Which macro lens?


TPF Noob!
Mar 28, 2006
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Hi, I'm a total beginning at photography. I just purchased a D70 with 18-70mm. By mail order. It hasn't arrived yet.

One thing I want to do is take pictures of my pet rats. I have been using a Canon S60 point&shoot. I like getting in very close. The Canon can actually focus at 10 cm.

I figure I would want a macro lens. What's the difference between these two lenses?



Also, as best as I can figure this out, I understand that different macro lenses have different "working distances", which I guess is the distance at which you get 1:1 magnification. First of all, I don't really want 1:1 magnification.. I'm photographing the rat's entire head or half of his body, which is probably much larger than the sensor. But I do want to get in close becasue I like the perspective that gives.

So I understand that some of these macro lenses with longer focal lengths are like "telescopes" in that you can stand fairly far back and yet get 1:1 magnification. Is that right?

So let's say I want to shoot from about 20 cm away and get a width of 4 inches at that distance. Would either of these macro lenses work for me?

Looks like they'd both do the job fine. As for the difference, I'd hazard a guess that it's something to do with the DG rating being the digital non-reflective inner element lens coating to minimise reflections. That is a guess though, I'm sure someone will be able to say for sure.

With macro lenses, you just focus it and get the right distance away from your subject to fit everything in, so it should be fine for rat portraits.

Thanks, Rob. I'm still trying to figure something out.. when the lens says that the minimum focusing distance is 20cm, (and it's a fixed focal length macro lens), does that mean 20 cm is the distance for 1:1 magnification? If so, that means I probably want to be further back.

I have this idea in my head that I want to be 20 cm away with a wide field of view. Perhaps this would do the trick:


Because it could be set to a focal length of 17 mm at a distance of 20 cm ???

It generally just means that 20cm is the closest you can get an object to the front element of the lens. I'm not sure whether it would be 1:1 at minimum focussing distance, that's a tricky one (someone else can answer that!!).

The zoom one would be more flexible, but usually primes are much better quality. Your choice really!

This is a quote from the sigma site...

These are large-aperture lenses with wide angles and short minimum focusing distances. With an abundance of peripheral illumination, they are ideal lenses for Digital SLR Cameras whilst retaining suitability for traditional 35mm SLRs.

I think they have stopped making the other, so it may be a little cheaper because of it.

I dont have the dg version but i have the other and it focus so close that i cant get any light in from the ring flash so i dont think you have to worry about getting close to the subject, the other way around, it can be annoying having to be so close as you invariably get so close to the subject that you mess up whatever 3point/ring flash lighting you have set up and can get shadows. the only way out of that is probably to go for the 105mm version, but the 50 can be nicer for getting some kind of perspective (given that it is about 75mm effective on the dslrs it isnt that much more though.


Here is the sigma link, it is a 1:1 macro with a min focal distance of 18.9 cm, although i am not quite sure what distance that is (ccd to subject?) as you can get much closer than 19 cm from the end of the lense to the subject


If you look here pictures http://thebort.net/tpe/ macro1.jpg to macro17.jpg are with the 105 and macro18.jpg to macro23.jpg are with the 50mm
I don't know these lenses specifically, but here's something I was told by someone I trust: get the 100mm macro. I was trying to decide between the Canon 50mm macro and the 100mm macro, and the 100mm allows me to be a little further from the subject. This matters a LOT if you're relying on natural light, because you won't have to hover over the subject while casting a shadow. The other reason is that skittish subjects such as insects tend to want to run and hide if you get too close.

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