This was super helpful! I'm a total beginner, haven't even bought any equipment yet and want to understand the basics so I can know what I'm buying. I'll be checking out your other videos.
I wish i had found this channel years ago. Very helpful! Esp. darkroom tips, I'm a college student so anything that saves money and space is greatly appreciated.
Glad you talked about reciprocity failure and/or correction. I have found out that for most films your actual exposure times will follow that simple rule ( based on tables in Kokak data books that you can cross-check for yourself) For 1s and shorter, no correction is needed. For 1s and longer, you just have to square the metered time in seconds. So, 1s would remain one sec, two would become four, four would call for sixteen and so on and so forth. This will work for times in seconds only, Le's go crazy and say that the metered time was 2 minutes. The answer wouldn't be 4 minutes but 120s squared, thus 14,400 sec or 4 hours ( just to say, since I've never experimented with such an extreme)
Good explanation! I would add to include on the label which f/number was used in the calculation, such as "4.56@f/128", just as a reminder when reading the light meter. Thanks, subscribed.
Very useful approach to exposure extrapolation. Those Luna Pro meters are accurate, use little energy, and are super durable. I tend to use incident readings when possible and reflected readings to confirm (or not) my incident reading. When there is disagreement I must think a moment and see what the best exposure would be. Unfortunately scenes with a lot of sky are generally short of sufficient when taken with reflected meter technique but the solution is to just meter the scene from the horizon to the foreground (tip the meter down). You have to be pretty accurate when making paper positives and transparencies! I have enjoyed your photo and typewriter posts. Hope your channel really takes off!
Thank you for explaining focus ratio. I finally understood why aperture values are sometimes referred to in this fomat, like F/2.8. Cool calculator btw.
Using my Chamonix 45 n-2 with a pinhole and this system made this way easier and works great. Can easaly choose between 45mm or 80-305mm focal length and has a little setup with 1mm, 0,5mm and 0,25mm pinhole. Thanks for sharing and keep snapping!
Joe! Many thanks for this video it has given me the best results ever although I am really new to pinhole camera exposure has been a real heartache. I can now use my homemade Pinhole camera with confidence. Thanks again. Regards Ken
I put your calculations into a spreadsheet. The spreadsheet is called: "The Joe Van Cleave Method". Not saying you invented it, just a handy way for me to know which spreadsheet to search for.
Nice video, Joe. I was making a table of pinhole correction factors when I found a source of error in the calculation you show. The method works fine for the odd-numbered f/stops (assuming f/stop 1 is f-number 0), but a subtle error creeps in for the even numbered stops. The conventional numbers used for the even f/stops (like f/2.8, f/5.6 etc.) are NOT the precise numbers used internally by a light meter. If the displayed f-number on the light meter is used, and the f/stop happens to be an even number, the calculation of the factor will be incorrect. What should be done is to determine the f-number (0 for f/1.0, 1, for f/1.4, 2 for f/2.0 etc.), raise the square root of 2 to the f-number and use the resulting precise f/stop as the denominator in your equation. Since the pinhole aperture calculation yield a precise value, a precise value (used internally by the meter) should be used here too. So, to figure the true f/stop for "f/11", you take the f-number for "f/11" (7) and raise the square root of 2 to the f-number. The result is 11.3137085, which should be used in the denominator of your equation. For a pinhole with a calculated aperture of, say, 300, the time correction factor would be the square of 300/11.3137085 = 703.12. If the conventional "11" value were used, the result would be an incorrect factor of the square of 300/11 = 743.80. Again, this only affects the even-numbered whole stops. This gets even more confusing if your meter displays decimal f/stops, like my Minolta IVf. These are fractions of f-number to the next f/stop, not an added decimal value to be added to the displayed f/stop. So a displayed value of "11.0 6" on my Minolta means f/11 plus 6/10 of a whole stop to the next f/stop value (f/16). Since "f/11" is f-number 7, an additional 6/10 of a stop would be f-number 7.6. If you raise the square root of 2 to the power of 7.6, you will get the precise actual f/stop used internally by the meter, which is f/13.92880901. Obviously an Excel-generated table of time correction factors is the way to go!
Another "gotcha" is that some of the long exposure times displayed by a light meter, are not the times used internally! If you use one of these times as a reference, the exposure might be way off. Exposure times follow the power of 2 sequence 1, 2, 4, 8, 16, 32, 64, 128.... A light meter usually shows correct times for 1, 2, 4, and 8 seconds. However, most will display "30" seconds when it is actually using 32 seconds internally. The same for a displayed "60" seconds. The meter actually used 64 seconds. This is normally not an issue with a meter or camera, as the software knows how to do the right thing and use the real values. If the odd "conventional" displayed values for some of the times are used in the calculations, the pinhole exposure can be significantly off.
Excellent description! Thank you so much! I just making a pinhole camera and that was EXACTLY what I was searching for! If you don't mind, I'll send you a link to the pix here on youtube so you see my results (with your calculation method and tips) THANKS ONCE MORE!!!!!!!
Great video, I've referred to this numerous times. Can I ask what one should do if they are working with a hybrid. I have a lens which I've attached to a box- which has numerous aperture options. Would the principle still be the same? Focal length (210) divided by 8 for example ? I'd appreciate any advice.
This is a great idea but how do you put the meter readings into a calculator? For example what would 1/125th, 1/15th, 1/4 or 2seconds look like in the calculator. Do you convert into a fraction? Thanks again for explaining.
The typical pinhole exposure is more than 1 second. But in principle you’d express it as a decimal fraction. I.e. 1/125 = .008. But in practice I’ve never seen a pinhole exposure that short.
@@Joe_VanCleave No of course. I threw in those examples as I take meter readings at f.22 which does give me 1/60th or 1/15th especially on faster films in good light. I then convert to whatever my pinhole f.stop is and then add reciprocity. I don't like doing field calculations. I prefer to prepare crib sheets to consult and your method lends itself well to that idea. Anyhow thank you again.
Hi Joe, I loved your videos. Any tips to getting better quality in camara obscura , I see shadows low quality pictures only. ( room camara obscura) here. Thanks for help.
Bigger diameter, faster lens, collects more light. Regular glass lenses of such sizes are expensive, but you may want to consider a fresnel lens. I may do a video about this.
Hi Joe. Great video. Is there a chart or some information on how to discover necessary adjustments for reciprocity failure when using 35mm film in a pinhole camera?
There are a number or resources on the Internet for determining reciprocity correction for long exposures. Here's one: mkaz.com/film-reciprocity-tables/
Hi Joe, thank You for this interesting video. Very informative and fun to watch. Surely a great way to set the exposure time using a normal lightmeter. I will surely try Your method. Please keep up the good work and have some very nice X- mas holiday - days ! All the best, Klaus
Did my first Test shoot with a van cleave inspired pinhole today and i am super happy with the First results on Paper negative.. quick question: can you also calculate a iso compensation factor like you did with the Aperture? I would like to Meter with the Spot Meter of my dslr and ist only goes down to iso 100. is it also (100/12)^2 * (320/22)^2* shutterspeed = exposuer time? If i rate my paper at iso 12 and my dslr is metering at f22,iso100
Film speed determines the recommended F-stops and exposure times, for a given scene brightness. This formula corrects for the difference between the F-ratio your meter uses and your pinhole camera's F-ratio. So, no, changing your film speed won't effect his formula directly, for a camera with a fixed aperture size. However, your meter will recommend a different F-ratio/Shutter speed combination for a different film speed. For a fixed-focal ratio camera (like a pinhole camera) the F-ratio stays the same, and you therefore have to change the exposure time for a different film speed.
@@Joe_VanCleave the other issue I'm having is reciprocity. I put it into the formula, spreadsheet but the results dont seem right. Not sure if im setting up the formula correctly for that. And thanks for responding so quickly!
Just seeing this video and interested in trying pinhole photography using my digital camera and a body cap pinhole. Do you have any info on calculating exposures? Thanks! Great video, BTW.
For using a digital camera just set it to Aperture priority, bump up the ISO a bit and see what it gives you, then adjust the ISO to get a usable shutter speed (if handheld in bright light), or a tripod in dimmer light.
The method used to measure ISO for film doesn't apply exactly for paper, but what I do is assume a starting ISO, take a meter reading and make an exposure, then develop the paper and evaluate the results; then I adjust my assumed ISO and repeat the process until I get good results. I do this for summer and winter daylight, and indoors under incandescent and LED lighting. One problem is light meters are reading a panchromatic spectrum of colors, whereas paper is sensitive to UV, blue and some green, depending on the paper. So I find it necessary to change my paper ISO depending on the light and time of year; in winter there's less UV in the sky, so I adjust my reducing my ISO value to compensate.
Hi Joe!, very interesting video, a first for me to see someone work out the exposure for a pinhole camera. I hope to do it onto 120 Film so I am assuming the meter will already have worked out the ISO for me as I set that before taking a reading. I have a Mamiya RB67 and hopefully make it into a pinhole camera with the body cap. Regards Ken
Ha! The meter had been used for film just before recording the video. The Exposure Index (EI) of paper is determined iteratively through testing. Assuming a starting value. Meter the scene using that value. Expose the scene as per the meter's recommendation using the assumed EI value. Develop the paper, then evaluate results. Based on the results, adjust the EI up or down accordingly and retest. I find winter and summer daylight have dramatically different amounts of UV light, which affects paper more than a panchromatic light meter might indicate. So in winter I find myself dropping the exposure index, while in summer I raise it. Also, it helps to understand your scene's reflectivity to blue and UV light. Shiny metal and water easily reflect blue light and will over-expose, while red and earth tones reflect a spectrum of light that photo paper is relatively insensitive to. So there's often a bit of last minute adjustment to the meter's recommendation.
I,i'm not a pinhole photographer ,i know that 300 and 128 are f/stop numbers as 8;11;22 etc can i calculate the exposure doing 300*2/128 thinking that numbers are prortionally like in the normal photograph ?Thanks
Hei Joe first of all thanks a lot for this video and all your tutorials which I find extremely useful! I just have one question I wish you could answer to: when measuring light how do you set the ISO value on the exposure meter? Maybe I have got something wrong from the whole explanation, but so far I have understand that you normally use photographic paper as "negative" when shooting, and if i'm not wrong the photographic paper speed is usually around 3 or 5 ISO but on your exposure meter the set value is 400 ISO (minute 4:00). Did I miss something or am I making a fuss of it? Thanks a lot in advance!
I'd been using the meter for regular sheet film, hence why it was still set to ISO 400. You are correct about photo paper as a negative, I'll set the meter much lower. The Arista brand of resin coated grade 2 paper that I commonly use for negatives I rate at ISO12. Thanks for watching.
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@@Joe_VanCleave Hi! Me again, trying not to give up w/ pinhole photo. So, my lightmeter can be setted at iso 3 at lowest. So using your formula, it's ok to set up my lightmeter at 3 (the same as my paper negative)? Best, Alvaro.
@ Hola Alvaro, soy de Argentina, tambien experimentando con Fotografia Estenopeica. ¿Pudiste resolver lo del tiempo de exposicion? De ser asi ¿podrias explicarme?
so you could make the distance between pinhole and photopaper to be meters apart camera in a tube and make photos that are extremely zoomed like a telescope? i can imagine the exposure time would really skyrocket
Greetings from Chile! I'm returning to the pinhole journey, with failed, and no so much, attemps. This time, I'm trying to study the process the best I can. So, how'd you found out the formula for calculate exposure? It's in a book that I can read? Best, Álvaro.
Just ran across this and thought "man! this is great!" Have a couple of questions. 1) Would the math be different or change if I used a spot meter like a Pentax V? 2) the math for sheet/roll film would like something like: "(Pinhole F Number/Light Meter F number)^squared * Light Meter exposure * Film Reciprocity = X" ? Thanks again. I'll be making a label on my 6x9 pinhole this evening.
@@Joe_VanCleave Joe - I had this hare brained idea about putting a pinhole on a Linhof 4x5 lens board for pinhole at different focal lengths. So I did some math and wondered if you could check the math for me? I want an f/stop of f255 at each focal length. I divided the focal length by f255. So the formula: Focal Length/ f stop = pinhole diameter. 90/255 = .353 150/255 = .588 300/255 = 1.18 So the pinhole diameter would have to .353mm at 90mm, .588 at 150mm, and 1.18mm at 300m. Does the math make sense? Thanks again.
@@BillPutnamPhoto Correct! Except … each focal length has an ideal optimal sized pinhole (for maximum sharpness) that doesn’t scale linearly. However, you may not notice the difference that much, and I do like your idea of keeping the focal ratio constant, that should make metering and exposure times more consistent. Go for it!
You camera is F-42? Is that the focal ratio (focal length divided by aperture size) or merely the focal length itself? The exposure time depends on the illumination of the scene you'll be photographing. Which is why having some kind of meter is handy. Absent a dedicated light meter, you can also use a digital camera's internal meter to get a reading. Or a light meter app on a smart phone. Alternatively, in bright summer sun you can go without a light meter and use what's called the "Sunny 16 Rule," which meters in those conditions (bright summer daylight) your exposure will be f/16 and your exposure time will be the inverse of your ISO. Like for ISO 100, it's f/16 at 1/100 s. You can then extrapolate for other aperture values or exposure times. Using the Sunny 16 rule you can also extrapolate for cloudy skies by using an aperture of F/11 instead of F/16. Same with winter daylight, which is less bright than summer. For pinhole photography (which is the context of this video), using "guess" exposures without metering often requires some testing and gaining experience. Which is why I recommend using some kind of systematic metering, for better results. Good luck and stay in touch.
I just watched someone on another video put a paper negative into a pinhole camera and then take it out and NOT develop it, rather he scanned the paper negative in color at like 600 dpi then inverted the image in software. I thought you had to develop it first...then scan it...
That's called a lumen print. With enough exposure, the silver halides will turn colors - autodevelop - a faint negative image. The image is still light sensitive, can't be fixed, and if developed will turn completely black.
@@Joe_VanCleave That's cool. He said he made a pinhole camera and placed it in a location for 6 months?? a 6 month exposure. I would have thought the paper would just turn black.
The only helpful video on TH-cam for Pinhole Exposures!
Thanks for making these videos - please accept my warmly extended, digital handshake of appreciation.
This was super helpful! I'm a total beginner, haven't even bought any equipment yet and want to understand the basics so I can know what I'm buying. I'll be checking out your other videos.
Thank you ever so much for this tutorial.
Straight forward and well presented for the amateur pinhole photographer...
I wish i had found this channel years ago. Very helpful! Esp. darkroom tips, I'm a college student so anything that saves money and space is greatly appreciated.
Glad you talked about reciprocity failure and/or correction. I have found out that for most films your actual exposure times will follow that simple rule ( based on tables in Kokak data books that you can cross-check for yourself) For 1s and shorter, no correction is needed. For 1s and longer, you just have to square the metered time in seconds. So, 1s would remain one sec, two would become four, four would call for sixteen and so on and so forth. This will work for times in seconds only, Le's go crazy and say that the metered time was 2 minutes. The answer wouldn't be 4 minutes but 120s squared, thus 14,400 sec or 4 hours ( just to say, since I've never experimented with such an extreme)
So glad to have found this information. It's probably saved me a huge amount of wasted time and paper etc. Big thanks.
Good explanation! I would add to include on the label which f/number was used in the calculation, such as "4.56@f/128", just as a reminder when reading the light meter. Thanks, subscribed.
Very useful approach to exposure extrapolation. Those Luna Pro meters are accurate, use little energy, and are super durable. I tend to use incident readings when possible and reflected readings to confirm (or not) my incident reading. When there is disagreement I must think a moment and see what the best exposure would be. Unfortunately scenes with a lot of sky are generally short of sufficient when taken with reflected meter technique but the solution is to just meter the scene from the horizon to the foreground (tip the meter down). You have to be pretty accurate when making paper positives and transparencies! I have enjoyed your photo and typewriter posts. Hope your channel really takes off!
Don't forget for film to raise the time to the power of 1.3 for reciprocity failure. Raisong to power of 1.3 covers most films.
Thank you for explaining focus ratio. I finally understood why aperture values are sometimes referred to in this fomat, like F/2.8. Cool calculator btw.
Using my Chamonix 45 n-2 with a pinhole and this system made this way easier and works great.
Can easaly choose between 45mm or 80-305mm focal length and has a little setup with 1mm, 0,5mm and 0,25mm pinhole.
Thanks for sharing and keep snapping!
The best Pinhole-Video for Pinhole. Thanks from Hamburg!
Joe! Many thanks for this video it has given me the best results ever although I am really new to pinhole camera exposure has been a real heartache. I can now use my homemade Pinhole camera with confidence. Thanks again. Regards Ken
Thanks, Ken. Post us a link to any photos you get, I'd like to see them.
Love this video! Thank you! 📷
Joe, thank you for sharing your knowledge. Your channel is a great resource.
I put your calculations into a spreadsheet. The spreadsheet is called: "The Joe Van Cleave Method". Not saying you invented it, just a handy way for me to know which spreadsheet to search for.
:)
Nice video, Joe. I was making a table of pinhole correction factors when I found a source of error in the calculation you show. The method works fine for the odd-numbered f/stops (assuming f/stop 1 is f-number 0), but a subtle error creeps in for the even numbered stops. The conventional numbers used for the even f/stops (like f/2.8, f/5.6 etc.) are NOT the precise numbers used internally by a light meter. If the displayed f-number on the light meter is used, and the f/stop happens to be an even number, the calculation of the factor will be incorrect. What should be done is to determine the f-number (0 for f/1.0, 1, for f/1.4, 2 for f/2.0 etc.), raise the square root of 2 to the f-number and use the resulting precise f/stop as the denominator in your equation. Since the pinhole aperture calculation yield a precise value, a precise value (used internally by the meter) should be used here too.
So, to figure the true f/stop for "f/11", you take the f-number for "f/11" (7) and raise the square root of 2 to the f-number. The result is 11.3137085, which should be used in the denominator of your equation. For a pinhole with a calculated aperture of, say, 300, the time correction factor would be the square of 300/11.3137085 = 703.12. If the conventional "11" value were used, the result would be an incorrect factor of the square of 300/11 = 743.80. Again, this only affects the even-numbered whole stops.
This gets even more confusing if your meter displays decimal f/stops, like my Minolta IVf. These are fractions of f-number to the next f/stop, not an added decimal value to be added to the displayed f/stop. So a displayed value of "11.0 6" on my Minolta means f/11 plus 6/10 of a whole stop to the next f/stop value (f/16). Since "f/11" is f-number 7, an additional 6/10 of a stop would be f-number 7.6. If you raise the square root of 2 to the power of 7.6, you will get the precise actual f/stop used internally by the meter, which is f/13.92880901. Obviously an Excel-generated table of time correction factors is the way to go!
Thank you for the detailed correction, it will prove invaluable for those desiring accurate exposures.
Another "gotcha" is that some of the long exposure times displayed by a light meter, are not the times used internally! If you use one of these times as a reference, the exposure might be way off. Exposure times follow the power of 2 sequence 1, 2, 4, 8, 16, 32, 64, 128.... A light meter usually shows correct times for 1, 2, 4, and 8 seconds. However, most will display "30" seconds when it is actually using 32 seconds internally. The same for a displayed "60" seconds. The meter actually used 64 seconds. This is normally not an issue with a meter or camera, as the software knows how to do the right thing and use the real values. If the odd "conventional" displayed values for some of the times are used in the calculations, the pinhole exposure can be significantly off.
Thank you sir
Excellent description! Thank you so much! I just making a pinhole camera and that was EXACTLY what I was searching for! If you don't mind, I'll send you a link to the pix here on youtube so you see my results (with your calculation method and tips) THANKS ONCE MORE!!!!!!!
Eres super didáctico. Muchas gracias.
Great video, I've referred to this numerous times. Can I ask what one should do if they are working with a hybrid. I have a lens which I've attached to a box- which has numerous aperture options. Would the principle still be the same? Focal length (210) divided by 8 for example ? I'd appreciate any advice.
Yes, it works the same.
This is a great idea but how do you put the meter readings into a calculator? For example what would 1/125th, 1/15th, 1/4 or 2seconds look like in the calculator. Do you convert into a fraction? Thanks again for explaining.
The typical pinhole exposure is more than 1 second. But in principle you’d express it as a decimal fraction. I.e. 1/125 = .008. But in practice I’ve never seen a pinhole exposure that short.
@@Joe_VanCleave No of course. I threw in those examples as I take meter readings at f.22 which does give me 1/60th or 1/15th especially on faster films in good light. I then convert to whatever my pinhole f.stop is and then add reciprocity. I don't like doing field calculations. I prefer to prepare crib sheets to consult and your method lends itself well to that idea. Anyhow thank you again.
Thank you for your great info. Well done.
Still valuable in 2020. Thanks.
Hi Joe, I loved your videos. Any tips to getting better quality in camara obscura , I see shadows low quality pictures only. ( room camara obscura) here. Thanks for help.
Bigger diameter, faster lens, collects more light. Regular glass lenses of such sizes are expensive, but you may want to consider a fresnel lens. I may do a video about this.
Hi Joe. Great video. Is there a chart or some information on how to discover necessary adjustments for reciprocity failure when using 35mm film in a pinhole camera?
There are a number or resources on the Internet for determining reciprocity correction for long exposures. Here's one: mkaz.com/film-reciprocity-tables/
That's fantastic. Thank you.
Hi Joe,
thank You for this interesting video. Very informative and fun to watch. Surely a great way to set the exposure time using a normal lightmeter. I will surely try Your method. Please keep up the good work and have some very nice X- mas holiday - days !
All the best, Klaus
So nice!! But I guess the ISO sensibility of the photographic paper will also have influence. What paper do you use for that normaly?
I use grade 2 RC paper from Freestyle Photo here in the US, Arista brand.
@@Joe_VanCleave thanks Hero!
Great video Sir. Thanks you!!!
Nice video
I have the same lightmetar but I cant find the battery.Please tell me wich battery you use???Thanks for answer
Mine uses a standard 9V battery.
Did my first Test shoot with a van cleave inspired pinhole today and i am super happy with the First results on Paper negative.. quick question: can you also calculate a iso compensation factor like you did with the Aperture? I would like to Meter with the Spot Meter of my dslr and ist only goes down to iso 100. is it also (100/12)^2 * (320/22)^2* shutterspeed = exposuer time? If i rate my paper at iso 12 and my dslr is metering at f22,iso100
Yes, I believe you are correct.
Thank you for doing this. My question is, if you should happen to rate your film at a different speed, will this effect the formula? Thanks!
Film speed determines the recommended F-stops and exposure times, for a given scene brightness. This formula corrects for the difference between the F-ratio your meter uses and your pinhole camera's F-ratio. So, no, changing your film speed won't effect his formula directly, for a camera with a fixed aperture size.
However, your meter will recommend a different F-ratio/Shutter speed combination for a different film speed. For a fixed-focal ratio camera (like a pinhole camera) the F-ratio stays the same, and you therefore have to change the exposure time for a different film speed.
@@Joe_VanCleave the other issue I'm having is reciprocity. I put it into the formula, spreadsheet but the results dont seem right. Not sure if im setting up the formula correctly for that. And thanks for responding so quickly!
Just seeing this video and interested in trying pinhole photography using my digital camera and a body cap pinhole. Do you have any info on calculating exposures? Thanks! Great video, BTW.
For using a digital camera just set it to Aperture priority, bump up the ISO a bit and see what it gives you, then adjust the ISO to get a usable shutter speed (if handheld in bright light), or a tripod in dimmer light.
Can these pinhole cameras go live streaming on the internet
what about ISO on photopapers? can i anywhere find that, that i would be able to measure at some static ISO?
The method used to measure ISO for film doesn't apply exactly for paper, but what I do is assume a starting ISO, take a meter reading and make an exposure, then develop the paper and evaluate the results; then I adjust my assumed ISO and repeat the process until I get good results. I do this for summer and winter daylight, and indoors under incandescent and LED lighting.
One problem is light meters are reading a panchromatic spectrum of colors, whereas paper is sensitive to UV, blue and some green, depending on the paper. So I find it necessary to change my paper ISO depending on the light and time of year; in winter there's less UV in the sky, so I adjust my reducing my ISO value to compensate.
Fantastic very informative! Excellent 👍👍👍
Sorry but I may have missed it, what is the ISO of the paper ? Thanks
Hi Joe!, very interesting video, a first for me to see someone work out the exposure for a pinhole camera. I hope to do it onto 120 Film so I am assuming the meter will already have worked out the ISO for me as I set that before taking a reading. I have a Mamiya RB67 and hopefully make it into a pinhole camera with the body cap. Regards Ken
The Gossen Luna Pro F light meter takes a standard 9v battery.
Thanks Joe
RR pinhole camera…F=150, d=0.52, so focal ratio = 288
Yes!
Hi! I have a doubt. Why the meter is set to ISO 400? and how do you determine the iso(?) of the paper. I have an ilford mgIV RC pearl
Ha! The meter had been used for film just before recording the video.
The Exposure Index (EI) of paper is determined iteratively through testing. Assuming a starting value. Meter the scene using that value. Expose the scene as per the meter's recommendation using the assumed EI value. Develop the paper, then evaluate results. Based on the results, adjust the EI up or down accordingly and retest.
I find winter and summer daylight have dramatically different amounts of UV light, which affects paper more than a panchromatic light meter might indicate. So in winter I find myself dropping the exposure index, while in summer I raise it.
Also, it helps to understand your scene's reflectivity to blue and UV light. Shiny metal and water easily reflect blue light and will over-expose, while red and earth tones reflect a spectrum of light that photo paper is relatively insensitive to. So there's often a bit of last minute adjustment to the meter's recommendation.
Oh! And I thought it would be easier! First of all let me thank you for your videos. They are great! I would start experimenting then...:)
My meter meters to 160. Should i use that number vice the 128
Yes, substitute the 160 in the formula, it should work the same.
I,i'm not a pinhole photographer ,i know that 300 and 128 are f/stop numbers as 8;11;22 etc can i calculate the exposure doing 300*2/128 thinking that numbers are prortionally like in the normal photograph ?Thanks
For an f/300 pinhole, if you meter for f/128, multiply the time in seconds by (300/128)^2.
Hei Joe first of all thanks a lot for this video and all your tutorials which I find extremely useful! I just have one question I wish you could answer to: when measuring light how do you set the ISO value on the exposure meter? Maybe I have got something wrong from the whole explanation, but so far I have understand that you normally use photographic paper as "negative" when shooting, and if i'm not wrong the photographic paper speed is usually around 3 or 5 ISO but on your exposure meter the set value is 400 ISO (minute 4:00). Did I miss something or am I making a fuss of it? Thanks a lot in advance!
I'd been using the meter for regular sheet film, hence why it was still set to ISO 400. You are correct about photo paper as a negative, I'll set the meter much lower. The Arista brand of resin coated grade 2 paper that I commonly use for negatives I rate at ISO12. Thanks for watching.
@@Joe_VanCleave Hi! Me again, trying not to give up w/ pinhole photo. So, my lightmeter can be setted at iso 3 at lowest. So using your formula, it's ok to set up my lightmeter at 3 (the same as my paper negative)? Best, Alvaro.
@ Hola Alvaro, soy de Argentina, tambien experimentando con Fotografia Estenopeica. ¿Pudiste resolver lo del tiempo de exposicion? De ser asi ¿podrias explicarme?
so you could make the distance between pinhole and photopaper to be meters apart camera in a tube and make photos that are extremely zoomed like a telescope? i can imagine the exposure time would really skyrocket
I once made a pinhole telescope for shooting a solar eclipse, made from a long shipping tube.
I use drill bits, insert the tightest one then use a machine's caliper to find it's diameter.
Hi Joe, Thanks a lot. its very informative video.
Super awesome video!! Cheers!
Thanks for the tips 👍
Greetings from Chile! I'm returning to the pinhole journey, with failed, and no so much, attemps. This time, I'm trying to study the process the best I can. So, how'd you found out the formula for calculate exposure? It's in a book that I can read? Best, Álvaro.
I’m not sure where I found it, maybe someone posted it years ago on apug .org
I’m not sure where I found it, maybe someone posted it years ago on apug .org
I’m not sure where I found it, maybe someone posted it years ago on apug .org
I’m not sure where I found it, maybe someone posted it years ago on apug .org
I’m not sure where I found it, maybe someone posted it years ago on apug .org
Just ran across this and thought "man! this is great!"
Have a couple of questions.
1) Would the math be different or change if I used a spot meter like a Pentax V?
2) the math for sheet/roll film would like something like: "(Pinhole F Number/Light Meter F number)^squared * Light Meter exposure * Film Reciprocity = X" ?
Thanks again. I'll be making a label on my 6x9 pinhole this evening.
1) The math should be the same with a spot meter, provided you’re metering the spot you want to be at middle gray.
2) Correct!
@@Joe_VanCleave Thanks! I've been metering color neg and b/w for Zone 7, and color slides for Zone 3, with that Pentax V. Appreciate it!
@@Joe_VanCleave Joe - I had this hare brained idea about putting a pinhole on a Linhof 4x5 lens board for pinhole at different focal lengths. So I did some math and wondered if you could check the math for me?
I want an f/stop of f255 at each focal length. I divided the focal length by f255.
So the formula:
Focal Length/ f stop = pinhole diameter.
90/255 = .353
150/255 = .588
300/255 = 1.18
So the pinhole diameter would have to .353mm at 90mm, .588 at 150mm, and 1.18mm at 300m.
Does the math make sense?
Thanks again.
@@BillPutnamPhoto Correct! Except … each focal length has an ideal optimal sized pinhole (for maximum sharpness) that doesn’t scale linearly. However, you may not notice the difference that much, and I do like your idea of keeping the focal ratio constant, that should make metering and exposure times more consistent. Go for it!
@@Joe_VanCleave thanks!!!
You have to make the exposure times much more longer then calculated, due the "Schwarzschildeffect"
Paper negatives are much less affected by this.
Interesting video.
my camera is F=42.What is my exposure time.I don't have that meter thing.pls reply
You camera is F-42? Is that the focal ratio (focal length divided by aperture size) or merely the focal length itself?
The exposure time depends on the illumination of the scene you'll be photographing. Which is why having some kind of meter is handy. Absent a dedicated light meter, you can also use a digital camera's internal meter to get a reading. Or a light meter app on a smart phone.
Alternatively, in bright summer sun you can go without a light meter and use what's called the "Sunny 16 Rule," which meters in those conditions (bright summer daylight) your exposure will be f/16 and your exposure time will be the inverse of your ISO. Like for ISO 100, it's f/16 at 1/100 s. You can then extrapolate for other aperture values or exposure times.
Using the Sunny 16 rule you can also extrapolate for cloudy skies by using an aperture of F/11 instead of F/16. Same with winter daylight, which is less bright than summer.
For pinhole photography (which is the context of this video), using "guess" exposures without metering often requires some testing and gaining experience. Which is why I recommend using some kind of systematic metering, for better results. Good luck and stay in touch.
thank you
I loved it ...
Thanks!!!!
Peace sign of chromatic aberration of white light perforated pinhole 3D Dispersion
I just watched someone on another video put a paper negative into a pinhole camera and then take it out and NOT develop it, rather he scanned the paper negative in color at like 600 dpi then inverted the image in software. I thought you had to develop it first...then scan it...
That's called a lumen print. With enough exposure, the silver halides will turn colors - autodevelop - a faint negative image. The image is still light sensitive, can't be fixed, and if developed will turn completely black.
@@Joe_VanCleave That's cool. He said he made a pinhole camera and placed it in a location for 6 months?? a 6 month exposure. I would have thought the paper would just turn black.
You Tube ad's very annoying, three in this 9 minute video..!
YOu paid $5 for that calculator?
I hate to be that guy, but there’s apps for this and calculators online. I hate math though
Some places I photograph are not within range of a cell tower, especially here in the wide open spaces of the American west.
@@Joe_VanCleave a very good explanation. Thanks
...or use an app on your phone, like Pinhole for Android. :-)
when you go into the back country wilderness where there is no cell phone reception, I guess you'll have to wing it!
f/128 isn't the largest aperture, it's the smallest WTF
and focal ratio?! This ain't astronomy boy.