70-200 Macro £600 v 70-300 Macro £100 or 150 macro?

I've been using a Tamron 70-300mm lens with macro for butterfly shots.

I'm now considering various options with vastly different sums of money involved!
1. Get the lens repaired for £80.
2. Buy the Sigma 18-250mm for £400 - I could do with a doitall lens and I believe this does close focus so should do the butterflies.
3. Buy a Sigma 70-200mm Macro for £600
4. Buy a Sigma 150mm Macro for £800

Questions are ....would the 18-250 serve as well as the Tamron for insect shots ... and would I notice £600 of difference in the quality of the images if I go for the macro lenses?

Any comments from anyone that's used all or any of these would be MOST welcome!!

martyn

Sigma 150mm would be ideal but they don't do it in Pentax mount.

Hi Martyn

I may have a siggy 18-250 in mint for sale. maybe a weeks time. Id accept £350.

Would you be interested?

Paul

ah ... sorry. Forget the 150mm... I was looking at a somewhat mis-leading ad! I thought there wasn't a pentax version -180mm anyway. Thought I'd missed something!!

I do already have a Sigma 70mm macro, but it's just not high enough magnification for butterflies etc. I did think about a 2x teleconvertor... I guess that's another option!

No 150mm or 180mm version unfortunately.

As for the 70mm I presume you mean working distance rather than magnification.

Might be willing to do some sort of trade with your 70mm for a Pentax 100mm macro if you are interested? Would give you more working distance to play with.

Be careful with IF macro lenses they are 150mm or 180mm at infinity, at 1:1 they will only be slightly longer than a 100/105mm macro (the FL become less as you focus closer). There's a thread about it on the US forum. I think there was only 7mm difference

either jessops or jacobs are doing the pentax 100 dfa macro (non wr version) for £299 just now. Was in both shops, cant remember which

How about, as a slightly left-field suggestion, a Tamron Adaptall 90mm 2.5 with an Adaptall 2x teleconverter? This would give you 180mm, 1:1 magnification and better quality than your 70-300 for a reasonable price.

I use my Tamron 70-200 for jobs like that, and have gotten a very good allrounder in the bargain! I do have the Tamron 90, a lovely lens, which is tack sharp, but you wanted a longer !

To improve the macro capacity of the 70-200 I use a 77mm Canon 500D screw-on close-up lens (not the cheapest add-on!) at times, but it makes the lens combo a bit front heavy. The results are excellent, though!