Understanding Exposure

[Worm324]

Kelly,

Thats a perfect example of how Experience comes into the mix of this maze Next time you go to an event your gong to know that the meter method you used for the Landscape shots would not work according to what you did at the event If you fallowed that rule, your pics would have come out overexposed I would imagine. Instead you used your instinct and it paid off

Jay

[KellyL]

Here is an example of what I did at the play. Not the best example from the set, but I need to get some other things done today! I swear, I could sit here at the Camel all day long.

Now that I have a basis for understanding things better, I will try the brightest spot step down 1 - 2 stops for landscapes.

Thanks.

I metered for the brightest spot on stage and snapped.

[heartseye]

Brooks, I suggested Provia for it's long tonal range....and the 400 version because it has an even longer tonal range than the 100. Also, I get all the dof this shot needs....cheers...Bob

[Brooks]

Heartseye, Provia only comes in 35mm and 120 rolls. 400 ISO film in 35mm and even 120 is pretty grainy for a landscape. I've always tried to use the slowest speed, smallest grain film possible when shooting small roll film. I might use 400 ISO on 4x5 and certainly on 8x10 film for a bit more depth of field but 100 ISO or less on 35mm with a tripod and would seem to give the best results and still provide a choice of DOF.

Kelly, if you are metering the brightest part (where you want textural detail) of a scene then you open-up 1.5-2 stops to place that value in Zone VI.5 to VII on a digital capture. You might even be able to open up a bit more and place it in Zone VIII on a large MF digital back. My point is that you open up rather than stopping down from a Zone V reading when placing a highlight.

[KellyL]

I was trying to logically think this through over lunch.

By taking a reading from the highlight, you are telling the camera that you want the highlight properly exposed. Therefore, everything else would be very dark. Correct?

Let's say a highlight meters at ISO 100 f/8 1/250. Opening it up would be either using 1/125 or 1/60...bringing in more detail into the shadows.

The reason I metered for the highlights at the school play is because I got tired of blowing them when I metered for midtones. I am going to try this this afternoon and take a careful reading of what I produce and return here and report my results. I have to go photograph band camp.

[JohnC]

Trying to catch up on a few things:

Brice: there are different types of handheld meters. You are describing an indicent meter (reads the light hitting the meter). But you can have a reflected light meter (such as the one in your camera). A spot-meter is a reflected light meter. Brooks covered the use of the spot meter.

Kelly, keep in mind that what you see in books and in online galleries is typically someone's best images. They may have had 200 throw-aways for each image they show. As a photographer, you are in the "unfortunate" position of seeing all your images, good or bad. Don't get discouraged by what you see. Or go do a random photo search on Flickr or Pbase and see what turns up. You will feel better about your capabilities.

Kelly: On your stage photo... great exposure on the faces and the main characters. The background, especially near the floor and way in back, doesn't reallly matter. Nor do thae shadows on the legs. If you did separate readings for the face and for the deep shadows you probably would have come up with a bad image. Sometimes you can't get everything in the scene. Then you go for the important parts and do you best to not blow out the highlights. I think you did that very well in this example.

[kgphoto]

Kelly,

The Sunny 16 rule works on the moon too. All it is is the reflection of daylight off the moon, so for detail in the moon, shoot Sunny 16. If you want it to be a shinny ball, open up a few stops. Run a series of tests and see which one is what you expected it to look like, and that is what you use in the future.

This is true of all subjects. Since the face of the girl was comprised of a variety of tones a reflected reading gave you an average. If you were able to spot meter just her high lighted cheek and set your camera to that, it would have come out middle gray in tone. So normally you would open up 1.5 stops. Take a brunette person outside and meter the hair, both high light and shadow, skin, high light and shadow and various clothing. See how many f:stops they range.

If you haven't already done it, get Ansel Adams - The Camera and look at the pictures with the lines and arrows that show the relationship between the tones of the image and the Zone Scale. I think that will make it clearer for you.

IF you are going to use skin at your meter target, use the palm of the hand. Almost everyone(blacks, whites, Asian) has the same tone there and then open up one stop.

If you want to be a master, stop looking for short cuts. Stop averaging readings. See what the multiple readings are, know the tolerance of your medium and set the camera to record the best look you want, adding light when necessary.

[Brooks]

Kelly, If you are using a reflected light meter, such as the internal camera meter or spot meter, the meter will indicate an exposure (combination of f-stop and shutter speed) which will render what the meter reads as an 18% grey, or 12% medium grey depending on the meter.

Meter white snow and the exposure given by the meter will render that snow a medium grey. Meter the dark wood of a tree and the meter will give you a different exposure, (combination of f-stop and shutter speed) that will also render that darker tone as a medium grey.

That's all that reflected light meters can do. They render a medium grey, the same medium grey no matter what they are pointed at. Some camera meters will be biased up or down from that medium grey or will favor one part or several parts of the scene but a straight reflected meter will render the same medium grey no matter what you point it at.

The only thing a spot meter does differently is measure a very small area, a 1 degree "spot" in your scene. And that's the value of a spot meter as it allows you to measure a specific area in your scene.

If you take the exposure the spot meter suggests then that area will be rendered as a medium grey. If the area you measured is indeed a medium grey then your exposure will be correct for that area in your scene.

That's what happened when you metered your theatre scene. Your spot meter read an area with a combination of tomes, light and dark which averaged out to a medium grey. If you had been able to get on stage and fill the meters field of view with the white color of the central character's costume you would have needed to over-expose that reading by 1.5-2 stops to render the white color as a textured white.

And that's what you would do in a landscape such as the first one you posted in this thread. Read the fog on the left side of the shot, open up that reading by 2 stops to place the fog as a white highlight with detail instead of the medium grey that the meter first indicated.

If you're shooting digital capture or trans film you want to avoid blowing the highlights. Shadow detail is more recoverable than blown highlight detail so you meter the highlights and place them up on the tonal scale around Zone VII if you want detail. Some highlights will want to be brighter at Zone VIII where there is just a small amount of texture and sometimes a pure white is indicated in the image.

If you're shooting color negative or BW negative the opposite is true. It's easier to recover bright highlights than it is to get detail from shadows where there is no detail. In this case you would meter the darkest shadow area where you wanted textural detail and under expose it by 2 stops to place it in Zone III.

If you are shooting BW film and controlling your development, after placing your shadow detail in Zone III you would then read your highlight and indicate an increased N+ development or decreased N- development to expand or compact that highlight up or down to Zone VII or Zone VIII. That's the basis of the Zone System for exposure and development control for BW processing.

With digital or color trans film capture we can't really control the development (there is some PhotoShop control of "processing" in digital capture) but we can use the exposure component of the Zone System to control exposure and highlight placement.

[cyclohexane]

If you haven't already done it, get Ansel Adams - The Camera and look at the pictures with the lines and arrows that show the relationship between the tones of the image and the Zone Scale. I think that will make it clearer for you.

The pictures with the lines and arrows are actually in The Negative. I recently finished reading The Camera, and there is only fleeting mention of the Zone System.

[KellyL]

If you want to be a master, stop looking for short cuts. Stop averaging readings. See what the multiple readings are, know the tolerance of your medium and set the camera to record the best look you want, adding light when necessary.

I didn't realize I was looking for short cuts. What I am looking for is understanding, which is why I started this thread. I haven't heard nor read an explanation anywhere of what you have written. I have read two books specifically on exposure and neither of them have given detailed explanations of what you just wrote. Those books were written by masters.

I am looking to understand as fully as I can. Please remember, I am learning this foreign language as I play with my toys.

Bob must be cringing as he reads all of this advice to follow Ansel's zoning.

Open up...I understand this to mean let more light in.

Step up, step down. I am just making sure that I understand the terms we are using.

Open up one or two stops: Adjust your camera settings to let more light in one or two stops.

Step down one or two stops: Adjust your camera settings to let less light in.

Just checking.

So Kirk, to understand what you wrote, I would imagine the world before me in black and white...various shades of gray, each with a specific point on the histogram. Since my medium is digital, I know that it can capture 256 shades of gray. 256 being pure white, 0 being black.

I have set my camera up at ISO 100 and want to use f/16 as my desired aperture. Such low ISO to reduce noise and a low aperture to increase depth of field. This is going to require a rather slow shutter speed.

Let's say the highlight measures at 1/200 and the shadow measures at 1/15. Okay...where do I go from here? There is roughly a five stop difference in these two readings, if I understand correctly...or is that a four stop difference? I think that would be a four stop difference because you don't count the stop you are on in figuring the differences.

1/15...one....1/30...two...1/60...three...1/25...four...1/250

Sorry that has to be so elementary, I am sure there is atleast on other person reading this thread who might appreciate its simplicity.

So what does that tell me? What do I set my camera at? How do I know what the tonal range of my camera is? What is the dynamic range of my camera? How can I use that information to create an accurate exposure? Why was this left out of two different books on understanding exposure, and why did Scott Kelby, in his book on The Digital Photograpy Book, recommend over and over that you should just put your camera on aperture priority and just leave it there?

Not trying to be a smart ars, but if you are going to bust my chops for looking for shortcuts I need a little help seeing the bigger path.

[cyclohexane]

Let's say the highlight measures at 1/200 and the shadow measures at 1/15. Okay...where do I go from here? There is roughly a five stop difference in these two readings, if I understand correctly...or is that a four stop difference? I think that would be a four stop difference because you don't count the stop you are on in figuring the differences.

That is a four stop difference.

How do I know what the tonal range of my camera is?

Experience. =)

What is the dynamic range of my camera?

stops that hold detail - noise (false detail) = DR

[Brooks]

Originally Posted by KellyL

Open up one or two stops: Adjust your camera settings to let more light in one or two stops.

Step down one or two stops: Adjust your camera settings to let less light in

That's correct.

The range of values: 1/15..1/30...1/60....1/125....1/250 is a 5 stop range. It's all inclusive in that there are changes in tones in all 5 stops of that exposure range.

You can determine the tonal range of your camera by photographing a large solid tone such as a painted wall etc. It's best to use something with texture so that you can judge visually whether you can see that texture at the extremes of dark and light exposure.

Set up your camera in manual exposure and manual focus. Focus on infinity to avoid any bellows factor and use a surface that is large enough to fill the frame AND be sharp at infinity focus. A stucco wall works well. Do a series of exposures starting at 5 stops under to 5 stops over the meter reading in increments of one stop. Using f-stops for these brackets is more exact than using shutter speeds. But you might have to adjust both f-stops and shutter speeds if you only have 9 f-stops ie: f1.4 2 2.8 4 5.6 8 11 16 22

Look at all 11 exposures and label them N-5, N-4, N-3, N-2, N-1, N ( which is the meter reading) N+1, N+2, N+3, N+4 N+5 You probably won't see any texture in N-5 and N-4 nor in N+4 and N+5. The darkest exposure that shows just a hint of texture is your shadow detail and the lightest exposure which shows some texture is your highlight detail. That's the dynamic range of your sensor. It will probably be N-3 and N+2 which is a 5 stop range. But it could shift either up or down from that range depending on your chip and whether you are using any custom curves in the raw file capture.

Now you know you can spot meter the highlight in a scene and place it on N+2 or N+3 and still have detail. If you then spot meter an important shadow area and it falls on one of the N- test exposures that show detail you know you'll have shadow detail there in your scene. If the shadow detail falls lower than the N- test exposure that showed detail then you know you won't have detail there. Always choose to favor detail in the important highlights if you are shooting digitally or with trans film.

Scott Kelby says to always use aperture mode because the aperture controls depth of field and, unless there's motion to consider, depth of field has the strongest effect on how your photo looks. And because it's the easy thing to do but it has nothing to do with controlling your exposure, just controlling your depth of field..

[KellyL]

I just returned from shooting some pictures at my daughter's band camp.

Michael and Brook...you are both experienced photographers so we need to come to an agreement on the number of stops. You both gave a different answer. Anybody else is welcome to chime in.

Brooks, I understand what you are saying about testing the dynamic range. I will set up a test this week and post the results here. I think an example would benefit others who are reading this thread. I know there are a few lurkers following this discussion who haven't chimed in. Every once in awhile they poke their heads in and make themsevles known!

Here is one of the pictures that I took at band camp. I post it because of the different skin tones.

[KellyL]

In this picture we have a darker skinned young lady, a fair skinned fore arm, a tanned girl, and a young girl not quite as tan.

ISO 100 f/16, 1/60. According to the f/16 rule, this shot is about one stop underexposed, right? But when I increase the exposure on stop in Lightroom, everything blows out.

With my handheld spot meter, the black shirt metered at 1/60. This was shot with center weighted meter mode. I think...but am not sure...that I metered with the camera on the black shirt and then checked it with the spot meter. I then took the photograph.

It isn't a fantastic picture, and I only post it because I am concentrating on understanding exposure at this moment not on compositon.

[heartseye]

Shakes his head......................................You can find the tonal or brightness range of your senson simply enough......Buy a Grayscale.....Photograph it. Then you will know.
For the rest of it,mmmmm,.....I'm going to pm you ......Bob

[KellyL]

I had to stop learning and get some pictures of band camp. I set my camera to Aperture priority and went to shoot. I think I used center weighted metering. For each shot I then took meter reading off of the cheek recomposed with button half pushed down and shot. This was with my 70 - 200 f/28 L lens. I think I am learning how to use it more successfully.

[KellyL]

Let me be clear about recomposing these shots, I did not zoom in or out, I just changed the position of the subject in the frame.

[expensive_hobby]

I think everyone is somewhat talking over my head-- making my brain hurt. But I am going to try that +/-5 thing and post what I get.

[harryd]

Originally Posted by KellyL

I know there are a few lurkers following this discussion who haven't chimed in. Every once in awhile they poke their heads in and make themsevles known!

Your right Kelly, I am following it but your have experts sharing knowledge which is way over my head but I am trying to learn from what I can understand. I can not add anything here but to say THANKS TO YOU ALL, I am ether learning or getting more lost with each post. (Still waiting on my AHH moment!)

[cyclohexane]

Michael and Brook...you are both experienced photographers so we need to come to an agreement on the number of stops. You both gave a different answer. Anybody else is welcome to chime in.

The difference is four stops. The total range is five. We didn't say anything different. =)