like the ones used to identify the suspects in the bombings might cost a few thousand dollars. experts say in a city like new york you may need tent or 20 cameras for just good visuals on one block. you add that up and keeping new yorkers safe is a very expensive business. hard to believe these eyes in the sky play such a vital role in protecting us from harm. >> we are releasing photos of these two suspects. >> thedry definitely felt that our work was worthwhile after the photographs were released identifying the suspects. >> a victory, yes, but one that comes with a price tag. >> a camera suffch as this with a decent megapixel count today is probably about a $3,000 investment. >> this particular camera you're watching me through costs about $1,500. it's installed about 150 feet away from where i'm standing. if you zoom in you really can't see that much detail. this camera on the other hand same distance but a lot clearer.