Thanks for the advice guys. I came across a minolta MD 35-70mm 3.5 macro (attached to a Seagull) in a second hand store a little while ago and will head over to pick it up today, with a bit of luck it should do the trick and maybe make for handy portrait lens. Rumours on old forums say it's a rebranded R lens, is that true?
Lots of zooms got labeled as "macro" without any real qualifications to back up the label. It might be OK, but any real macro lens would most likely kill the zoom WRT image quality, especially as magnification increases.
I've done slide copying with my Canon DSLR with a variety of lenses
(bold = still have and use it):
- Pentax S-M-C Macro Takumar 50/4 : much better than the 55/1.8 which is another step better than the 50/1.4 for copy work) : ~$100
- Takumar 55/1.8 : could be a great budget solution as they are generally quite sharp and work well on extension tubes.
- Pentax M 50/4 Macro : similar to the Takumar except no Auto/Manual switch so I sold it : ~$100
- Pentax M 100/4 Macro : good IQ but I wanted more magnification at the time so sold when I got the Vivitar : $125
- Vivitar Series 1 105mm f/2.5 : excellent IQ apart from some CA if used near wide-open in high contrast situations, very sharp with lots of resolution : $250-400
- Canon EF 50mm f/1.4 : sharp enough with extension tubes but it was a hassle using them and AF is no benefit for me. Lack of flat field never really bothered me much but maybe I'm not picky enough
- Sigma 50mm f/1.4 EX DG : very sharp, less vignetting than the EF50, better colors, but was huge and seemed to have less working distance due to being so big.
For copying duties, I have an Asahi Pentax bellows in M42 mount and the related Pentax slide copier, so I can run basically any magnification I want with the 50mm Macro.