Marvin
07-08-2010, 12:45 AM
Lenses designed specifically for macro work can be quite useful but are a bit costly. There are several alternatives and we will look into them here.
But firstly, you will almost certainly need a good tripod and remote shutter release (or use your self-timer).
When you get really close to your subject, the apparent magnification will also magnify any camera movement so it is essential to have the camera supported solidly.
The close proximity to the subject will also give you a very shallow DOF so you will probably want to close down your aperture to help with focusing. Unless you are using a flash you will need a slow shutter so again, the tripod is needed.
Be aware, if using a flash, the lens may be too close to allow a camera-mounted one to light the subject effectively. A pop-up flash will probably leave a lens 'shadow'.
The easiest way to convert your lens for Macro / Closeup use is by adding an extra lens to the front of it. These can be bought quite cheaply and are usually made by Kenco or Fox.
Bought singly or in sets, they are marked in Diopters (just like reading glasses) and are typically made as +1, +2, +4 & +10. These may be your only option if you are using a Bridge or Compact camera.
The disadvantage is that you are introducing an extra bit of glass into the light path and it may not even be a coated lens, let alone colour-corrected. But they can give surprisingly good results.
The next step, for DSLR users, is to move your lens further from the camera body. Notice how your lens gets longer when you focus on a close subject? For macro work you need to place something between the lens and camera body.
Traditionally, we use either bellows or extension tubes. Both do the same job but bellows allow a gradual adjustment from max to min while tubes are in set lengths and you need to add the right length. Get it wrong and you just remove them and start again, simple.
Some Bellows are expensive whilst tubes are dead cheap for a simple set. Even cheap tubes are quite sturdy but less expensive bellows can give rise to some wobbling.
BUT - and it is a BIG but... Tubes and bellows usually disconnect all the 'auto' functions of your lens so if you are not comfortable with manual settings these are probably not for you.
Your lens will also need to be of the type where you can set the aperture when it is not attached to the camera (Nikon 'G' series will close the aperture to minimum when removed).
Macro work will inevitably need manual focusing and the use of tubes or bellows will mean that all the exposure settings will become manual too.
The primary function of a 'normal' lens is to focus a distant subject onto a nearby sensor (or film). Using a 'normal' lens for macro work is working against this rule by focusing a nearby subject onto a more distant sensor.
We are trying to use the lens backwards! Some lenses don't mind this but others object strongly. They show their objections by refusing to focus sharply.
So we need a way around this. The answer arrives in the form of a 'Lens Reversing Ring'. This has your normal body fitting one end and a lens filter thread (male) on the other. If we are to use the lens backwards, lets fit it backwards.
Used in conjunction with the extension tubes (or bellows) this may coax a non-focusing lens to behave itself. Again, some lenses work fine, some don't.
We are trying to use a lens for a purpose which it wasn't designed for. It might work but it won't harm your camera or lens to try it out.
http://www.tog247.com/gallery/data/507/thumbs/diode_macro.jpg (http://www.tog247.com/gallery/showphoto.php?photo=7913)
"Normal" lens, Reversing Ring, Extension tubes.
But firstly, you will almost certainly need a good tripod and remote shutter release (or use your self-timer).
When you get really close to your subject, the apparent magnification will also magnify any camera movement so it is essential to have the camera supported solidly.
The close proximity to the subject will also give you a very shallow DOF so you will probably want to close down your aperture to help with focusing. Unless you are using a flash you will need a slow shutter so again, the tripod is needed.
Be aware, if using a flash, the lens may be too close to allow a camera-mounted one to light the subject effectively. A pop-up flash will probably leave a lens 'shadow'.
The easiest way to convert your lens for Macro / Closeup use is by adding an extra lens to the front of it. These can be bought quite cheaply and are usually made by Kenco or Fox.
Bought singly or in sets, they are marked in Diopters (just like reading glasses) and are typically made as +1, +2, +4 & +10. These may be your only option if you are using a Bridge or Compact camera.
The disadvantage is that you are introducing an extra bit of glass into the light path and it may not even be a coated lens, let alone colour-corrected. But they can give surprisingly good results.
The next step, for DSLR users, is to move your lens further from the camera body. Notice how your lens gets longer when you focus on a close subject? For macro work you need to place something between the lens and camera body.
Traditionally, we use either bellows or extension tubes. Both do the same job but bellows allow a gradual adjustment from max to min while tubes are in set lengths and you need to add the right length. Get it wrong and you just remove them and start again, simple.
Some Bellows are expensive whilst tubes are dead cheap for a simple set. Even cheap tubes are quite sturdy but less expensive bellows can give rise to some wobbling.
BUT - and it is a BIG but... Tubes and bellows usually disconnect all the 'auto' functions of your lens so if you are not comfortable with manual settings these are probably not for you.
Your lens will also need to be of the type where you can set the aperture when it is not attached to the camera (Nikon 'G' series will close the aperture to minimum when removed).
Macro work will inevitably need manual focusing and the use of tubes or bellows will mean that all the exposure settings will become manual too.
The primary function of a 'normal' lens is to focus a distant subject onto a nearby sensor (or film). Using a 'normal' lens for macro work is working against this rule by focusing a nearby subject onto a more distant sensor.
We are trying to use the lens backwards! Some lenses don't mind this but others object strongly. They show their objections by refusing to focus sharply.
So we need a way around this. The answer arrives in the form of a 'Lens Reversing Ring'. This has your normal body fitting one end and a lens filter thread (male) on the other. If we are to use the lens backwards, lets fit it backwards.
Used in conjunction with the extension tubes (or bellows) this may coax a non-focusing lens to behave itself. Again, some lenses work fine, some don't.
We are trying to use a lens for a purpose which it wasn't designed for. It might work but it won't harm your camera or lens to try it out.
http://www.tog247.com/gallery/data/507/thumbs/diode_macro.jpg (http://www.tog247.com/gallery/showphoto.php?photo=7913)
"Normal" lens, Reversing Ring, Extension tubes.