Lets talk about AF speed

So many threads about this... and how lame Pentax is...

K7-DA*200mm - ISO100 - f4.5 - 1/320

In flight, panning, then composed 3 shots. The middle one is fractionally less sharp then the other 2, but in general, at this distance, and in difficult light (shooting against the sun), the K7 tracked the bird amazingly i think.

[IMG]http://i517.photobucket.com/albums/u332/nathanever82/Inflight.jpg[/IMG]

It aint' what you got its how you use it

Nice examples Nathan, I refused to join in the "other" recent thread on this subject (too many whingers), maybe Pentax dont see fast AF as a priority, perhaps while other marques were developing superfast AF systems Pentax were developing far more useful things like Hyper-Program mode, in body SR, self leveling, multi-coloured cameras etc etc etc.

While I agree with the sentiment that we're making a mountain out of a molehill with regards to AF speed, your example isn't helping to settle the argument. The bird looks like its flying across the scene, which isn't going to be as difficult for the AF system to handle since the distance between subject and camera doesn't change as much. If the bird was flying towards or away from the camera, now that's something else.

I don`t think that this question will ever be resolved satisfactorily as there are so many variables as to make it virtually impossible to draw conclusive comparisons.
I tried AF on a car ralley and got consistently sharp series of shots of cars using my K7 and 50-135DA* in a forest with fading sunlight by using the bottom edge of the cars windscreen as the point of focus and high speed shooting mode. Yet the same combination photographing a Cyclo Cross event last week i had to resort to "catch in focus" to get any sharp images at all probably because the riders shirts did not have sufficient contrast or maybe i could not hold the subject point of focus so easily.
Things like Lighting, Contrast, lens focal length and construction, Maximum aperture and user skill and experience are all going to affect the results whatever kit you use!
I recall a comparison in a pro camera mag between a full frame Canon and Nikon, the subject was a boy running towards the Camera. They took 100 shots with each Camera, The Canon had 18 perfectly pin sharp images the Nikon none!

Regards - Pete

What model Nikon and Canon were the cameras Pete?
You don't mention how long ago you saw those examples Pete, but there have been quite a few advances in technology recently and I have seen some stunning shots captured of extremely fast subjects running towards the camera and also in very difficult conditions. Mike-P has mentioned one for example, of the dog running towards the camera which I would assume is faster than the boy running towards the camera.

There is a persistence in misunderstanding the real issue when we debate about fast AF, and the moment the subject is touched its immediately covered under a general blanket that a)we are talking down Pentax, and b)people are saying other brands are better. This is not the case exactly. All we are saying is that why are SDM (DA*60-250 a very good example) so sluggish on the Pentax bodies to the point of being so annoying. I have handled the DA*300 also and it was slow too. Fantastic piece of glass but painstakingly slow. Some of the arguments put forward such as its to increase reliability of focusing because speed would ruin it simply doesn't hold water.

Nathan, great shots by the way

No, let's not talk about AF speed any more.

We don't really need yet another thread on this subject do we?

Definately not, apparantly these long threads slow down the forum

You're right Gwyn, one is certainly enough

Is it just my laptop or is this thread wider than most?

It's not just you - same on my screen but I can't see an obvious reason why

Because of the photo

But I can see the whole photo - it's only around 800pix wide on my screen. There's just a huge blank space following it...

But I can see the whole photo - it's only around 800pix wide on my screen. There's just a huge blank space following it...[/quote]The photo is 3.933 x 1.588 pixels and is resized by the forum but some browsers or computers don't render/use the resize code well and that give the problem you've now for some members.

What browser do you use?
Opera renders the site perfectly, don't know about the rest.

Thanks Stefan, Mine is IE8 and it works fine most of the time.

Doesn't seem any different to normal on mine (FF3.6)