Re: 18% Gray (again) - summer reading
The Picture of Dorian 13% Gray Light Used to be Better in August Shoot the Piano Player with the Best Portrait Lens sorry, I'm procrastinating again. annsan - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again) - summer reading
On Mon, 16 Jul 2001, Ann Sanfedele wrote: The Picture of Dorian 13% Gray Light Used to be Better in August Shoot the Piano Player with the Best Portrait Lens Heart of Maximum Black Close Encounters of Zone III Memoirs of a Super-Multi-Coated Man procrastinating, chris - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
aimcompute wrote: A thought: Why can't camera and film manufacturer's just consistently tell the truth? Because we can't handle the truth. --Mike - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
Interesting. I too have found that foliage, trees, mountains, which are all typical of an Ansel Adams photograph, are very close to 18%. On the other hand, typical caucasian skin is at about zone VI or 13%. And since most cameras are used to take snapshots of the rug rats, a meter calibrated to that value serves the average point and shooter quite well. Paul Tom Rittenhouse wrote: Gee whizz, wowie! Well I must be old then because I do remember why 18% was chosen. Go out and meter a field of foliage and compare that to your gray card reading. Average reflectance of scenes is 18% If you meter that as 13% reflectance you will over expose it. It is simple the average scene reflects 18% of the light that hits it. It is not an arbitrary value. It is a fact of the real world out there. As for Ansel Adams 12.5% would give zone VI, so 13% would fit the zone system exactly. However, photography goes back 160 years, according to you guys no one knew what they were doing for the first 159 of them. You quote Shutterbug to me as proof that I and every one else have been doing it wrong for all those years. As for checking my meters, the four of them are with in 1/3 stop of each other, and the incident meter matches the reflected reading from a gray card. BTW, why does an incident light dome for a meter transmit 18% of the light? I have heard that meters, especially built in meters, are calibrated with a 4 stop neutral density filter from a calibrated standard bulb. That explains why they would say their meter is calibrated to 13$, but that does not change the average reflectance of the real world. What that means is that the meter is off by a certain percentage for all exposures made with it even when you use an accurate metering technique. I had thought that the film manufactures were being optimistic about their film speeds but the fact that adjusting the film speed that same percentage gives excellent exposures tends to indicate the meters are in fact off by that much. --Tom - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
Most cameras?? Not mine. --- PAUL STENQUIST [EMAIL PROTECTED] wrote: Interesting. I too have found that foliage, trees, mountains, which are all typical of an Ansel Adams photograph, are very close to 18%. On the other hand, typical caucasian skin is at about zone VI or 13%. And since most cameras are used to take snapshots of the rug rats, a meter calibrated to that value serves the average point and shooter quite well. Paul __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
I am the one who argues that this 13% thing is bull. Take your incident meter and meter a gray card in reflected mode. Then take an incident mode reading. The readings will be the same. If the meter was calibrated for 13% gray the readings would be different because that dome is definitely 18% transmitance. No, Herbert Klepper had an article in Modern Photography back sometime in the seventies is seems like that had the 13% bs in it and every one who pretends to be and expert has continue that erroneous bs since. If I hadn't wanted to build a meter checker for myself and found out about the 8x ND filter used to bring the reference bulb down to the proper level to place the meter cell in the center of its I might have gone for it. In fact I almost did this time before I actually read Bob Shell's sidebar about this and remembered. As for the regrets Paul mentions, Caucasian skin is one stop brighter than 18% e.g. 36% not the other way around. I find it interesting that all the exposure fanatics over all the years before someone found out that all the exposure meters in the world were off by a half a stop never noticed that. Not even back in the days when film barely had the exposure latitude to cover a half stop error. Of course you guys can believe what you want, but you are still comparing apples to oranges as I said in my Ah ha post. Believe me, with modern film you won't notice a half stop error. --Tom [EMAIL PROTECTED] wrote: Let me see if I understand. Cameras are calibrated for 13 percent. 13 percent is darker than 18 percent. So, if you meter from a 18 percent graycard, the meter will try to make it darker, then you increase the exposure by a third or half stop. I'm doing it right? Somebody knows if ALL cameras and ALL incident meters are calibrated for 13 percent? All Asahi cameras or just modern ones? All meters? Gossen? Albano, a bit confused - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re[2]: 18% Gray (again)
Hi, this assumes that most camera users are white, which is a highly dubious assumption given that most people are not white. It would be commercial suicide to base meter calibration on any particular skin colour. If it's true that white skin is about 13% then I'd suggest it's probably coincidence. I've just metered by own skin - typically N. European with a slight suntan - and compared it against an 18% grey card. No appreciable difference. --- Bob mailto:[EMAIL PROTECTED] Friday, July 13, 2001, 11:02:57 AM, you wrote: Interesting. I too have found that foliage, trees, mountains, which are all typical of an Ansel Adams photograph, are very close to 18%. On the other hand, typical caucasian skin is at about zone VI or 13%. And since most cameras are used to take snapshots of the rug rats, a meter calibrated to that value serves the average point and shooter quite well. Paul - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Re[2]: 18% Gray (again)
On Fri, 13 Jul 2001, Mark Roberts wrote: Chris Brogden [EMAIL PROTECTED] wrote: On Fri, 13 Jul 2001, Bob Walkden wrote: I've just metered by own skin - typically N. European with a slight suntan - and compared it against an 18% grey card. No appreciable difference. And thus was Bob henceforth known as The Grey Man. I guess he just has Grey's Anatomy *L* Not to question his grey matter, but I wonder if he was using a genuine card or a grey market one. chris - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
RE: Re[2]: 18% Gray (again)
Chris Brogden brough forth: On Fri, 13 Jul 2001, Bob Walkden wrote: I've just metered by own skin - typically N. European with a slight suntan - and compared it against an 18% grey card. No appreciable difference. And thus was Bob henceforth known as The Grey Man. Soylent Grey is Bob! -- John Francis . . . . . . . . . . (650) 429-4427 MyWay.com 444 Castro St. Suite 101,Mt. View, CA 94041 Hello. My name is Darth Vader. I am your Father. Prepare to die. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re[4]: 18% Gray (again)
Hi, that's ok - I'm colourblind anyway. --- Bob mailto:[EMAIL PROTECTED] Friday, July 13, 2001, 8:22:29 PM, you wrote: On Fri, 13 Jul 2001, Bob Walkden wrote: I've just metered by own skin - typically N. European with a slight suntan - and compared it against an 18% grey card. No appreciable difference. And thus was Bob henceforth known as The Grey Man. chris - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
Tom R. exploded: I am the one who argues that this 13% thing is bull. Tom, Actually it's not. The ANSI standard is around 12% and a lot of manufacturers use 13%. Of course, as with film speed, the manufacturers do what they want to do, so many of them do calibrate to 18%. I wouldn't be surprised if some of them have enough tolerance built into their calibrations that they VARY from 12% to 18%! g Just because you get two meters to agree with each other doesn't mean all other meters are like those two. Try comparing a Nikon and a Contax meter, for instance. As I said before, Ctein has tested this and reported his findings in his book. His original source was Dick Dickerson, who is just a wee tad more authoritative than Bob Shell--Dick oversaw the development of the T-Max films, Polymax papers and chemicals, the Kodak chromogenic film, and Xtol, among other things. You want me to ask Dick about it? Or Ctein? I will if you want. The thing is, I really think that since Ctein went to all the trouble to write it all down in his book, the least we can do is give him the courtesy of going to read about it there, instead of asking him to rewrite it again in an individualized e-mail. But I'll ask him if you'd like me to. His book is called _Post Exposure_, Focal Press (www.bh.com), ISBN 0-240-80299-3. The whole book is well worth having. --Mike P.S. Mark Roberts, No, I don't know the title of the relevant ANSI document, but perhaps I can find out. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
Well, Mike, even if the meters are setup for a 13% gray, and I still doubt that because as I have said my Sekonic 308 gives the same reading with light reflected for an 18% gray card as it does in incident mode, all you have to do is reduce your ASA by that amount and use 18% because all that is affected by that is where the calculator scale is set relative to the meter reading . The meter calibration is actually done as I have describe here several times. BTW is the difference between 13% and 18% 1/3 stop or is it 1/2 stop? (I don't have a scientific calculator any more). --Tom Mike Johnston wrote: Tom R. exploded: I am the one who argues that this 13% thing is bull. Tom, Actually it's not. The ANSI standard is around 12% and a lot of manufacturers use 13%. Of course, as with film speed, the manufacturers do what they want to do, so many of them do calibrate to 18%. I wouldn't be surprised if some of them have enough tolerance built into their calibrations that they VARY from 12% to 18%! g Just because you get two meters to agree with each other doesn't mean all other meters are like those two. Try comparing a Nikon and a Contax meter, for instance. As I said before, Ctein has tested this and reported his findings in his book. His original source was Dick Dickerson, who is just a wee tad more authoritative than Bob Shell--Dick oversaw the development of the T-Max films, Polymax papers and chemicals, the Kodak chromogenic film, and Xtol, among other things. You want me to ask Dick about it? Or Ctein? I will if you want. The thing is, I really think that since Ctein went to all the trouble to write it all down in his book, the least we can do is give him the courtesy of going to read about it there, instead of asking him to rewrite it again in an individualized e-mail. But I'll ask him if you'd like me to. His book is called _Post Exposure_, Focal Press (www.bh.com), ISBN 0-240-80299-3. The whole book is well worth having. --Mike P.S. Mark Roberts, No, I don't know the title of the relevant ANSI document, but perhaps I can find out. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
18% Gray (again)
A couple of weeks ago there was some discussion here about how the camera manufactures are calibrating their meter to 13% rather than 18%. Someone commented that Kodak is now suggesting that you open up a 1/3 to 1/2 when using a gray card to set exposure. WHAT 18% gray was chosen because the real world approximates that. If you average the exposure for all outdoor scenes it comes out to 18% reflectivity. So if the meters are calibrated to 13% you will always get the wrong exposure. I do believe that maybe the meters really are calibrated to 13% that would explain why I get the best exposure when down rating the exposure index of the film 1/3 to 1/2 stop. That would compensate for the difference and give correctly exposed film. An interesting aside is get the proper response from my film scanner when I use ASA 320 instead of 400, or 80 instead of 100, with the films I use. Which further leads me to suspect that the meters in my cameras are off about 1/3 stop. Does anyone have anything info to contradict the above? BTW, 12.5% would indicate that he manufactures are using ND filters to calibrate their meters from a reference standard light source. --Tom - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
RE: 18% Gray (again)
Repeated study under controlled conditions has demonstrated that the correct average reflactance is 13%. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Tom Rittenhouse Sent: July 12, 2001 17:26 To: Pentax Discussion Malling List Subject: 18% Gray (again) A couple of weeks ago there was some discussion here about how the camera manufactures are calibrating their meter to 13% rather than 18%. Someone commented that Kodak is now suggesting that you open up a 1/3 to 1/2 when using a gray card to set exposure. WHAT 18% gray was chosen because the real world approximates that. If you average the exposure for all outdoor scenes it comes out to 18% reflectivity. So if the meters are calibrated to 13% you will always get the wrong exposure. I do believe that maybe the meters really are calibrated to 13% that would explain why I get the best exposure when down rating the exposure index of the film 1/3 to 1/2 stop. That would compensate for the difference and give correctly exposed film. An interesting aside is get the proper response from my film scanner when I use ASA 320 instead of 400, or 80 instead of 100, with the films I use. Which further leads me to suspect that the meters in my cameras are off about 1/3 stop. Does anyone have anything info to contradict the above? BTW, 12.5% would indicate that he manufactures are using ND filters to calibrate their meters from a reference standard light source. --Tom - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
Tom Rittenhouse wrote: A couple of weeks ago there was some discussion here about how the camera manufactures are calibrating their meter to 13% rather than 18%. Someone commented that Kodak is now suggesting that you open up a 1/3 to 1/2 when using a gray card to set exposure. WHAT 18% gray was chosen because the real world approximates that. If you average the exposure for all outdoor scenes it comes out to 18% reflectivity. So if the meters are calibrated to 13% you will always get the wrong exposure. Well, Tom, considering that Kodak practically invented film, and is the largest manufacturer of film in the world, and also markets grey cards, one might give a little credence to Kodak's assertion. Of course, since most people only use the meter in their camera, they have no idea what they're metering. Most people don't even know the pattern of their camera's meter. Go out and get a Kodak grey card. Put it in a scene and meter from it, and only it. Follow Kodak's instructions. Bracket your exposures in 1/3 stop increments, and, upon processing the film, see what the correct exposure is. You may be surprised at the results. Oh, one other thing - be sure your meter's properly calibrated. -- Shel Belinkoff mailto:[EMAIL PROTECTED] It matters little how much equipment we use; it matters much that we be masters of all we do use. - Sam Abell - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: 18% Gray (again)
This is discussed in the latest issue of Shutterbug. There is no international standard but there *is* an ANSI standard. And it's 13%. The writer in Shutterbug contacted Kodak to ask why there gray cards are 18%even though the ANSI standard (to which cameras and handheld light meters are calibrated) is 13%. It turns out that it's been going on so long that no one at Kodak remembers! (Or has been with the company that long.) The people at Kodak speculated that, because Ansel Adams lobbied hard for 18% when the standard was originally being decided upon, Kodak used 18% to please Ansel... Even though ANSI eventually settled on 13%. Tom Rittenhouse [EMAIL PROTECTED] wrote: A couple of weeks ago there was some discussion here about how the camera manufactures are calibrating their meter to 13% rather than 18%. Someone commented that Kodak is now suggesting that you open up a 1/3 to 1/2 when using a gray card to set exposure. WHAT 18% gray was chosen because the real world approximates that. If you average the exposure for all outdoor scenes it comes out to 18% reflectivity. So if the meters are calibrated to 13% you will always get the wrong exposure. I do believe that maybe the meters really are calibrated to 13% that would explain why I get the best exposure when down rating the exposure index of the film 1/3 to 1/2 stop. That would compensate for the difference and give correctly exposed film. An interesting aside is get the proper response from my film scanner when I use ASA 320 instead of 400, or 80 instead of 100, with the films I use. Which further leads me to suspect that the meters in my cameras are off about 1/3 stop. Does anyone have anything info to contradict the above? BTW, 12.5% would indicate that he manufactures are using ND filters to calibrate their meters from a reference standard light source. --Tom - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
RE: 18% Gray (again)
Tom, your explanation differs with what I have read in many places. For example, Burian and Caputo, in the National Geographic Photography Field Guide (p. 137), write: Scientific studies now indicate that an average scene actually reflects 13% (not 18%) of the light that falls on it. For the sake of consistency, grey cards have continued to be 18 percent grey, as is the one in this book. When using any 18% grey card for substitute metering, increase exposure by a half stop. Your explanation of the way meters are calibrated makes good intuitive sense, and, as you say, it's not relevant. However, in your example, a scene of foliage reflects approximately the same amount of light as an 18% grey card. This fact can only be used to deduce that the foliage reflects 18% of the light that falls upon it, not that foliage is an average scene. As I have understood things, the 13% standard simply indicates that they (bless their hearts, whoever they are) have decided that the average scene, whatever that is, actually reflects 13% of the light that falls upon it. Of course, as long as one knows how to meter, this is all kind of academic, but I am keen to know what the real story is. Cheers, Mike -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Tom Rittenhouse Sent: July 12, 2001 21:36 To: [EMAIL PROTECTED] Subject: Re: 18% Gray (again) Sorry, I didn't know what I was talking about here. See Ah ha (was 18% gray) for the answer. --Tom - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
