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Many photographers consider 'true' close up photography to be a 1:1 reproduction of the thing being photographed, i.e. the image produced on the sensor is the same size as the actual subject, which is not the same as close up techniques. micro and close up photography is niche and not for all folks, however it is something all snappers should try at some point to see if it is their bag. In order to create the 1:1 reproductions it is easy as pie to buy specially manuafactured macrolenses, such as the Canon EF100m f/2.8 macro USM, although these are quite expensive and a lot of people are not prepared on spending a few hundred pounds (or dollars) to see if macro photography is for them. luckily, there is a cheaper alternate available to pay for. For those wishing to try their luck at close up and micro methods a less costly alternate is to use auto focus close up tubes which in a nut shell are hollow plastic tubes that are put between the glass and the camera body. extension tubes contain no lenses whatsoever, and byexpanding the distance between the optics and the sensor the digital camera is made to focus closer to the subject, creating a macro and close up type effect. extension tubes can be used with all lenses, therefore they are ideal for everyone. Most new digital SLR camera optics contain autofocus technology, which in order to work needs the electrical contacts on theglass to be in contact with the electrical contacts on the digital camera body, therefore sticking a hollow tube, i.e. the auto focus close up tube, between the glass and the camera body may create a problem with the autofocus system. Fortunately, some auto focus close up tubes, such as those made by Canon and Kenko, have got the electrical contacts to preserve the autofocus feature however some extension tubes do not. This is worth bearing in mind before purchasing some auto focus close up tubes, although if you are comfortable using manual focus using close up tubes with no electrical contacts should not present any issues. As you'd expect, the close up tubes using the electrical contacts that preserve autofocus are more expensive than those that do not. many people who take photos prefer to use manual focus when taking close up and micro shots because of the shallow depth of field. As well as autofocus most up to date day optics allow the photographer to the aperture, and this is also achieved through the electrical contacts. Whilst many people who take photos will be willing to lose the autofocus feature it is unlikely they will be prepared to lose the ability to change the aperture of the lens. using auto focus close up tubes that do not have the electrical contacts means the lens will be wide open which is likely to lead to an unacceptable depth of field and blurred photographs. Very few optics are sharp when wide open therefore using extension tubes that do not allow the aperture to be varied means the lens will not be at its sharpest. When using close up tubes without the electrical contacts there is a way of fooling the digital camera in to retaining a chosen aperture setting but this is fiddly and time consuming. The process involves putting the camera in to aperture priority mode and setting it to the required setting. By holding down the depth of field button, taking off the lens and then inserting the extension tube before putting the glass back on, all whilst holding down the depth of field button, the camera will retain the aperture set. Sounds a bit of a pain right? Well, it is. As the process is so long winded and cumbersome there is the added problem thephotograph may be missed. For example, if the photograph subject is a bug by the time the camera and auto focus close up tube has been set up the subject may well have crawled away or flown off, however you shouldn't have any issues if photographing still life, insects or flowers. taking off the optics over and over again to change the aperture setting increases the possibility of dirt and debris sticking to the sensor, which may cause issues. In addition, the lens fitting is likely to get worn out quicker and there is an increased opportunity of damage to both the camera body and the piece of glass, which could prove to be very expensive. There is no doubt about it, auto focus close up tubes are an ideal way of getting in to the world of close up and macro photography, although it is unlikely you will get accurate micro 1:1 reproduction. That said it is possible to get some very good photos using extension tubes and a standard optic. Because of the all the issues associated with extension tubes. For some essential micro methods tips click here
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