Top 20 Questions to Consider When Buying a Digital Camera
Sep 22, 2008 Photography
My top 20 key questions to ask yourself when buying a digital camera.
1. How many “megapixels” /resolution?
Once and for all, at least to me, you have to get the highest resolution your money can buy at the time you buy. Period.
2. Who made the lens?
Most cameras will give you an idea where the lens was made just by looking at the front of the lens. Know if the lens of your camera came from a reputable company like Leica, Zeiss, Canon, Etc… Lens quality is one of the most important factors you should consider especially if you’re going to use it for commercial, technical or scientific purposes.
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Tags: Digital Camera, Photography
Photography - Understanding How Image Stabilizing Lenses Work
Sep 22, 2008 Photography
If you have not yet purchased an image stabilizing lens, you might nonetheless have heard the term “image stabilization” or “vibration reduction” bandied about in reference to various point-and-shoot cameras and SLR lenses. In that case you probably understand that IS or VR technology supposedly results in sharper images. But does the technology really work, and how well? What actually happens to make it work? In what situations does it not work at all? And most important of all, do you really need it?
The answer to the first question is yes, image stabilization technology not only works, it works well. If it did not, the remainder of this article would be entirely unnecessary. But it is useful to understand exactly what image stabilization is, and when it can be used to improve your photography before you shell out the extra few hundred dollars for a lens that has IS built into it.
Note: While the term “image stabilization” is used more frequently by writers when discussing this topic, “vibration reduction” is the term that Nikon uses to describe the same feature in its lenses, and it also happens to better describe what is going on. You should consider the two terms as interchangeable.
To understand how vibration reduction works, let’s consider for a moment the effect that it corrects for. When a camera is hand-held, and the shutter is open for a duration longer than the camera can be pointed in one direction without moving, then the resulting image is seen to be blurred. What happens is that as the camera lens tilts upwards, sideways, or a combination of the two, the focused image shifts position on the image sensor. A focused point of light ends up being rendered as a line. The accumulation of all the shifted points of light that make up an image results in a blurred image.
The obvious correction therefore would be to shift the image sensor by the same amount that each point of light is shifted, so the image and the image sensor move together in relative lock-step. Some camera manufacturers implement this exact solution, and float the image sensor so that it can track the image if the camera shifts during exposure. But this is the exception, rather than the norm. Generally the solution is achieved by adding the vibration reduction to the lens, rather than the camera body.
So how does this work? Actually it is fairly simple to understand. Instead of a floating image sensor, the lens body contains floating lens elements. The position of these lens elements is controlled by motors that are coupled to sensors which detect how much the lens body is rotated vertically or horizontally during exposure.
If the lens body rotates upward, the sensors compensate by telling the motors to drop the floating lens elements down a little to maintain the optical path of light traveling through the lens elements. If the lens body is rotated to the left, the lens elements shift to the right to compensate. The end result is that the image maintains its position on the image sensor during the exposure, creating a much sharper image than if the vibration reduction system had been deactivated (which it can be).
It might seem remarkable that the system can track camera shake so well. In fact, it is remarkable, but it all works because camera motion can be monitored about every 1/1000th of a second, while the camera wobble occurs on a time scale of, say, 1/30th, 1/15th, or even 1/4th of a second.
Vendors of these image stabilizing lenses claim that the technology allows you to gain about 3 to 4 stops on your exposures. This means that if, for a given photographic situation, the slowest hand-held shutter speed that consistently results in an OK image is 1/125th of a second, then by adding vibration reduction you ought to be able to shoot at 1/15th or perhaps even 1/8th of a second. This is a big deal if you are forced to shoot into shadow, or the light is fading, or you need to close down the aperture to improve depth of field.
But image stabilization only proves itself in a range of shutter speeds that are neither too great, nor too small. If you try to hand-hold a 1 second exposure it’s unlikely your VR compensation will be able to keep up with the erratic motions you supply it. Likewise, if you are shooting at 1/500th of a second or higher, the camera won’t have a chance to experience any wobbling, so the VR system will not add any improvement.
Another thing to remember about vibration reduction is that it has to do with compensating for camera motion during exposure. It has nothing to do with the speed of the object you are trying to photograph. So that fast-moving baseball will still be rendered as a blur unless you capture it at 1/500th of a second.
Do you need IS or VR lenses to improve your photography? This one is fairly easy to answer. If you regularly find yourself shooting at speeds less than 1/250th of a second then there is a very good chance you can rid yourself of a substantial number of those blurred, or unsharp, shots by investing in a good VR lens. Better yet, when you buy your next digital camera, simply go for a point-and-shoot with vibration reduction built in, or if you purchase a digital SLR, try to grab a model with vibration reduction built into the supplied kit lens.
Author: Stephen Carter
Tags: lens, Photography
Photography - Understanding Auto Focusing Lenses
Sep 22, 2008 Photography
Virtually all but the cheapest digital cameras have some form of auto focusing feature built into them. In practice, using the system is fairly easy and intuitive - we are going to let the camera decide where the object is that we are photographing, so that it can then adjust the focus accordingly to capture the sharpest possible image. But how does this actually work?
The explanation of how auto focusing works is actually tied to a concept that is getting more exposure in newer digital cameras: the histogram of pixel intensities for a given digital image. You can view this histogram on your LCD screen after you have captured an image. What it shows is a graphical display of the number of pixels that have recorded a given brightness value in the image.
Basically the graphical display is a series of thin vertical bars stacked side by side. On the leftmost side of the display is the bar showing the number of pixels that recorded a dark value (no light was captured by these pixels), while on the very right of the display is the bar showing the number of pixels that recorded the brightest possible value. As you move from left to right, the intensity associated with the pixels increases, and the height of the bar indicates the number of pixels which recorded that intensity.
So what use is viewing a histogram?
Well, if an image is excessively underexposed, virtually all the pixels will be dark and the vertical bars in the histogram will all be pushed to the left. Alternatively, a histogram with all the bars pushed to the right suggests that most of the pixels recorded a high light intensity and therefore the image is probably over exposed. Most properly-exposed images show a distribution of pixel light intensities that are crowded toward the middle of the histogram.
There are exceptions to this rule. For example, if you shoot a picture of a model silhouetted against a bright window, most of your pixels will either be on the underexposed model, or on the overexposed background provided by the window pane. The histogram will therefore show a sizable number of bars at both the left and right of the histogram, and nothing much in its center.
For regular photographic scenes, however, the histogram offers a great way to size up the overall exposure of the image in a non subjective way. Moreover, the histogram provides a quantified measure of image exposure that the brains of the digital camera can use to understand what it is that it is looking at.
This insight into the nature of light intensity histograms is the key to understanding how auto focusing works.
Some of the newest high-end digital SLR models feature over fifty separate auto focusing areas in the metered image. This means that most of the image can be metered before a final focusing length is selected for the shot. For purposes of this article we need only consider how one of these auto focusing, or AF, elements does its job.
The metered area of a single AF element might represent only one percent of the overall image, but it nonetheless represents a tiny digital image in itself and it has its own little histogram associated with it. So how might looking at a histogram tell us whether or not the image it represents is focused or not?
To make the explanation as simple as possible, let’s suppose the AF element contains a dark insect, a fly, hanging in the air far from the background elements behind it which have merged into a light blurred backdrop. When the fly is in focus, the contrast between the fly and its background is very distinct. There are dark pixels (the fly) and light pixels (the background). Sound familiar? The histogram would have peaks in the lower and upper parts of its intensity distribution, similar to the silhouetted model standing in front of the window pane.
Now consider what happens as the AF element containing the fly is defocused. The image grows increasingly less distinct as the fly blurs into a grey smear that now diffuses throughout the entire element. The corresponding histogram shifts from a bimodal distribution to a much more uniform one as the peaks spread out toward the center of the histogram.
This is how the camera can quantify the degree of sharpness, or contrast, in any given image element. Auto focusing works by optimizing the histogram for non uniformity in the distribution, which it assumes defines the best focusing.
In practice the method works fairly well. But there are situations in which the surveyed scene does not lend itself well to accurate auto focusing.
For example, poorly-lit scenes offer low contrast, and therefore make the point of sharp focus hard to define. Other times, if multiple AF elements are being used to select the best focus, the background might provide the most contrast in the image and the object you are hoping will be targeted for focusing is actually ignored because its contribution to the auto focusing argument is outweighed by the contributions due to the background.
If you were trying to focus on a hummingbird that hung a few feet in front of a tree you might be surprised when the bird blurred into a non distinct spot and the leaves of the tree rendered perfectly sharp - the precise opposite of what you had hoped would happen. In cases like this you need to switch off the multiply metered AF elements and use a single AF element to monitor just the object you are intending to focus upon. You might use just the center AF element in a case like this.
Auto focusing is an extremely useful element of modern photography, virtually indispensable to practitioners of sports and wildlife photography. But it also proves handy in a wide range of everyday photographic situations, since the world around us is rarely ever at rest. So learn to appreciate the auto focusing mechanism in your camera, understand its strengths and limitations, and in the long run this will help you to increase the quality of your photographic portfolio.
Author: Stephen Carter
Tags: digital photography
What Exactly Does Depth of Field in Photography Mean?
Sep 2, 2008 Photography
Depth of field in photography can sometimes be a difficult and tricky thing for quite a lot of people to get their heads around. I know this for a fact since I was one of these people. And just to prove that I’m not making this all up, I’ll have you know that a number of my photography friends also admitted to this fact! The problem doesn’t come in the beginning, but more towards the middle when you’re mired knee deep in the explanation and you realize that what you thought you understood wasn’t really what you should have understood.
Luckily for me though I now understand what depth of field in photography is, and can make things work properly so I can take a good photograph. To put it simply though and to start you out in your explanation, let’s take a garden scene with a solitary rose right in the middle of it. You want to take a picture of the rose, but you’re not sure how you want it to look so you start fiddling around with your camera and take a variety of different shots. In the first shot, you make it so that the rose and everything around it – the garden and its surroundings – are very sharp. Everything in this picture is sharp and clear.
Then you take another shot, but this time you place more emphasis on the rose, and put everything else slightly out of focus. You can still see various different forms from the background and you might be able to recognize them for what they are, but they’re not so well defined as earlier. Foreground elements though, are still very much recognizable. Then you go the next step and take another photograph. This time the rose is more prominent and eye catching, while both the foreground and the background aren’t as much, and most of it is blurred and blended in together.
The next shot that you take, you focus solely on the rose to the exclusion of everything else, and make both the foreground and the background completely unrecognizable as anything other than a convenient anonymous backdrop for you main focal point, the rose. Now, although that was a demonstration of what depth of field in photography can look like in a picture, it probably didn’t explain very well exactly what it is.
You might have guessed, but for those of you who are wondering what on earth I’m talking about, just like I used to wonder on earth, depth of field in photography was all about, here it is in nice simple sentences. depth of field in photography, very simply stated, is how much of foreground and background you put into your photograph.
If you take any photographic scene, the sharpness in front of, and behind your subject is what you would call depth of field in photography. If your subject is the main attraction with an out of focus front and back, you would have a shallow depth of field in photography, and if you have the whole scene in sharp focus, both front and back, you would have a wide depth of field in photography.
It’s not exactly confusing just yet is it? It might not be exactly clear either, but then again, just reading this article isn’t really going to solve all of your camera problems. You need to get out there with your camera and try different settings for you to be able to fully grasp and appreciate what depth of field in photography is.
That said, there are a few things that come into consideration when you’re looking into depth of field in photography and those go along the lines of, image magnification, lens aperture setting and the focal length of your lens.
Author: Muna wa Wanjiru
Tags: Depth of Field, Photography
The Benefits of Printing Photos at Home
Sep 2, 2008 Photography
Gone are the days when you had to hold down a button and wind a tiny crank to roll up your film. The digital age has begun and having to get film developed is a thing of the past. But even though it’s easier to take pictures, you still have to go through the complicated process of waiting in line at a drugstore’s photo kiosk with your memory card to get them printed, or do you? Maybe it’s time to look into printing from home.
The main benefit of printing your digital pictures at home is its simplicity. Many of even the cheapest digital photo printers allow you to connect your camera or plug in your memory card and print directly. With photo editing tools built into the menus of new cameras, a computer is usually not even necessary!
Consider it as an investment. Sure the initial cost of a printer may run you a couple hundred bucks, but ultimately it’s going to pay off because the cost per photo is drastically cheaper than what you might pay in a store. Sure there’s ink you need to buy, but even with the cost of ink and paper, it still ends up being cheaper.
The newest photo printers are able to rival the quality of even the best prints you can get in a store, so this really adds to the reasons of why you should purchase a printer. Depending on the paper you use and the ink you buy, prints can last a very long time, too. Imagine no more having to drive or wait in lines. Photo printers allow you to print without having to wait to pick up your pictures later on. Actually printing of prints is fast, too.
Okay, so now that you’re convinced in that you need to buy a printer instead of going to a store, how do you go about choosing which printer to get? One of the biggest things you should consider is the size of the prints you’re going to want. Some printers only print 4×6, some let you print as large as 8×10 or even 11×14! There’s no point in spending on what you don’t need, so be sure to think about what you’re buying.
The next thing you’ll want to look into is the quality. This is usually measured in DPI (dots per inch). Also a part of the quality is the type of printing the printer does. Dye-sublimation printers use a completely different technique than actual ink or toner. Be sure to research and weigh the options of what you really want.
The last thing you should look for are the printer’s features. Are you going to need borderless printing? Double-sided printing? Some printers are easier to use than others, so one of the best things to do is check out the printers in the store. Most places let you print a test page so you can see the quality and speed of each printer. Do a little research and figure out how much ink is going to cost, too. Some printers are cheap, but overprice their ink, while other printers are expensive but their ink is cheap. It’s almost always better to just make an investment.
Author: Johnny Smallhat
Tags: Photography, Printing Photos
Quickly Fix your Digital Camera
Sep 2, 2008 Photography
Digital camera has made its way into our daily life. One can not tolerate a holiday without digital camera. However, the advanced device often has troubles with itself which make us annoying. A digital camera can cost hundreds or even thousands of dollars to its owner. Once it is out of order, most people suffer and have no choice but send it back to manufacturer to repair. A rarely known truth is that there are chances that some abnormal issues are temporary or just caused by misoperation and these issues can be fixed by yourself at home with no cost at all.
Save your precious money and the boring waiting from factory returns. Check carefully and think twice before you send your camera in.Some of these simple scenarios include camera occasionally cannot start, pictures are wrongly-colored or blurry and data cannot be downloaded to the computer.
Camera occasionally cannot load. Most people will encounter this issue that your camera cannot be loaded when you are sure there is no damage to it. Try the following three methods. One, check external equipments such as battery. Check if the battery is packed correctly according to the requirement. Note that there are always electrode icons marked near the battery cartridge. Then check if the battery power is completely drained. Digital camera consumes power much more quickly than you think, a 700mAh Li-ion battery can only last for one hour if the camera is constantly left on. So be aware of the battery conditions. Second, follow the right starting procedure. Due to the manufacturing and design difference, some camera require a long press to load, while others only need a quick touch or simply flip open the LCD. Read carefully through the operation menu coming with the package. Wrong operation may lead to freeze to your device. Third, system error. This is rare but possible. Try a master restart or take out the battery then place it back.
Pictures are wrong-colored or blurry when taken indoors. Wrong-colored pictures can be caused by your custom color effect setting that your forgot to turn back or wrong scene match. For instance, you shoot at beach using the scene mode for landscape. Blurry indoor photo, this is a very common mistake and nine out of ten times it’s the same scenario: people taking shots indoors without the flash. Just because the camera is digital it doesn’t mean that the laws of physics don’t apply. If the shutter you’re using is slower than 1/30 or 1/60 of a second, odds are that the shot will be blurry! A lot of people migrating from film cameras say “well my photos were always sharp with my film camera in these situations”, and a likely explanation for that is the use of ISO 400 film. So what’s the solution? Here are a few suggestions:use the flash; add more light to the room, if possible; use a tripod; turn up the ISO sensitivity a notch or two. Note that doing this will increase the amount of noise in your image; if you haven’t bought a camera yet, consider one with image stabilization
Pictures cannot be downloaded to computer. Other than the malfunction of the software or camera defect, there is a easy way to fix this. buy a card reader. Then, when you insert the memory , it will mount to your desktop just like another disc, and you can copy the photos directly to your hard disk. You can then use your favorite photo editing software to retouch your photos.
Author: Tom Fred
Tags: Digital Camera, Photography
