The DA is a lot easier to live with, and the extra bottom range will be very useful when you feed the ducks, although it`s not the sharpest below 100mm.
As regard to the extra range of a 400mm, you are only a crop away from that, the DA at 300mm is good enough to handle it.
This was taken through bars with the DA, not the sharpest but could you handhold a 400mm zoom to the same quality?




if you do get a big siggy zoom will you be able to handhold it at 400mm? if not then you will find using it a pain, tripods,beanbags,etc.

Davex,

Quite like this one;



Davex.

Agreed,
I think this series of post`s demonstrates the futility of the "which system is best" argument, there are so many variables the question is unanswerable.Somewhat similar to the "what was there before the big bang" question,both are invalid questions because there can be no definitive answer.
hang on my head is starting to hurt.
Davex.

Surely the lost choice by which i think you mean film type is now replaced by choice of system. Pentax i think is known for richer more vibrant colours than Cannon,which I believe is also different to the way Nikon images look. You pays your money and takes your choice.

Davex.

For a moment then I thought you meant the asking price
Nearly wet my pants

Davex.

Keep;
Samsung AF 10-17mm
Pentax AF 16-45mm
Pentax SMC F 50mm 1.7
Tamron AF SP Di 90mm 2.8
Tamron 70-300mm 4.
Sigma 400mm AF not APO
Tamron 500mm SP A/A 5.6 32
P/K Sigma 1000mm 13.5
Pentax AFA 1.7 TC

You can do most things you want with the above,
Would also keep the 18-55 and the Siggy 28-300, if only because you wont get much for them, and one day you may want a "sacrificial" lens. Sell the rest and put the cash toward a K5.

Davex.

There are lots of references to a DIY fix for some SDM failures on the internet, no cost or skill required.
Look HERE

It is a fantastic lens, I fell for mine immediately. How much do they want?

Davex.

As a relative newcomer perhaps I am missing something here, but surely the ISO setting on the camera has no effect on the speed of focusing?
I thought that was due to the lens characteristics and maximun aperture.

Davex.

Thing is, I just love the focus action on my 50-135.
If it jams will get it sorted out.
It is just so much better than screwdrive.

Davex.