Because lighting is probably the most important aspect. You need the right lighting, and the right AMOUNT of light.
This was taken with a Nikon Coolpix 4500 - a 4 megapixel camera made about 8 years ago.

4 megapixels!!?? You can't even BUY a 4 megapixel camera now! Heck, a lot of phones have a 5, or even up to 8 (I've heard), megapixel sensor! lol
That picture turned out so well because I had GREAT lighting.
If you don't already have a camera, I'd first learn about aperture, shutter speed, and ISO. Then, find a camera in your price range that has a good rating for all three settings by an independent source (like dpreview.com or similar). For photographing boas, really good performance at fast shutter speeds with a higher aperture will be very important. As you learn more about what you're doing, you'll want a camera that has excellent results at higher ISO's.
Quick info:
Shutter speed - how fast the camera shutter operates to capture a picture. The larger the denominator, the faster the shutter operates - ie, 1/5, 1/100, 1/200. 1/200 would be the fastest of these three speeds
Aperture (or F-stop) is a number indicating how much of the picture will be in focus. The higher the number, the more of a picture will be in focus.
ISO is a rating of how sensitive the sensor is to the light that is present. The higher the cameras capabilities, the better (as long as performance is good). My new camera has an ISO capability of 800. And mine is only a couple of years old. Newer models are coming out with capabilities in the 5 digits! The higher the number, the better it will perform in low light situations which translates into less blurring of the images - especially if something is moving... like a boa!
Hope that helps!
jb
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What's written above is purely my opinion. In fact, MOST of what you read on the internet is someone's opinion. Don't take it too seriously 
Jonathan Brady
DeviantConstrictors.com
Deviant Constrictors picturetrail
