Understanding Exposure

[Sidebyte]

IMHO I subscribe to the use of "bracketing" frequently, both for exposure and white balance. Wonderful tool that does much of the calculating for you. Eats up space on a card pretty fast but you can chimp and eliminate many.

[peekay]

I also say thanks Kelly for starting this I have been having trouble with exposure since I started I have taken coarses and am currently reading "understanding exposure" I also will be rereading this forum.Thanks all who are contributing.
PS I was also feeling I was the only one who couldn't get my head around it.

[heartseye]

Originally Posted by Tom Swaman

Just a thought and not to be contrary, but to try to be helpful, I do not believe that exposure with a digital camera is any more important than is exposure with a film camera. It is simply different. Frankly, I feel that the histogram is to the digital camera what the Zone System is to a film camera. Bothe systems are tools for optimizing images through exposure control. I think the problem lies with people wanting everything to be automatic. Blue Ribbon exposure requires human selection and not an automatic setting! If you disagree, do not tune in for more. If you agree, I think you just have to bite the bullet and learn the subtleties of working with histograms or switch to films and learn the subtleties of the Zone System.

Tom

Not so! They are NOT both systems which adjust thru exposure control. The zone system is about 40% exposure, 50% film development, 10% choice of film.
And the "subtleties of the Zone System" are almost entirely irelevant to the digital photographer.....

[expensive_hobby]

Originally Posted by Tom Swaman

If you agree, I think you just have to bite the bullet and learn the subtleties of working with histograms or switch to films and learn the subtleties of the Zone System.

Where does someone even learn how to clearly understand histograms? I have never come across info to teach the ins and outs of the graphs. My extremely basic understanding is try to be sure it's even across the graph. Doesn't mean my understanding is accurate, nor applicable for every photographic situation.

Originally Posted by peekay

...PS I was also feeling I was the only one who couldn't get my head around it.

Nah, I'm about as lost as you are, if not more. For me there is just too much to try to remember, and too many variables to comfortably say: okay this is exactly what I should do. So just like sidebyte I do alot of bracketing.

[Tom Swaman]

Dear Heartseye,
Either I said it wrong or you misunderstood what I intended to say. What you say is very true. I was trying to say that the Zone System does not work well for DP, but knowledge of the use of histograms does work well for DP! Exposure is important in both film and in digital photography! The control methods are practically different, but important!

Tom

[heartseye]

Histograms are not of real value all by themselves. They are best used to compare what YOU see the image as being compared to the histogram the camera shows you. Visualisation of the final result is a vital part of the process.....cheers...Bob

[heartseye]

Thanks Tom...I gotcha! Cheers...Bob

[heartseye]

EH.......how the histogram looks depends on the image you are creating.....A black cat in the shadows would have a histogram with most of the pixels at the left end. A white cat in snow....most of the pixels at the right end. The "average" scene would have the whole width filled with more in the middle 2/3 than at the extremes.....That help any? Cheers...Bob

[expensive_hobby]

Originally Posted by heartseye

Histograms are not of real value all by themselves. They are best used to compare what YOU see the image as being compared to the histogram the camera shows you. Visualisation of the final result is a vital part of the process.....cheers...Bob

Thanks for reinforcing that concept Bob. But I have to admit, I must have *issues* (please don't let my husband see me writing that! ). I really find my camera's lcd screen worthless-- zoomed in or out, doesn't matter.

So yes, I do check out the histogram thing. Primarily I'm using it to see what's glowing/flashing on the image (you know that box that comes up with a tiny pic of the image)-- particularly in snow and on extremely bright sunny days.

[expensive_hobby]

Originally Posted by heartseye

EH.......how the histogram looks depends on the image you are creating.....A black cat in the shadows would have a histogram with most of the pixels at the left end. A white cat in snow....most of the pixels at the right end. The "average" scene would have the whole width filled with more in the middle 2/3 than at the extremes.....That help any? Cheers...Bob

Yes it does! I kind of assumed it should lean one way or the other.

[Tom Swaman]

FWIMBW. the real value of the histogram lies in the not so normal pictures. I use histograms as a guide to determine when I have detail in my highlights or shadows. I really do not need much for shooting "average subjects". Sidebytes bracketing does it every time if you have a static subject. .......but how do you bracket your black cat leaping for the black yarn held in the dark on one side of the cat when the camera is on the other?

.....And the answer is, tell 'em how gigantic that fish was and how long it took the six of you to land it.

Tom

[heartseye]

Well, Tom.....I use a special cat for those shots.....lol....Bob

[kgphoto]

Kelly,

I can 't believe you asking these questions after all we've gone over!?

Here are a few of my OPINIONS.

The Histograms give a picture of the average range of tones, but don't show you which ones are where on the graph other than the dark ones are to the left. So for precision, they are basically worthless.

IF you are just shooting portraits and only really care about the faces, draw an elipse in PS or zoom in in camera and shoot a close up of a face mask histogram a-la Will Crocket and that will get the job done.

The Zone System should be read by everybody and everybody should periodically get out some film and play. It is, as Heartseye has commented a SYSTEM of film, exposure and Development, but the basic principal of knowing what the tones are in the image space does carry over to digital.

A more easy to understand explanation would be Dean Collins exposing for reproduction and Chromazones.

Since digital has a narrower contrast range than film, it is more critical, not difficult to expose it properly. Part of proper exposure is making sure the info is on the film/file to make the prints later and part of proper exposure is deciding how this info will reproduce on the prints. How dark and how light, what color and contrast, etc. The Zone System handled that by film, paper and development choices, we do it now with PS and levels and curves and masks, and . . . who knows what else.

The best thing to do is use a hand held meter to read the various light values in a scene and see if they fall within the contrast range of your sensor. If not, either add or remove light or change locations until it does. You can do some HDR techniques as well.

My personal favorite meter is the Gossen Luna-Pro SBC with a 7.5 degree spot meter. It easy to see what you are pointing at and the needle moves around showing you the range as well as the specific value. Now I am learning to use the Sekonic 758 DR.

What I am talking about works for flash and constant light, portraits or landscapes. It is simple really.

The reason you don't want (IMHO) the camera to make the choices for you, is that you are not learning and are giving up your control. After taking notes and practicing you may find that you and your specific camera agree most if not all the time and in time crunch moments you may elect to allow it to choose, but then you will have the knowledge and comfort that the choice will be close or correct.

[KellyL]

Tom, a little confused by your comments. The whole point of this thread is to dig in and learn from others. I don't think it was ever implied that we just wanted the easy way out and hope the camera would do all the thinking for us. If you have some specific advice you would like to share, then we, I, am ready to tune in for more.

[KellyL]

KIRK...ROFL....

I have been thinking about you ALL day, buddy. In one of your posts you talked about exposure and white balance. So far, I have only used a gray card for white balance, I have never used one for exposure. So when you began talking to me about using cards for exposure...cards for white balance...you were introducing me to some new ideas. Okay...now I have to read your post. I only got the first sentence before I burst out laughing.

[KellyL]

The reason you don't want (IMHO) the camera to make the choices for you, is that you are not learning and are giving up your control.

Precisely. I want to know everything I can possibly know. I am starting to put it all together. Remember, I am starting from SCRATCH here. No mentors around. No classes. Just me, my books, my experience, and my Camel friends. So when a 25 year veteran says "Easy" I say, "Easy for YOU! You are a trained professional."

According to what I have read on the Sekonic meter, it will tell you if the scene is outside of your dynamic range...although the article I read said it wasn't explained very well in the manual.

Now, this idea of zooming in to the face and taking a reading, like a face mask in PS, except with your camera is intriguing to me. If I understand what you are saying correctly, it would be like doing some PP work prior to the shot. One could even meter, take a shot of a tight face crop, chimp with the histogram, proceed from there. That's not going to help on shoot and run, but when one is trying to compose an outdoor portrait in available light, then that would seemingly be a nice place to start.

Now...you once talked to me about gray cards, white cards, and another card you carry in your pocket. I cleaned out my PM's and lost the name brand. I didn't realize that until today when I went to look it up on the internet.

If I remember correctly, you CW balance with a white card...for Canon. Do you ever use a gray card, Kirk?

[KellyL]

Pensive:

Here is a nice thread on Histograms: http://www.photocamel.com/forum/ligh...istograms.html

[KellyL]

This is me saying, "Whoops! Didn't realize there was a whole second page already!"

Okay...truth or myth...I have read in one of my early photo books that by learning to expose correctly, you eliminate the need for bracketing. In the book, the author reported that in his early days of photogrpahy, he bracketed to the point of embarassment. This was when he was an apprentice to a photographer. Once he learned how to master a handheld light meter, the need to bracket diminished.

True or False: In one of the books I have recently read, and I can't for the life of me remember which one right now, the author said that many times a photographer had no idea that his images were routinely under or over exposed because the lab did a lot of work that the photographer wasn't really aware of. For those who did their own developing and printing, dark room techniques made up for lack of skill with correct exposure.

I also read in the latest book that Ansel Adams did quite a bit of dark room work to make his images what they were.

Tom, my first comment to you was before I realized there was a second page. I interpretted your comment to mean that you thought I was trying to figure out if the camera wouldn't do all the work for me, whereby I would not have to do any learning, and I was a bit insulted because I work so hard at learning this stuff. For some folks who will remain nameless (Kirk) it all seems so easy. For those of us who tap along with canes and have come relatively late in the game, it isn't quite so easy.

I just want to be the best that I can be.





I want to get better at understanding exposure.

[kgphoto]

Kelly,

Resistance is futile, you will be assimilated.

I use a Whi-Bal Card for white balance. It is a light grey in color, but the big deal is that it is designed and each individually tested to be neutral to tight tolerances.

i will send one of the PM's to you with the long discussion. I would recommend printing it out with a word processor and framing it and putting it over your bed at night so it is the last thing you and you wife sees.

Although, I wonder if I should, after all this help and then you bash me here. Of course it is easy, just do it and don't over think it. ( I think I need a smiley here so you know this is tongue in cheek - )

It really is simple keep all the important tones to a 4 f:stop spread and you will be fine.

[Sidebyte]

Originally Posted by Tom Swaman

FWIMBW. the real value of the histogram lies in the not so normal pictures. I use histograms as a guide to determine when I have detail in my highlights or shadows. I really do not need much for shooting "average subjects". Sidebytes bracketing does it every time if you have a static subject. .......but how do you bracket your black cat leaping for the black yarn held in the dark on one side of the cat when the camera is on the other?

.....And the answer is, tell 'em how gigantic that fish was and how long it took the six of you to land it.
Tom

Tom,
My suggestion for bracketing was to LEARN how to expose properly once you absorb what the camera is telling you. Once you have mastered exposure (especially for a given camera) then you don't need to bracket.