John explained how by inserting these hollow tubes between the camera body and his 18-55mm lens it moves the front-element of the lens closer to the subject, which allows you to focus closer resulting in a greater magnification. His explanations were aided by a great series of images of a cool-looking bee looking for warmth in the morning sun, each one having a greater degree of magnification. The camera was mounted on a tripod and to keep the depth of field as large as possible most of the shots were done at f/32.
The only disadvantage of extension tubes is that there is some light loss. Adding an extension tube increases the effective aperture of the camera lens, which means you need to use either a longer shutter speed or higher ISO to compensate for the loss of light. They work best with short to medium focal-lengths being less effective with longer telephoto lenses.
Discussion was then directed towards how best to capture shots of certain insects or bugs which don't usually hang around smiling waiting for their photo to be taken. Techniques vary from hypnotism to freezing in order to make the subject remain still for a short period of time. Some examples given were by stroking a lobster or eel will make them remain perfectly still for a brief time period or placing a small bug in a freezer for a few minutes will produce similar effects without (in theory) harming the subject. Other tricks includes baiting your target subjects with food or sweet smelling substances such as jam or honey etc. Inevitably some of these practices are deemed wrong and or unethical by some individuals, suggesting everyone should stick to only capturing images of animals/insects in their natural habitat and without interference. Nothing is ever black and white and it's up to individuals to make that call. However, we all agreed that no animals or insects should be intentionally harmed for the sake of a photograph.