Which one is sharper

Don't think you will do much better than this with a £100 budget tbh.

The Sigma 50mm F2.8 Macro you asked about is a 1:1 lens and it's a very good one too. You might find a manual focus one for around £80, this would do the job very nicely. I prefer the Sigma 105mm DG EX Macro, not only because of the extra working distance for macro, but also because it is a superb portrait lens with great bokeh - I use it for weddings all the time.

The other lens I've found that I like for macro is the Pentax-M 50mm F1.4, although it has to be used reversed or with tubes / bellows for true macro. It's extremely sharp and renders details well. You will find these for between £40 and £80 although they are not the commonest 50mm lenses they are well worth seeking out.

Regards
David

How about posting an image or two so we can see what you are trying to achieve? Then any recommendations can be more considered.

John K

I think you'll be very lucky to find a true macro lens at a price that is within your budget. The closest you'll get is possibly a smc Pentax-M 100mm f4 lens, but you can still expect to pay more than your £100 budget.

Have you considered using a Raynox macro converter?

The Raynox DCR-250 can be bought for about £50 and will fit your 50mm/1.7 lens.

Thank you all.
I think I was misunderstood. My budget for a proper 1:1 macro lens is higher (around £200), but if I was to compromise and go for an older, manual 1:2 macro lens then I wouldn't want to spend more that around £100.

Thank you again. I think I will experiment with the tubes a little bit more to exactly what I need before I decide.

Did you see my comments about the Sigma 50mm F2.8 Macro (manual focus)? These are usually available at around (or less than) the £100 mark - they are true 1:1 macro without any converter and are very good lenses.

Regards
David

I'd highly recommend the Vivitar 55/2.8 manual focus macro, which doesn't come up terribly often but sells for less tan £100 when it does. Unusually, it's a true 1:1 lens, nicely made and great IQ. Can't remember whether it was made by Kiron or Komine - but it was one of those two.

There's a Sigma 50/2.8 Macro lens for sale here.

thank you all for comments. Learned a lot here. Both sigmas AF and M are tempting.I will wait a bit more to be sure what I really need and then decide. Thank you.