Where can i find a grey card?greenspun.com : LUSENET : Large format photography : One Thread
I am looking for a grey (18%) card to use with subject lighting in field. I know I can just find a middle tone subjest to meter from, but I would rather use a grey card. Can I buy one, make one, where or how?
-- Clark King (email@example.com), August 19, 2001
They are fairly common, most photo shops can supply the kodak ones, or you can sometimes find them as a inside cover in basic photography books.
-- Michael Mahoney (firstname.lastname@example.org), August 19, 2001.
Try the B&H site (http://www.bhphotovideo.com). Enter "gray card" in the search field and you should see cards from Kodak, Delta, Sekonic, etc. The prices range from $1.95 to about $30 depending on the size, etc.
-- Dave Willison (email@example.com), August 19, 2001.
Try to find one made from a plastic rather then paper or cardboard. They can be cleaned and last much longer.
-- Bob Salomon (firstname.lastname@example.org), August 19, 2001.
Another source would be Porter's Camera in Iowa at www.porters.com. They sell a plastic 8x10 gray card (under $10.)
-- Merg Ross (email@example.com), August 19, 2001.
Thanks for all the responses it is greatly appreciated! Is a grey card as good the next? The delta lifetime card seems the best offer since it is more durable, and $8.95, but is the sekonic better at $39.95?
-- Clark King (firstname.lastname@example.org), August 19, 2001.
Light meters area skewed to 13% grey, not 18% grey. Why in the world doesn't anyone make a 13% grey card? I was quite surprised to learn this. You can confirm this with Mamiya USA, the Sekonic importer. They offer a good book on this subject.
-- Bill Glickman (email@example.com), August 20, 2001.
Before you buy a grey card, consider why you really want one. They're one of the most misunderstood and frustrating pieces of photographic equipment ever invented. For example, if you take one outside (where they're useless), you can hold it up and meter from it, and you will quickly find that if you adjust its angle even slightly, it will give you radically different meter readings, covering a range of about three stops or more typically. Finding that it will not give you an accurate reading within this huge range, you will resort to the correct ways to meter-- looking around the image at the different elements and making the metering choice based on what's actually in the picture.
The problem with grey cards is that they stay the same shade of grey always, which means that when you expose from one (if you can get it at the correct angle), it will always produce the same shade of grey on film under any lighting conditions. For example, if you took one to the top of mount everest on a sunny day and exposed for it, it would come out perfectly 50% grey on film, even though if you LOOKED at it up there it would be extremely bright grey-- close to white, and that how you would want it to look on your photo. having used it for your exposure, however, your photo would come out horrendously underexposed because the metering process doesn't take into account that you WANT it to come out brighter than neutral grey because you are in an extremely bright place.
the grey card also doesn't take into account differences in the range from grey to white-- in some images that might be 2 stops, and in others (such as in the snow in sunny weather) it might be six stops. in either case, if you metered from a grey card, you'd get the wrong exposure.
same thing in reverse when it's dark out: if you held a grey card up and looked at it, it would LOOK DARK, and if you photographed the scene with the card in it, you would WANT the card to look dark. but if you metered off the card, your photo would be exposed such that the card would look the same as it did in the Mt. Everest photo-- perfectly 50% grey, which means your photo would be way overexposed.
So, the only time grey cards are useful is under controlled lighting conditions (i.e., in a studio) when you want the card to look in your photo just the way it does in "real life." In the studio, they're great because they let you peg your exposures perfectly. usually. but you bracket just to be sure, which makes using the card useless in the first place.
The secrets of metering all come down to knowing how your film reacts at the edge of the exposure scale (i.e., in the highlights if you use transparency film, and the shadows if you use negative film), and exposing for those things. If you properly expose for the highlights on transparency film, then everything else will fall where it is supposed to. Same thing with negative film. Where you place the greys in either situation is not very relevant.
But, with all of that said, if you really want a great grey card, go to your local mega-hardware home depot type of store, and go to the countertop department and take get free sample pieces of all of the grey formica-type materials they have, and then meter those in comparison to a grey card until you find one that gives the same reading. you can actually make a whole greyscale for yourself using these little chips, and practice metering and experimenting under different lighting conditions.
One really interesting thing to do is take ALL of the samples, colors included, and make a big board with them all, and then meter them and photograph them and see what results you get. This will help you understand how different colors meter (i.e., Pacific ocean blue is 1.5 stops darker than neutral grey; grass green is about equal to grey, etc.), so when you're looking around your image you can take the colors of things into account when metering.
whoa, that was quite a brain dump-- i hope it helped...
-- chris jordan (firstname.lastname@example.org), August 20, 2001.
I agree that gray cards are problematic outdoors if part of the scene is in the shade and part is in the sun. In this situation, you can get misleading results depending on where the gray card is placed (sun or shade). However, as long as one understands the limitations in a scene with sun and shade, then I think it is a useful tool, but not the only tool, to be used for determining exposure.
I think that the use of any kind of plastic material for a gray card exacerbates the extremes in meter readings. The best gray card is cardboard with a matte surface because it will have the least amount of variation in exposure when placed at various angles to the meter. Insofar as being able to wash a gray card, a small amount of dirt will not make any difference. I have a cardboard gray card that is over 20 years old that is a little dirty but works perfectly. If the cardboard gray card gets so grungy that it is disgusting, then you can always buy a new one.
-- Michael Feldman (email@example.com), August 20, 2001.
hey Michael, you are just Mr. Counterpoint around here , aren't you?! comments well taken though.
-- chris jordan (firstname.lastname@example.org), August 20, 2001.
That really answers alot of questions, thanks cj. I was actually going to use it meter for outoors (environmental) portraiture! What did I know? Due to a recent situation I thougt it might help with balancing exposure when the subject is brightly lit but the bkgnd is shaded by trees. I'm getting too much contrast between my subject and the bkgnd. I guess not enough bkgnd detail or shadow detail, but I don't want my subject to be overexposed. (Something like a 3 stop difference between these two) I try to find a middle toned something to meter from. The ideal sit. would be an evenly lit scene foregnd (subject) and bkgnd, right? According to your advice I should try exposing for some of this shadow detail in the bkgnd? Anyway thank you very much for the input, i'm still learning!
-- Clark King (email@example.com), August 20, 2001.
You will get a lot more consistent results if you angle the card somewhat to just 'catch' the ambient light rather than just pointing it directly at the camera. Kodak's grey card comes with instructions that kind of illustrate this. After some experimentation I find I get surprisingly consistent results with this. That said, I use the grey card strictly as a reference point and rarely, if ever base my exposure on a grey card reading. It can be tricky but useful on some occasions if you do some experimentation with it beforehand.
-- Andy (firstname.lastname@example.org), August 21, 2001.
Of course with a three stop range between the subject and the background, depending on the film you are using the contrast might just be too much regardless of exposure. Are you using transparency, color neg., or B&W film? With slide films the three stop range is too much and although I don't shoot color neg. film I suspect the result would be pretty much the same.
-- Andy (email@example.com), August 21, 2001.
"Light meters area skewed to 13% grey, not 18% grey"
Are you speaking about Minolta and Gossen?
They usually don't post specs on the Sekonic site.
-- Bob Salomon (firstname.lastname@example.org), August 21, 2001.
The way I look at it, you can spend 8.95 on a gray card and confuse the hell out of yourself watching it give you different readings as you turn it slightly toward or away from the sun, or you can spend ten times that on a really good incident meter and never be confused again. (at least about what settings are appropriate for the light!) That's what I did and my gray card sits in my closet forevermore. I think incident meters are definitely the way to go for people like me who are exposure-challenged.
-- Erik Ryberg (email@example.com), August 21, 2001.
Bob, it was my understanding that all the silicon chips used today in reflective meters are calibrated to 13% grey. This 18% grey was a figure that came about from Kodak in the early 1900's to simulate NY's grey clouds and these grey cards have been produced ever since. Here is a clip from the Luminous Landscape web site.... this guy is very sharp...
A meter capable of taking incident light readings, like the Sekonic L508 reviewed on these pages, features what looks like a half of a golf-ball-sized hemisphere, usually on a swiveling support. To take an exposure reading instead of pointing the meter at the subject, as one does with in-camera and reflected meters, you instead place the meter in the same light as the subject.
The hemisphere, or lumisphere as some call it, is designed as a 13% gray object and thus provides a reading equivalent to that which you would get if you took a reflected reading off a theoretically perfectly integrated scene, or a Kodak 18% gray card. (It really should be 13%, but don't ask!?)
The beauty of the incident metering approach is that you needn't carry a large gray card around with you on location, and you don't have to worry that your subject matter — whether because of its colour or reflectance characteristics, will give an erroneous reading.
From what I have learned it seems all meters use this 13% standard. The 18% card was also appreciated since it was 1/2 way between white and black. The difference between 13% and 18% is approx. 1/2 a stop, which is very significant with chrome film. Assuming all this is true, then it does not make sense to use a grey card in the field for exposure purposes unless you use a compensating factor. But as one poster mentioned above, there is many other reasons to not use this method.
Bob, since you have many industry conacts, maybe you can shed some light on this 13% issue, as there seems to be no written information from the makers of these meters.
-- Bill Glickman (firstname.lastname@example.org), August 21, 2001.
I read somewhere (exactly where I have forgotten) that Ansel Adams lobbied for the 18% value very heavily, and Kodak accepted this figure. For Adams, 18% was convenient because it corresponded to a Zone V value, whereas 13% is about IV 1/2. But does it really make much difference if one calibrates their film speed to the proper Zone I density?
-- Michael Feldman (email@example.com), August 21, 2001.
>> Bob, since you have many industry conacts, maybe you can shed some light on this 13% issue, as there seems to be no written information from the makers of these meters. <<
I'm not Bob, but I can state with some authority that the instruction manual for a new Minolta Autometer IV F states, on page 14 (Reflected-Light Readings), "Like all reflected light meters, the Auto Meter IV F is calibrated to provide an exposure which will reproduce the metered area as a tone with 18% reflectance (zone 5) regardless of its true shade.".
I don't necessarily take this as "proof"; it's simply what the manual says.
-- Bill C (firstname.lastname@example.org), August 21, 2001.
Apparently Sekonic showed different recommendations then some other meters when compared under identical lighting at the same time.
The Sekonic factory, when questioned about this, responded that it was because they picked 13% rather then the 18% most other makers use.
This doesn't make it right or wrong since you calibrate the meter you use to the results you prefer.
-- Bob Salomon (email@example.com), August 22, 2001.
The best gray cards I've ever seen or used are the ones made by PhotoSystems, Inc., in Dexter, Michigan (they are also the manufacturers of Unicolor chemistry) and I've been using theirs for at least ten years. They are made of a non-warping plastic, are completely flat, and are18% gray on one side with an extremely carefully executed matte finish that doesn't seem to have any glare angle at all, and is surprisingly durable (although it will eventually get scratched). The back is glossy white. They also have a hole punched in them, so that it's easy to put the card up on a studio wall with a pushpin. They don't seem to be listed as an individual item on the manufacturer's web site, http://www.photosys.com/, but I just called and they can be ordered over the telephone at (800) 521-4042. The only proviso I would add is that these cards are expensive, currently $20.00 for the 4x5, and $28.00 for the 8x10, but as usual, you get what you pay for, and these are well worth the cost.
-- Christopher Campbell (firstname.lastname@example.org), August 27, 2001.