Category: Cameras

As anyone with a digital camera knows, pictures are saved as files on a memory card. They can then be downloaded and printed. Some of the higher end digital cameras, however, have an option of saving the pictures in two different file formats: JPEG or RAW.

Both formats are completely different. One can easily be used by many different systems and applications, while the other is proprietary and needs to be converted first. One is compressed, while the other isn’t (although some say it can be). One is result of processing performed by the camera, while no processing is performed to get the other. As you can see the two formats are completely different, and yet there is a great debate on which format to use.

This purpose of this article is to discuss the differences to help you make a decision on which one fits better with our needs.

JPEG

The famous JPEG (Joint Photographic Experts Group) file format is beyond a doubt the most common digital camera file format. This format is used by all digital cameras, and can easily be downloaded and printed. It has the ability to compress images with 24 bits of colour data (8 bits each for red, green, and blue), or 16.7 million colours. This is more than enough colours to produce photo-quality images.

A JPEG file is also compressed, and uses a lossy compression. A lossy compression discards some data when in compresses an image. Usually applications, or in this case a digital camera, have a method of controlling the amount of compression applied to the image. The less compression applied to the picture, the better it looks, but the larger the size. If the compression is set too high, JPEG compression artifacts may appear in the picture. These can be seen as irregularities in the picture.

The JPEG format is very popular for posting images to the World Wide Web, or to send in an e-mail.

RAW

This format can be found in higher end digital cameras, such as DSLRs. Unlike the JPEG this format can’t just be downloaded and printed without first processing and saving the picture into another format. A RAW file is a proprietary format which is unique to each camera maker. This causes problems as vendor applications that provide the ability to edit RAW files must update their application to accept any new camera RAW formats. Usually, however, a camera will also include software that can edit the RAW format.

The RAW file is unprocessed data from the camera, meaning it is exactly what the camera’s CCD sees. No in-camera sharpening, contrast, or white balance settings are applied to the file before being saved to the memory card. This provides the flexibility of being able to set these settings manually after downloading the file to a computer.

While a JPEG file is 24 bits total, a RAW file stores up to 48 bits (16 bits each for red, green, blue). This provides more room for correcting the colour when processing the image on a computer.

It is important to note that many of the DSLR cameras also have the option of saving both a JPEG and RAW file of the same image. The downside to this is that it will use up more memory since you will be saving two images instead of one.

Comparison

Item	JPEG	RAW
File Size	Small. Depends on the compression.	Large.
Compatible	Can be used by any photo editor and Web browser.	Limited to specific photo editors that support the format for the camera.
Compression	Lossy	None, but if used the compression is non-lossy.
Printing	Can be printed right from the camera.	Needs to be edited and saved to another format first before printing.
Colour Bits	24bit (8 bits red, green, blue).	Up to 48 bits (16 bits red, green, blue).
Editing Ability	Can be edited but not too much or banding may occur. Should not be saved too many times or artifacts will become worse.	Can be edited many times before banding occurs. Should save to a standard non-compressed format such as TIFF when editing.
Processing Time	None. Can be printed from camera.	Much. Must be edited (sharpened, colour balanced) and saved to another format first before printing. Could use automation and bulk-editing to reduce the time.

Summary

Determining which format to use depends on your photo editing skills. If you enjoy editing photos, and have a powerful computer then you may want to choose the RAW format. If you don’t feel like sitting in front of a computer and edit a photo, or can’t wait to print your photographs, then choose JPEG. In the end, it’s really a personal preference.

I have been using digital cameras for about five years now. Over the course of those five years, I have learned a lot about what to look for with regards to buying a new camera. This article will outline what to look for when buying a digital camera.

Megapixels

Whenever I ask anyone about their new digital camera, they are always quick to point out the number of megapixels. When shopping for a new digital camera, I don’t usually put too much thought in how many megapixels a camera has. Why? Because digital cameras today have more than enough megapixels than I would need.

The digital cameras of today have more than 5 megapixels. This is more than enough to printout a good quality 8×10. Most people usually only print a 4×6, meaning a 3-megapixel camera would do the job fine.

Most high-quality pictures are printed at 300ppi (pixels per inch). For a 4×6 the number of pixels in both dimensions is 1200 (4×300) and 1800 (6×300). Multiply the number of pixels together to get the total number of pixels (2,160,000) in the picture. The total number of pixels for a 4×6 is less than 3-megapixels.

Digital Zoom

Digital zoom is well advertised by the camera companies for both digital and video cameras. In reality, this really isn’t a zoom at all, and unless you want a blurry picture, you should turn this off. All digital zoom does is enlarge a portion of the picture by cropping out the edges. The space that is filled by the cropped pixels is filled using a process known a interpolation. Interpolation uses the surrounding pixel tonal values to determine what the missing pixels should be. This results in an image that is not as sharp as the original.

The better option to the digital zoom, is to use a photo editing program. A photo editing program will allow you to crop a portion of the image and enlarge that portion to any size you want, essentially perform the same task as the digital zoom.

When comparing the zoom capability of cameras, pay attention to the optical zoom, and not the digital zoom.

Batteries

The first digital camera that I owned was a Canon G2. I liked this camera, mainly because of the battery. The camera used a rechargeable Lithium-ion that could be charged right in the camera. I never once ran out of battery power with the camera.

My new camera is the Canon S3 IS, which uses four AA batteries. Depending on how many pictures I take with the camera, I sometimes run out of battery power. To avoid being unable to take pictures, I always carry a spare set of fully charged batteries with me. Once one set runs out of power, I simply insert the spare set. If I’m at a place that has electricity, I can charge the first set, which would then become my fully charged space set.

This brings me to my point about AA batteries: always have at least two sets of rechargeable batteries, and a charge with you at all times. They do come in handy at times.

Storage Medium

Digital cameras store the pictures in files on a memory card, or in some cases a small hard drive. Some cameras allow for two types of memory cards to be used. The most common are SD (Secure Digital), CompactFlash and the Memory stick. There are other types of memory, but if you have one of the ones just mentioned, you won’t have trouble finding memory for your digital camera.

There is some debate on whether you should buy two memory cards or one. What I mean is, should you buy two 1GB cards or one 2GB cards. Some professional photographers like two because when they fill up one card, they can download the pictures, while still taking pictures with the second. I only have one card because I rarely take enough pictures at one time to fill up the card. Pricing could also affect your decision. If you happen to find a 2GB card that costs more than two 1GB cards, then pick up the 2GB card.

Make and Model

In my opinion, choosing a make of camera is a personal preference. Many people who own cameras are usually comfortable with a particular make. If you prefer one camera-maker over another, then stay with them. Chances are if you have a film SLR from one maker, and upgrade to a DSLR, many of your lens and flashes will work with the DSLR as well.

As for the model, you may want to research the various cameras to find one that suits your needs. At this point you should list what you are looking for in a digital camera, and then read reviews of specific models that meet your needs. A good place to start for reviews is Digital Photography Review. They have a lot of information about practically every digital camera ever made.

Summary

• Megapixels: Don’t worry too much about this. Any digital camera that has more than 3-megapixels can print out a high quality 4×6. The higher megapixels are useful for large photos.
• Digital Zoom: This isn’t really a zoom – it simply enlarges a portion of your picture. If you want more zoom, look for a camera with a higher optical zoom.
• Batteries: If the camera you want takes AA batteries, ensure that you buy at least two sets of rechargeable batteries, and keep them both fully charged. Just charge both sets the day before you plan to use your camera.
• Storage Medium: The most common memory types are SD, CompactFlash and the Memory stick. If you purchase a camera with either of these types of memory, you won’t have trouble finding memory for you camera.
• Make and Model: Camera-maker is a personal preference-stay with who you are comfortable with. The model would require some research. Determine what you are looking for, and compare cameras that have those features.