This is just an attempt from me to explain what macro photography is as it came up in the forums. The following explaination is lifted from my forum reply.

Macro shots for me need to fulfill 2 conditions. The subject is very small. The subject appears almost in actual size on your frame/sensor. Some people technically classify macro as shots where the subject is taken at 1:1 magnification or more. So what does 1:1 magnification mean?

Let’s assume you are using a film SLR .. your ’sensor’ is your film which is 35mm = 3.5cm (1000D sensor is 1.6x smaller than that hence you will hear people say we have a cropped camera). Let’s use a ruler as a subject. If you see the pic below .. you see that from left to right I managed to get 14cm into the frame 14cm/3.5cm = 4. Hence we managed to get 1:4 magnification or the image ON the frame/sensor/film is 1/4 the size of the actual thing.

Now I went in closer and got 7cm coverage and now I have 1:2 magnification.

Finally I went in even closer and got side-to-side 3.5cm that means 1:1 magnification.

Technically the 1000D is a cropped sensor so the sensor is 22.2mm wide .. so the following shot is closer to being 1:1.

Macro lenses usually are capable of at least 1:1 magnification. They allow you to do that by having optics that allow you to still focus when the subject is relatively (relative to the focal length of the lens) near.

Think of the Raynox DCR-250 as a very good magnifying glass. It increases the magnification and allows you to take fantastic shots especially if it is combined with a macro lens. It is the same thing if you reverse the 50mm lens in front of your lens. You get a +20 diopter. I believe the DCR-250 is a +8 diopter.

“Macro Photography on Wikipedia”