DSLR Essentials: Class Notes The digital SLR has seen a surge in popularity in recent years. Many are enjoying the superior photographic experiences provided by these feature packed cameras. Interchangeable lens systems allow users to choose from a wide array of lenses for virtually every purpose. Fast auto focus provided by silent focusing motors and phase detect AF contribute to the SLR s responsive handling. Larger sensor sizes provide superior image quality and better low light capability. The one aspect that separates the SLR from other cameras is the unique optical viewing system that uses a mirror to direct the image from the lens to the viewfinder. Figure 1 The mirror in an SLR directs the image from the camera lens up to the pentamirror/pentaprism where the upside down image becomes upright at the viewfinder. Get to know the parts of your SLR. When taking a picture, the mirror must flip up out of the way for the light to pass through the open shutter and then to the camera s sensor. This causes the viewfinder to go black when the shutter is open. Figure 2
Figure 3 Power Switch: When performing tasks such as changing lenses, attaching or detaching an accessory flash, or changing memory cards it is recommended that you turn off your camera s power. Shutter Release button: Besides being the button that takes the picture when half pressed this button activates the camera s auto focus and light meter and displays shooting info. Viewfinder: An SLR has an optical viewfinder not an electronic one which means you are looking through glass not at a monitor. This gives you a clear view in real time. Because of the mirror system of an SLR the viewfinder blacks out when the shutter is open. Diopter Adjustment: Look for a dial or slider marked +/- beside the viewfinder. Use it to adjust the viewfinder for your own eyesight. Command Dials: When in aperture priority, shutter priority or manual modes use the command dial(s) to change aperture or shutter speed. These dials can be used for many types of adjustments such as selecting your auto focus points and when used in combination with other buttons it could adjust things like ISO, AF modes, etc. Command Dials are sometimes found near the shutter release button.
Multi Selector: This multi directional touch pad is used to make many types of selections including AF points and menu navigation among others. During playback use it to go from photo to photo and on the Nikons use up or down directions to change playback information displays. When using playback zoom use the Multi Selector to move around the magnified photo. Playback button: Used to view the photos currently on your camera s memory card. Review your photos occasionally when shooting so that you can correct for mistakes as they happen. With the appropriate video or HDMI cables you can playback your shots on your TV or projector. Flash Release: This button is found on the left side of the camera near the built-in flash. When using the creative modes, use this button to pop up the built-in flash. In auto mode the flash pops up automatically. Many Nikons utilize this button or a second button nearby to access flash settings like red-eye reduction, slow synch and flash exposure compensation. Auto/Manual Focus Switch: Found on the left side of most lenses; use this switch to go from auto focus to manual focus. With many lenses attempting to adjust focus manually without first switching to manual can damage the lens. VR/Stabilizer Switch: Used to turn the lens stabilizer on/off. Leave the feature on when shooting with a hand held camera but turn it off when locked down on a tripod. Info/Display Button: This button changes the information displayed while viewing photos or while in shooting mode. Shutter, aperture, ISO, white balance, exposure and more can be viewed. Highlights warning and histograms during playback can be a valuable tool for judging exposure. Newer Nikon cameras allow users to press info twice when in shooting mode to access many camera settings quickly. Canon has the same feature found in the Q (quick access) button.
Switch out of Auto and get creative Your camera s Auto exposure mode allows the camera to make most of the decisions. Auto mode can block you from changing things like the White Balance, ISO, Exposure and Picture Styles among other things. Notice those options are greyed out and made unavailable in the display shown here. Take control. Switch to the creative modes Program (P), Shutter Priority (S or Tv), Aperture Priority (A or Av), and Manual (M) and get access to all of your settings. To change modes turn the Exposure Mode dial found on the top of most cameras. Some professional camera models use a button and dial to change modes. Most pro cameras only offer the creative modes. P Program Mode The Creative Mode with training wheels. Program mode is similar to Auto in that Aperture and Shutter are selected by the camera, allowing the user to concentrate on other things. Unlike Auto mode, Program allows adjustments to exposure, ISO, white balance, meter mode, picture styles, image quality, etc. Program Mode lets you get creative with some peace of mind. Remember to pop up the flash if you want to use it. The flash does not pop up automatically in creative modes.
S or Tv - Shutter Priority Mode to blur or not to blur Shutter Priority mode allows you to select the shutter speed while the camera selects the aperture. The shutter speed that you select affects how moving objects appear in your photos. Slower shutter speeds allow movement blur while fast ones freeze the action. Using a shutter speed that is too slow, when hand-holding a camera, causes the whole photo to blur. The shutter is the mechanism that controls how long the camera s image sensor is exposed to light. This period of time is called the shutter speed or time value. Modern SLRs have a very large range of shutter speeds. A typical SLR camera will have shutter speeds ranging from 1/4000 of a second to 30 seconds. A large range of shutter speeds allows you to freeze the fastest action or shoot a night landscape. The kayaker was photographed with the shutter set to 1/2000 of a second in bright daylight conditions while the northern lights were shot at 15 seconds. One key to understanding shutter selection is knowing that not all speeds can be used in a given lighting situation. Fast shutter speeds will work in bright conditions but will underexpose if used in low light. Slow speeds are needed for night shots but if used in bright light will cause overexposure.
In the example above the camera is being used indoors under fluorescent lights and the ISO is set to 1000. In shutter priority mode with the shutter set to 1/4000 a warning appears to tell you the photo will be underexposed with these settings. At 30 (30 seconds) the camera warns of overexposure. With the shutter set to 1/30 of a second there is no warning so it should yield a good exposure. For any given lighting situation and ISO there will be a range of shutter speed settings that will provide good exposure results. In the example above 1/30 is shown but there are other shutter settings that would work. Shutter speed affects how moving objects appear in your photo. Use a fast shutter speed to freeze action or a slow one to allow blurring. Some examples of minimum shutter speeds required to freeze action are: Candid people shots- 1/250 sec. People dancing- 1/500 sec. Fast sports action- 1/2000 Humming bird wings- 1/4000 What shutter speed for hand held cameras? A hand held camera requires a shutter speed that is fast enough to prevent blurring from camera movement. In general if your shutter speed is below 30 or 1/30 sec. you should consider using a tripod. But, a more specific rule of thumb takes into account the lens focal length. If you use a telephoto lens then any camera movement is magnified and so is the blurring. Here s the rule of thumb: 1. For APSC format SLR cameras including Canon s Rebel series (T5i, T4i, T3i ) and 7D, 60D, 70D as well as Nikon s D3200, D3300, D5200, D5300, D7100, and Pentax Kx, Kr, etc: The minimum recommended shutter speed for handheld is equal to 1.5X the lens focal length. When shooting with your zoom set to 20mm use a 1/30 shutter speed. For a 200mm lens use 1/300 shutter speed minimum. 2. For full frame cameras like Nikon s D800, D610, D4, or Canon s 5D MkIII, 6D or 1Dx: The minimum hand held shutter speed is equal to the lens focal length. Ex. 60mm lens= 1/60 shutter.
A or Av- Aperture Priority Mode control depth of field for great effects Much like the pupil in your eye, it is an adjustable opening in the lens used to vary the amount of light during exposure. Both the aperture and the shutter control the exposure. The most important thing to know about the aperture is that it affects the shutter speed. Opening to a large aperture (smaller F number) yields a faster shutter speed while closing the aperture (larger F number) gives a slower shutter speed. The aperture is often designated by placing the letter F in front of the number. An aperture of 4 is written as F4 or F/4. F/4 is a larger opening than F/8 which is larger than F/16. The fact that a smaller number represents a larger opening can be confusing unless you know where the F number comes from. The F in the F number stands for the lens Focal Length. Focal length is defined as the distance from the image plane (camera s sensor) to the optical center of the lens when the lens is focused at infinity. Let s use the example of a 40mm lens and compare the apertures F/4, F/8 and F/16. An aperture of F/4 means that the diameter of the aperture opening is equal to the lens focal length divided by 4. If F=40mm then F/4 is 40/4 or 40 divided by 4 which equals 10mm. F/8 means the aperture is 40/8 or 5mm across and F/16 means 40/16 or 2.5mm across.
The Aperture and depth of Field The aperture setting is one of the factors that affect depth of field. Depth of field refers to the area of acceptable sharpness on either side of the plane of focus. As seen in the examples below, a small aperture like f/29 produces a great depth of field in which objects in front of and behind the main subject are acceptably sharp. A large aperture like f/3.5 produces a shallow depth of field causing the foreground and background to blur. The Lens - Focal Length Prime lenses have fixed focal lengths and zooms have variable focal lengths. Below are examples of a 40mm prime lens and an 18-105mm zoom with the zoom ring set to 40mm.
Focal length is the distance from the optical center of the lens to the image plane when focused at infinity. Focal length determines the lens angle of view and it affects subject magnification. A normal lens is one that produces an angle of view and perspective similar to that of human vision. Different sized camera sensors mean different focal lengths are designated normal lenses. This shot was made using a 35mm lens on a Nikon DX (APSC sensor) body. It gives about the same angle of view and perspective as human vision and so it is considered a normal lens. Most digital SLRs are known as cropped sensor cameras and use the smaller APSC sized sensors. This includes Canon s rebel series and Nikons such as the D3300 and D5300. The normal lens for APSC sized sensor camera is around 35mm. Full frame cameras have sensors that are 36mm x 24mm. Cameras such as Canon s 6D or Nikon s D610 are in this category and a normal lens for them is 50mm.
Lenses that are a shorter than normal focal length, such as the 18mm example seen here, are considered to be wide angle. Lenses with longer than the normal focal length are telephoto. The Lens - Maximum Aperture Because the aperture is a mechanism that is built into the lens, the aperture settings available are dependent on the lens in use. Since the size of the aperture affects the shutter speed, a lens maximum aperture directly affects the range of useable shutter speeds. The larger the maximum aperture; the faster the shutter speed that you can use. In the example below 2 photos are taken at 400 ISO under the same lighting. Here a lens with a maximum aperture of F/5.6 offers a maximum shutter speed of 1/15 of a second which is not fast enough to freeze even slow movement. Here is the same situation using a lens with a maximum aperture of F/1.4. The resulting shutter speed of 1/200 of a second is fast enough to freeze the spinning umbrella. The term fast lens refers to a lens ability to provide faster shutter speeds because it has a larger maximum aperture. The ISO factor- the F/5.6 lens could reach a 1/200 second shutter in the situation above only if the camera s ISO were increased from 400 to more than 3200. This means that to achieve a 1/200 shutter speed a decrease of image quality would occur due to increased noise and other high ISO issues.
The Lens - Maximum Aperture continued The size of the aperture also affects a photo s depth of field. A lens with a larger maximum aperture is capable of creating a shallower depth of field and therefore is capable of softer backgrounds. This can be seen in the previous examples. Auto Focus (AF) The speed of auto focus in today s SLR cameras makes it a convenient and essential option. Activate auto focus by half pressing the shutter release button. When you press the shutter button you will see the active AF (auto focus) points or areas light up red. When the focus is achieved a green indicator light appears as seen above on the Canon T3i. A flashing or absent focus indicator may mean that the camera could not achieve focus. Auto AF Area - This default setting has many names depending on your brand but the most descriptive name for it is Closest Subject Focus. The camera searches through all of its focus areas and uses the one that has the closest subject. Manual AF Area select- With this option you can select the focus area/point that you want to use. Typically you would move the active AF point to where your main subject is. Many photographers choose to use the center focus point and then lock their focus on the main subject.
Focus Modes Single or One Shot AF is best used when shooting a subject that is not moving. When the shutter release is pressed halfway the camera performs auto focus on the selected focus area or nearest subject. After focus is achieved the focus motor is shut off. Holding a half press of the shutter button locks the focus. This focus mode is focus priority which means if the camera cannot focus it will lock up and not let the shutter release. Continuous or AI Servo is best for moving subjects. Since the camera focuses continuously when the shutter release is half pressed the focus is more likely to stay on target. Focus cannot be locked with a half press in this mode and the camera. This focus mode is release priority and will not prevent the shutter from releasing if out of focus. Some cameras allow users to choose between focus priority and release priority for their focus modes. Find this custom setting in your menu.
Composition Basics Center Circle Syndrome Avoid the temptation to place the main subject in the center of your viewfinder. The result of doing this is a static and dull composition. A good kind of centering When an object is close to filling the photo be careful to leave some space between the object and the edge of the frame. Rule of Thirds The rule of thirds is a compositional rule of thumb in photography and other visual arts such as painting. The rule states that an image can be divided into nine equal parts by two equally-spaced horizontal lines and two equally-spaced vertical lines. The four points formed by the intersections of these lines can be used to align features in the photograph. Proponents of this technique claim that aligning a photograph with these points creates more tension, energy and interest in the photo than simply centering the feature would. Text Source: Wikepedia
Tips for composition techniques You are the decider. You decide what to include or exclude in your photos. If there is something that bugs you when you are looking through your viewfinder it will likely bug you and other viewers when looking at that photo. Try moving around or zooming to exclude the bad and include the good. Look at the edges and corners. Objects in the corners and edges of the photo are still in the photo and will have some effect on the composition so don t forget to look at the entire viewfinder. S curves, Lead in lines Pathways, roads, railway tracks, fences and rivers provide lines that draw the viewer s eyes into the photo. Curved lines, especially S curves help create a more interesting composition. Notice the background. The background can make or break your photo. Bright colored objects in the background can distract from the main subject. A misplaced tree can seem to grow from a person s head. A background that is the same color as the main subject will cause the subject to blend into the background. Decide on a main subject for your photo and compose your shot so that we know what your main subject is. Get close. Don t be afraid to move close to your main subject. (unless it s a grizzly bear) Near/far perspective: Remember that zooming your lens to get closer is not the same as moving closer. The results will be different so use the method that works for the situation at hand.
Quality Settings Quality settings affect the file type, image quality and image size of your photos. By default the camera produces JPEG files. JPEGs are compressible picture files that take up less space on your card so that you can shoot more shots. Fine quality JPEGs are less compressed so are larger files but offer better picture quality. If you want to be able to crop your photos or if you just want the best possible quality out of your JPEGs choose the Fine/ Large option. Raw files contain all the raw data captured by the camera and allow for much greater image adjustments. If you want the ultimate in picture quality then Raw is what you want. Unlike JPEGs, Raw files are not ready to use right out of the camera. Raw files need to be converted to JPEGs or TIFFs to be used in many applications. Adjustments and conversion can be done using the software that came with your camera or with software like Photoshop or Lightroom. Raw files are much larger, causing you to get fewer photos on a card. Useful Links: http://www.dpreview.com/ Camera and lens reviews and digital photography news. http://www.spacew.com/ Northern lights forecasting. http://www.microsoft.com/download/en/details.aspx?id=26829 Raw file viewing codec for Windows 7 http://labs.adobe.com/wiki/index.php/dng_codec DNG format raw file viewing codec for Windows 7 http://www.imagerybykeith.com/resources/ For more links, and then some. The contents of this document including all photos and illustrations are Keith Starks All Rights Reserved For more information about classes by Keith go to http://www.imagerybykeith.com Contact Keith: keith@imagerybykeith.com