The above in a K-7 body rather than a K10D body but with FF, not so much because I want/need FF but because I want the larger VF.

I don't need a tiltable screen, but will have it if it doesn't impact on longevity and useability.

Huw,

Thank you for your impressive samples. It just goes to show that the K-7 can have excellent high ISO noise results using good post processing techniques and compare very favourably with the competition.

SDM lenses don't all have a long focus throw. The DA 17-70 is very small and the DA*60-250 is not that much more either, the DA*55 is very long and is very slow end to end.

In decent light the 17-70 is about as fast as the DA 16-45, the 60-250 is maybe a bit slower. I compared my DA*60-250 againt the Sigma 150-500 HSM on a fairly dull day in December and I didn't notice much difference in the AF speed, both were fairly quick and positive.

Tha fastest focussing lens I ever had was the FA*24, it was faster than the DA 40 which is very quick. I've had, or tried, most of the FA and DA lenses (including *'s and Limiteds) at one time or another and would say that SDM has no speed advantage over screwdrive AF lenses or vica versa. AF speed seems very dependent on the rotational length and the mass of the focussing element, and, of course, the light levels and contrast.

I've used a Canon 1D mkII, the 70-200 f4 L and 100-400 L lenses and it was blisteringly quick with both, you almost didn't notice it focussing. I wish you could get the same performance in a package in less than half the size and weight! Some say the Oly E3 and their latest SWM lenses is a fast combo.

I find my K20D more than adequate with the 60-250 and I would say I get around 70% in focus shots when I'm birding and that's pretty high. The number of keepers is much less due to my inadequate skills! [/quote]I concur with Richard's assessment of the Pentax system, although I have not formerly tried the Canon 1D. Much of the "slow" AF has to do with long focus throw of some of the Pentax lenses and the desire for accuracy over speed. Having said that, I am sure it could be sped up to some degree.

As a few other's have pointed out, having good technique and knowing how your equipment operates/functions/reacts in certain situations is a good way to "getting the shot". Pro's are pro's as much because they are well versed in their trade and part of this is knowing how their equipment works under all conditions. This is partly why they "get the shot" more often than not and not always simply because they "have the best equipment".

You can say that again. Hang on, wait a minute, I need to see what this "dial a matic automatic automatic sponge sharpener" thingy is that they are advertising. It comes with a free set of steak knives!! Let me get back to you....

You can say that again. Hang on, wait a minute, I need to see what this "dial a matic automatic automatic knife sharpener" thingy is that they are advertising. Let me get back to you....

Sounds like a good trip.

There are only a few times when you may need the tele lens, but other than that, you could get away with the 17-70 (good choice of lens) for most shots. It's not much of a zoo, but you can get photos taken with a adult tiger!! and also with an orangutang. The crocodile show, monkey show and the elephant show aren't too bad, but the rest of the zoo needs a bit of work.

Maybe you could take the 28-300 as well just for the long shots or it might be just as good to crop the 17-70mm shots at the 70mm end.

I have just been to Thailand for 2 weeks - Phuket and Bangkok.

I took the DA15 Limited, DA*16-50 f2.8, DA*60-250 and DA35 macro. I only ever used the DA*16-50 70% shots and the DA*60-250 for the other 30%.

The reason for not using the DA15 Limited and the DA35 macro Limited was because we were on holidays with a group of 21 people and I really didn't have much time nor did I feel like taking time out for photography other than general holiday type photos and I didn't the extra wideness of the DA15 nor did I feel the need to take any macro shots.

I used the DA*60-250 at Phuket zoo and also when some of the group did parachute sailing behind a speed boat. Other than that, I didn't use the DA*60-250 for anything else and so, the DA*16-50 did all the other work and performed flawlessly. I did use the 16mm end of the DA*16-50 quite extensively and used a polariser very regularly to get those dramatic saturated shots that I like, especially out on the water near Phuket and Phi Phi Island etc.

It is quite hot and humid in Thailand and lugging aroung camera gear can be a bit of a chore, especially if you want to relax, so travel light if you can.

Enjoy your holiday as it is a great place to relax and the shopping in Bangkok is amazing and cheap!

Firstly, the most obvious factor is price. Usually the higher the price, the better the lens, especially within the same brand, but of course this is not always the case. Generally, the higher the cost reflects the higher production and development cost of the lens.

Secondly, there are the Image Quality factors like sharpness, contrast, colour balance, bokeh and low CA etc are just some of the IQ issues with a lens.

Thirdly, there are the build quality aspects like, weather resistance, compactness, type of materials used in construction, Internal Focus and/or Internal Zoom (for a zoom) are the main factors that dictate the build cost.

As for discerning what makes a good lens is sometimes a bit of the "eye of the beholder" approach.

Sharpness is generally easily detectable, but then there is contrast which can also assist in the illusion of sharpness. Lack of contrast shows itself in a washed out look to photos when compared to a lens with higher contrast.

In many instances, there are subtle differences between a good lens and an outstanding lens. Things that may not be at first apparent, like the quality of the bokeh or the colour balance can sometimes make the difference between a good photo and a great photo.

I had 3 lenses that the focus was out on the K10D, the FA31, the FA50 macro f2.8 and the FA*80-200. Like you, I chose to manaully focus these lenses as they are all too good to not use.

It is a stunning lens in every sense of the word. IQ is syuperb for this sort of zoom and zoom range and it is beautifully built. I also have the DA*50-135, but ever since I obtained the DA*60-250, the DA*50-135 has not been used! Have a look at some of my images:

http://www.pbase.com/lance_b/da60_250

http://www.pbase.com/lance_b/image/114357456/original

Some from this gallery:

http://www.pbase.com/lance_b/taronga_zoo_280609