but with practice I believe it will be easy to calculate out in the field. Numbers are constant if I stick to the same ISO, and I go from there.. thanks so much ... bo

[@ChristopherMay]

I dig this channel. Glad to see you back!!

[@TheScienceofPhotography]

Glad to be back. Thank you for the support!

[@dierktopp4780]

I like your channel very much! On this one I have some remarks. When you are calculating an f-stop of 278,5 it looks very scientific. If you use f/250 or f/320 instead it will not make any difference. If you imagine the difference between f/8 and f/16 this is one stop, the difference between f/250 and f/320 is about 1/4 stop. This does not affect the result of your final exposure! 1. this depends much more on you exposure measurement, for example if you use a spotmeter and measure the shadows and lights it depends on your judgement and experience (zone system), where you place your exposure 2. and it depends very much on your knowledge and experience of the Schwarzschild effect of this film I use the great App Photopills for all my pinhole shooting and get great results. I really can recommend this great App for all kinds of photography!! Regards Dierk

[@alanwilliams9842]

Thanks for doing this, very helpful. I'm going to give it a try tomorrow.

[@TheScienceofPhotography]

Good luck!

[@thevalleyofdisappointment]

So refreshing to see someone pronouncing ISO correctly. Gives extra credibility to the info. Good job.

[@bystry70]

Great video. I have one question: Schwarcschild effect and reciprocity factor are the same thing?

[@paulinovarela7476]

Very clear explanation. Thank you.

[@TheScienceofPhotography]

You are welcome!

[@franklittle6702]

Thats great clear and concise information, I will get a cheap calculator and start shooting. Thanks

[@TheScienceofPhotography]

You're very welcome. Glad to help!

[@katiemartin1224]

Thank you very much for this! I've been using this to great success with my work and am no longer having to rely on luck and guesswork or an internet connection to find equivalent exposures for my pinhole cameras. At one point you mention maybe deriving this formula in another video for those interested and I haven't managed to find if you did this or not. I would be incredibly interested in the derivation of this formula, did you do that video in the end and if so would you be able to point me in the direction of this? Thank you very much :)

[@zbigniewadygin4026]

Based on the tabular data, calculate the coefficients for the following negative films: Rollei RPX 25 1,33 Rollei Retro 80s 1,53 ADOX 100 CHS II 1,45 Retropan 320 soft 1,45 Fomapan 100 1,60 Fomapan 200 1,63 Fomapan 400 1,45

[@andrewgreen1355]

Nice explanation. Thanks

[@mitymous1]

Super helpful and very clear!

[@jlaw8882]

Thanks for this tutorial. I think I understood it all! 🍺

[@leemccomish1923]

Thanks for posting

[@marcpehkonen5296]

Very helpful and informative, thank you! Many years ago, I was poised to try pinhole photography. I bought a pinhole lens cap for my camera, a Nikon FM10, but then put it all away in a drawer. Fast forward ~20 years, and I'm ready to try for real this time! My problem - I didn't keep the literature that came with the pinhole, so I have no idea what its diameter is. Aside from putting it under a microscope (which I don't have) I'm not sure how to perform the very first calculation, F=f/d. I'm also not exactly sure what the flange distance of my FM10 is - the literature I've found doesn't call out that property specifically, unless there is another name for it! With so many unknowns, what would be your recommendation? Buy some film and start shooting a huge bracket of exposure times, or is there a way to narrow down my settings more efficiently? Thanks!

[@TheScienceofPhotography]

Glad you're getting into pinhole photography. Nikon has the advantage of using nearly the same lens mount for decades. The flange distance should be close to other 35mm cameras of the era which I believe is 46.5mm. If the pinhole was designed optimally it should be around 0.25mm wide which would give you an F-Stop of f/186. So if you are going to bracket I would start there and maybe use shutter times that were +/- 1 stops in half stop increments. So meter for the following: f/128, f/152, f/180, f/215, f/256. Most pinholes are designed in this range. An even better way is to borrow a Nikon digital camera. Most of the dSLRs should share the same lens mount as the FM10. Take a picture with a 50mm lens that is normally exposed. Then put on the pinhole and keep increasing the shutter time until you get something similar in exposure settings (you can look at the histogram). Let's say with the lens took a correct exposure at f/4 at 1/125sec and the pinhole got close to the same exposure with 30 seconds. Keep dividing 30 by 2 until you get to 1/125 (30, 15, 8, 4, 2, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125 is the shutter speed scale) that's 12 stops of difference. Then go 12 stops up from f/4 to get to the aperture of the pinhole (4, 5.6, 8, 11, 16, 22, 32, 45, 64, 90, 128, 180, 256). So in this example it would be a f/256 pinhole.

[@marcpehkonen5296]

@@TheScienceofPhotography wow, just wow! Thank you! The proxy Nikon dSLR is a very smart suggestion, as is the rest of your detailed advice. I will see what I can do. You can be sure I will check back in here to let you know how it goes. Many thanks once again!

[@joturchet]

Hi. First up, I am a pinhole newbie and I am absolutely terrible at maths - but I am determined to get my head around this science! Your video has been super helpful and I've watched it several times. I think my numerical brain fog might be clearing a little! Am I correct in thinking that with a f number of 160 and all my calculations taken at a f22 my T22 number will be 52.89, which I then multiply by my meter reading (at f22) ? To this I then 'xy' the reciprocity factor. I would be grateful of confirmation that this is correct or indeed welcome correction! Thank you in advance. Best wishes and stay safe!

[@TheScienceofPhotography]

Yes, 160/22 squared gives you 52.89 so if you meter the scene at f/22 and it gives you an exposure time of 1/2 seconds at the ISO of your film your new pinhole exposure time would be ~26.4 seconds. Then you apply the reciprocity factor for your film if you know it. If you have access to a smartphone there are a lot of great pinhole exposure apps that you can always use to double check your work. Best of luck and thanks for watching!

[@joturchet]

@@TheScienceofPhotography that's great - thank you so much 😊

[@abstractbybrian]

I have a 4x5 pinhole camera (CH Levy from B&H) and I’m photographing inside my house in natural light and I’m calculating exposures around 35-45 MINUTES! (With rf). I’ve gone over the math several times…seems way to long but…math don’t lie.

[@abstractbybrian]

I figured it out! When do you converts seconds to minutes? Say I calculate a 10 second exposure from my light meter at f16… My multiplication factor for my pinhole camera is 208.44 = 2084.4 seconds. If I take that squared to 1.31 (my films rf) that = 22,277.4 seconds Now divide that by 60 = 371 minutes. !!? But if take my 2084 seconds and convert that to minutes…I get 34.7 minutes Now adjust that for RF = 104 minutes…

[@keeszondervrees8787]

thank you!

[@PiratePhD]

How do I find the reciprocity factor for a certain film? I couldn't find it for Portra 400.

[@TheScienceofPhotography]

Google is your friend. Also it looks like Fausto has provided a link.

[@jlaw8882]

@@FaustoSaporito Thanks 💚

[@ramnanda4826]

how do you know that focal length of pin hole camera is 80mm ?

[@hiuyuc24]

What is the f number so that it can called a pinhole camera？

[@emiliovaldes907]

If I am using photographic papel . What is the ISO?, What is the reciprocity factor?. Thank you.

[@TheScienceofPhotography]

On one of my videos here: kzbin.info/www/bejne/b2qmiJiPopmMg5o I discuss this. Check around the 10:30 mark for the information. All photo papers are different so testing will be required, but generally between ISO 1.5 and ISO 3 is normal. I use ISO 2 in the video with good results. I usually do not account for reciprocity in paper. I hope that gives you a good starting point!

[@emiliovaldes907]

Thanks for replying, it was good to see the video

[@facundobravo4643]

@@emiliovaldes907 hola, pudiste averiguar cómo calcular el tiempo de exposición con papel?

[@diforbes]

How do you calculate focal length and f number if you're using a body cap pinhole? Thanks.

[@TheScienceofPhotography]

F Number is always focal length/pinhole diameter. If you are using a body cap you should look at the "flange distance" of your specific camera (use google or the camera's spec sheet). This is the distance from the film or sensor to the lens mounting ring. Then depending on where the pinhole is on the body cap you may need to add a few millimeters (use a caliper to measure). Hope that helps.

[@TheScienceofPhotography]

en.wikipedia.org/wiki/Flange_focal_distance here is a list of common cameras

[@JonEOGara]

First time I've lol'ed at one of your videos. 69... Nice.

[@TheScienceofPhotography]

I try to throw some humor in there every once and a while haha