Camera Resolution. Image Size

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Camera Resolution

The sensor in a digital camera is composed of pixels, which are tiny light-sensitive squares. The sensors in most cameras today are made up of millions of pixels, each one registering the brightness of the light striking it as the photo is taken. The number of pixels in the image is about equal to the number of pixels on the sensor. This number is referred to as the image's resolution.

Simply put, the greater the number of pixels in an image, the higher the resolution. And the higher the resolution, the better and larger the print you can make. Put another way, resolution affects the output options for your photo. It's important to keep this in mind as you explore the resolution options on your camera.

Image Size

Image size is measured in pixels. With a Nikon D300 SLR they are called Large (4288 x 2848 pixels), Medium (3216 x 2136) and Small (2144 x 1424).

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JPGs and TIFFs can be saved in these different sizes. Raw data can't have it's image size changed in-camera. Most people shoot the largest image size and either JPG fine.

I shoot in Medium if I'm shooting zillions of people shots. You'll see that they look as good, and halve the amount of time and space taken by the files for shooting, transfer and burning.

Large, Medium and Small are relative.

Resolution Affects Output

Most digital cameras allow you to change the resolution (quality) setting, so you can fit more or fewer images on your memory card. This can be a helpful feature if you only have one card or if you are on a trip and can't transfer photos to your computer. But if you take a photo of a spectacular sunset, and you capture it on a lower resolution setting like small image size (2144 x 1424)and a JPS fine, medium or small image quality, you may be unhappy with the result if you want a 5x7 or 8x10 print. That's because the low resolution image lacks detail, and may also appear jagged. Carrying additional memory cards and keeping the camera set on one of its higher resolution settings is a better solution.

The higher the photograph's resolution, the more plentiful printing and sharing options exist. With this in mind, the best bet is to understand what you intend to use the final photograph for and then work backwards.

Setting your camera to shoot photos to one of it's higher resolutions is better than a low resolution as it can easily be adjusted downward on your computer.

However, there is a limit to how effectively photo resolution can be adjusted upward by a computer. This means, for example, you can always make a sharp, clear, small print from a high-resolution photo, but you can't make a rich, detailed, large print from a low-resolution one.

Choosing a File Format

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other settings. Then, as its last step before transferring the photo to the memory card, the camera saves the picture into the file format you've selected. The file format you choose can impact the clarity of the photo. A number of digital cameras offer both TIFF and JPEG settings:

TIFF: This file format is uncompressed. Choosing TIFF means that you're always assured of getting all the image quality captured and processed by the camera. But TIFF files can be quite large, which means that only a few will fit onto a memory card. They can also take a while to be written to the card, which, with some cameras, means it might be a few seconds before you can take another picture.

JPEG: This file format is compressed, which means that the picture information is squeezed to a smaller size before it's stored on the memory card. Though this compression does not alter the photo's image size (resolution), it does come at the expense of a slight loss of detail and clarity in the photo. Typically, a camera will offer several JPEG settings, each offering progressively more compression (which translates into being able to store more photos on the memory card), with a

commensurate drop in image quality.

RAW: This file format (camera setting) should only be used if you want to spent hours in front of your computer or printing extremely large (wall size) prints.

The file format you choose doesn't affect the resolution of the photo, but if you choose a JPEG setting that compresses the photo heavily, the detail in the photo may be irretrievably damaged. This type of damage is called JPEG artifacting, and often appears as a pattern of large, square blocks sprinkled through the picture. JPEG artifacting limits your ability to make a large print from the photo, even though the resolution of the photo hasn't been changed by the JPEG compression. It would seem that shooting on the TIFF setting, if your camera offers it, is the most sensible way to eek out every ounce of quality from a digital camera. While this is true, it isn't the whole story. That's because shooting TIFF (instead of JPEG) means that you need to have lots of memory cards to shoot with, a faster memory card reader and a larger hard drive to store the large files and more blank CDs since not as many TIFF files can fit on a CD as JPEG files. TIFFs can quickly become impractical.

Fortunately, the highest-quality, lowest-compression JPEG setting on most cameras offers

fractionally less quality than TIFF, but without the headaches of really large photo files. In fact, few photographers ever notice the difference between a best-quality JPEG and TIFF, even though the JPEG will be six to eight times smaller when stored on the card. The same can't be said of the

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lower-quality JPEG settings—clarity and detail can drop off fast.

To maximise both the resolution and clarity of your photos, while not bogging down the camera and limiting its usefulness, set your camera on its highest image size and best image quality JPEG settings.

Caution Using this technique to shrink and compress an image file invariably causes a loss of data. When you're sending a snapshot to your parents, the drop in quality is probably a fair trade-off for the faster, slimmer e-mail attachment. But if the scanned image contains text, or if the recipient wants to be able to print a high-quality copy, check the compressed image before you click Send. Where quality is crucial, you might have better results using the Zip format to compress the original file without losing any data. Or look for a third-party image editing program which gives you greater control over compression.

Camera Resolution tips

Step 1

Determine your final use. As mentioned before a higher resolution will give you a better result. Step 2

Decide what type of picture you will be taking. If you desire to take a photo of a beautiful sunset that you will keep and cherish forever, you will want a higher resolution. If you're just taking a photo that will become an email to a friend, you may with to use a lower resolution.

Step 3

Determine the clarity you will need in your photos. If you are going to take a photo of something with a lot of detail, you'll need a higher resolution. If you wish to take a close-up picture of a

flower, with acute detail, you'll need more resolution. If you are taking a picture of something large, like the sky or ocean, you may not need as much clarity.

Step 4

Assess how large you will want your prints to be. If you want a 4 x 6 print, you could use a low image size and quality. If your prints will be larger, such as a 16 x 20 inch print, you should use at least large image size with TIFF or fine JPG setting.

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Take this image for example. It is a picture taken from a raw editing program showing both the JPG and raw CR2 file side by side. It's clear to see how much data is lost in the JPG on the right. If your image is destined to be printed very large. Then it's

recommended to open the RAW CR2 file and save it as a TIFF file before printing. TIFF files also keep a high percentage of the data's quality when compared to JPG. JPG is really only recommended for medium size printing (up to 61cm x 92 cm). This all depends on file size (actual dimensions) and quality settings.

How to convert and edit RAW files?

If you need to convert a raw file into a jpg so you can use it on a web-site or have it printed, then you need a conversion software package that can read this format. Chances are, if your DSLR camera has a raw file option, then your purchase should also have included a raw software package on a CD.

Disadvantages to shooting in RAW

Like most things, there are also some disadvantages that must be taken into account when setting your digital camera to photograph in RAW format. RAW CR2 files are very large and take a lot of space on your cameras memory card and on storage disks. If you plan on shooting in this mode then I recommend having at least two 8gig memory cards for your camera. Backing photo's up on DVD disks instead of CD will also let you save more images per disk. Having a fast computer on which to edit the RAW files is also a necessity. If you own a 5 year old computer you might find it takes an hour just to open your folder of RAW files.

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