How to choose digital cameras? What is "Megapixels"? How many pictures can I store on a memory card?

• What should I look for when I want to buy a digital camera or a digital binoculars?
• What does megapixels mean in digital cameras and how many megapixels do I need buy?
• How many digital pictures can I save to a memory card? 

How to choose digital cameras

While camera salesmen at some other stores will start the conversion by asking you "What is your budget?" or "How much you want to spend?", we at OpticsPlanet.com always start with "What is the intended application for the device you are looking to buy?"   Digital cameras industry is constantly moving forward, and all major Digital Camera Manufactures are forced to come up with new digital camera models every 4 to 6 months.  How can we make people buy new digital cameras more often?  How can we make people spend more on digital cameras or flash memory?  These are the questions that the camera manufacturers ask themselves everyday.  While we as a camera retailer are always happy to sell you the latest and greatest in digital cameras or digital camera binoculars, we want you to get what you really need and make an educated decision in your digital camera selection.    We could write a 500-page book on how to buy a digital camera, but we will try to condense the knowledge to a few pages and give you a few major pointers.  We are here to help if you need any additional help!

Brand, type (Point-n-shoot vs. Digital SLR), usability, optical zoom, and size/weight digital camera parameters are usually clear to most people.  Mega pixels (resolution) and storage capacity usually need more explanation.

• Brand of a Digital Camera is often a matter of personal preference and all digital camera reviews reflect the personal preference of the reviewer.  All digital camera brands that we offer are major optical brands that have been in the business for a long time and stand behind the products.
• Digital Camera Type.  As much as we absolutely love Digital SLR cameras, there should be a very good reason why you might need one.  We always advise our customers to go for a point-and-shoot digital camera because they are much easier to use and already have 99.99% of the features that most amature photographers will ever need. There are some good reason why you might need a digital SLR camera  Let us try to list these good reasons
  • You are Pro, and you do not need to read the rest of the page
  • You are in astrophotography or microphotography, and you need a digital camera to connect a telescope or microscope.  While there are now dozens of digital camera adapters available for point-n-shoot digital cameras, correct mounts for SLR cameras are more readily available, and using the optics of your telescope or microscope should give better image quality than having to deal with a combination of eyepieces and camera objectives/lenses.
  • You already have a nice set of SLR lenses and accessories from your film SLR camera, and you want to re-use your lenses.
  • You want to have full control over the way you take pictures and your are not afraid to mess with the options.  You need to be a true photography enthusiast and not be afraid to read a camera manual.
  • You want to have the latest, greatest, most advanced and most expensive camera available on the market today, and all you care is the get a great deal from a reputable Authorized US Dealer.  Well, we at OpticsPlanet.com love customers like that, but we still suggest to think and see if there is something else besides the bragging right that you need in your digital camera.
• Digital Camera Usability or User interface is a matter of preference as well, and to be honest, all of the Point-and-shoot digital cameras that we sell are easy to use and connect to the computer.  All of them come with image editing software, and toll-free technical support from the manufacturer.  If you are in trouble, you are a phone call away from getting help.  Hold time varies, but customers have not had any major issues with any of the manufacturers we carry.  Our digital camera manufactures stand behind the products - they want you to come back for another one in a year or two, and the brand is a major factor for many consumers.
• Optical zoom is nice, but do not be fooled - More and more camera manufacturers are choosing to label their digital cameras with the total (optical + digital) zoom.  "Digital zoom" does not really do zooming, but it just enlarges a part of the image imitating optical zoom.  It is not bad, but when you are comparing digital cameras, you should always use optical zoom, as you can do "digital zooming" and cropping in any image editing software.
• Camera Size and weight - in point-n-shoot digital cameras these parameters are very important - after all you plan to take your camera somewhere, and you do not want to carry a brick in your pocket.  Larger camera also harder to hold steady in your hands, and often you need a sturdy photo tripod to take good pictures with an SLR camera.  We have done a lot of field tests and our customers always send us their camera reviews, so we know for sure that smaller and lighter compact digital cameras such as Pentax Optio and Canon Digital Elf always get used more frequently than their more advanced, but larger in size brothers.
• Digital Megapixels / resolution is the most hyped, and less understood parameter in digital camera selection.  More is better? Not always. Without a doubt, higher-resolution digital cameras from the same manufacture with the same optics will produce sharper, cleaner pictures, but we are not in 1998 - most new brand name consumer digital cameras sold now are high-resolution, and most people are not using their full capabilities as is!  In addition, there are a few drawbacks that you should keep in mind.
  • Higher resolution cameras are more expensive than lower resolution digital cameras. We keep telling our customers - pay for what you will actually use!
  • Higher resolution digital cameras of the same type / brand will work slower than their lower resolution brothers.  It takes more time to process, compress, and save a larger image.  We do know people who take high-res photos, transfer them to their PC's, and then immediately resize them to make them usable for emailing, storage, editing, or web publishing. 
  • Higher Resolution digital cameras do need more storage.  Again, we will be happy to sell you a larger flash memory cards,  in fact we do recommend them as a good upgrade, but get what you need!  Read more on it below. 

What does megapixels mean in digital cameras and how many megapixels do I need buy.

Most digital camerass store digital pictures in JPEG (JPG) format. JPEG image format can easily provide 20:1 compression of full-color data. The second fundamental advantage of JPEG is that it stores full color information: 24 bits/pixel (16 million colors).  However, unlike TIFF or RAW digital image formats, JPEG uses "lossy compression".  For full-color images, the uncompressed data is normally 24 bits/pixel.  The best known lossless compression methods can compress such data about 2:1 on average.  JPEG can typically achieve 10:1 to 20:1 compression without visible loss, bringing the effective storage requirement down to 1 to 2 bits/pixel.  30:1 to 50:1 compression is possible with small to moderate defects, while for very-low-quality purposes such as previews or archive indexes, 100:1 compression is quite feasible.  An image compressed 100:1 with JPEG takes up the same space as a full-color one-tenth-scale thumbnail image, yet it retains much more detail than such a thumbnail.  The only real disadvantage of JPEG's lossy compression is that if you for some reason repeatedly compress and decompress an image, you lose a little more quality each time.
So for all practical purposes, you got nothing to worry about - JPEG is more than capable of storing mind-blowing pictures of high-quality without any visible to a human loss. 

Why did we tell you all that technical digital camera stuff? Because we want you to understand why most digital cameras list MegaPixels (MP) (resolution or maximum number of dots, in millions, that a digital camera can make up the image in) as their key technical parameter.  Most digital cameras capture images on a CCD (Charge Coupled Device) sensor. The camera's resolution is calculated by multiplying the maximum number of pixels along the length and width of the CCD sensor. Modern digital cameras and digital binoculars typically capture between one million and seven million pixels per image, and also have a setting to lower effective resolution of the camera.

Most modern digital cameras also offer different "picture modes" - Best, Better, Good - for the same resolution, and therefore store different number of digital photos on the same card.  When you select Quality Level or Resolution Mode, you select the type of compression or resolution that your digital camera will use to store the images.  Better quality requires less compression and needs more flash memory card storage.  If you plan to print your digital pictures on paper, select the highest resolution possible, but keep in mind that when you increase the quality setting, you create larger files that might be inappropriately large for e-mailing or web publishing.  Please remember - most if not all digital camera come with some image editing software, so you are always able to shrink your digital pictures to a smaller size by discarding extra pixels you don't need, but this process doesn't work in reverse. If you enlarge a lower resolution digital picture, the image will appear blurry and distorted.

Image pixel resolution is important for many reasons. Not only will higher pixel resolution result ingreater detail, but it also dictates what size prints you can get before your digital photos appear jagged. For example, here are suggested MIN. image pixel resolutions to ensure high-quality paper prints:

Flash memory card pictures and movie capacity

As a reference, below we offer you some sample data of how many pictures or 30 frames per second movies you can store on a SanDisk SD memory card with a 3.2 Megapixel Digital Pentax camera.

STILL DIGITAL PICTURES

STILL DIGITAL PICTURES

STILL DIGITAL PICTURES

DIGITAL MOVIE

DIGITAL MOVIE

We offer full line of digital flash memory cards in our online store - including PC Card (ATA and Linear Card), CompactFlash, SmartMedia, SD cards, Memory Sticks, MultiMediaCard, USB drives, and Card Accessories and adpaters from SanDisk and SimpleTech.  Please make sure to check what memory cards are supported by your digital camera. Most modern cameras use either SD (Secure Digital) cards or CF Compact Flash memory cards.