Tamron 90mm 2.8, you can find these on ebay at decent prices.
I am planning to buy the sigma but still saving money at the moment. As far I could understand that is something that cannot really be avoided as as to do with the amount of light reaching the sensor. Does it do that even when using high apertures Paulo?I have no experience with the Sigma macro, but the Tamron has a tendency to focus hunt if you are using auto focus, but when I use my Tamron 90mm I always do manual anyway, just be aware of that.
With £200 you have to look into used market. Both the Tamron or the sigma will give you excellent results and you can also try to hunt eBay for the non stabilized versions which are going cheaper than the current ones and are equally as good in image terms. Also remember that you will be using it on a crop factor sensor so the focal length needs to be multiplied by 1.5x
Does it most of the times regardless, I tend to use manual but makes using a tripod impossible on manual focus!Does it do that even when using high apertures Paulo?