Question on Digicams:
I'm new to this forum and have many question about digicams. What is F2.8-4.9? How can it be calculated? What relation does it have with the 28mm, 35mm that we normally talk about? Is the range such that the bigger, the better? Please help as I am looking for a good compact camera.Submitted by Reader
Answer:
Damian Koh
Senior Writer
(1) The numbers F2.8 to F4.9 refer to the aperture of the camera. Aperture refers to the camera's diaphragm opening and is often used interchangeably with f-stops. To put it in layman's terms, the smaller the f-stop (e.g. F2.8, compared with F4.9), the larger the aperture and the wider the size of the opening in the lens. Having a large aperture will allow more light into the lens of the camera, and in most cases, create the blurred background effect in portrait shots.
(2) The numbers 28mm, 50mm, 100mm refer to the focal length of the camera. Focal length refers to the distance from the surface of the lens to the focal point or center point at which light rays converge. It also determines the field of view of the camera. For example, a 24mm lens usually refers to a wide-angle lens which gives you a broader perspective as compared with a 50mm lens. The optical zoom of a digital camera depends on the focal length of the unit. For example, a 28mm-to-280mm lens is equivalent to 10x optical zoom. Do note that optical zoom is different from digital zoom.
(3) Aperture sizes are fractions of the focal length and higher f-stops represent smaller apertures.
(4) If you're looking for a good compact camera, you might also want to take into account these factors: Handling; viewfinder; battery types; compatible memory cards and image stabilization features. There's a complete digicam shopping checklist on our Web site which you can refer to here.
(5) Further to that, you might want to check out Panasonic's Lumix DMC-FX9 and Sony's Cyber-shot DSC-T9 which scored high ratings in our reviews.
Got a question of your own?
