Calibrating Your Photographic Light Meter
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- เผยแพร่เมื่อ 20 มิ.ย. 2024
- How to calibrate your photographic light meter so you get proper meter readings and consistent results while using a light meter. Calibrating your meter should be the first thing you do when you buy a new or used light meter for photography, for use in any film or digital format.
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Very practical. Thanks a lot!
Glad it was helpful!
Great stuff, Mr. Korol. Cogent, detailed, no distractions, and very easy to understand. Best photography 'splainer I have seen so far on You Tube. Hope to see more soon.
Thanks so much for watching! Glad you enjoyed.
You get an instant like for making me aware the meter needs to be calibrated! Waiting for a used meter to arrive tomorrow, I would never have known if it's out and assumed I'm using it wrong. Thanks!
Thanks for watching.
I wish it was easier to find a controlled light source for calibrating meters against (or that knowledge of doing this was actually known to the community). While Sunny-16 might be a good rule of thumb, the brightness of the sun isn't necessarily the same everywhere on Earth. Also, just because the meter gives the right reading in bright light doesn't necessarily mean it'll also give the correct reading under dim light.
I know some of the fancier Sekonic meters also let you use your computer to build a whole calibration profile, but the process for creating those is more geared towards matching your specific digital camera and not quite as easy to use with film.
Derek Konigsberg for sure, this is about checking your equipment out and getting it close for your system. It’s better than having your meter way out. I do know that if I left my Sekonic meter unchecked, it underexposes my photos.
Bingo! EXACTLY 👍😀
Hi! 🖐🏻 I guess that if you travel to another latitude, it just takes seconds to calibrate the light meter to the new location. Probably it is a good practice to do it when the season changes. So don't stick to your first calibration forever! 👍🏻
Very helpful. Thanks
Wonderful! Thank you for sharing this video.
You bet, thanks for watching.
Ohhhhh, this is so eye opening and educational. Thank you!
You are so welcome!
Love your tutorials! Very good instructional video. Thank you very much for the same 👍😎
I have the same Sekonic meter which I’ve owned for many years, and never knew about this. Thanks for sharing
Edward Crosby You bet!!
And learned something new again. Thnx.
Glad to help
Great video Todd
I did not know you could do this. I will be checking my meter on the next sunny day in New Zealand.
Thanks
Awesome, thanks for watching!
@@toddkorolphoto Tried it out, my 758 light meter was out by one third of a stop for the incident meter. The calibration doesn't move across to the spot meter so I had to do that separately. Using the same setting you suggested, I pointed my meter up to the clear blue skies. Is that what you would suggest? I was also taking meter reading of green grass in full sun light.
I bought a Minolta IVf light meter and was questioning the accuracy when I noticed my exposures were still too bright after setting up my flash. I just performed this test outside at ISO-500, SS-1/500 and the reading came out at f16. Now I feel more confident in the light meter. Thank you for this valuable tip.
Ok, I see a lot of banter telling this guy how wrong he is, but he isn't doing sensitometry tests here. He's just showing how to calibrate a light meter. For those who have a better way, go for it! Make a video, and post it out here. I'd like to see what you have to teach. Criticism is easy to offer, so please explain your method for us. There are so many variables in making a good negative. Has the film been properly stored while in your hands, and before? Is your light meter calibrated properly? (Meaning do you understand what it is going to do?) Do you have a base starting point based on your equipment, film/developer combo, development methods of time and temps, and on and on and on...? Everyone has to have a starting point, and until you settle on your own personal parameters for your meter, film/developer, each one of your lenses, and each one of your cameras, (because they all use either a shutter curtain, or copal shutter type of shutter) you're really just shooting into the dark. Oh, and use a sensitometer to measure your results, that has been calibrated too! Are we getting the message here folks? This guy has done a good service for people who haven't used a light meter much, Kudos to you Todd!
It still remains that his video gives wrong information about calibrating a light meter, which was the topic. The Sunny 16 (suggestion) has the shutter speed and ISO (ASA) being the same. This calibration method isn't anything new, it's been in use for many, many years.
Extremely interesting. I did not know this. Thanks
RS. Canada
Cool. Thanks
Very nice and this is very accurate calibration!!! have been using it for years now with great results! I have a question though...how about calibrating for the reflected spot metering? in my case i have the L-758DR, do i have to meter on a sunny day a grey card? perpendicular to the ground? or just a bit angeled to the sun?
yep! lay your 18% grey card on the grass and spot meter it in overhead sunlight and it should give you an F16.0 reading when the shutter speed it set for your film speed.
Thanks for that! I completely took my readings for granted. Could you provide info (or another video) on how to calibrate a spotmeter? (I have a Pentax V)
Andre Agnew Hmm good one, never thought of that. I’ll get back to you.
Todd Korol I read that I could simply point the spotmeter into the sky in similar weather conditions, and expect the same readings. However, I suspect calibration of the unit itself may be impossible.
I look forward to hearing your thoughts.
Maybe using a gray card?
In theory if you take a spot reading from a 18% reflectance grey card in full sun, it should be the same reading as when take an incident reading in the same conditions
For the Pentax spotmeters, you can send it off to Richard Ritter (lg4mat [dot] net) who provides a calibration service for those. I don't think its as simple as one adjustment, since there were like 3 different dials inside the meter he tweaked with I sent mine in. Just because its easy to check the high end of the range, doesn't mean the mid/low ends are behaving correctly.
Fantastic!! I’ve had my Sekonic® (L-508) for about 20 years and I never knew this! Thanks! 🙏😃
Do you have any videos on how to adjust the Sekonic for shooting with a cropped sensor?
Thanks. You don’t need to make any adjustments for a cropped sensor. It’s exactly the same.
@@toddkorolphoto
Oh. I did not know know that.
thank you.
one more question though:
I cannot get tacky sharp images no matter what I do;
• Tripod ✅
• Shutter speed greater than twice the focal length of the lens ✅
• Low ISO ✅
my images are “sharp” on my camera’s preview screen but not so much when I look at them thru my iPad or laptop.
is THIS because of the smaller sensor?
I’m using a Canon 80D and Sigma lenses.
Do I have a good excuse to tell my wife why I _NEED_ to upgrade to a full frame Canon body? 🤔😃
@@alitlweird No sounds like something is not working right for you. The sensor size has nothing to do with it. Take it to your local camera store they should be able to help you out.
@@toddkorolphoto 👍
Thanks.
I shade the dome or use the flat diffuser
Just a couple of observations, first 16.4 is not a half stop off. A half stop off would be somewhere around would be closer to 19. Secondly, strictly speaking, if you are using 400 speed film, sunny 16 would actually mean that you use f/16 @ 1/400th of a second, not 1/500th. What I'm trying to say is that the original reading of f16.4 was probably correctly calibrated. Otherwise, your instructions on how to calibrate the Sekonic light meter is greatly appreciated!
Actually, the Sekonic meter measures light on a scale of 1-10. So 16.4 is actually almost half a stop, ( 16.5 would be exactly 1/2 a stop) And yes, 1/400 @ F/16 would also be used for the sunny 16 rule, however, as this applied to older cameras and manual lenses for film, the closest shutter speed is usually 1/500. (And most shutter speeds I have seen tested are off on older lenses and are not exactly 1/500 or 1/400 of a second.) So it would be perhaps an 1/8 of a stop off. After shooting film my entire life, not sure you would be able to see a difference in negative film that is an 1/8 of a stop off either way. In the end these are to get you very close to the exposure as it is never an exact exposure but an approximate exposure. And regardless, it's also all about creating a system with your light meter and film and developing and then judging if it is working for you. If your images are consistently too dark or too light, then you need to adjust your system. But this hopefully gives people a very close starting point to then make adjustments for their system. Thanks for watching!
@@toddkorolphoto Thanks for your reply and I apologize for any confusion. The Sekonic meter I use (L-358) can be set to either half or third stops and the numbers appear on a regular f-stop scale (16.3=18, 16.7=20, etc). It also allows you to choose a third of a normal shutter speed, like 1/400th of a second which is what I would probbaly use to calibrate my light meter. It certainly wouldn't make much difference regarding what settings I would use on my camera but… I was late switching to digital but got back to film only recently. I appreciate your content. All the best!
Does the 'Sunny 16' calibration also calibrate the meter for using strobes?
After my meter is calibrated yes it works with strobes or in daylight.
It is a great idea to check if your light meter is in somewhere on the track. But I do not se the point in using ISO 400 and then check it with 1/500s? Why not follow the 16 rule by setting the meter to ISO 125 and look for the shutter speed to be 1/125s? The sunny 16 rule is very useful and I like it is used and pointed out from time to time on YT. That said, I like your videos very much Todd.
Thanks. The reality is with the latitude in black and white film it really is not going to make a difference. And, with old mechanical shutters, I would bet my lens does not even shoot at 1/500. Also I would bet if I showed you a photo shot at 1/500 and 1/400 you would not tell a difference. There are also factors of film developing that come into play.This was a real world test to see if the meter is usable and how close it was, and as you can see by the results, very close. But, you do make a good point and next time I will use 125 iso film if I do another one of these tests. Cheers!
@@toddkorolphoto So, if it doesn't make a difference, why calibrate. I disagree about having to calibrate a new meter. My new Sekonic L858 is perfect out of the box. All of my other meters have been too.
What about on a gloomy day, do you just stick to the sunny 16 rule? F11/f8?
Well you need to calibrate it on a full on sunny day. The use your meter for the gloomy days.
@@toddkorolphoto thank you so much!
Good to see you back! Since you carry a grey card I was expecting to see you using it. I still wonder how reliable the sunny 16 approach can be used. Sekonic manual does not show such method but they don’t actually advise anything in terms of a good light source to use for calibration.
Yes it is a problem, I just know at times their meters are out, right out of the box, that's why they have this feature as well. Also, now that I think of it, a guy should shoot a photo of a subject in the same light under full sun and see how they like the exposure, and then if they need to adjust further. with black and white. Although from using mine, I find after I adjust my meter using this Sunny 16 method, my exposures from the meter are right on the money now.
I disagree - sunny 16 rule is 1/box speed. so you just set your meter to a shutter speed of 1/500 instead of your box speed of 1/400 - So you are underexposing by 1/4 stop. If you had used box speed of 100 would you calibrate your meter to 1 /125? Most people tend to shoot black and white film at 1/2 box speed so calibrating the meter to under expose you are in effect offsetting the additional exposure you just added for your personal EI. That is why we do film testing. If you use EV as your guide that on a sunny day your EV should be 15 for f/16 and ISO 100 you will see your speed is a 1/4 stop under the box speed at 125. If you did the math for 1/100 @f16 your EV is closer to 14.6 So these rules of thumb have a lot of play in them as does your calibration .
Indeed, however this is to get people and their meters very close to the correct exposure. As I'm sure you know, two photographers with the same meter can have two different exposures just by how they hold the meter reading the light. Exposure is not exact, there are a lot of variables, but this just narrows the variables. The whole point is that meters right out of the box can be off by 1/2 stop and more sometimes. Photographers need to be aware of that and do their own testing for their own system. Thanks for the info, and for watching!
@@toddkorolphoto Hi Todd! should I do this at 500 or 400? I'm a bit confused now :/
@Eric Actually, an EV of 15 (about 80,000 lux) in "standard" bright sunlight is indeed 1/500 of a second at iso 400, f/16. Which is a third (not a quarter) of a stop difference from what the sunny 16 rule would imply. And the lux of the brightest sunlight on Earth can go up to roughly 110,000 lux at high altitude with the sun directly overhead, so that's another third of a stop even brighter than EV 15. The sunny 16 rule was adopted for film because of it's simplicity and because it works. It doesn't work as well for digital cameras - try it on a really bright sunny day and you'll find overexposure, washed out colours and blown highlights, by around a third to half a stop. So, technically the guy who created this video was right . To calibrate a meter on a bright sunny day with no haze and the sun high in the sky, EV is 15 which corresponds to a 1/3 stop less exposure than what the sunny 16 rule would dictate.
@@timwomble2483 500
I can't remember a time where I used a camera that needed a handheld light meter and also had 1/3 stop or 1/2 stop shutter speed adjustments available. They have all been full stops which is why 1/125 applies to 100iso film with sunny 16 and so on.
How do I do this in winter in a very dark and cold city?
Yes that's an issue for sure, perhaps if you have a friend who has an accurate meter calibrate it to his, or it will just require some film testing, if your negatives are constantly under or over exposed, then adjust your meter accordingly until you get the results you want.
My Minolta FM-V is calibrated fine for incident but appears to over read my Nikon SB-800 by 1 stop. I end up using the 2nd ISO button
One wonders if light intensity may vary from the sun depending on latitude and time of year with regard to metering calibration? I would say it seems to me one would best calibrate at Noon in Rochester NY in mid summer. I am sure the calibration is off in Wuhan since they have Chernobyled the planet.
If a meter comes from the factory out of calibration, it should be returned to the dealer. The problem that Todd has is that both of his meters are very old. The Minolta Autometer IV-F is 30 years old and the Sekonic L-503 is about 25 years old. It is very likely that both are out of calibration. Meters are calibrated with special calibrated light sources at a specific color temperature.
Using natural light to determine if a meter is good is not ideal. Meters vary in their sensitivity to different colors of light, depending on the type of metering cell it uses and the corrective filtration the manufacturer uses. The Silicon photodiode that almost all modern meters use is very sensitive to infrared and not very sensitive to blue; so corrective filters are used to make it respond more closely to the sensitivity of film and the human eye. Daylight, which varies in color depending on the weather, the geographic latitude you're located at, and the time of day; so it is possible for two perfectly calibrated meters to give different results in some types of light.
That said, Todd's method may be the only available way of doing it if you have an older meter. Minolta no longer makes meters and will not service them anymore. Gossen won't service most of their older models either. I think Sekonic will still service the L-508, though. There used to be a place called Quality Light Metric in Los Angeles that specialized in nothing but meter repair and calibration. They almost always installed a new meter cell as part of a calibration because the cells do age and change in sensitivity. Unfortunately, they closed a few years ago when the elderly owner decided to retire.
Really good info! Although I have seen meters come out of the factory and their readings were off. I should have explained it better as well.
If you calibrate using the sun, at least you have a starting point and then can evaluate your negatives afterwards and make any adjustments in b&w. This at least gives you consistent results.
Having said that, I have calibrated the meter using the sun, and I now get very constant results with colour and b&w.
Thanks for the input and for watching.
Some say it's: F16 100s ISO100 - not 1/125s. I think I'll compare with the metering of my favorite camera metering (Pentax K-1 or 645D).
Yes but older manual lenses don’t shoot at 1/100 of a sec.
Just rewatched this a year or so later again…. One thing strikes me, Todd. Your light meter shows a suggested f value of 16.5 and you say “that’s half a stop out”. If it was half a stop out, would it not have suggested an f value of f/19? (or in that ballpark?). The difference between f/16 and f/16.5 in stop terms is almost negligible, like a tenth of a stop.
Or does f/16.5 on your meter literally mean f/16 closed down half a stop? I don’t own a digital light meter so I am only asking out of curiosity!
Yes I look at the scale and see that it's in-between 16 and 22, so I call it 16 and 1/2. Old school ;-)
Wow, that was a quick response! Yeah, I see on another video of yours that it’s how your light meter expresses f stops. So it really was half a stop out. Hmm. Nothing wrong with old school! Happy 2024.
The "sunny 16" rule states to use the inverted ISO/ASA @ f16. So it seems to me that the shutter speed for your ISO 400 film should be 1/400 sec rather than 1/500. That would be more accurate, IMO, than setting your lens to 1/500 sec @ f16, which, in actuality, would be 1/3 stop under exposure. Now granted, your Zeiss lens does not have a 1/400 sec. But...in the spirit of being as accurate as possible, you could set your shutter on your Zeiss lens to 1/500 sec, and then move your aperture dial back from f16 about 1/3 the way down to f11. Back in the day, we simply called that "f11 & 2/3." On modern digital cameras that would f14 today.
Indeed you are correct, but it’s a little easier to learn the concept with round numbers, and it would be pretty hard to see that 1/3 of exposure unless it was slide film. I used to push and pull film 1/8 tho of a stop or 1/4 of a stop. And, most of these older manual lenses with the shutters built in are probably out a 1/3 of a stop either way. Usually slow, but I hope this helps people understand the exposure concept. Thanks for watching.
@@toddkorolphoto Thanks for your quick reply. I'm glad I found your channel, and just subscribed. FYI - I've been shooting with a Hasselblad since 1972, and hand meters just as long. Currently I've got a slightly newer Sekonic L-758 DR that I've been using for several years now, plus a much older Minolta Flash Meter IV (circa 1980's) just sitting in my cabinet. I am going to attempt to "calibrate" both of them according to your video, if the sun ever decides to come out!
And yes, you are also correct that the difference between 1/400 & 1/500 should be negligible. In fact, I remember back in the day when powers-to-be told us that the best the average human eye can detect is 1/3 stop. I presume that is why all modern digital cameras can now be adjusted in 1/3 stop increments.
I wonder if the time of year will have much of an impact on calibration? Right now the sun is very low in the sky at noon, whereas, in June, it should be much higher. I would imagine there might be somewhat of a difference in sunny 16 settings. But on the other hand, I wonder if it would be enough to make a difference.
Anyway, I'm going to calibrate as soon as we get a clear sunny day, but I'll do it again in late June, just to see!!
all of these people claiming the shutter speed should have been 1/400th obviously don't have much experience using "vintage" film cameras. These cameras aren't like your Nikon F5 there is no 1/3 or 1/2 shutter speed adjustment it's full stop increments only. the sunny 16 rule was never modeled around that much precision it's literally just a system of guesswork based on the conditions and the known characteristics of film sensitivity.
Yes exactly.
Hi, I just came across your channel and have been scrolling through some of your videos. Others may have pointed this out, I think your system is flawed in several places. Even if you were to take the “Sunny 16 rule” as accurate, the inverse of 400 is 1/400, not 500. The “sunny 16 rule” can only be truly accurate at certain locations and certain times of the day. Also “box speed” is not accurate either. Manufacturers will round up or down to fit a certain parameter that the consumer expects. At best this gives you a ball park figure to work with. Now, all of this is fine except for the fact that the whole purpose here was to show that you need to have your meter 100% accurate, when in fact there are so many other variables that a 1/3 or a 1/2 of a stop in your meter will make No difference at all. It’s a bit like trying to measure the speed of a car over a certain distance. You send your stop watch away to be calibrated to within 1/1000th of a second, and then measure the distance by pacing it out. Everything in the equation has to be accurate or none of it matters. I really enjoyed your video of your 8x10 portraits at the rodeo 👍🏻
Well, exactly. Nothing is absolute. Almost all large format lenses and cameras do not shoot an accurate 1/500th of a second. Everything is going to be out, perhaps higher or lower. And, if your developer is 1 degree warmer than normal then that will be out too. But, the whole point is to get your system CLOSE and reputable so when you are out in the field you can expect consistent results. I always say, test everything and your system then make adjustments. But, this at least gives you a starting point to be close and consistent. So many photographers don't have a starting point at all. Also, this method has worked really well for me that I use it in my day to day work as a professional photographer. Lastly, thank you for watching! ;-)
It's a good start but wont get accurate results. Your spectral illuminance will drastically alter your exposure based on the spectral curve of your film stock, let alone the spectrum your light meter is being calibrated for. In short, if you do this in the middle of the day versus just before sunset, you'll get very different results. Yes, calibrate, then make a compensation for time of day, film stock, aperture tolerances and shutter speed tolerances...i.e. the zone system done correctly.
Well you are looking for the ultimate system and exposure. This gets you close so you will have consistent results. There are a ton of variables in photography. It’s just the first step to getting a consistent system.
@@toddkorolphoto it's not even close. Take FP4+ and tell me if you get correct exposure within 1/3 stop at Sunny 16? No chance as almost everyone shooting it knows it's not really ISO 125. Just like Ilford Delta 3200 is 1600 or slower. If you use that to determine zone IV shadow values, you miss the mark by 1+N stops.
@@PhilTaylorPhotog don’t know what to tell you. My negatives look great and print up really well.
So you are saying that the sunny sixteen rule is more accurate than a new light meter? So why buy a light meter.
Well how do you meter when there is no sun? When it’s early in the morning or backlit or in the shade…
You should not point direc at the sun rather at the horizon.
You actually need full light on the dome part of the meter.
Sunny 16 rule is definitely not the way to calibrate a light meter
The idea of re-calibrating my Minolta meters to conform to the Sunny-16 Rule makes my skin crawl. The intensity of the sun on a "sunny day" varies widely by latitude, atmospherics, and a host of other variables. What is important is, if you are using multiple meters, including those built into cameras, that they are calibrated as much as possible to give matching readouts under identical circumstances. For absolute exposure values, your careful film tests and/or accumulated experience will let you set a base line, probably based on film box speed or some standard deviation from that value. I didn't quite catch the last part of the presentation, but I hope he's not further spreading that nonsense about always exposing film at half box speed.
Exactly, you need to do a bunch of testing to establish your box film speed especially in b&w. But, by setting a standard base for your meters for the Sunny 16 rule you now have a baseline, and provided you use your meter correctly, you will be much closer to a proper exposure. As I stated in the video, I have seen meters come out of the factory at plus or minus 2/3 rd's of a stop out of whack. This simply gets your meter much closer to a proper exposure. Then after you shoot a couple of rolls of film you can judge how well your meter is working with the new settings. Just by doing this simple adjustment, my meter is way closer to the correct exposure for all kinds of film. For those setting their meter at half box speed, that is an aesthetic decision, not necessarily a right or wrong one. That decision is based on the final "look" you want to achieve, not what's right or wrong in another photographers eye.
@@toddkorolphoto I disagree regarding the "half speed school".. Those who set half box speed all of the time are lightening shadows which may not need it. They are certainly blowing out highlights, assuming they started with any. They are in effect killing a their dynamic range by a stop. If they want the over-bright positive image they get from halving box speed as a matter of artistic creatively, there is nothing stopping them from shooting a properly exposed negative, then making those adjustments in digital processing, or even darkroom printing. The difference is that if you throw away your film's potential at exposure,its gone for good and you have no option. Let's cut the crap here. This half box speed idea was started with the premise that the tolerance to overexposure of color negative film would provide a safety valve against accidental under-exposure, not as a creative control. At best it trades a bit of image quality for not having to learn how to use a light meter properly.
Buy a lux meter if you haven't already. They are dirt cheap and accurate to within about a twentieth of a stop (4% accuracy quoted on mine - I think that's about a twetieth of a stop!). Bright sun = 80000 lux = EV 15 = 1/500s @ iso 400 @ f/16. You're right though, the sun does subtly dim and brighten even on a sunny day, not to mention due to other variables. All good fun.
@@randallstewart175 surely you know that if you pull a film then you adjust for that in development right? We are obviously talking about black and white film here not slide film. This technique actually produces cleaner highlights than if you exposed at box speed. if you shoot a 400 speed film at 200 then you pull development by a minute or two and you get a negative with much more dynamic range and highlights that are not blown out.
@@Raevenswood I do know, and you are wrong. First, most folks today who shoot at "box speed" do not pull process their film, so they are just risking blowing out their brightest highlights. For those who do pull process to compensate for over-exposure, they are compressing one stop range of highlights, thereby loosing highlight tonal separation. In effect, they a crunching their highlights together and loosing highlight detail, assuming that such was there to loose. The usual argument for shooting at half box speed is that it raises the density of shadow details and preserves them against errors in exposure. Again, if there are important shadow details, and concern over exposure measurement, that is perfectly reasonable, but that is very often not an issue, and to do so all of the time thinking that it makes no difference is just the thought of someone too lazy to learn how to use his meter. Unhappily, that seems to include a large percentage of the guys who espouse half speed shooting if judged by the images they post. In summary, push or pull processing, done with matching exposure compensation, is a valid and useful device, but it is not going to take best advantage of what a film has to offer unless used in those appropriate, and limited, lighting situations. The error in your thinking is that you do not create more dynamic range in the film response by pull processing. You may be able to cram a wider range of tones down into the range a film can actually respond to, but you do so by seriously distorting your highlight tonal separation. That is practically impossible to repair in a darkroom print. Digitally, you can't restore what its not there to begin with..
This is EXACTLY how NOT to do a calibration of a light meter!
This is an eyeball Mk.1 😂😂😂
Hmmmm Strange, all my negatives are properly exposed.