TOKYO – Nikon Corporation is pleased to announce the introduction of its newest DX-format digital SLR, the D90. More than just a new camera, the D90 represents a new era of digital SLR fun and creativity.
The first thing that will amaze photographers about the D90 is its stunning image quality, which takes its inspiration from Nikon’s flagship DX-format digital SLR, the D300. The D90’s image sensor and 12.3 effective megapixels combine with Nikon’s exclusive EXPEED image processing to deliver outstanding images featuring fine details, smooth tones, rich colors and low noise across a wide ISO sensitivity range.
The D90 is the world’s first* digital SLR camera with a movie shooting function that delivers genuinely cinematic results, enhanced by the creatively shallow depth of field made possible by the DX-format sensor. This is further refined by the optical quality and broad selection of NIKKOR lenses — the same lenses relied upon by professional photographers the world over. Thanks to the D90’s large image sensor, D-Movie images exhibit less noise than those of a typical camcorder, most notably in low-light situations.
The D90 also provides remarkable performance and operability, featuring Nikon’s exclusive Scene Recognition System that advances precision in auto focus, auto exposure, and auto white balance in diverse shooting situations. Live View mode allows shooting while confirming the subject on the large 3-in., approx. 920k-dot high-density color LCD and offers three contrast-detect AF modes to allow photographers to focus on any point in the frame, enabling a greater variety of composition. In addition to wide and normal area AF, the D90 offers face priority AF in Live View mode for even sharper pictures of people.
All of these powerful features and more are housed in a compact, comfortable-to-hold body, with intuitive controls. In other words, the D90 is a camera that will satisfy the requirements of passionate photographers who demand superior image quality and crave exciting new photographic possibilities.
Nikon D90 spec:
-12.3 effective Megapixel CMOS sensor
-Supports all Nikkor F-mount lenses, with a 1.5X focal length conversion ratio
-3-inch LCD display with 920,000 pixels
-Optical viewfinder has a 0.94x magnification
-Live view with contrast detect AF and face detection
-Full manual controls, with ISO range of 200 - 3200, expandable to 100 - 6400
-11-point autofocus system with 3D tracking
-Can take up to 100 JPEGs in a row at 4.5 frames/sec (not sure about RAW yet)
-Can record "D-movies" at 1280 x 720 (720p) at 24 fps, with sound
-The time limit for a single 720p movie is around 5 minutes
-Lower resolutions are available, with longer recording times
-As you'd expect, the zoom and focus must be operated manually once recording starts
-Movies are saved in AVI format, using the M-JPEG codec
-Built-in wireless flash support
-Dust reduction system
-Other features include Active D-Lighting, distortion control, image straightening
-HDMI out port for connection to an HDTV
-Optional GPS unit allows for easy geotagging; the GP-1 ships in November, pricing TBD
-Uses EN-EL3e lithium-ion battery; 850 shots per charge
-Includes new F3.5-5.6, 18 - 105 mm ED VR lens; lens will be available separately for $399
-Ships next month for $999 body only, or $1299 with the 18 - 105 mm lens
LAKE SUCCESS, N.Y., August 26, 2008 – With the demand for digital SLR cameras reaching unprecedented levels, Canon U.S.A., Inc., a leader in digital imaging, is answering the call with the announcement of the next evolution in advanced amateur digital SLR photography, the EOS 50D Digital SLR Camera with 15.1 megapixel resolution and Canon's new DIGIC 4 image processor. Designed to offer extraordinary quality and image control for the advanced photographer with a passion for the art, the Canon EOS 50D Digital SLR camera includes an expanded ISO range, improved noise reduction, and in-camera photo editing features. Canon has loaded the EOS 50D camera with a number of enhancements and some trickle-down technology from Canon's professional Digital SLR cameras, as well as a new Creative Auto Mode (CA) that gives users more creative flexibility to make image setting adjustments conveniently without the need to be a photo expert.
Canon has built upon the success of the popular EOS 40D model - which will remain in Canon's line - with the EOS 50D Digital SLR camera. Expected to be the camera body of choice for advanced amateur photographers this holiday season, the Canon EOS 50D Digital SLR camera carries over the EOS 40D's 14-bit Analog-to-Digital conversion process for smooth tones, and also includes enhanced noise reduction, especially at higher ISO ranges which will help bring those romantic nighttime shots into greater focus and clarity. Capable of shooting 6.3 frames per second (fps), the EOS 50D Digital SLR camera is ideal for shooting everything from beautiful night landscapes to fast-action sports.
"Advanced amateur photographers blur the line between the hobbyist and the professional, looking for professional features and capabilities in their equipment that will allow them to capture that awe-inspiring image. Canon is constantly striving to provide these shooters with the most advanced imaging technology, like the new EOS 50D Digital SLR camera, to fuel their passion for photography, and help them achieve their creative potential," stated Yuichi Ishizuka, senior vice president and general manager, Consumer Imaging Group, Canon U.S.A. 
Improved Image Quality
The EOS 50D Digital SLR camera's 15.1-megapixel CMOS APS-C size image sensor has been improved thanks to the use of newly designed gapless microlenses over each pixel to reduce noise and expand sensitivity up to ISO 12800. The faster processing speed of the camera's DIGIC 4 image processor contributes to the fast 6.3 frame-per-second (fps) continuous shooting capability (for bursts of up to 90 Large/Fine JPEGs or 16 RAW images on a UDMA CF card), to give shooters the tools they need to capture that perfect moment in perfect clarity.
The Canon EOS 50D camera provides ISO speeds from ISO 100 up to ISO 3200 in 1/3-stop increments, along with two high-speed settings - H1 and H2 - of ISO 6400 and ISO 12800, respectively. Along with a wide ISO range, Canon gives shooters more tools to help maximize clarity and color. The EOS 50D Digital SLR camera offers multiple levels of noise reduction during high-speed shooting. Users can choose from one of four settings- Standard/Weak/Strong/None - to help reduce digital noise that can result from poor lighting conditions.
As part of the camera's internal image processing, the Canon EOS 50D Digital SLR camera conducts peripheral illumination correction, which automatically evens brightness across the image field, making an image of a blue sky even toned throughout, a function previously accomplished through post-processing software on a personal computer. Thanks largely to the DIGIC 4 processor, this automatic adjustment can be made in-camera during shooting with JPEG images or corrected in post-photoshoot processing with RAW images through Canon's Digital Photo Professional (DPP) software, which is supplied at no extra charge.
Helping to ensure each picture's subject is clearly visible, Canon's enhanced Auto Lighting Optimizer analyzes the brightness of subjects and automatically adjusts dark images so that they appear brighter, perfect for subjects in shade or in backlit situations. The Auto Lighting Optimizer on the EOS 50D Digital SLR camera has been updated not only to optimize images while they are being taken, but can also optimize images post-capture, during playback, to help ensure the subject of each image does not appear too dark. This is especially helpful when an amateur photographer uses the camera, because post-capture enhancement can help maximize image quality without the need of a computer.
A significant upgrade to the Canon EOS 50D camera is its large, clear 3.0-inch Clear View LCD screen which features 920,000 dot/VGA resolution, four times the pixel count of the EOS 40D camera's screen, for better clarity and color. To help show off those fantastic shots, the EOS 50D camera includes an HDMI (High-Definition Multimedia Interface) output to display crisp, clear images on a High-Definition TV. The EOS 50D recognizes the needs of today's photographers, and the faster processing speed of the DIGIC 4 processor helps support UDMA cards for faster writing of image files.
The camera is also equipped with a high-performance viewfinder featuring 0.95x magnification and the same high-performance Autofocus (AF) system as the EOS 40D camera with nine cross-type sensors for accurate target subject acquisition with lenses possessing maximum apertures of f/5.6 or faster and a high-precision diagonal center cross-type AF point that's effective with f/2.8 and faster lenses, helping photographers ensure better focus of their targets. The AF Microadjustment feature, originally introduced last year with the Canon EOS-1D Mark III professional digital SLR camera, has also been added to the EOS 50D for maximum control over focusing precision.
Canon Gets Creative For Advancing Amateurs
Canon is taking steps to give advanced amateurs more flexibility with a new "CA" Creative Full Auto setting on the EOS 50D Digital SLR camera's mode dial. This new setting goes a step beyond Full Auto, by allowing users to make adjustments before shooting while still in an Automatic mode, without needing to know the meaning of technical terms such as aperture, shutter speed, etc. In this mode, the camera menu on the back screen spells out options in common language for average photo enthusiasts, allowing them to "blur the background" or "lighten or darken the image." These easy-to-comprehend image options will help amateur photographers improve the shots they are capable of taking, while helping them learn new techniques. When in the new CA mode, users will be able to adjust flash settings, brighten or darken images, blur the background, set the camera's drive mode, and select a picture style directly on the camera's LCD screen.
Better Live View
For photographers who prefer to frame their shots using the camera's 3.0-inch Clear View LCD screen, Canon has improved the Live View function of the EOS 50D Digital SLR camera to include "Quick Mode AF," "Live Mode AF," and "Face Detection Live Mode AF" that detects up to 35 individual forward-looking faces for better focus and clarity when taking group or portrait shots. The camera's Quick Mode AF setting flips the mirror down and carries out regular phase-detection autofocus, while the Live Mode AF and Face Detection Live Mode AF use the camera's CMOS image sensor for contrast detection autofocus. Two detailed grid displays have also been added to Live View shooting as optional settings for easier composition.
Two Small RAW Formats
In addition to the RAW and JPEG image capture modes that photographers are accustomed to, the EOS 50D Digital SLR camera now offers more manageable resolution settings and file sizes with two sRAW recording formats, sRAW1 and sRAW2. At the sRAW1 setting, resolution is 7.1 megapixels with a file size that is approximately 25 percent smaller than a standard 15.1 megapixel RAW image. With the sRAW2 setting, resolution is 3.8 megapixels at less than half the file size of a standard RAW image, retaining all of the flexibility and creative possibilities associated with full-size, conventional RAW images. The EOS 50D is the first Canon Digital SLR that allows the use of RAW and sRAW settings in Basic Zone as well as Creative Zone shooting modes, even further improving the camera's flexibility.
EOS Integrated Cleaning System
The Self-Cleaning Sensor Unit for the Canon EOS 50D has also been upgraded and now includes a fluorine coating on the low-pass filter for better dust resistance. The Self-Cleaning Sensor Unit uses ultrasonic vibrations to shake dust particles off of the low-pass filter in front of the sensor each time the camera is powered up or shut down. The second part of the system includes a software component where sensor spots are mapped and saved as Dust Delete Data that is attached to the image file for removal during post processing using Canon's DPP software.
Pricing and Availability
The EOS 50D is compatible with the full lineup of Canon EF lenses as well as the Company's ever-growing line of affordable EF-S lenses created specifically for Canon Digital SLRs with APS-C size image sensors. The Canon EOS 50D Digital SLR camera is scheduled for October delivery and will be sold in a body-only configuration at an estimated selling price of $1,399.00*. It will additionally be offered in a kit version with Canon's EF 28-135mm f/3.5-5.6 IS USM zoom lens at an estimated selling price of $1,599.00*.
New EF-S 18-200mm f/3.5-5.6 IS Lens
Canon has answered the call from advanced amateur photographers looking for a solid all-around lens with the introduction of the new EF-S 18-200mm f/3.5-5.6 IS zoom lens. With an incredible focal length range equivalent to 29-320mm in the 35mm format, the new EF-S 18-200mm lens will make an excellent addition to any camera bag, and it gives shooters a great lens to capture both standard as well as telephoto images. The new lens features Canon's built in Optical Image Stabilization system which gives the equivalent effect of a shutter speed roughly 4 steps faster, for better image clarity, even in shaky shooting conditions. With a minimum focusing distance of 0.45m/1.5 ft. at all zoom settings, this new lens should prove to be ideal for those situations where swapping lenses isn't an option. An ideal complement to the EOS 50D SLR camera and all other EF-S compatible EOS SLR cameras, the EF-S 18-200mm f/3.5-5.6 IS lens is scheduled to be in stores this October at an estimated selling price of $699.00*.
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Canon 50D spec:
-15.1 effective Megapixel CMOS sensor
-Supports EF and EF-S lenses with a 1.6X focal length conversion
-New DIGIC 4 image processor
-3-inch LCD display, with 920,000 pixels; screen has multiple coatings for dirt, reflection, and scratch resistance
-Live view with three AF modes (including contrast detect), plus face detection
-Full manual controls; ISO can go to 12,800
-Can take up to 16 RAW or 90 JPEGs at 6.3 frames/second when using a UDMA CF card (there will be fewer JPEGs if you are not)
-Has three different RAW sizes: full resolution, 7.1MP, and 3.8MP
-Adjustable noise reduction (apparently only in continuous shooting mode)
-New Creative Auto Mode gives point-and-shoot users a little more manual control
-Quick Control screen lets you quickly adjust camera settings (like Olympus SLRs)
-Automatic vignetting correction + auto lighting optimizer (brightens shadows)
-Dust reduction system (same as the 40D)
-CompactFlash Type II slot; compatible with UDMA high speed cards
-HDMI output
-Optional battery grip and wireless file transmitter
-Uses BP-511A battery; 640 shots per charge
Priced at $1399 body only, $1599 with the 28 - 135 mm EF lens
www.canonusa.com
Sometimes when you don’t have a lightmeter at the hand ( handheld lightmeter or a old film camera without through-the-lens light meter), then you may wonder how to set manually aperture and shutter speed of your film camera for correct exposure. Luckily, there is a very usefull rule called “Sunny 16” to help you with a exposure on a sunny day.
The Sunny 16 Rule
The basic guide to photography exposure is very simple. If you have a bright, sunny day, then use f-stop 16 for your camera lens aperture. The shutter speed should then be set to the equivalent of your ISO film speed – or the next number over. For example, if you are using an ISO film speed of 100, your shutter speed should be set to 1/125. More than often, your shutter speed number will be higher than the ISO film speed, but it is much easier to remember that film speed equals shutter speed.
The Sunny 16 rule can also help to determine aperture and shutter speed settings when conditions are not typical sunny days. For example, super bright areas like snow or sand will require you to open one f-stop to f/22 and a hazy sun will require you to close one stop to f/11. This will, of course, require you to change the shutter speed settings. Remember, when opening your aperture you are doubling the amount of light and halving the shutter speed and when closing the aperture you are halving the amount of light and doubling your shutter speed.
Here is a quick table to help you understand the Sunny 16 rule, how it applies to different film speeds, and how different amounts of sun will affect the f-stop and shutter speed.
Part III Using the 18% gray card to get a correct exposure.
Reflected light meters are calibrated to give an accurate exposure when pointed at subject with reflectivity somewhere near 18%; the exact value varies and the details are complex. By placing a gray card in the scene to be photographed and taking a reading off of it with a reflected light meter, the photographer can be assured of consistent exposures across their photographs. This technique is similar to using an incident meter, as it depends on the illuminance but not the reflectivity of the subject.
Using the gray card to determine exposure
For artificial light place the card to and in front of the subject, aimed halfway between the main light and camera.
When using daylight place the card in front of the subject pointing at the camera.
You can take your your readings with the card near your camera if you place the card so it is in the same relationship to the light source as the subject.
Exposure compesation:
- if the subject is very dark -> increase your calculated exposure by 1/2 or 1 stop
- if the subject is very light -> decrease your calculated exposure by 1/2 or 1 stop
- if you are unsure of the best exposure -> use bracketing technique to be sure you have the appropiate exposure.
Using the gray card to determine lighting ratios
Lighting ratios are very important in studio portraiture and product photography because they reflect how much contrast there will be between important light and dark areas in a picture.
Some contrast is essential to give a three-dimensional quality to a photograph, however too great a difference will exceed the ability of the film to capture both the highlights and shadow detail. For best quality prints, the lighting ratio should not exceed 3:1 for color film and 5:1 for black and white film.
In calculating a lighting ratio, the combined illumination from the main light and the fill light are compared against the illumination provided by the fill light alone. This ratio is expressed as two numbers, as in 2:1. The first number represents the combined strength of the main light and fill light, while the second number represents the fill light alone.
Lighting Ratio Technique
You can use an incident light meter to determine the lighting ratio, or a gray card and your camera light meter can do the same. Let's see how this is done.
Placing the gray card close to the subject, first read the main light plus the fill light, positioning the card for the highest reading on your light meter. Usually this means aiming the gray card at the main light. (Position 1 in the diagram.) Note the reading. Turn off the main light, aim the gray card toward the camera lens (position 2) and read the fill light illumination. Note the reading and calculate the difference in f. stops.
Part II Get exposure readings with camera-in lightmeter
Digital cameras have a build in lightmeter. This lightmeter measure the amount of light (luminance) reflected from subject to the camera. Read the Reflected-light readings from Part I. With other words camera in lightmeter is very similary with reflected lightmeter, but in this case exposure readings depends by metering modes.
Spot metering
With spot metering, the camera will only measure a very small area of the scene (between 1-5% of the viewfinder area). This will typically be the very centre of the scene.Spot metering is very accurate and is not influenced by other areas in the frame. It is commonly used to shoot very high contrast scenes. For example, if the subject's back is being hit by the rising sun and the face is a lot darker than the bright halo around the subject's back and hairline (the subject is "backlit"), spot metering allows the photographer to measure the light bouncing off the subject's face and expose properly for that, instead of the much brighter light around the hairline. The area around the back and hairline will then become over-exposed. Spot metering is a method upon which the zone system depends.
Another example of spot metering usage would be when photographing the moon. Due to the very dark nature of the scene, other metering methods tend to overexpose the moon. Spot metering will allow for more detail to be brought out in the moon while underexposing the rest of the scene.
Partial metering
This mode meters a larger area than spot metering (around 10-15% of the entire frame), and is generally used when very bright or very dark areas on the edges of the frame would otherwise influence the metering unduly. Like spot metering, some cameras can use variable points to take readings from, (in general autofocus points), or have a fixed point in the centre of the viewfinder. Partial metering is found mostly on Canon cameras.
Center-weighted average metering
In this system, the meter concentrates between 60 to 80 percent of the sensitivity towards the central part of the viewfinder. The balance is then "feathered" out towards the edges. Some cameras will allow the user to adjust the weight/balance of the central portion to the peripheral one. One advantage of this method is that it is less influenced by small areas that vary greatly in brightness at the edges of the viewfinder; as many subjects are in the central part of the frame, consistent results can be obtained.
Average metering
In this metering mode the camera will use the light information coming from the entire scene and averages for the final exposure setting, giving no weighting to any particular portion of the metered area.
Multi-zone metering
This mode is also called matrix, evaluative, honeycomb, segment metering, or esp — (electro selective pattern) metering on some cameras.
This metering mode was first introduced by the Nikon FA, where it was called Automatic Multi-Pattern metering. On a number of cameras this is the default/standard metering setting. Here the camera measures the light intensity in several points in the scene, and then combines the results to find the settings for the best exposure. How they are combined/calculated deviates from camera to camera. The actual number of zones used varies wildly, from several to over a thousand. However performance should not be concluded on the number of zones alone, or the layout. In general, the most advanced metering is found on single-lens reflex cameras.
Many manufacturers are less than open about the exact calculations used to determine the exposure. A number of factors are taken into consideration, including the following: Autofocus (AF) point, distance to subject, areas in focus or out of focus, colours/hues of the scene, and backlighting. Multi-zone tends to bias its exposure towards the autofocus point being used (whilst taking into account other areas of the frame too), thus ensuring that the point of interest has been exposed for properly. A database of many thousands of exposures is pre-stored in the camera, and the processor can use a selective pattern to determine what is being photographed.
Some cameras allow the user to link or unlink the autofocus and metering, and allow the option of locking exposure once AF confirmation is achieved, AEL, (auto-exposure lock). Using manual focus, and on many compacts/bridge cameras, the AF point is not used as part of the exposure calculation, in such instances it is common for the metering to default to a central point in the viewfinder, using a pattern based on that area. There is considerable variation from different manufacturers as to how multi-zone metering is implemented, and even from the same maker in their model range, and how much "priority" is given to the AF point itself. Some "Scene" modes, such as sunset, sports, night exposures etc, also often affect the calculations of this metering pattern.
However, some photographers may be uncomfortable with multi-zone metering. This tends to stem from a lack of clarity about "how" the camera reacts in certain situations. The design concept behind multi-zone is to reduce the need to use exposure compensation.
Some users have problems in wide-angle shots with high contrast, due to the large area which can vary greatly in brightness. It is important to understand that even in this situation, the focus point can be critical to the overall exposure.
Reference:
Light metering
Understanding metering
Part I Take exposure readings with handheld lightmeter
Exposure can be measured in two basic ways. One way is to measure the light incident on the subject, i.e. the brightness of light illuminating the subject (illuminance) (see Fig1.); the second way is to measure the light reflected by subject, i.e. the intensity of the light reflected from the subject in the direction of the camera (luminance)(see Fig.2).
Before selecting the most suitable measuring method, you need to fully understand the different sources of light you are working with, as well as the influence of the positions and directions of receptors during measurement.
Incident-light readings
In general photography, light from the illuminating light source reflects off the subject and passes through the lens to form an image on the film or digital sensor for exposure.
To accurately calculate exposure in incident-light readings, you need to know how much of illuminating light is actually reflected from the object to the camera. To do this, you need to know how light or how dark the subject is, i.e. the reflectance of the subject.
Since a typical value of reflectance for many scenes is 18%, this value is used to calculate the light intensity reflected from the subject towards the camera. The exposure reading ( f-number and shutter speed) are then calculated to reproduce the metered area as a midtone with 18% reflectance.
Thus, incident-light readings are based on this standard value of 18% reflectance.This means that areas of subjects having a reflectance higher than 18% will turn out brighter (e.g. white), while areas of reflectance lower than 18% will turn out darker (e.g. black).This will produce a clear contrast in the picture of the subject.From this we can see that this measuring method provides for natural tonal range over the entire composition.
When make incident-light readings with a handheld lightmeter, you must use spherical diffuser and flat diffuser creatively. When photographing three-dimensional objects such as people, the highlights and shadow areas of scene depend on the direction of main illuminating light source. Exposure is also influenced by any light reflected towards the camera from the sides or rear of the subject (Fig.3.a) 
In these situations, the Spherical Diffuser captures the illuminating light coming from different directions at the position of the subject, so that the exposure readings takes into account the contribution of this light on illuminating the subject.
On the other hand, with flat subject such as pictures or documents, light from the sides or rear of the subject generally make little or no contribution to illuminating the subject (Fig.3.b).So, for these situations, accurate exposure readings are made using a Flat Diffuser to capture only the illuminating light from the front of the subject.
Incident light readings is a proper method to take correct exposure for portrait, still life photography or studio, i.e. subjects can be separate from background. This method is not indicate for landscape photography.
Reflected-light readings
Reflected-light exposure readings directly measure the amount of light (luminance) reflected from subject to the camera.Unlike the case of incident light reading, this method does not rely on the assumption of standard subject reflectance of 18%.Based on the measured amount of light falling on the subject, the meter calculates the appropriate exposure value for reproducing the subject on film at a suitable medium density (midtone). This means that in reflected-light readings, all subjects, regardless of their reflectance, i.e. regardless of whether they are bright or dark (white or black), will be reproduced at the same tonal density (midtone).For this reason, when making reflected-light exposure readings, it is important to decide which area of the subject to measure, since the reflectance will generally vary quite widely over composition under different conditions.
There are two basic methods for making reflected-light readings with a handheld lightmeter.These methods use different distances and angles between exposure meter and subject. One method is “averaging metering” where the entire scene is measured for calculate exposure readings (Fig.4).
The other is “selective metering”, where illumination is measured only for a specific part of the composition (Fig.5).
In averaging metering, all the reflected light from the entire subject that fits within the field of view of meter is measured using a receptor with a relative wide acceptance angle.If the average reflectance of subject is close to 18%, the exposure reading will be close to the value produced by an incident-light reading. For this kind of situation, this is the fastest and easiest kind of reflective-light reading to make.
However, if there is a large bright or dark area within the camera’s field of view, or if there is any backlighting, these factors may cause the exposure reading to be too high or to low.So caution is needed in these situation.
In selective metering, measurement are taken so that only light reflected from specific, selected part of the subject falls within the acceptance angle of the meter. This is achieved by using a receptor with a narrow acceptance angle, or by placing the receptor sufficiently close to the subject.Since the meter is not affected by light from other parts of the scene, the selected part of the subject is reproduced at a suitable tonal density.When the measured part has a normal reflectance, e.g. human skin, then, as in the case of averaging metering, the exposure reading will give a very similar result to incident-light reading. Thus, for photographing subjects of normal reflectance, such as people, this method offers highly accurate exposure readings. However, this method can cause problems if you selectively measure very bright (high reflectance) or very dark (low reflectance) subjects, because the meter assumes that the whole image should have the same tonal density as the selected area. So take special care about which part of a subject you selected area.So take special care about which part of a subject you select to measure when using selective metering.
Some examples of tricky exposures
-Point your camera at a scene with a lot of snow, sand, water, or sky - the camera doesn't know what it's looking at. Take pictures without adjusting the exposure and you'll get badly underexposed photographs - snow will look dirty and gray, landscapes with big expanses of sky or water will be too dark.
-Take a picture of a person standing in the shade with a bright background or with the sun behind them, backlighting their head. This can be very flattering portrait lighting if you know how to use your light meter correctly, but if you don't adjust your exposure to compensate for the bright background, you'll end up with near silhouettes.
