|
Home / Hobbies / Photography
Advanced Exposure and Metering
By:Jennifer Clarkson
Most humans see the world in living colour, but did you know that your camera’s light meter does not? Then how does it capture photos? Does it see the world in black and white? No! When your camera left the factory, it was calibrated to see the world as neutral grey, no matter what the lighting conditions! Neutral grey is defined as an object that reflects 18% of the light rays that hit it.
What this really means is that your camera thinks
ALL light that hits ALL of your grey subjects will
reflect back approximately 18% of that light.
Even in the dark!
The 18% isn’t important – just think of it as a mid-shade or midtone colour and slot the following concept into your wallet of knowledge:
The trick to ensuring your camera exposes the colour scene correctly is to meter off an image that emits 18% light, and use your camera's suggested settings from the grey scenario after recomposing your ultimate scene.
More specifically, point your camera at a midtone shade under the same lighting conditions, note the f-stop and shutter speed that your camera’s meter recommends with the given ISO, and use those values to snap your photo once you recompose your scene, despite your camera's tendency to use a different set. You will need to either lock your exposure or use manual settings to do this.
=> TIP: you can purchase an 18% grey card and use it to meter off of in tricky conditions. Grey cards are sold at most camera stores in the Photo Accessories section, but I got mine from the National Geographic Field Guide
Let’s recap:
Steps to meter a tricky scene correctly
1) Set your camera to spot metering and point it at an object that is neither dark nor light, but is instead a midtone.
2) Press your shutter release button half way and note what f-stop and shutter speed it recommends under the current ISO speed
3) Lock your exposure, or change your camera to use manual settings and set the recommended f-stop and shutter speed
4) Recompose your scene and snap that photo!
=> scenarios your camera should automatically expose correctly:
1) frontlit subjects
2) sidelit subjects
3) overcast skies
=> problem scenarios:
1) waterfalls or rapids
-- white water will look grey in auto-exposed photo, and the scenery will be under-exposed
2) snow
-- white snow will turn out grey, and the rest of the scenery will be under-exposed
3) bright yellow flowers
-- flower will turn out darker than you expect, as will the background
4) black animals
-- black animal will turn out dark grey, and the background will be over-exposed
5) dark-skinned people
-- skin will turn out light brown and the background will be over-exposed
6) backlit portraits
-- subject will turn out very dark and background will be less bright than you would expect
Again, the secret to properly exposed photos is to meter off something that uses midtones, but there are some caveats to that rule. Check out the list:
Frontlit Snowy Landscape
- take out your 18% grey card and place it in the sun, which is the same lighting as what your snowy landscape has
- point your camera at the grey card and fill your frame with it – no need for the card to be in focus
- meter off the grey card (i.e. check the f-stop and shutter speed it recommends)
- put down your grey card, recompose your snowy landscape, and snap your photo with the f-stop and shutter speed determined in the previous step
Of course, if you don’t have a grey card, use the next scenario instead
Sunny Days
- meter off the blue sky
Coastal Scenes or Lake reflections at Sunrise or Sunset
- meter off the sky in the reflection
Backlit Sunrise or Sunset landscapes
- meter off the backlit sky, always without a sun in your frame
City or Country scenes at Dusk – this is a tricky one!
1) set your aperture to f/4: don’t ask, just do!
2) meter off the dusky blue sky
3) do the math and figure out which exposure works based on the f-stop you actually want to use
When you increase your f-stop by one setting, you must double the length of time your shutter stays open. For example, suppose f/4 results in a recommended shutter speed of ½ second
Then f/5.6 ~ 1 second
f/8 ~ 2 seconds
f/11 ~ 4 seconds
f/16 ~ 8 seconds
f/22 ~ 16 seconds
f/32 ~ 32 seconds
Do you see the pattern yet? Let’s look at another example: Suppose f/4 results in a recommended shutter speed of 1/15th second
Then f/5.6 ~ 1/8th second
f/8 ~ ¼ second
f/11 ~ ½ seconds
f/16 ~ 1 seconds
f/22 ~ 2 seconds
f/32 ~ 4 seconds
TIP: for those of you who don’t want to carry an 18% grey card around in your camera bag, you can calibrate the palm of your hand against your grey card, and then leave your card at home. How?
1) set your aperture to f/8 and place your grey card in the sun
2) set your camera to spot metering and check the shutter speed it recommends
3) meter off your palm and check the difference – approx 2/3 or one full stop over exposed?
4) move your grey card to the shade and repeat the exercise; you should observe that your palm is consistently 2/3 to a full stop over exposed, regardless of the lighting conditions
Digg
del.icio.us
Blink
Stumble
Spurl
Reddit
Netscape
Furl
Article keywords: Photography photographer camera overexposed underexposed f-stop ISO aperture
Article Source: http://www.articles2k.com
Jennifer Clarkson is a Canadian photographer living in Ottawa. To read more of her Photography Tips and browse her Photo Galleries, visit her website at www.jclarksonphotography.com
. You can also browse her Photography Forum and quickly sign up to post photos for review.
|
|
| Top Photography Articles |
- 1). How to Select a Local Model Agency Without Getting Burned By : Bob Pardue
If you are an aspiring model, especially a beginner, you'll want to read this article before making any
contacts to model agencies. It's tough enough pursuing a modeling career when you are prepared but almost
impossible if you aren't!
The old cliche that says, "I'll just go down to the corner of Main or to the mall and get discovered." is totally
bogus! Believe it or not you're going to have to do some honest work to create a need for your modeling
services.
|
- 2). Fashion Models - Start Your Engines By : Bob Pardue
How to Promote Yourself as a Freelance Model
If you would rather promote yourself ...
Some models would rather promote themselves instead of listing through an agency. Nothing wrong with this but it does require more work on your part.
If your are signed with an agency, they promote the business, they talk to the clients in your behalf, they set up the shooting dates, they take the heat if you don't make it to the session, etc.
|
|
|
- 4). Underwater Cameras:Discover A Whole New World Underwater By : Albreht Moy
It is a known fact that over seventy-five percent of our world is covered in water, this world has just as many interesting things to take pictures of and is always changing with every ripple and wave. Underwater cameras are a great way to capture these scenes that are ever changing. Underwater cameras are great for deep-sea divers and the snorkeling community alike.
|
- 5). Get The Most Out Of Your Camera. (Part 1). By : TJ Tierney
Did you ever see an image where only a small part of it is sharp? Using the aperture ring correctly can maximise the artistic look of your image.
Not only does it determine the depth-of-field, it also has the power to direct the human eye.
The human eye is instinctively drawn towards noticeable points of an image. These are usually the sharpest and most important parts of an image.
|
- 6). How do Underwater Cameras Work? By : Nicola Kennedy
Underwater Cameras are cameras that are specially designed for underwater use or in circumstances that requires protection to prevent any water and pressure damage. There are many types of underwater cameras, depending on your budget and uses.
There are underwater cameras that are simply disposed of after use. These are the cheapest type of underwater camera available in the market.
|
- 7). Photography as a Fun and Interesting Hobby By : James Hunt
Photography is a fun hobby that interests many different people across a broad range of ages. Enthusiasts of all types have found a creative recreational outlet in the hobby of photography and with the advances in technology that have occurred in recent years ...
|
- 8). Filters For Landscape Photography. By : TJ Tierney
Filters are used in photography to bring back an image to the way our eyes have perceived the original scene. Some times it’s not possible for our cameras to record an exact scene - so we have to rely on the manufacturers of camera products.
Filters also help us to create mood in our images and bring out the best in a scene. A small selection of filters is well worth packing when heading off for a trip.
|
- 9). Use multi flash card readers to overcome data storage format incompatibilities. By : Ron Donnelly
As advanced consumer electronics like digital cameras, PDAs, multimedia mobile phones, and similar devices become increasingly affordable to the everyday user, we find ourselves having to keep track of more and more types of technology, which makes keeping all of our devices compatible with each other increasingly difficult. The technological marvels.
|
- 10). How To Take Better Kitten Pictures By : achiever
I compare my kitten with my kids and the love for my kids is equal to the love I have for my kitten, and that is why I make time to take my kitten pictures as my kittens grown into a lovely adult cat.
When anyone visits my home, they notice how well groomed my kitten is, and how well treated, and they also notice the collection of pictures I have of my kitten, I place my kitten pictures all over my home.
|
| New Photography Articles |
- 1). Digital Photography: Passion and Hobby Becomes Art By : John Darby
This article has put together a few tips to help you get convinced on the advantages of going digi and we have summarized the things that need your first priority or utmost attention toward the learning curve as soon as you begin to implement it in your work flow.
|
|
|
- 3). Digital Photography: In Focus By : John Darby
Learn how to take, edit and print your photos the right way using your digi cam through this article. This article discusses the tools and the features of a digital camera as well as the necessary tools in printing your digital photographs thereby eliminating the strange feeling that you will feel upon handling a digital cam.
|
|
|
- 5). How to Select a Local Model Agency Without Getting Burned By : Bob Pardue
If you are an aspiring model, especially a beginner, you'll want to read this article before making any
contacts to model agencies. It's tough enough pursuing a modeling career when you are prepared but almost
impossible if you aren't!
The old cliche that says, "I'll just go down to the corner of Main or to the mall and get discovered." is totally
bogus! Believe it or not you're going to have to do some honest work to create a need for your modeling
services.
|
- 6). SLR Film Photography Special Effects (Part 2) - Impressionist Effect By : Photo Views
This is a second article addressing SLR film photography Special Effects techniques that can be accomplished “through the lens”, being immediately immortalized on the film and ultimately the negative.
It requires no special instructions to the developing agent, whether your local photography shop or mail in developing service. Your prints will be developed with perfect exposure.
|
- 7). Panasonic Combination Digital Cameras By : Mike Reed
All About Combination Digital Cameras
Digital cameras are starting to become less attractive than all in one digital cameras which can often do many things other than just snapping photos such as record video, and play music. This certainly comes true in the Panasonic digital camera models. In an effort to show this wonderful technology, this article will look at one of the combination digital cameras.
|
- 8). Photography Q&A: The Basics Of Developing Photographs By : Travis Partrige
* Can I develop my own photographs?
Yes, you can. By having your own darkroom, it is possible that you can develop your own photos. You first need to set up your own darkroom and buy darkroom equipment.
* What equipment and supplies do I need in a darkroom?
A darkroom requires many kinds of equipment to get you started in developing your photos. It is expensive, so you should prepare a sufficient amount of money to get into this hobby.
|
- 9). How to be Prepared for Your Fashion Model Shoot By : Bob Pardue
The fashion model session - What to pack in your model case
OK, you're off to a model photo shoot. But, did you remember to pack your bag? Did you put everything you need in it? I hope this article will be helpful to you and start you on the right foot in making sure your model bag is complete.
What do you bring?
What you bring to your model photo session will depend upon whether this is your first shoot for a portfolio or a paying job.
|
- 10). Getting Photo Printing Help By : Matthew Noel
Photo printing help is commonly needed. With more individuals purchasing digital cameras, there is a wide need for help in printing off their pictures. While most standard computers with a decent printer can handle a good quality photo, others are looking for exceptional quality photos. The good news is that there is a wealth of help to be found for those who need it.
|
|
|
