Small aperture (large f number) is to increase field of depth for macro photo. Fixed focal length is not necessary, but a macro lens (with short focusing distance and high magnification, e.g. 1X) or close up filters are necessary. Thanks everyone for the comments.

是否一定要大光圈及定鏡焦哩?

很好投一票

Nice!

好sharp! 仲以為係strawberry top 既蛋糕... :)