The Extension Tube EF 12 has a dry weight of only 66 grams with a maximum diameter of 66.5mm and an overall length of 12.3mm. To give you an idea of the types of close-ups the EF 12 can provide with EF lenses, the photos on this page as well as the next, will show just exactly that. Fitted to the EF 20mm f/2.8 USM Super wide-angle lens Shot at the closest focusing distance without tube Shot at the infinity position with EF 12 attached     Shot at the closest focusing distance w/EF 12 As I have stated in the field-test of this lens in issue No: 51 of the Nuts & Bolts column, the distance of the front element and the subject is less than half a centimeter away when the EF 12 is attached and the focusing distance is set at the closest range. This is the reason why both the EF 12 and EF 25 Extension Tubes are not recommended to be used with certain EF lenses as described in the previous page. For the final shot of the model bike above, I had to make sure that the engine valve does not come into contact with the front element of the EF 20mm f/2.8 USM lens. The magnification is almost 0.5x (half life-size) but due to the wider field-of-view and exaggerated perspective of the 20mm lens, the background appears to be further away than the engine valve. Fitted to the EF 17-35mm f/2.8L USM zoom lens (28mm and 35mm focal lengths) Closest focusing distance at 35mm At the infinity position with EF 12 attached     At the closest focusing distance w/EF 12 The EF 12 can be safely used with all the focal lengths of the EF 17-35mm f/2.8L USM zoom lens even though only the 28mm and 35mm positions were actually utilized for this evaluation. Compared to the EF 20mm f/2.8 USM, the distances between the front elements of the zoom lens, when focus was set at the closest focusing positions, were at 3.5cm (35mm) and 3cm (28mm). Again, the exaggerated perspective of wide-angle viewpoint of these focal lengths will cause slightly distorted images of their respective subject matters when focused in extreme close-up ranges. However, those that were shot at the zoom lens' 35mm focal length do not exhibit this tendency as the subject matters' angle to the lens was parallel to the film plane as opposed to 45-degrees angle viewpoint captured on the 28mm photos. Closest focusing distance at 28mm At the infinity position with EF 12 attached     At the closest focusing distance w/EF 12 << Back to Main . 1 . 2 . 3 .