Sigma 50mm F2.8 Macro

Hi there,


I'm another newbie who's been lurking on this forum for a while now since buying the K10d and I'm over the moon with it.

I'm looking to buy an autofocus 50mm and I was wondering whether anyone has used the Sigma F2.8 50mm Macro? I'm stuck between this and the Pentax 50mm F1.4 everyone is raving about on the forums. I occasionally do some macro work which I'm using close up filters for with a Pentax-A 50mm and I'm pleased with the results but I know these are generally frowned upon for quality compared to extension tubes and a genuine macro.

Any input appreciated to help me make my mind up!


Cheers


Rob.

I strongly suggest you consider a 100mm macro if macro is what you want. 50mm is OK for copying documents, but for things like bugs the extra reach of a 100mm (or best of all, a 200mm) lens makes a big difference.

Macros from any manufacturer are likely to be pretty sharp, so just look out for the best deal you can get. The various flavours of the Tamron 90mm are well-regarded, and the Pentax F and FA 100mm macros are lovely.

G

I use the Sigma 50mm 2.8 (pre-DG version) and like it a lot for macro work on my GX10:



More macro pics here:
http://www.flickr.com/photos/chirpy_uk/sets/72157600713278315/

Chirpy - That is superb and I think you've sold it to me!

Can I ask how the focussing works on a macro lens as I currently have a set of close up filters , x1, x2, x4 and x10 and I find I have to use different ones depending on the zoom I want. When the lens is in macro mode, what is the focusing range?


Cheers


Rob.

Proper macro lenses don't have a "macro mode", which is more the stuff of zoom lenses. What they do is to have an extended focusing range that, without interruption, goes down to 1:1 magnification. That is, a 1cm long object is 1cm long on the film/CCD. Obviously when the enlarged image is printed there is huge magnification with much better critical quality than using close up lenses.

I concur with George that the 100mm macro lenses are much more versatile. Pentax make an excellent one, but equally well there are second hand macro lenses on eBay for more realistic prices.

Don't discount manual focus macro lenses either as at very close distances AF is not very useful for many subjects. AF lenses can be used to focus manually when required, by the way.

I use the SMC Pentax-FA 100mm f2.8. Superb lens.

Thanks for the advice John. My primary reason for comparing the 50mm's is that I'm after a great quality lens which I can use for general stuff. The macro functionality of the sigma is really a bonus and I have to weigh that up with the aperture of F1.4 on the Pentax 50mm.

I got my Sigma 50mm Macro second-hand on ebay for under £100. I only use manual focus for macro work. It's quite tricky to use AF because you are so close to your subject it's harder for the AF system to find the right place to focus on. If you're trying to get insects you usually want to focus on the eyes which won't necessarily be where you want them for the AF to work (i.e. not central).

Usually, in those cases, you centre the eyes in the image and then AF and then move the lens to frame the subject as you want. However, if you do that in macro you'll probably go out of focus again as tiny movements change the point of focus dramatically. DoF is controlled by changing the aperture size.

MF is the way to go, for me.