Understanding Exposure

[KellyL]

There ya go! Thanks Jay. You are good company to have.

[jfrancho]

1. I use Partial almost exclusively. I want to be able to meter for elements in the scene, not an average of the whole scene.

2. Only for landscapes. 1 stop is probably too much, you can narrow your exposure down within a 1/3 stop.

3. Yes, but read it through metering, using spot or partial metering, not intuition.

4. Manual is a better AE lock than trying to hold your thumb on the * button for me.

5. Yep, but don't just chimp, hit the info button twice to see the histogram, and use that as your guide. The thumbnail is only good for rating composition.

6. See #5.

7. I find metering much more convenient than calculating shifts with the Sunny-16 rule.

8. Yes, in most cases this is a good idea, but not for correcting exposure. Its better for making subjective decisions about WB, contrast, and saturation later in the work flow.

9. I see this more af a landscape technique than a portrait thing, though it can be done. Multiple developments of a single raw don't give you much gain in DR, but it can give an interesting look. You can get more out of the Exposure, Shadows, and the Recovery sliders than you think, if you keep the Curve linear, and the contrast down. You can add contrast later in the work flow, if capturing maximum DR is the goal.

10. That was what I was saying all along.

Good stuff Kelly.

[kgphoto]

Kelly,

Brace your self.

You have come a long way. Thanks for all the Karma points. Scott seems to be following the amateur path to pro photography. By this I mean, he starts without a basic understanding and allows auto to do a lot of the work and then tries to understand what is happening and eventually learns what went wrong.

I gave you the rules you said you were looking for. Calibrate, meter and evaluate. As your understanding of the what numbers come up most often grows, so will your ability to evaluate a scene. I truly believe this is the fastest way to learn the scientific part of photography, not the fastest way to get just an image, any image on film.

Photography is a science and an art. Good science is the ability to develop procedures that will give a consistent result so that you can identify the factors that give a different result.

Art is just not taking pictures of ugly things.

[KellyL]

Kirk, I definitely am following the amateur path...Ihave no other path to follow! Calibrate, meter and evaluate are good tools, but learning what to meter and what to evaluate have been the substance of this thread. It is good to have the details.

[KellyL]

John,

Thanks for the commentary. It is just as it has been throughout this thread. There are a set of rudiments, and each photographer will find preferences and how to use those rudiments.

Your comment on partial metering has answered a long time question. Most things I have read tell folks to use evaluative 90% of the time. Partial metering makes more sense. Is partial metering one step away from center weighted? I'd need to google that and check that out.

One of my projects I want to do in the near future is to go out, survey a scene, record specifically what the meter readings are for each part of the scene, and determine what the range of the picture is. I think it would be a very interesting project and would help me understand the dynamic range found in any given scene. After learning to see the scene, I would be able to start developing a greater intuitiveness about how to read and meter from the beginning. I know...meter and expose for the highlights. Jay has helped me understand that more thoroughly with his cloud picture and the understanding that I gained by making the exposure ruler.

I FORGOT TO SAY THANKS TO BROOKES! Sorry Brookes. And you were so involved in the discussion!

The author of the article also concurred with you...get the best exposure possible and only tweak in raw.

Number 10: It was an article on landscapes. I see no real need to do this in portrait photography.

[KellyL]

I know...I said I was closing this chapter...but I wanted to respond.

[jfrancho]

Number 10: It was an article on landscapes. I see no real need to do this in portrait photography.

If its an available light picture, then you'll want to consider it.

[jfrancho]

Is partial metering one step away from center weighted? I'd need to google that and check that out.

To me, center weighted average says it all in the name - it's closer to evaluative, but prioritizes metering data from the center. Partial, only considers the data from the center ring, marked in the viewfinder. Spot metering is an even smaller area.

[Worm324]

My camera does not have spot metering, so I use partial to survey the scene. The 30d may have it though

Jay

[jfrancho]

Neither does my 20D. The 30D does have spot metering.

[Max@Home]

Originally Posted by jfrancho

4. Manual is a better AE lock than trying to hold your thumb on the * button for me.

...you do not have to hold it, press and it's locked...

...using Partial (or Spot if you have a 30D or 40D), after a press you have time to read the value, evaluate, take another meter reading, evaluate, take another, etc, and come to a balanced exposure

...€0.02...

Kindest regards!

Max@Home

[jfrancho]

you do not have to hold it, press and it's locked

shows how much I know. I use C.Fn.4-1, so the * button is focus lock for me.

[KellyL]

John, I meant number 9, typed number 10...oh well...

[jfrancho]

Originally Posted by KellyL

John, I meant number 9, typed number 10...oh well...

Darn keyboards! Mine goes to eleven

[Brooks]

Originally Posted by jfrancho

Darn keyboards! Mine goes to eleven

Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean it's louder? Is it any louder?
Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
Marty DiBergi: I don't know.
Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
Marty DiBergi: Put it up to eleven.
Nigel Tufnel: Eleven. Exactly. One louder.
Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel: [pause] These go to eleven.

[jfrancho]

Listen to the sustain. Just listen. WAHAHAHAHA!

I can't hear anything?

Well you would if it were plugged in.

[KellyL]

Feeling culturally illiterate. I think I need to read or listen to something other than photography books and videos.

[jfrancho]

Originally Posted by KellyL

Feeling culturally illiterate. I think I need to read or listen to something other than photography books and videos.

LOL. Yer the man, Kell. Go rent This is Spinal Tap, Best in Show, A Mighty Wind, or Waiting for Guffman. As a guy that has been in bands playing out since I was 15, I can say that everything that happened in Spinal Tap happened in real life, save the wandering cold sores.

[blumesan]

Now I understand why this thread has gone on for 27 pages and Kelly still hasn't found the holy grail.

[silentrob]

Originally Posted by KellyL

Full increment f/stops:

1.4 2.0 2.8 4 5.6 8 11 16 22

Each increment halves/doubles the light. Jay, we need to memorize these. With our digital wands, we can more f/stops in tighter increments.

You guys are so busy in this thread I can barely keep up. I don't think this has been really mentioned elsewhere, so here it is...

There are 2 ways to think of f stops. The more technical, and the simple. I'll handle them in that order.

You often see aperture written as f/2. This is because the aperture is actually a calculation based on your focal length (represented by f). Let's assume you're using a 50mm lens. At f/2 the diameter of the opening is actually 25mm or 50mm/2.

I'll skip the most detailed math (unless anyone requests it) but to reduce the size of the aperture by a full stop you need to cut the area in half, which means multiplying your f-stop number by 1.4 (square root of 2 rounded to one decimal). So f/2 minus a stop is 2.8 (2 x 1.4). Another stop gives us f/4 (2.8 x 1.4 = 3.92 and round up)

And by multiplying by the square root of 2 each time means that every other f-stop the number will double. This brings us to the easy way to remember.

Knowing that your aperture value doubles every 2 stops, you can get all the full stops pretty easily by just remembering two of them, 1.4 and 2.0.

Here's every other stop starting at f/1.4
1.4 2.8 5.6 11 22
And here's the others, starting at f/2
2 4 8 16 32

Combine those 2 and you have
1.4 2 2.8 4 5.6 8 11 16 22 32

And of course you've probably noticed that the numbers get rounded starting at f/11. I'm guessing this is just something that started to save space. Once the numbers hit 2 digits, including a decimal makes the numbers 4 characters. Easier to just round them back when these numbers were actually printed on the lens.