Another very informative video. Such a great weekly rendez vous that Large format Friday. Fits perfectly for I just received my first LF. Your channel is a gold mine for me. Thanks for that man
Thanks for all the good info! I was aware of bellows extension factor so on my first close up shot I calculated that and then added reciprocity failure into the mix. That turned a normal exposure reading of 2 seconds into 26 seconds. I took the shot but was doubtful it would turn out. Not only did it turn out but it’s been one of my favorite shots so far! You just have to trust those who have gone before you :)
Hi Mat. I have just discovered your channel and I am really excited to see so much information about large format, since I have just made the leap to this size and I assure you that I will be one of your best followers. Thanks for the channel and greetings from Spain.
BTW: I’d call my method the diaphragm-diameter-extension approach. If you keep the opening of the diaphragm that at 150mm focal length equals f/11 when extending the bellows to 300mm, it then equals a mere f/22. Which means you need to double the diameter of the opening to make it an 11 at twice the focal length. I know the principle is the same as the inverse square law, just looked at from a different angle.
yes, matt, and Gossen had an adaptor for their lunasix 3 which had a straw at the end, like the sinar one, just put the straw into the exposure area, and the meter got its light.
Hi, I use the Reciprocity Timer App on my iPhone. It has a section where you can set Bellows Extension, in addition to all the other settings like film stock, lens, f-stop and shutter speed that are set in separate sections. I see no reason to use any other method, since my phone is always with me and it takes seconds to do the calc.
Just looked. Seems great but wish bellows etc was not just in f stops. Maybe I'll look at the quickdisc ruler to work back. But I love the calculator with seconds and minutes.
Great question!! It sure does and is part of the reason why when using an enlarger for contact printing or enlarging the height of the enlarger is so critical.
Thank you for this video! Am I correct to say we have to apply BEF when the bellow length is more than the focal length? Or it is something we have to factor in no matter the bellow length.
This is really only a concern when the bellows are extended 30% or more beyond their infinity focal legnth. Be sure to check your lens' data sheet to see what the "flange to focal distance" is to calculate accurately.
Quick Disk all the way, gotten solid results from it! The worst part about it is when you switch bags and forget it in the other one. Gotta print out another 2 or 3.
Film plane light measuring is key when the bellows (because of the angle of view, the different distances in the subject, etc.) has different extensions (what distance would you measure to do the math?). The probe will give YOU the right measure of light on the film plane!
Another great video, Mat! Question - aren't there phone apps that can be used to do this as well? I haven't needed it as of yet but as I take LF more seriously, I have been expected to come across this problem and anticipated having a phone app to assist me. Not that I don't enjoy math... haha
With how simple the calculation is, every phone made in the last 20 years has a calculator, that should be plenty. I'm not a big app user myself, but there's over a dozen I've seen that will get the job done, many in the realm of pinhole and film reciprocity timers.
Hello Matt, I have a question for you. I know there are several apps for smart phone for bellows extension calculator. I was wondering you experience with any of these bellow extension apps. and Second if I have F/stop compensation for exposure by using and bellows extension app, it is easy to convert the f/stop correction to a shutter speed change, equal to the f/stop correction factor. Thanks for the great advice, I enjoy watching your videos.
Hey Mark thanks for the question. I don't play with a lot of apps for film photography related tasks, but I'd wager their math is pretty solid. Guess I'm a bit old-fashioned carrying around a cloth tape and tiny note cards with reciprocity failure tables!
I'm still working through the Season 1 playlist, so apologies if this has been addressed in the later videos, but could you also make a video on Reciprocity Failure? Considering the small apertures that large format photographers are working with, I'm guessing multi-second exposures are not unusual and the way film behaves under these conditions can also create unexpected problems for novices like myself. :) As a owner of a Sinar F1 kit, I would love to see more videos that explore the Sinar ecosystem. For example, I'm still not quite clear if I can "upgrade" the F1 setup to support 8x10, and if so, what parts would need to be replaced?
I can't do math but I'm wondering if anyone has made a DIY job of the latter film plane meters? Like the large format back would allow a normal lightmeter to be put inside, you'd just need a remote way to trigger or even sacrifice a meter, put the receptor inside and the wired body outside to take a reading?
Hello! How do you calculate the factor for a tele lens? I'm getting the fujinon EBC T 400mm f8 and was wondering do I use the working focal length of 400mm to calculate or 250mm which will be the bellow extension at infinity .
Hey Mat, I have an interesting digital rig that can illustrate the bellows extension factor. Medium format camera with bellows and a digital back. Can shoot some footage and samples images with and without the addition of exposure stops if you are interested in plugging it into your channel.
How would I use this with a flash? I did the calculation for factor but I’m not sure what to do with it. I have a 360mm f10 lens I have set to f45 I have 1800mm of extension. My factor is 25. I have 2 300 watt seconds strobes. I also used an add on lens DCR-250. I know it’s a lot 😂 but I went ahead and hit my subject with two rounds of the strobes basically giving it 1200ws 600x2 worth of light. I believe I’m about two-three stops underexposed. How would I have found that out without guessing/testing?
Hey thanks for the question and the math homework! My first recommendation would be way more flash power or some faster film, since you've got 5 stops of bellows extension factor to account for. When metering your lights, you're looking for stops down from f/45 so ~ f/180!
Dumb question from a LF beginner here - in your example, didn’t you simply double the focal length, thus doubling your f-number? Because you’re taking a 2D image, this means 4x less reflected/radiating light entering the lens. Since the f-number tells you the actual aperture diameter (D=f/N, or N=f/D), if you double the focal length with the same aperture setting, you end up with double the f-number (even if the lens says the same number). Don’t see how the explanation of light intensity in the video is applicable here, since you simply removed 3/4 of the light by removing 3/4 of your original subject when you doubled your focal length. I don’t think the light intensity reacted to the change in a camera setting? Or am I missing something?
Thanks very much for continuing this series, Mat. I only recently forgot to compensate for bellows extension when playing around to make this one: instagram.com/p/B_XIWx6HOzC/?igshid=1mda5ngkxwj71 (hope this link will work...). Luckily I realized right after I took the photo, plus I was using Ilford HP5+. So I could easily push-develop the film by 2 stops, using Rodinal at 1:50. Actually I quite liked the result, although usually I try not to forget about these things.
Hey Norbert thanks for the comment and sharing your results. In working with a low contrast scene, sometimes bellows extension factor can work in our favor!
I’m using a different kind of measurement disc. Similar to the QuickDisc and also free to print, but a bit more versatile: www.southbristolviews.com/pics/Graphic/CloseUpCalc.html
Another very informative video. Such a great weekly rendez vous that Large format Friday. Fits perfectly for I just received my first LF. Your channel is a gold mine for me. Thanks for that man
Thanks for the kind words Florian. Happy LF shooting!
Thanks for all the good info! I was aware of bellows extension factor so on my first close up shot I calculated that and then added reciprocity failure into the mix. That turned a normal exposure reading of 2 seconds into 26 seconds. I took the shot but was doubtful it would turn out. Not only did it turn out but it’s been one of my favorite shots so far! You just have to trust those who have gone before you :)
Reciprocity can be a bear in longer exposures. As a lover of IR film, I know that pain well!
Hi Mat. I have just discovered your channel and I am really excited to see so much information about large format, since I have just made the leap to this size and I assure you that I will be one of your best followers. Thanks for the channel and greetings from Spain.
Thanks Alfredo and I hope you enjoy your adventures with large format photography!
BTW: I’d call my method the diaphragm-diameter-extension approach. If you keep the opening of the diaphragm that at 150mm focal length equals f/11 when extending the bellows to 300mm, it then equals a mere f/22. Which means you need to double the diameter of the opening to make it an 11 at twice the focal length. I know the principle is the same as the inverse square law, just looked at from a different angle.
Heya Mat! Loving this your new video series! This is a real Masterclass on large format 🙌
Hey Arnaldo, thanks man I appreciate it!
yes, matt, and Gossen had an adaptor for their lunasix 3 which had a straw at the end, like the sinar one, just put the straw into the exposure area, and the meter got its light.
Hi, I use the Reciprocity Timer App on my iPhone. It has a section where you can set Bellows Extension, in addition to all the other settings like film stock, lens, f-stop and shutter speed that are set in separate sections. I see no reason to use any other method, since my phone is always with me and it takes seconds to do the calc.
Thanks for the info!
I use a tape measure and the Art of Foto app, and love it.
Just looked. Seems great but wish bellows etc was not just in f stops. Maybe I'll look at the quickdisc ruler to work back. But I love the calculator with seconds and minutes.
Hi Mat - thanks for this video.
Flubbed more than enough shots before learning this was a thing!
No worries Bill, even after learning about it I've been burned plenty of times with bellows factor!
Thank you, very informative
Thanks Craig!
Does this apply during the enlarging process too?
Great question!! It sure does and is part of the reason why when using an enlarger for contact printing or enlarging the height of the enlarger is so critical.
@@MatMarrash Thanks for replying to a comment on a video you made a year ago! I ordered my first enlarger after being inspired by your videos. 💚
Thank you for this video! Am I correct to say we have to apply BEF when the bellow length is more than the focal length? Or it is something we have to factor in no matter the bellow length.
This is really only a concern when the bellows are extended 30% or more beyond their infinity focal legnth. Be sure to check your lens' data sheet to see what the "flange to focal distance" is to calculate accurately.
Thanks.
Quick Disk all the way, gotten solid results from it! The worst part about it is when you switch bags and forget it in the other one. Gotta print out another 2 or 3.
Thanks Andrew! I've definitely had to reprint a few myself, now they're hiding in all parts of my large format kit.
Film plane light measuring is key when the bellows (because of the angle of view, the different distances in the subject, etc.) has different extensions (what distance would you measure to do the math?). The probe will give YOU the right measure of light on the film plane!
Another great video, Mat! Question - aren't there phone apps that can be used to do this as well? I haven't needed it as of yet but as I take LF more seriously, I have been expected to come across this problem and anticipated having a phone app to assist me. Not that I don't enjoy math... haha
Reciprocity Timer app will calculate for most films. It calculates both bellow factor and reciprocity factor if needed.
With how simple the calculation is, every phone made in the last 20 years has a calculator, that should be plenty. I'm not a big app user myself, but there's over a dozen I've seen that will get the job done, many in the realm of pinhole and film reciprocity timers.
Hello Matt, I have a question for you. I know there are several apps for smart phone for bellows extension calculator. I was wondering you experience with any of these bellow extension apps. and Second if I have F/stop compensation for exposure by using and bellows extension app, it is easy to convert the f/stop correction to a shutter speed change, equal to the f/stop correction factor. Thanks for the great advice, I enjoy watching your videos.
Hey Mark thanks for the question. I don't play with a lot of apps for film photography related tasks, but I'd wager their math is pretty solid. Guess I'm a bit old-fashioned carrying around a cloth tape and tiny note cards with reciprocity failure tables!
I'm still working through the Season 1 playlist, so apologies if this has been addressed in the later videos, but could you also make a video on Reciprocity Failure? Considering the small apertures that large format photographers are working with, I'm guessing multi-second exposures are not unusual and the way film behaves under these conditions can also create unexpected problems for novices like myself. :)
As a owner of a Sinar F1 kit, I would love to see more videos that explore the Sinar ecosystem. For example, I'm still not quite clear if I can "upgrade" the F1 setup to support 8x10, and if so, what parts would need to be replaced?
I can't do math but I'm wondering if anyone has made a DIY job of the latter film plane meters? Like the large format back would allow a normal lightmeter to be put inside, you'd just need a remote way to trigger or even sacrifice a meter, put the receptor inside and the wired body outside to take a reading?
Hello!
How do you calculate the factor for a tele lens?
I'm getting the fujinon EBC T 400mm f8 and was wondering do I use the working focal length of 400mm to calculate or 250mm which will be the bellow extension at infinity .
Hi and thanks for the question! I believe you'll need to calculate based on the infinity extension, in your case 250mm.
Hey Mat, I have an interesting digital rig that can illustrate the bellows extension factor. Medium format camera with bellows and a digital back. Can shoot some footage and samples images with and without the addition of exposure stops if you are interested in plugging it into your channel.
How would I use this with a flash? I did the calculation for factor but I’m not sure what to do with it.
I have a 360mm f10 lens I have set to f45 I have 1800mm of extension. My factor is 25. I have 2 300 watt seconds strobes. I also used an add on lens DCR-250.
I know it’s a lot 😂 but I went ahead and hit my subject with two rounds of the strobes basically giving it 1200ws 600x2 worth of light. I believe I’m about two-three stops underexposed. How would I have found that out without guessing/testing?
Hey thanks for the question and the math homework! My first recommendation would be way more flash power or some faster film, since you've got 5 stops of bellows extension factor to account for. When metering your lights, you're looking for stops down from f/45 so ~ f/180!
Dumb question from a LF beginner here - in your example, didn’t you simply double the focal length, thus doubling your f-number? Because you’re taking a 2D image, this means 4x less reflected/radiating light entering the lens. Since the f-number tells you the actual aperture diameter (D=f/N, or N=f/D), if you double the focal length with the same aperture setting, you end up with double the f-number (even if the lens says the same number). Don’t see how the explanation of light intensity in the video is applicable here, since you simply removed 3/4 of the light by removing 3/4 of your original subject when you doubled your focal length. I don’t think the light intensity reacted to the change in a camera setting? Or am I missing something?
Thanks very much for continuing this series, Mat. I only recently forgot to compensate for bellows extension when playing around to make this one: instagram.com/p/B_XIWx6HOzC/?igshid=1mda5ngkxwj71 (hope this link will work...). Luckily I realized right after I took the photo, plus I was using Ilford HP5+. So I could easily push-develop the film by 2 stops, using Rodinal at 1:50. Actually I quite liked the result, although usually I try not to forget about these things.
Hey Norbert thanks for the comment and sharing your results. In working with a low contrast scene, sometimes bellows extension factor can work in our favor!
I’m using a different kind of measurement disc. Similar to the QuickDisc and also free to print,
but a bit more versatile: www.southbristolviews.com/pics/Graphic/CloseUpCalc.html
Cool, thanks for sharing!
I am shooting 4x5 and learning darkroom again. Oh and Subscribed :)
Thanks Terry, happy shooting!
Cool video. Came across this from listening to fpp
Thanks for stopping by, each and every Friday there's going to be a new topic we discuss!
How can a Film photographer wear that shirt, have you never heard of the Van Allen Radiation Belt? Time to wise up.
You're right, the shirt Hasselblad made was way off brand for a film photography channel.
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