Some basic Macro Lens questions

[kirbinster]

I would like to get a Macro lens for my Nikon camera, but really know nothing about them. What is the difference in using the 60mm versus the 105mm? I am confused since for macro work you are up close so why is the focal length much of an issue? Also is the Nikon 105 f/2.8 AF Macro better than the 60mm? Do I need VR or is it ok to just buy a used AF model. Am I best to stick with Nikon, or does Sigma or others offer good macro lenses. Thanks

[OsmosisStudios]

Uh... Kirbinster, you get a knock on the head?

[kirbinster]

Last I checked, no. I really am clueless about macro lenses.

[OsmosisStudios]

My mistake: let's take a look.

Originally Posted by kirbinster

What is the difference in using the 60mm versus the 105mm?

I am confused since for macro work you are up close so why is the focal length much of an issue?

Also is the Nikon 105 f/2.8 AF Macro better than the 60mm?

Do I need VR or is it ok to just buy a used AF model.

Am I best to stick with Nikon, or does Sigma or others offer good macro lenses.

1: The big difference is the focal length. Both are exceptionally sharp, but the big difference is the focal length. Which leads me to...

2: Focal length determines the working distance you need. Macro refers to the 1:1 reproduction of something. In short: if your subject is 5mm across in real life, it is 5mm across on the sensor plane. Longer focal lengths get you this reproduction ratio at a farther distance. What it means is that a longer focal length lens means you can be further away and still get the "close-up" effect. If you're shooting anything that's alive, you'll want a longer focal length so that youre not literally on top of it. Longer FL also means you don't block your own light (as much). For instance, 1:1 reproduction is achieved at: (All Nikon)

60mm AF-D     220mm        8.8"
60mm AF-S     185mm        7.4"
105mm AF-D    314mm        12.5"
105mm AF-S    300mm        12"

The big difference here is that the AF-D gets longer as you focus closer, so the front of the lens is actually only a few inches from the subject. The others are IF lenses and therefore dont get any bigger

The General consensus is that a longer FL is preferable, though I've had great experiences with the 60mm AF-S version.

Unlisted: the 85mm f/3.5 DX. I've heard both good and bad about this lens, and not enough for me to recommend it without trying it out extensively. It also means some weird math to get an equivalent for macro.

3: The AF-S 105mm f/2.8 G VR is the best (current) Nikkor macro lens. The older 200mm f/4 is better, but the 105 isn't very far behind. That being said, the current AF-S 60mm f/2.8 G is a hair under it.

4: VR is fine at for general use, but becomes less effective the closer you focus. At 1:1, the VR only gives about 1 stop of effective stabilization, so that's your call. Most of the time macro is done on a tripod anyway. YMMV. In either case, I'd recommend the AF-S regardless: they're IF and dont extend with focus.

5: Nikons are, generally speaking, tops. There are some exceptions. Sigma has a great 150mm and Tokina has a great 90mm (f/2 to boot!). I don't particularly like off-brand, but that one is up to you.

One other thing to consider is that almost all Macro is done at extremely small apertures: f/22 is common. This is important to note because most lenses are tested wide open. Its also important because "wide open" changes as you focus closer. The effective aperture changes as you focus closer to things, in most cases by about 2 stops at 1:1. Most cameras dont see this (and report f/2.8) so if youre using flash you may want to adjust. That being said, you'll almost never be wide-open for DOF reasons.

Finally, if you're getting into SERIOUS macro, consider the 45mm and 85mm PC-E lenses. Both are capable of 1:1 and allow tilt and shift to be used to maximize DoF while still shooting at "normal" apertures. I didnt list them: they're prohibitively expensive, a pain and a half to set up and only really work well on a D3 series body because of their design.

Hope that helps.

[vandergus]

5: Nikons are, generally speaking, tops. There are some exceptions. Sigma has a great 150mm and Tokina has a great 90mm (f/2 to boot!). I don't particularly like off-brand, but that one is up to you.

I think you're thinking of the Tamron 90mm f2.8. Or maybe the 60mm f2. Either way, they're both nice lenses, though the 60mm has been having metering troubles on some Nikon bodies.

Also, the actual working distance (the distance from the front of the lens to the subject) can be helpful when choosing a lens. Here are some numbers.

Nikon 105mm f2.8 AF-S - 6"
Nikon 85mm f3.5 DX AF-S - 5"
Tamron 90mm f2.8 - 4"
Tamron 60mm f2 (DX only) - 4"
Nikon 60mm f2.8 AF-S - 2"

The reason the Tamron 60mm has a longer working distance than the Nikon 60mm is beacuse the focal length of the Nikon actually changes at closer working distances. Remember that the focal length speced for a lens is only measured at infinity, so manufacturers can fudge a little bit at closer focus distances. I think the focal length for the Nikon works out to be about 46mm at 1:1 magnification.

If you're just looking to dabble without making a big investment, you could also look at some of the old manual focus Nikkors. The 55mm Nikkors are all great and can be found super cheap. Some need an extension tube to get to 1:1 magnification, though.

[OsmosisStudios]

Originally Posted by vandergus

I think you're thinking of the Tamron 90mm f2.8. Or maybe the 60mm f2. Either way, they're both nice lenses, though the 60mm has been having metering troubles on some Nikon bodies.

Possibly: I don't know the third party stuff well at all. As for metering troubles: as I noted, most Nikon bodies give a metering reading based on the max aperture and not the "actual" aperture at 1:1. Since the aperture gets smaller at closer focusing distances on these lenses, it leads to underexposure. Some of the older Nikon lenses used to do it too.

Originally Posted by vandergus

Also, the actual working distance (the distance from the front of the lens to the subject) can be helpful when choosing a lens. Here are some numbers.

Nikon 105mm f2.8 AF-S - 6"
Nikon 85mm f3.5 DX AF-S - 5"
Tamron 90mm f2.8 - 4"
Tamron 60mm f2 (DX only) - 4"
Nikon 60mm f2.8 AF-S - 2"

Good point: it should be noted that the lengths I gave earlier at form the imaging plane (ie the back of the camera, pretty much). So add in the depth of the body and the length of the lens...

[kirbinster]

Thanks to both of you for the excellent explanations. Sounds like I should probably look for a 105mm.