18% gray card is the most cost-beneficial tool I've found!

[New Daddy]

If you want to get the correct hue for the scene than that is here the grey card comes in, it has nothing to do with exposure which would affect the histogram.

Allan

I don't understand.

Let me rephrase: in the high key portrait with the white dress in the white backdrop, how would the histogram be of help in nailing the exposure? I'd take the 18% gray card near the subject's face, spot meter off the gray card, and bob is your uncle. I can't see how the histogram would be of any use in that situation other than making sure white will be white.

http://digital-photography-school.co...roper-exposure

[William W]

"I mostly shoot environmental/candid portraits of my family . . .

These two particular genres of Photography, do not lend themselves to taking multiple exposures and then blending them together in post processing.

WW

[Colin Southern]

I don't understand.

Let me rephrase: in the high key portrait with the white dress in the white backdrop, how would the histogram be of help in nailing the exposure? I'd take the 18% gray card near the subject's face, spot meter off the gray card, and bob is your uncle. I can't see how the histogram would be of any use in that situation other than making sure white will be white.

http://digital-photography-school.co...roper-exposure

+1

It's useful from the point of view of being able to compare the histogram you have with the one it should be for the subject matter you're shooting and how you're choosing to expose it, but I agree -- a gray card (or incident light meter) is usually much easier (for reflective scenes anyway -- different story when there's incident light to consider as well) (eg shooting into the light).

Many (most?) people don't understand histograms (but think they do) -- the common misconception is that there shouldn't be data bunched up at one end of the other; in many cases there isn't (eg a properly exposed typical landscape), but it TOTALLY depends on the subject matter. eg if one correctly exposes a close up of a teacher's blackboard then you can bet your last dollar that it'll be (correctly) bunched up towards the left. If one does the same for a closeup of a bride's dress then it'll sure-as-taxes be bunched up towards the right. Both are 100% correct.

The key is knowing where it SHOULD be to be able to compare it where it IS. That's why I like to use it in conjunction with the blinkies; if I have blinkies in an area (indicating loss of detail) then I need to check that area to see if it's an area where loss of detail is unacceptable or not. Conversely, if I have highlights in an image - and perhaps some negative exposure compensation applied and the histogram stops well short of the right hand side then it may well be a sign that I have too much -ve EC dialed it.

[Colin Southern]

These two particular genres of Photography, do not lend themselves to taking multiple exposures and then blending them together in post processing.

WW

Holy heck you're up early Bill!

[Polar01]

Rick to take your reply from post #41, the last line, "I can't see how the histogram would be of any use in that situation other than making sure white will be white". The histogram has nothing to do with colour, it will tell you once you learn how to read it is if you have lost detail in the shadows or detail in the highlights. Colin stated about the "blinkies" which I also use, if you get these, it tells you that there is no detail in those areas or no data, if you get these then you dial in the correct amount of exposure compensation get rid of the" blinkies" now you have detail in those areas. The exposure will be correct for that lighting or very close, however it will not give the correct hue of the skin of the person, as the camera will give it a WB that it thinks is correct for the lighting. By you adding a grey card to WB off of, you can adjust the WB as you now have a reference to netural grey thus getting the correct WB. Another however it will not be correct as we a people like skin tones to be a little warmer for our own personal tastes, the WB may be 6800K but we may adjust it warmer to 6950K to get the hue that is pleasing to our eye.
Again the histogram only shows where the amount of the light energy has fallen, if the image is light than most of the light energy is to the right of centre, if it is dark then the amount of light energy has fallen to the left of centre. This in know way affects as you state: "making sure white will be white".

Allan

[New Daddy]

Rick to take your reply from post #41, the last line, "I can't see how the histogram would be of any use in that situation other than making sure white will be white". The histogram has nothing to do with colour, it will tell you once you learn how to read it is if you have lost detail in the shadows or detail in the highlights. Colin stated about the "blinkies" which I also use, if you get these, it tells you that there is no detail in those areas or no data, if you get these then you dial in the correct amount of exposure compensation get rid of the" blinkies" now you have detail in those areas. The exposure will be correct for that lighting or very close, however it will not give the correct hue of the skin of the person, as the camera will give it a WB that it thinks is correct for the lighting. By you adding a grey card to WB off of, you can adjust the WB as you now have a reference to netural grey thus getting the correct WB. Another however it will not be correct as we a people like skin tones to be a little warmer for our own personal tastes, the WB may be 6800K but we may adjust it warmer to 6950K to get the hue that is pleasing to our eye.
Again the histogram only shows where the amount of the light energy has fallen, if the image is light than most of the light energy is to the right of centre, if it is dark then the amount of light energy has fallen to the left of centre. This in know way affects as you state: "making sure white will be white".

Allan

Allan, I think you lost me somewhere. I advocated the use of 18% gray card for both correct metering and correct white balance. It's evident from my very OP if you care to re-read it. Along the way, someone insisted that the histogram would be more useful to a person knowledgeable with histogram, and my response was in refutation to that post. It had nothing to do with white balance. Yes, it got confusing because some posts were directed to white balance and some to metering.

[New Daddy]

+1

It's useful from the point of view of being able to compare the histogram you have with the one it should be for the subject matter you're shooting and how you're choosing to expose it, but I agree -- a gray card (or incident light meter) is usually much easier (for reflective scenes anyway -- different story when there's incident light to consider as well) (eg shooting into the light).

You brought up a point that I always wondered.

How do you expose for a scene with incident light? A incident light meter (or 18% gray card) won't work, as your subject is not at the same angle to the incident light as the camera, unless you are going to expose for the subject anyway and blow the hell out of the background. Is chimping the way to go in situation like that?

[Polar01]

Rick I need to get my head around something, your statement " I advocated the use of 18% gray card for both correct metering and correct white balance". Now I understand that correct white balance is, what is you description of "correct metering" so I know that we are talking the same thing? Now I have been using a WhiBal card for a couple of years now, as my grey card, now they, I believe tell you that it is not for exposure, X-Rite passport also I believe states not for exposure, some grey cards that come in some photo mags state not for exposure. Now the WhiBal card also has a white and black patch on the grey side, these are to help you if you want to set you white and black points, when working in raw. Now the time it takes to take at shot, look at the histogram, see if I need more or less exposure takes only a few seconds and I know I'm good to go. This is what a few years of experience teaches you, set the f-stop you want, take the shot, check the histogram or Blinkies, adjust if needed and go. Grey card or a passport in first shot can't blow it out, use that shot to set WB of all other shots.

Allan

[William W]

Holy heck you're up early Bill!

A bushfire to put out at 0200 . . . the joys of business.

[Inkanyezi]

I don't understand.

Let me rephrase: in the high key portrait with the white dress in the white backdrop, how would the histogram be of help in nailing the exposure? I'd take the 18% gray card near the subject's face, spot meter off the gray card, and bob is your uncle. I can't see how the histogram would be of any use in that situation other than making sure white will be white.

http://digital-photography-school.co...roper-exposure

Here's where understanding the histogram comes in.

First of all: The histogram doesn't show you where tones are blown (or saturated), and the general histogram doesn't even tell you which colours that saturate. For a situation where you are happy to over-expose some part of the image, the histogram will not help you to set exposure, but blinkies often will.

However, in those situations where you may be helped by the histogram, it is the far right side of it that is of utter importance, and it shall NEVER pile up against the right wall of the diagram. It should end just in the bottom right corner, without climbing as much as a millimetre on the right side. You may also be helped by looking at the three colours separately, particularly in the case of red, as in red roses. If the red channel climbs a tiny bit on the right wall if it does not go down to the corner, some red has lost any tonality and is "flat", saturated with no tonal values but the most saturated red. This is very common, and it is the very reason for some of us to choose the UniWB to get a better indication of how much we can fetch at the top end, check that we don't saturate that red rose.

And remember still, that the histogram is only a statistic diagram, it does not in any way tell you the location of those saturated pixels. If they are more or less evenly spread around the image area, it is not a problem. It is the blinkies that will tell you whether there are larger areas that are saturated. But lo and behold - the blinkies won't kick in for only one channel saturated, so it's only the histogram that can show you that you'd better compensate a bit to minus if you want to retain gradation in the saturated parts of the image.

Your white dress should not pile up to the right. The white dress should be a hump on the histogram, far to the right, but the right edge of that hump shall slope all the way down to the baseline. It shall meet the baseline in the very corner of the histogram, if it is the brightest part of the shot. So the histogram shall not go to the far right at any height. It is allowed to reach the lower corner only, not climb the wall. If it climbs the wall, you have blown out any tonality in it. Therefore, in some cameras you may set a lower threshold for the blinkies, so if you set it to 251 or 252 instead of 255, you might get a warning.

But still, just where the saturated pixels sit in the image area will not be shown by the histogram. In case you have a bright background that you allow to be blown, the histogram isn't of much help to you. Then chimping is your only way to tell, and EVIL cameras have an advantage, as there are live blinkies and live histogram and you see the image on the screen, very close to how the camera will render it.

[Colin Southern]

You brought up a point that I always wondered.

How do you expose for a scene with incident light? A incident light meter (or 18% gray card) won't work, as your subject is not at the same angle to the incident light as the camera, unless you are going to expose for the subject anyway and blow the hell out of the background. Is chimping the way to go in situation like that?

It's usually going to be a compromise. I do a lot of this with my landscape work and I'll usually just shoot a bracket of 3 to 5 shots -- it works 2 ways (1) I can choose the best frame to work with exposure-wise, and (2) if that doesn't work well then I still have all the shots to make an HDR composite.

If you're trying to also retain foreground detail then there's no guaranteed way to meter it because the shot is ultimately limited by the exposure of the highlights - and they'll usually blow anyway ... so it becomes a balancing act between large areas of blown highlight - peripheral areas on one channel blown/non-linear response curve - v - more protected highlights and under-exposed foregrounds; all of which is balanced too much on a knife-edge to meter with impunity. In those situations - whatever else you do - be sure to shoot at base ISO if possible.

If I don't want to shoot brackets then I'll usually just leave the camera on AV and put in -ve EC (typically around -2) and watch the blinkies.

[New Daddy]

Rick I need to get my head around something, your statement " I advocated the use of 18% gray card for both correct metering and correct white balance". Now I understand that correct white balance is, what is you description of "correct metering" so I know that we are talking the same thing? Now I have been using a WhiBal card for a couple of years now, as my grey card, now they, I believe tell you that it is not for exposure, X-Rite passport also I believe states not for exposure, some grey cards that come in some photo mags state not for exposure. Now the WhiBal card also has a white and black patch on the grey side, these are to help you if you want to set you white and black points, when working in raw. Now the time it takes to take at shot, look at the histogram, see if I need more or less exposure takes only a few seconds and I know I'm good to go. This is what a few years of experience teaches you, set the f-stop you want, take the shot, check the histogram or Blinkies, adjust if needed and go. Grey card or a passport in first shot can't blow it out, use that shot to set WB of all other shots.

Allan

I think you should find out how camera's meter works and connect the dots between that and 18% gray. It will all become clear to you at that point that 18% gray, by definition, achieves the correct exposure in camera.

[New Daddy]

Here's where understanding the histogram comes in.

Your white dress should not pile up to the right. The white dress should be a hump on the histogram, far to the right, but the right edge of that hump shall slope all the way down to the baseline. It shall meet the baseline in the very corner of the histogram, if it is the brightest part of the shot. So the histogram shall not go to the far right at any height. It is allowed to reach the lower corner only, not climb the wall. If it climbs the wall, you have blown out any tonality in it. Therefore, in some cameras you may set a lower threshold for the blinkies, so if you set it to 251 or 252 instead of 255, you might get a warning.

But still, just where the saturated pixels sit in the image area will not be shown by the histogram. In case you have a bright background that you allow to be blown, the histogram isn't of much help to you. Then chimping is your only way to tell, and EVIL cameras have an advantage, as there are live blinkies and live histogram and you see the image on the screen, very close to how the camera will render it.

I don't agree.

First of all, in the high key portrait, who says the white dress piled up to the right in the histogram and didn't come down to the base without hitting the right side? How do you know? How do you know that it's the WHITER backdrop that blew, not the woman's dress? (you can easily see that the backdrop is whiter than the dress.) You don't! That's the problem with histogram. And who cares if the white backdrop blew in that high key portrait? As long as I expose for the woman's skin tone correctly and I don't lose detail in her clothing, I don't give a damn if the white backdrop blew at 255, 255, 255 and made a big hump hitting the right side of the histogram.

http://digital-photography-school.co...roper-exposure

Second, histogram is based on the camera's JPEG rendition of the RAW. When you're shooting raw, the same RAW data can present in different histograms depending on how you set up the JPEG engine. There is no reason to get hung up on what the histogram is showing you. The same photo that shows you a peak that doesn't come down on the right side may have all the tonal detail you need if you are going to develop RAW.

My understanding is that histogram is an "aid" for better exposure. It is not to be worshipped with religious fervor. You should know how and when it works and interpret it, not make it a rigid rule that "clipping on the right side or left side of histogram is wrong".

[Polar01]

Well RicK I think I shall bow out of this thread, I will now go off to read my manual on how the camera's meter works as I thought that I had some understanding but I do know that I have a problem with that connect the dots thing. I will be looking forward to when you post an image you have gotten using your methods. Until then good luck with your photography.

Cheers:

Allan

PS: Rick did you know that some cameras do not show a live histogram in live view, some Cannon will Nikon will not.

Again Cheers:

[New Daddy]

Well RicK I think I shall bow out of this thread, I will now go off to read my manual on how the camera's meter works as I thought that I had some understanding but I do know that I have a problem with that connect the dots thing. I will be looking forward to when you post an image you have gotten using your methods. Until then good luck with your photography.

Cheers:

Allan

PS: Rick did you know that some cameras do not show a live histogram in live view, some Cannon will Nikon will not.

Again Cheers:

Good luck to you too. BTW, I'm not a huge fan of histogram anyway as you can tell from my posts, although I use it to some degree.

[Inkanyezi]

I don't agree.

In fact you do agree, although you might have missed the message.

In the case where you have a backdrop that is allowed to be blown, the histogram WILL climb on the right edge, and it cannot help you to evaluate correct exposure for the white dress. That is why I stressed "in those situations where you may be helped by the histogram" and put it in italics, in the same sentence.

The situation you outline is one where the histogram is of no help to you, and it is not relevant to the statement you reject, and which is also not my statement, but an assumption of yours.

[Colin Southern]

First of all, in the high key portrait, who says the white dress piled up to the right in the histogram and didn't come down to the base without hitting the right side?

Grrrr. I wish they'd stop calling images like that high-key. It's not - it's just a normal key image with a white background.

How do you know? How do you know that it's the WHITER backdrop that blew, not the woman's dress? (you can easily see that the backdrop is whiter than the dress.) You don't! That's the problem with histogram. And who cares if the white backdrop blew in that high key portrait? As long as I expose for the woman's skin tone correctly and I don't lose detail in her clothing, I don't give a damn if the white backdrop blew at 255, 255, 255 and made a big hump hitting the right side of the histogram.

On a side-note, white cloth / sheets has to be absolutely the WORST thing ever for white backgrounds; they invariably need to be lit separately (or they expose as a shade of gray due to light falloff), but you need to nuke them with at least a couple of extra stops to kill the wrinkles, and that in-turn nukes fine hair detail. Just can't win.

My understanding is that histogram is an "aid" for better exposure. It is not to be worshipped with religious fervor. You should know how and when it works and interpret it, not make it a rigid rule that "clipping on the right side or left side of histogram is wrong".

Absolutely. No histogram is right or wrong as an absolute; it ALWAYS needs to be evaluated in the context of the image. A wide-angle shot of the moon is going to have a spike all the way to the left; a photo of someone that also has full and direct sun in it is ALWAYS going to have a spike on the right. Both perfectly acceptable in that situation. The same spikes whilst shooting a close-up of a gray card for a catalog definitely wouldn't be a good thing.

I should pass a quick comment on a previous thing you mentioned though:

18% gray, by definition, achieves the correct exposure in camera.

Yes and no. It achieves a "standard exposure" - or a known reference point, but that doesn't necessarily make it correct (or incorrect), as so many other things come into it. Even when basing an exposure on a gray card (or an incident lightmeter) one will still need to adjust the exposure in post-production as middle gray will always be 2 stops below (reflected) white, but a reflected white (+2EV from a middle gray) won't max out a sensor (it'll sit around 1.3 stops below it typically) - so those tones above middle gray need to be stretched up in PP -- and those below it stretched down (setting black and white points). Typically in portraiture I'll push them a full stop and then drag the midtones back into place using the brightness slider; it removes a lot of the flatness in an image (but it's another secret, so don't tell anyone!).

[Inkanyezi]

Like Colin says, the grey card gives you a "standard" exposure, which is not necessarily the correct exposure for the scene and your intentions. In the days the meter was not usually integrated in the camera, we used separate light meters to reach that standard exposure, and in the case of incident light meters, the grey card was not needed.

The incident light meter does not necessarily give the correct exposure without some tweaking. We had to calibrate our methods to suit each other. The transmission of the lens, the development of the film, and errors in shutter timing all had to be taken into account, so perhaps I would set my meter to 160 ASA for TRI-X film, although someone else might set his meter to 600 for the same film, reflecting different calibrations of the meter, different timing of the shutter, different light transmission and different development.

But in essence, the incident meter does the same as a grey card, and it is also not intended for white balancing. It provides the photographer with a standard for exposure, a reading of the light that reaches the subject. The one in the image below is mine, and I have used it for more than forty years. It still works as designed, and it can be used instead of a grey card for the purpose of setting exposure in tricky situations that may fool the meter in the camera.