Have a plan for how images move from the camera to the computer. Establish an approach and then stick with it.
You can change it at a later date to upgrade to a better or more refined approach, but you’ve got to start somewhere and remain consistent for a while in order to develop a stable platform. It’s the foundation of your organizational system.
Download your photos from your digital camera memory card to your computer’s hard drive.
I connect my digital camera to my computer and hit the download button.
Some prefer to import using a high speed USB card reader. Be aware that all card readers are not the same.
After my images are transferred to my hard drive, I reformat the memory card.
When you open Picasa, you’ll notice that your photos are arranged by folder. You can drag and drop to rearrange your albums and create new albums.
There are as many filing systems as there are photographers. No matter how you determine your file-naming convention (by date, by location, by subject, by keyword, etc.) the system must work for you.
I create my folders by location. My procedure goes as follows:
Download my 4GB memory card to my computer using Picasa.
Select my folder and name for these images, e.g. BC, Okanagan Valley_2012_08
After an initial run-through of my files, I delete the obvious throwaways and keep the rest.
You can also tag your photos. Tagging is a concept found in photo management software where you attach descriptive text called tags (e.g. Birds, Hiking, Christmas, RV Parks,) to each photo in your collection.
If I have any ‘message’ worth giving to a beginner it is that there are no short cuts in photography.
The Digital Photography and RVing series will now focus on the second of the three steps of digital photography: Organizing and editing photos.
You’ve taken photos with your new digital camera. Now what?
You can download your photos to a computer, organize them using a photo management program, and edit them using a photo-editing program.
Photographers refer to this process as digital workflow.
In simple terms “digital photography work-flow” is a systematic process of downloading, organizing, editing, backing-up, and sharing digital photos.
Walking along the path of a beginning digital photographer, I learned much the hard way.
I slowly came to realize that it was necessary to have a systematic work-flow for my digital photo processing.
Slowly, by numerous trials and errors, I’ve found a simplified way that works for me to develop, sort, organize, and archive my digital photo collection.
Select a Photo Management Program
If you shoot just 40 photos a week, you’ll end the year with more than a two thousand digital files—that’s a lot of photos to keep track of without some help!
For one thing, it’s going to be tough to find a specific photo. If you want to view the photo of a roseate spoonbill you took two years ago on South Padre Island in Texas, for example, you’ll have a difficult time finding it.
How can you put those photos into some semblance of order?
The first step in organizing your photos is to select a photo management program.
There are a number of excellent programs that organize, categorize, and keyword your photos so that you can store and locate all your digital files without losing track of them.
One of the most important factors in selecting a photo organization program is ease-of-use.
Picasa is free photo management software from Google that helps you find, organize, edit, and share your photos. Picasa is one of the better photo managers available. Its ever growing popularity can be attributed to its simplicity and ease of use. And did I mention that it’s FREE. Picasa is available as a download for Windows, Mac, and Linux.
When you install Picasa, it automatically scans your hard drive for images.
Picasa does not store the photos on your computer. When you open Picasa, it simply looks at the folders on your computer and displays the photos it finds. It displays the file types that you tell it to find, in the folders that you tell it to search.
Your original photos are always preserved. When using editing tools in Picasa, your original files are never touched. The photo edits you make are only viewable in Picasa until you decide to save your changes. Even then, Picasa creates a new version of the photo with your edits applied, leaving the original file totally preserved.
First of all, let’s clear up one point: Dust on your lens will rarely show up in the photo because you’ll always be focusing much farther than the front element of your lens—the location of the dust.
For dust on your lens to be visible as specks in your photo, you’d have to be focusing your lens to an extremely close distance—even closer than what most macro lenses can do. So, any specks of dust you see in your final image most likely were caused by dust on the camera sensor.
Use your camera’s sensor cleaning function. Most D-SLRs have a built-in function that uses ultrasonic vibrations to vibrate dust off the sensor. Sometimes this function is automatic when you turn your camera on and off, but check your camera’s manual to see if it has more options.
Change your lenses carefully. You just can’t escape dust: it’s everywhere outside and yet we still need to change lenses, so it’s important to be very careful and minimize the amount of time your camera is without a mounted lens.
My method for switching camera lenses:
Put your camera on a flat surface, so that the lens is pointing straight up
Unlock the lens on your camera body, and turn the lens just a little bit so you can let go of the lens and it remains unlocked but is still resting on the camera body
Remove the cap on the bottom of the new lens you want on your camera
Hold the new lens in your right hand, and twist off the lens on your camera with your left hand
Quickly mount the new lens with your right hand and lock it onto the camera
Put the cap on the bottom of the old lens
When possible, avoid switching lenses in windy or dusty areas and take advantage of protected areas when you can: Switch your lenses in your RV or toad/tow vehicle.
If you must switch your camera lenses while on the trail, try to do it inside your camera bag, or at least use part of your camera bag to shield your camera and lens from the wind. Also, if it’s especially windy out, then try moving to a less windy spot to switch your lenses.
The basic strategy is to avoid changing your lens in windy conditions, where the most dust is flying around.
How do you switch your lenses?
Have you found another way to switch your lenses that minimizes exposure to dust?
Automatic Exposure Bracketing (AEB)
Bracketing is the intentional over or under exposure of your image.
When in doubt about the correct exposure, take several “bracketed” shots.
When you select AEB the camera takes one regular shot, then a second shot under exposed/slightly darker (-1 stop) and a third shot over exposed/slightly lighter (+1 stop).
You end up with the three images in a series with exactly the same composition but at different exposures for you to select the most pleasing one after you download them to your computer.
If you have the camera in burst mode (continuous shooting) the three shots will be taken if you hold down the shutter for a burst of three shots.
Check out your manual to see how AEB works on your digital camera. Most will allow you to change the variation between shots by different stops.
Always Have Your Camera Ready
And let’s not forget the most basic rule for shooting great photos: Take your camera with you everywhere you go…and take lots of photos.
You can’t “capture the moment” if you don’t have your camera.
Oh, and Don’t Forget to Take Lots of Photos
Once you’ve purchased your camera, digital photography is free. You can shoot as many photos as you want, and you’ll never pay a nickel for film or developing.
Never put off taking a photo because you think you’ll have better light another time. There may not be another time.
Get out there, get moving, and get busy!
The more you shoot, the more you will learn. Try out new ideas and challenge your old ones. Nobody has to see the photos that do not turn out so great. In their book, Outliers, Malcolm Gladwell theorize that the only real difference between being great at something and being only average at it is practice. Talent often is nothing more than practice and tenacity.
If you ask any professional the secret to great photographic results, one of the first things you’ll hear is, “Shoot a lot.”
The renowned photographer, Henri Cartier-Bresson, said, “Your first 10,000 photographs are your worst.”
Yes, it’s true—you’ll wind up deleting most of them. But shooting a lot increases the odds that, somewhere in that massive pile of photos, there are some true gems.
Above all, shoot, shoot, shoot—lots and lots of photos!
You never know when you’ll catch that once in a lifetime shot!
There’s another life lesson that we’ve heard many times: Never put off until tomorrow what you can do today.
In today’s post I discuss the use of memory cards and histograms.
Ensure that you always have sufficient memory capacity for your digital camera.
But how do you know how much is enough?
As a quick rule of thumb JPEG files are generally half the size of the sensor capacity. With my 18-MP Canon EOS Rebel T3i camera each JPEG will be about 9 MB. This means a 1GB card will hold about 113 photos.
Since memory cards are now relatively inexpensive, buy more memory capacity than you anticipate needing and ALWAYS carry a spare.
Just like any kind of technology, memory cards can fail. If you just use one giant card, and that card fails, you just lost all your photos! I use a 4MB card and ALWAYS carry a 4MB spare.
Tips for avoiding memory card problems:
Format a new memory card as soon as you get it. Even if your memory card came “preformatted,” it’s still a good idea to format the card again with your own camera.
Use multiple small cards, instead of one big one. With the huge memory cards available today, it’s tempting to buy one with a large capacity. But, what if your 128GB card fails? Then you just lost thousands of photos!
Format your memory card after each download. Formatting your memory cards is sort of like resetting them, and making them fresh again. It will help correct any disk errors that may have occurred during your last shoot.
Store your cards in a safe place. It’s important to protect the contacts on your memory cards, because the smallest piece of dust can cause reading/writing problems and ultimately loss of photos. Always store them in their plastic case.
A histogram is a graphical representation of the light values of the image. Yeah, I know, that really helps. A histogram display is actually one of the most useful features you can have on a digital camera.
The histogram is a tool that provides instant feedback about an image. Having your camera set to show histograms during the view process will tell you how your image is exposed. The histogram shows, in graph form, the distribution of the tones in an image. You can see at a glance whether portions are blown out or underexposed.
Represented as a graph, a histogram looks like a mountain range. The left side depicts the darkest parts of the photo and the right side depicts the lightest. Anything beyond the left edge is pure black and anything beyond the right edge is pure white—both are outside the range of the image sensor.
Every histogram will be different and there is no right or wrong shape.
Depending on which is more prevalent in your photograph—shadows or highlights—the histogram visually may favor one side or the other. By checking the histogram, I’m able to analyze the amount of dark tones (on the left), bright tones (on the right), and all the mid-tones in between. I like my histograms to stretch 80% to 90% of the way to the right end, but not all the way, to avoid blown-out highlights.
The above illustration and following explanation is courtesy 500th.net, website of photographer Martin Joergensen.
Each histogram has been overlaid with a line that indicate its general shape. The middle one shown is a so-called perfect histogram. All tones fall within the edges and we have a fairly even distribution of tones.
Above that is a contrasty image. This has a saddle-shaped curve, and the danger here lies in loss of both dark details and highlights.
Below you will find a dull image with little contrast. That has a narrow curve with few tones.
Histograms shifted too much to the left means dark images and danger of underexposure and loss of dark detail and curves shifted too much to the right is a warning of a light picture with possibly burnt-out highlights.
You have a tool that helps you nail those exposures—use it!
A filter is a seemingly simple piece of glass that screws onto your lens in a rotating mount, and has an effect on your image. Filters come in various sizes according to the needs of your specific lens.
There are few more important things a nature photographer can do to improve his or her photography than using a circular polarizing filter.
This is one filter you must have for your landscape photos especially in Red Rock Country. The polarizer is the only filter that I use.
To understand how it works would require a seminar in the physics of light. But using a polarizer is easy; simply screw it on the front of your lens, look through your viewfinder, and rotate it until you see the effect you want, and then shoot.
The way a polarizer works is simple but the results produced can be extraordinary. A polarizing filter removes glare—the distracting light waves that radiate from smooth surfaces like shiny leaves or reflections on water. With the glare eliminated, you capture the true color and texture of the subject.
Polarizing filters also deepen blue skies without altering the color of the clouds. Color saturation is also significantly enhanced. Brilliant red and orange foliage really pops when framed against a deep blue sky.
A polarizer doesn’t give the same effect everywhere in the sky. Optimum polarization is when the light source is 90 degrees from the direction you are pointing your camera, i.e. side lit. But when the sun is directly in front or in back of the direction your camera is pointed, it renders virtually no effect at all.
There are two types of polarizing filters—linear and circular.
If you’re shooting with autofocus lenses, you need a circular polarizing filter. Linear polarizers are designed for manual focus lenses only.
In summary, polarizing filters:
Darkens a blue sky and brightens white clouds
Reduces haze and glare in the atmosphere
Reduces reflections from glass, water, rocks, and metal
Enhances color saturation
Eliminates stray light and glare from reflective surfaces
Helps reduce incoming light, when you need longer shutter speeds
Take care to use sky-darkening in moderation; too much saturation can actually make skies look almost black.
However, there is one downside to polarizing filters: you lose approximately two stops of light.
Beware when shooting with a wide-angle lens. Because of the 90-degree rule, a wide angle lens often will show wide variations in the sky.
Since polarizing filters are frequently quite thick, beware of vignetting, the darkening of the corners relative to the centre of the image. Choosing a thin polarizer helps, but the thinner models tend to cost more. The degree of vignetting varies from camera to camera and lens to lens.
I never leave home without my polarizer; actually I leave it on my camera all the time. By never removing the polarizing filter from the lens, I’m always prepared when that great photo opportunity arises. And since I use my standard lens almost exclusively for landscape shots I really don’t have a good reason to remove it.
When purchasing a polarizing filter you have the choice of a number of quality manufacturers.
The Cokin Creative Filter System has been around for 30 years. Filters fit in a special holder that attaches to the lens via an interchangeable metal ring.
B+W filters are widely recognized for outstanding quality as well as technological innovation.
Tiffen produces professional-quality filters. It takes a lot of know-how to win two Technical Achievement Awards and a Scientific and Engineering Award from the Academy of Motion Picture Arts and Sciences, as well as an Emmy Award from the Academy of Television Arts & Sciences. That proficiency is apparent in every Tiffen product.
Hoya is one of the world’s largest manufacturers of optical glass, including glass used for camera lenses, eyeglasses, and photographic filters. Their production process involves the introduction of raw elements and chemicals to molten optical glass to produce a filter of uniform coloration.
Singh-Ray calls its polarizers “lighter, brighter,” meaning that they transmit more light than average.
Heliopan filters are made from glass supplied by Schott (wholly owned by Carl Zeiss) and set in black anodized brass rings that screw in with precision. They’re available in every conceivable size and configuration, including 13 different types of polarizers and special-effects filters.
In today’s post I discuss the merits of using a quality tripod, use of a cable release, and camera cases.
Use a Tripod
A quality tripod is a basic part of any photographer’s kit.
The tripod is the single most important factor in shooting sharp photos.
Yes, they can be heavy, take up a considerable space, time consuming to set up, and an expensive accessory, but it is difficult to get sharp photos without one—especially when it comes to shooting landscapes. New designs using modern composite materials continue to make tripods lighter—and yes, more expensive.
A camera tripod can make a huge difference in the sharpness and overall quality of photos. It enables you to shoot photos with less light or a greater depth of field and capture fast moving objects in addition to enabling several specialty techniques.
Look for a tripod that’s convenient to carry around. You don’t need a huge one.
A good tripod really consists of two components—the legs and the head. Without the legs, you have no stability, and without the head, there’s no way to mount a camera to the legs.
With so many options out there not only in terms of vendors, but also in terms of head types and styles—there’s a lot to choose from. One of the most popular types of heads is the ball-head.
At times when a tripod may be inconvenient or prohibited, consider other alternatives—a monopod or bean bag to rest your camera on, or lean against a wall or other sturdy surface.
Just because you’re able to hold the camera steady enough to take a sharp photo using a given shutter speed, doesn’t necessarily mean that you should not use a tripod. A tripod enables you to choose a more optimal combination of aperture, ISO, and shutter speed. For example, you could use a smaller aperture in order to achieve greater depth of field.
Using a tripod for any kind of photography will always decrease the probability of an out of focus image due to movement or camera shake.
And if you do have an image-stabilized lens, be sure to turn it off when the camera is used on a tripod.
Cable releases are ideal for situations in which the slightest camera shake can ruin an image—and that’s certainly the case with time exposures and macro photography. The simple pressure of your finger on the shutter release can be enough to totally change the perfect composition.
A cable release not only allows you to keep your camera safe and steady during the exposure, but often can make it easier to fire the shutter when the camera is in a tricky position.
With the many smart options available, you can program your cable release to make interval exposures, create long exposures of a precise duration or even make time-lapse videos of seeds sprouting and other macro transformations.
You’ll also require some type of case for carrying and protecting your camera, lenses, and other photo equipment. The size and style will depend on the camera and number of lenses and other accessories you own.
Camera bags are available in several different styles, shapes, and sizes.
A small waist pouch may be convenient for a small point-and-shoot camera; but if you’re toting a hefty D-SLR and several lenses, filters, and a spare battery you are probably a good candidate for a shoulder bag or back pack.
If it’s worth taking a picture, it’s worth the time to set up a tripod.
In today’s post I discuss the merits of shooting in a manual mode, the importance of holding your camera steady, and weigh in on the Raw vs. JPEG debate.
It’s often said that auto exposure is faster than manual exposure. But is it?
After all, you just focus, compose, and shoot and don’t need to concern yourself with the exposure settings.
But, auto exposure can be inaccurate. If well exposed images are important to you, manual exposure really is quicker. There are just too many problems with auto exposure and too many things that can go wrong.
Make the bold move and switch the camera dial from Auto to Aperture Priority or Manual.
Many point-and-shoot cameras now include manual features in which users can control aperture and shutter speed, features that were once limited to D-SLRs.
I shoot over 95 percent of my photos in aperture priority mode (Av setting), which is crucial to control depth of field. However, I monitor my shutter speed especially with bird photography. If necessary, I increase the ISO setting.
A lack of sharpness due to camera shake or blur is a common problem for beginners.
Avoid “camera shake” by holding the camera steady. Holding the camera out in front is the least steady posture for taking a photo.
The best way to hold your camera depends upon the type of digital camera you’re using and the size of lens.
The following technique is used by many advanced photographers:
Use your right hand to grip the right hand end of the camera
Your forefinger should sit lightly above the shutter release
Your other three fingers curling around the front of the camera
Your right thumb grips onto the back of the camera
Position your left hand under your camera and lens to support its weight
Also, keep in mind that it’s best to gently squeeze the shutter—don’t jab at it.
Raw vs. JPEG: Which is Right for YOU?
Raw files are just the raw sensor data. They must be processed further to become a photo.
JPEG files are processed from raw data within the camera then thrown away since the raw data is no longer needed. The process varies with camera manufacturer and from model to model.
Using raw files takes considerably more time and patience and requires dedicated software such as Photoshop or Lighthouse.
If you love spending considerable time tweaking your images one-by one and shoot a minimal number of shots at a time than raw could be for you.
There is a myth floating in photography cyberspace that raw is a superior format and that only amateurs shoot in JPEG format.
One’s preference for JPEG or raw depends on what you’re trying to do. Each format has no absolute goodness; it’s all in how appropriate the format is to your particular work at hand. Everyone’s needs vary and I just happen to prefer JPEG. After all, I can do minor tweaking later using Picasa or PicMonkey.
I don’t shoot anything in raw. I have no reason to shoot raw.
I’m satisfied to let the camera and its processing algorithms handle the image, and I’m satisfied with the results I get. I have no motivation to shoot RAW.
Raw is needlessly tedious if you can get the right image to begin with.
Shoot Raw if you enjoy post-processing or feel the subjects you shoot are too complex from a dynamic range perspective and/or the camera cannot capture the scenes you shoot as you see them.
Shoot JPEG if you don’t enjoy post-processing and have your camera set up such that the photos that come straight out of it are to your liking.
If you are strapped for space on your computer, shooting JPEG will allow you to store many more files, and you can also fit more images on each memory card when you’re out shooting.
Should you be using one or the other, or both? That’s your call.
You buy the latest digital camera available, come home, rip open the box, and then proceed to play with your new toy.
You turn on the camera and try to figure things out. You briefly flick through the hundred or so page camera manual and never look at it again. Does this sound familiar? Not a good idea!
Study the Camera Manual
If you buy a new digital camera, you owe it to yourself to understand its ins and outs.
Read the camera manual! No, don’t just read it—study it carefully. I’m not the first to say this, and I won’t be the last. It’s because studying your camera’s manual is that important.
Read the manual to understand the new features and functions. Practice using them, then read it again, practice again, and so on.
Learn how to control exposure, how to use different camera modes, and how to use the flash.
Go through the manual and experiment with each setting on your camera. And then go through it again; checking off all the settings you understand thoroughly. Then go through the manual again and learn those settings that you still baffle you.
Get to know and use the mode dial to your advantage. The Mode Dial is the round dial on top of your camera that you adjust to switch from fully manual exposure mode to Program, Aperture Priority, Shutter Priority, and so on.
You can learn about photography by using and understanding the workings of this dial. If you know how the different modes work, then you will understand how, when, and why to make particular shutter speed and aperture decisions to achieve particular effects.
Modes vary with camera manufacturer and model.
Following is a mode-by-mode breakdown of some of the more common and what you can learn.
Manual Mode. The M could also stand for “Man, you better know what you’re doing.” Actually, working in Manual mode can be a great way to learn about the basics of exposure, because you have the instant feedback of the LCD to teach you exactly what a modification to the shutter speed or aperture will do to your photos.
Program or Auto Mode. Program or Auto mode is the polar opposite of Manual. Program controls both aperture and shutter speed automatically. Since you can’t set specific settings like shutter speed or ƒ/stop, you should use this mode only if you think the camera can make these decisions better than you. As you understand the workings of your camera, use this mode less and less frequently.
Aperture Priority. This mode is best when you want to minimize or maximize depth of field, e.g., wildlife and landscape photography respectively. When photographing landscapes, you want maximum depth of field to ensure the entire image is sharp; and when shooting wildlife minimal depth of field is desirable. I use aperture priority for most of my photography.
Shutter Priority. This mode is best when you want control over the shutter speed. Shutter Priority lets the camera automatically adjust a corresponding appropriate aperture. When would you want to adjust the shutter speed but not the aperture? When you want to stop something moving fast—like for sports or wildlife photography—or when you want to use a long shutter speed for motion blur or at night. I also use shutter priority for indoor flash photography.
Portrait Mode. The Portrait setting works much like Aperture Priority, but it sets a wide aperture for a softer out of focus background and keeps attention on the portrait subject. For best results, position the subject as far as possible from the background, and use a short telephoto focal length.
Landscape Mode. The Landscape mode works much like Aperture Priority, but it sets a small aperture to maximize the depth of field over a wide scene. The smaller the aperture, the more area will be in focus—and that can be crucial when you’re photographing a large landscape. In this mode, you get best results with a wide-angle lens.
Sports-Action Mode. The Sports or Action mode works a lot like Shutter Priority, but with a fast shutter speed set by default. This faster shutter speed is used to freeze fast-moving objects—like athletes. When you want to freeze motion, you need a fast shutter speed.
Sunset. As you’d expect, Sunset mode punches up the warm tones—reds, oranges, and yellows—and optimizes the exposure for sunsets. When the sun is right on the horizon, the light level is fairly low, so the use of a tripod is wise.
While aperture is responsible for controlling the amount of light that passes through the lens, shutter speed is responsible for controlling the length of time that light is allowed to hit the digital camera’s sensor.
The shutter determines HOW LONG the light hits the sensor of your camera—the sensor records light the entire time the time the shutter is open.
Shutter speed controls the amount of time the shutter is open. The longer the shutter is open, the more light that hits the surface of the sensor.
How do we measure shutter speed?
Shutter speeds are expressed in fractions of a second. The faster the shutter speed, the more action will be frozen; and the slower the shutter speed, the more action will be blurred, e.g. 10 seconds, 1 second, 1/8 second, 1/15 second, 1/30 second are all SLOW shutter speeds and 1/250 second, 1/500 second, 1/1000 second are all FAST shutter speeds.
In most cases you’ll use shutter speeds of 1/60th of a second or faster. Anything slower is very difficult to hand hold without getting camera shake which results in blurry images. With a shutter speed slower than 1/60, you will need to use a tripod.
As you change shutter speed you’ll need to change one or both of the other elements (aperture and ISO) to compensate for it.
In conclusion, shutter speed controls motion. Whether we want to freeze motion or show motion, shutter speed is the portion of exposure that will control that aspect.
The last element that contributes to a proper exposure is the ISO setting.
ISO is an indicator of sensitivity of the image sensor to light. The ISO setting determines how much light is needed for a correct exposure.
ISO is the acronym for International Standards Organization which developed a system for film where a 200 ISO is twice as fast (i.e. it reacts twice as quickly) as a 100 ISO. You may have also heard of ASA or DIN—these were two other standards which were replaced by the ISO.
How do we measure ISO?
Similar to aperture and shutter speed, ISO is measured in full stop increments and represented by numbers.
ISO has a number ranging from 100 to 12800 or higher.
As a general rule, image quality goes down as ISO goes up, with any camera.
Today’s digital cameras can deliver unbelievably high ISO settings with a very low noise profile. (Noise being the digital version of film grain—it increases at higher ISOs.) So how do you know which ISO setting to use?
My starting point is always use the lowest ISO setting that will provide the other exposure settings (aperture and shutter speed) that meet my needs.
The lowest ISO ensures the lowest noise in the final image file.
High-ISO performance has changed the way we shoot, and it’s the best thing to happen for RVers who wish to photograph their life on the road.
With today’s cameras, you can shoot photos inside museums and other buildings where flash is prohibited. You just dial up your ISO and shoot away.
I use a Canon EOS T3i and I can easily shoot at ISO 3200 and get quality images. High ISO constantly allows me to capture images I would have missed in the past.
The concept of Exposure Triangle was introduced as a means of explaining how individual aspects of exposure—aperture, shutter speed, and ISO—relate to light and how it affects the final exposure of the photo.
Lighting and composition aside, the thing I think about most when I’m taking a photo is aperture.
Simply stated, an aperture is a hole or an opening through which light travels.
Aperture refers to the size of the opening in the lens (NOT the camera) that determines the amount of light falling onto the digital camera sensor. We adjust it to let more or less light hit the digital sensor.
The primary function of the aperture is to regulate the amount of light that’s allowed to pass through the lens. No aperture, no light.
The size of the opening is controlled by an adjustable diaphragm of overlapping blades that can be opened up and closed down to let in more or less light—similar to the pupils of our eyes.
The aperture or lens opening is referred to using the term f/numbers or, more commonly, f/stops, e.g., f/2.8, f/4.5, f/5.6,f/8,f/22.
All lenses, regardless of manufacturer or focal length, use the same f-stop numbering system.
Some lenses may have more f-stops than others, but the sequencing of the numbers is the same.
A large opening, of course, lets in more light than a small one. Unfortunately, this simple fact can get confusing because large openings are referred to with small numbers, while large numbers mean that a small opening is being used.
In simplest terms it’s a result of f-numbers being fractions of the focal length.
Each number in the traditional f-stop sequence represents a whole stop difference in light gathering from the adjacent number. If you move to a larger f-stop (a smaller number) you double the light entering the lens; if you move to a smaller f-stop (a larger number) you halve the light.
Aperture is one of the most confusing aspects of photography for new photographers—and some of us old hands, too. As stated earlier the thing that causes the most confusion is that large apertures—where lots of light gets through—are given f/stop smaller numbers; and smaller apertures—where less light gets through—have larger f-stop numbers. So f/2.8 is in fact a much larger aperture than f/22.
It seems the wrong way around when you first hear it but you’ll get the hang of it.
In summary, the relationship between aperture size and light can be simply stated in the following terms:
Large f-stop number = less light enters
Small f-stop number = more light enters
Aperture size also affects depth of field.
Depth of Field (DOF)
Depth of field (DOF) is the range in a photo that appears to be in focus. Although it’s simple in principle, it can also be fairly complex.
Depth of field is determined by three factors:
Lens focal length
Large aperture (remember it’s a smaller number) will decrease depth of field while small aperture (larger numbers) will give you larger depth of field.
When shooting a landscape, you’ll want as much of the photo in sharp focus as possible, so a greater depth of field is required.
However, when photographing birds it’s best to have a blurry background in order to ensure that other elements in the image are not distracting, so you want a shallow depth of field.
Other things being equal, shorter-focal-length lenses (e.g. wide angle lens), smaller apertures (larger f-stop number), and greater distance to your subject all increase depth of field (range of sharp focus).
And the reverse is also true, longer lenses (e.g. telephoto lens), wider apertures (larger f-stop number), and shorter distance to your subject all decrease depth of field (range of sharp focus).
Most D-SLRs have a DOF preview button located on the body adjacent to the lens. Pressing this button will physically stop down the lens to the selected aperture, allowing you to see through the now darker viewfinder exactly what elements will be in focus when you take the photo.
Personally I don’t use the DOF preview button. Comments I hear is that its usefulness is questionable for many digital camera. Most experienced photographers don’t really need to use it because they know from experience what the DOF will look like for the aperture they choose.