I use a full frame Nikon camera and would love to play with macro photography. Is the Nikon 105 macro strong enough or would you rather recommend some bigger third party lens?
Which macro lens you get would probably depend on what kind of macro photography you want to do. There are a variety of macro subjects: flora, insects, still-life objects, abstract closeups.
If you wish to photograph insects, and are a beginner, a longer focal length that gives you more working room in front of the lens would probably be better. I am a Canon user, and I know that Canon offers a 180mm Macro lens that fits the bill. The greater distance between you and your subject reduces the chance you'll be scaring your subject off.
If you wish to photograph flora or still life objects, a 105mm Macro will do the job. I have the Canon 100mm Macro myself, and it is a great focal length. You have a lot of control over depth of field with this focal length. Its not too long, so you don't have to be over a foot away from your subject. If you need to get in really close, you can always get a set of extension tubes to reduce your distance to subject.
There are also macro lenses in the 50-60mm range. They tend to have a shallower depth of field, but let you get closer to your subjects. To me, DOF is one of the most important factors of a macro shot, and I like the extra DOF versatility a 100mm lens gives me.
So, to answer your question, the Nikon 105 Macro would probably be an ideal lens for most subjects, although if your subject of interest is the insect world, you might end up scaring off more of your subjects than you would wish (at least as a beginner.)
jrista has given you a great answer already. I shoot with a full frame Nikon so I can add a bit of Nikon flavour. When I started to become interested in macro work I picked up a cheaper Tamron 90mm f2.5 MF lens which I used for many years. It was a great lens and pretty good at portraits too. It had two main draw backs - it only went to 1:2 with out adding an extension tube and its working distance was pretty short so insect photography was difficult.
Working distance is the distance from the focus point (the subject) to the front of the lens.
When I upgraded my gear in 2000 I replaced the Tamron macro lens with the Nikon 200 f4 micro. I am very happy with that lens. It is really sharp and has a very good working distance and a very shallow angle of view. The angle of view is important for controlling backgrounds. The narrower the angle of view the easier it is to frame your subject with a nice background. The longer focal length also makes it easier to have that background thrown out of focus.
In answer to your question the Nikon 105 f2.8 micro lens is excellent. If you want more working distance then the Nikon 200 f4 is the choice. You can also consider the Nikon 70-180 micro but it is no longer made and it does not focus down to 1:1.
Some further reading I would recomend: http://www.bythom.com/105AFSlens.htm (at the bottom of this there is information about the latest Tamron 90mm)
You may also want to consider the tamron 180mm 3.5 with a nikon mount. It's much cheaper than the 200mm f/4, but about comparable quality. I figured that out by writing a little program that sucks images down from pbase.com, which organizes images by equipment used to take them, and then scrubbing the equipment information and asking the rater to indicate the quality. Neither I nor others who used this software could tell the difference between the tamron and the nikon. The sigma in this category (180mm as well, I believe) was clearly lacking.
The Nikkor 105mm "Micro" lens is an awesome lens, considered to be one of the best out there.
I had one for years before I switched to Canon, and loved it. It actually makes a great portrait lens too, though mine was a bit slow focusing.
Personally, I would take a 105mm over any of the shorter lenses as the 105 gives you a bit more reach, which is really important when trying to shoot insects. A 50mm macro will put you a few inches away, where the 105mm will put you about a foot away. That can mean the difference between having a shot or just wandering the field hoping to get close. It can also mean not having shadows in your shot because the closer you are to the subject, the more likely you are to block your own light.
The strength of a macro lens is called its magnification.
The Nikkor 105mm Micro has a 1X (or 1:1) magnification. All but one (the Canon MP-E 65mm) macro lens of major camera brands have the exact same magnification. Some third-parties like Sigma also have 1:1 lenses but all their other lenses are less powerful, sometimes putting Macro on 0.5X (1:2) or 0.33X (1:3) magnification lenses.
So, as far as lenses for Nikon go, the 105mm has the highest magnification. Take a look at the list of macro lenses for Nikon mount.
The primary difference between various 1:1 macro lenses is the focal-length which determines how far you have to stand from your subject to get maximum magnification. You can see that it varies from 35mm to 200mm. At 35mm you have to focus at 14cm from the sensor which makes it hard to get the lens not to cast a shadow on your subject.
You can see a small variance in maximum aperture (F/2 to F/4). Most macro shooting though tends to be done at smaller apertures since DOF becomes so shallow at those distances.
My personal favorite is the Zeiss 100mm 1:2 macro lens. I also use the Nikon 200mm f/4 macro. They are both outstanding macro lenses and the differences between the sharpness and crispness of each is negligible. This is only my personal taste, but I just like how the Zeiss "feels" when holding it and focusing it. As sturdy and strong as most pro Nikon lenses are, the Zeiss feels like it was hewn from solid granite, and the focus ring is buttery smooth and incredibly precise. The nikon 200 allows slightly closer focusing, and the fact that its a 200mm enables closer shots from further distance (roughly twice as far for the same reproduction size)...it's that reason alone why I have both lenses. Sometimes I can't get as close as I need to with the Zeiss, so the 200 f/4 is invaluable in these circumstances.
But, all things being equal, if I'm in a situation where either lens can be used with equal efficiency, I'll go with the Zeiss every time. It just feels like mechanical perfection.
I can't speak to the ability of the nikon 105, but I have a Canon 100mm f/2.8 USM macro (which i believe is the rough canon equivalent), and am completely happy with it. It is the sharpest lens I own, and gets in tight enough to get great detail for large insects and flowers.
I also have used this lens for portaits and have been very happy with the results, which wouldn't be as easy with a longer lens.
I use the old 60mm AF-D micro Nikkor (on my DX format camera): it's a very well built lens and supremely sharp for general shooting, so it's pretty versatile.
I'd say for serious macro work you want something longer than 60mm though, because being so close to your subject means:
- It's very easy to accidentally shadow your subject
- Bugs get scared away :)
Just note that this lens (Nikon 105 macro) goes up to f/57 but the quality degrades very much after f/22 This lens does not have manual aperture control which means that you cannot use extention tubes. I have this lens and it is very very good, but I also had a Sigma 150macro which was a bit better and a very old sigma 90mm which is better than this lens.. so considering the price differences I would suggest a Sigma lens. And finally, the VR is not really useful in serious macro photography so there is no reason to pay extra for it...
You already got a lot of good answers. So I add my experience on the 105. I use the 105mm f2.8 VR on my D7000 (not full frame) and I love it. The lens though is a full frame lens, so you will be just fine. I do not love it just because it's a great macro lens, but also because I can use it as a shorter tele lens, which happens more often than I imagined before I purchased it. At this point the VR makes pretty much sense. I also did get some pretty good results with the VR on some "walk-by hand-held" close ups.
However, one thing to consider is, that the frame size (image size) changes while focusing. For me this is no issue, but it might be for you. Personally I would not go below that focal length unless, as pointed out by others already, you know you will never need a longer working distance.
Well for the time being the 2 best macro lenses for Nikon (I won't mention Zeiss because they are 1:2, too bad) are the 200mm f/4 and don't believe those that say the Sigma 180mm is comparable, it's not! The other is the Sigma 105mm F2.8 EX DG OS HSM which is better than Nikon's own 105mm in many point and is cheaper.
Avoid the Sigma 150mm macro...
Hope this helps.