How to gauge minimum distance
It is important to be able to visually gauge the distance you need to be from your subject to get the maximum magnification. There is a simple way to check this distance when you start shooting with a new lens.
1| Switch the lens to its manual focus (MF) setting – the switch is typically on the side of your lens (occasionally a button on camera or menu item).
2| Turn the focusing ring so that the lens is set to its closest focusing setting. (If using a zoom lens, make sure it’s at its longest focal length.)
3| Start at what you think is the right distance away from your subject and gradually move yourself closer or further away until the subject looks sharp – do this without changing any setting on the lens. Then, without altering your distance from the subject, look to see how far away you are. Once you have taken a mental snapshot, put the lens back to its autofocus (AF) setting. Then, in future, you’ll know roughly how close you need to get to achieve the best possible magnification with your lens.
Carry out this test with all the lenses you are likely to use for shooting close-ups or macro. If you are going to use accessories such as close-up lenses or extension tubes, then test these as well in the same way. If your camera refuses to fire or focus when switched back to AF, try moving slightly further away – if you are too close and therefore out of focus the camera will refuse to fire when shooting in One Shot AF.
