Lens for SONY DSC H50

[Kaustav]

Hi,

I own a Sony DSC H50 camera. I am ameteur photographer, trying to learn.
Want to buy a Macro Lens, but I am confused by the range mentioned about 1:4. Need help to understand the same.
Another thing I noticed while reading through another forum is that, Sony comes with 74 mm lens holder. What do that mean? is it the diameter of the open end of the hood. The forum mentioned about buying an adapter to convert 74mm -> 72mm , because the available macro lens for 72mm are cheap priced and easily available.

Basically, I will need a lot of input so that I can buy a Macro lens, for phototgraphy of small objects from a distance.

Thanks in advance,
KD.