Both with "macro", what does that mean?

And how come "0.4x" fish eye capture more angle than the "0.7x" wide angle lens?

"maco" normally means close-up lens.

A fish eye is designed to distort the image, it is a type of wide angle lens: http://en.wikipedia.org/wiki/Fisheye_lens



Rich

Both with "macro", what does that mean?

And how come "0.4x" fish eye capture more angle than the "0.7x" wide angle lens?

Basic math: You multiply a number by .4 and you get a figure lower than multiplying for .7 . A 40mm lens will be 16mm with the .4 or 28mm with the .7. As you know, 16 mm is wider than 28mm. Capice ?

this is probably where I was confused at, what do u mean by 16mm is wider than 28mm? what does those numbers mean?

That is how lenses intended for 35mm cameras are measured. The 16mm or 28mm is the focal length of the lens.

A shorter focal length creates a wider field of view (i.e. zoomed out further) and thus a longer focal length creates a narrower field of view (i.e. zoomed in further). To understand this better, make your index finger and thumb into a circle and notice the differences in the field of view through this circle as you move it toward and away from your eye. The closer it is to your eye the more you can see through it and the further it is the less you can see.

The .4x and .7x ratings are the amount of magnification. These ratings can be equated to their equivalent 35mm lens focal length (what slimoli was doing), but in most cases this is completely unnecessary for these types of lenses since the magnification rating is all you really need to know. Magnification works the same as the focal length: smaller = wider and further, larger = narrower and closer.

With all that said, almost every lens is actually made of multiple individual lenses and those are what determine the focal length/magnification.

This is a pretty good primer on lens nomenclature and how they work:
http://en.wikipedia.org/wiki/Photographic_lens

I see, I understand it now, thanks for the explanation.

there is actually another question that puzzles me, hopefully u know the answer too.

Whenever I use self timer, lets say 10 seconds count down, after I press the button, I have 10 seconds to get myself into the picture, however, I found that if I actually moved farther away or closer to the camera during the count down(thus focus changed), the camera won't find the new focus, is this normal? or is it a flaw in design? my camera is Sony DSC-W300.

PS. I have turn auto-focus to "continuous" from "single", face-tracking feature is on as well.

That is normal. On most cameras when you start the timer it sets the focus and everything so there won't be any lag when the timer runs out. It's meant for situations where most of your subjects are already in their positions. Because of this, changing the auto focus and face tracking settings won't effect the behavior of the timer.

I see, I got worried and thought I got a defective camera.
what a relief, thank you~

another lens related question:

I've seem some sample photos taken with and without wide angle lens, however, isn't photo taken with wide angle lens simply equals to moving a few steps back when taking the photo so that more scenes can be captured?

I've seem some sample photos taken with and without wide angle lens, however, isn't photo taken with wide angle lens simply equals to moving a few steps back when taking the photo so that more scenes can be captured?Not exactly, for the same reason that standing up close to someone's face is not the same as standing far away and zooming in on their face.

You change the point of view and this can dramatically change the image.

You are correct however to conclude that a wide angle lens is useful in a small room or space where it would be impossible to back up a few steps.

I understand what you are saying; however, I found two reviews on the wide-angle lens for my DSC-W300:
http://katzho.blog.so-net.ne.jp/2007-08-21
http://www.bangkoksite.com/DigitalCamera/SonyW300/W300A.htm

I really can't see the difference, the none-wide photo looks like a crop from the wide-angle photo, to my eyes anyway.

The reason I am going to buy wide-angle lens is like what u said, for indoor use when there is not enough room to back up a few steps.

The flaw that I see on compact camera is the flash light which is blocked by its relatively large adaptor and lens, when flash is required for most of the indoor shots, it kinda defeats the point. (but I am getting it anyway.....)