Sigma 105 Macro

just looked at SRS and Clifton Cameras and this lens appears to be unavailable in Pentax fit, when did that happen?

At least a year back! In April 2013 after much searching I found (in Eire) what was possibly the last new Pentax fit 105 on the planet.

Optically the DFA 100 macro is every bit as good as the Sigma - but who wants a fully automatic macro lens?

that is a real shame.

"Optically the DFA 100 macro is every bit as good as the Sigma - but who wants a fully automatic macro lens?"

exactly, the ability to switch to manual and use catch in focus is a great advantage of the Sigma over the Pentax.

Just add a short extension tube with contacts between the camera body and lens to give full manual control and catch in focus, OK you lose focus to infinity but how many times do your need that when shooting macro.

Aye Brian - and there's the rub, my DFA 100 WR does not like the 7/8 contacts extension tube(s)I use. The connections can be unreliable due to a slight looseness twixt lens and tube which seems to be peculiar to the Pentax lens - dont know why. However trying to bend the the tabs that pull the lens against the tube is definitely a butt-clenching experience...

Roger.

Sorry, I haven't used the Sigma 105 on Pentax, so please correct me, but I activate catch in focus generally by setting AF.S on the camera - it is deactivated by switching to manual ... but then this is with lenses that don't have a focus switch .... ??

All of the manuals back to the K20 are quite specific on this point;
'Catch in focus' only works using a manual lens or a DA or FA lens that has a AF & a MF setting on the lens which must be set to MF before setting camera to AFS and shooting....The Sigma 105 has such a switch, my Sigma 50mm macro does not and neither does the current Pentax 100 macro.

Roger

Ahoy!

There are 3 dedicated macro lenses that I've used that I can gladly recommend (don't bother with the Pentax version of the one marked with an * as this is the same lens) and the Pentax version commands just insane money and you'd have to be 'not too tightly wrapped' to buy the Pentax branded version:

Tamron SP AF 90mm F/2.8 Di LD 1:1 macro (272EP) - Just superb. Don't bother with the latest USD version as it's not worth the money compared to the 272EP. (1).

Sigma AF 105mm F/2.8 EX APO /EX DG 1:1 APO macro - Again, superb. Early EX APO version has plastic AF gearing, though I don't know if the same applies to the later EX DG. (2)

* Cosina/Promaster/Vivitar/Phoenix/Soligor/Voightlander AF 100mm F/3.5 MC 1:2 macro (plastic fantastic) - Budget lens with premium optics and just the best of it's type under £80.00 (I've bought these for £50.00). Normally supplied with an 1:1 adapter lens, but it sucks big time and it's best in native 1:2 mode though you can buy better +1/+2 etc adapter lenses from Amazon. Stunning results. (3).

The numbers in the brackets are guide prices from most expensive (1) to cheapest (3) on the used market. All are full frame.