Hello, I'm a bit of a newbie.. and I know absolutely nothing about lenses. I have a Nikon D3000 and I want to buy a Macro Lens. Which one would be the best for this camera? As I said, I am a newbie, so I am looking for something that is easy to use and that I don't need to fiddle around with settings much (auto focusing?). Clearly I have no idea what I'm talking about, HELP!
The current macro lenses will focus close enough to see 1:1 magnification. 1:1 magnification means the image is the same actual size as the object photographed. In film days, after we developed the film, 1:1 meant the image on the film was same actual size as the subject object.
We cannot take a digital sensor out and look at it, but still same meaning, and 1:1 can be compared this way:
An object that is one inch in size (a coin or a stamp say) is 25.4 mm.
At 1:1, the image of this one inch object would be slightly larger than the width of a DX frame (24mm),
or it would be slightly larger than the height of a FX frame (24mm).
Either way, it would be magnified to 1:1 actual size.
Since most macro lenses do 1:1 today, the other difference is their focal length. Some Nikon macro lenses are 40 mm, 60 mm, 85 mm, 105mm, or 200 mm focal length. Other brands of macro lenses might be 90 or 150mm, etc.
Longer focal length is a telephoto lens (which is yet another effect), and we have to stand back farther to get everything in the frame. This can be a plus at 1:1, it allows more working room, the lens itself does not block the lighting (shadow on the the subject), and greater working distance may scare live bugs less.
However, this greater working distance can be a negative on a larger table top scene, the room may not be large enough to let a telephoto see the entire table top scene. For example (assuming 35mm film or FX), copy stand work typically uses 55 or 60mm lenses, since the copy stand cannot be tall enough to use a 105 or 150 mm lens.
At 1:1, the 60mm lens will have less than three inches in front of the lens (to the subject). About 2 7/8 inches.
At 1:1, the 105mm lens will have about six inches in front of the lens (to the subject). This is rather noticeable, and better (if at 1:1). But... of course the 60mm still can work. It just has to be closer, nearly half the distance.
Focus Distance is measured to the image plane at the rear of the camera, but this distance in front of lens is called the Working Distance. Six inches is a plus at 1:1. But for table top scenes, working distance of say 7 feet compared to only 4 feet may be awkward, if we cannot reach both subject and camera at same time, or if we don't have 7 feet of room.
Here is an excellent chart showing working distance (WD) of many macro lenses for Nikon.
http://www.jeffree.co.uk/pages/macro-lens-calcs.html