[Class A]

Based upon my experiences with Pentax gear and what I have read about Nikon gear, I would expect that the auto-focus of the Pentax will not be nearly as responsive as the Nikon.

With respect to the bodies, I don't think it is such a night & day difference anymore.

The Pentax 50-135, however, is known to have relatively slow AF. For action photography, the K-5 would be much quicker with a Sigma 70-200 with HSM, I reckon. I haven't used this gear but from what I've read I think the above is true.

[Pentaxor]

I'm reminded of the times when I worked in computer sales(during college years) where I saw countless people paying huge premiums for performance advantage they would never see.

And this was of course in the 486 era where PC performance was rated with minute frequency ratings which wouldn't even register on today's processor scores. In fact I think the nominal variance in my current CPU frequency exceeds the larges jump in processor speeds in that day(+/- 20Mhz lol )
And yet... people came-in and payed-up as much as a thousand dollars to get those minuscule performance gains onto their desks!

And you know what's even weirder about all this... ?
Its that I know for a fact... that if I had to drop cash for a new body right now. That I would buy the one with the highest measured rating.
Not because I could can quantify it...
but for the simple fact, that know, that I just bought the best there is.

Behold human nature!

that's quite true. although atleast, a 100mhz nominal difference is still accepted. I don't think that increase in processor speed has changed that much at all for the last 10 years. from what it appears, engineers are just able to optimize speed for certain uses and software application. in fact an extreme edition quadcore would spank any modern day quadcore with HT processor (except the modern extreme edition). if we noticed, processor speed nowadays run on average from 2GHZ to 3.5GHZ. not much different from what it was a few years ago. my old Penryn processor even run as fast as the existing rebadged dual cores. and people still buy them. the only difference that I see is the features and capabilities of the recent computers. SATAII/III,HDMI, firewire, USB 3, etc... which were not offered before.

this is quite the same with cameras. some upgrades here and there, but little difference on the area where it should matter a lot. call it economics or business strategy.

[zxaar]

that's quite true. although atleast, a 100mhz nominal difference is still accepted. I don't think that increase in processor speed has changed that much at all for the last 10 years. from what it appears, engineers are just able to optimize speed for certain uses and software application. in fact an extreme edition quadcore would spank any modern day quadcore with HT processor (except the modern extreme edition). if we noticed, processor speed nowadays run on average from 2GHZ to 3.5GHZ. not much different from what it was a few years ago. my old Penryn processor even run as fast as the existing rebadged dual cores. and people still buy them. the only difference that I see is the features and capabilities of the recent computers. SATAII/III,HDMI, firewire, USB 3, etc... which were not offered before.

this is quite the same with cameras. some upgrades here and there, but little difference on the area where it should matter a lot. call it economics or business strategy.

As far as computers are concerned things are now changing very much.
With advent of computations in GPUs (graphic cards) timings are going to get boost.
A personal super computer is now a reality. At least for research work in 2-3 years of time i might have a small super computer on my desk. And the reason i am sure about it is because i am working on it (i have basic softwares running and working on now supercomputer concept with multiple gpus).

Other than that good and faster algorithms also boost timings, but innovation is first not guaranteed second its difficult to innovate.

Edited to add: Sorry for so much out of topic.

[falconeye]

Based upon my experiences with Pentax gear and what I have read about Nikon gear, I would expect that the auto-focus of the Pentax will not be nearly as responsive as the Nikon.

That is the expectation.

However, K-5 AF seems quite a step up from K-7 and D7000 AF seems to disappoint quite a few expecting the level of performance from the D300 that I think the final verdict is still open.

At Photokina, I tried the D7000 and it's AF didn't convince me at the Nikon booth. May have been the lens though. But it was the left selected by the Nikon staff, so well ...

[ManWithCamera]

With respect to the bodies, I don't think it is such a night & day difference anymore.

The Pentax 50-135, however, is known to have relatively slow AF. For action photography, the K-5 would be much quicker with a Sigma 70-200 with HSM, I reckon. I haven't used this gear but from what I've read I think the above is true.

The Sigma 70-200mm f/2.8 w/ HSM is available at cameralensrentals.com, too:
CameraLensRentals.com - Sigma 70-200mm f/2.8 II EX APO Macro HSM Lens Rental

That is the expectation.

However, K-5 AF seems quite a step up from K-7 and D7000 AF seems to disappoint quite a few expecting the level of performance from the D300 that I think the final verdict is still open.

At Photokina, I tried the D7000 and it's AF didn't convince me at the Nikon booth. May have been the lens though. But it was the left selected by the Nikon staff, so well ...

If the AF is indeed faster in the K-5 than in the K-7, then I want one even more! My main reason for wanting the K-5 is the performance of that amazing sensor it contains! The performance at high-ISOs would be very nice to have for weddings/receptions and for when I photograph my wife's drama students on stage. Unfortunately, I can't justify the cost of upgrading just yet -- my K-7 isn't even a year old yet!

[m8o]

The Sigma 70-200mm f/2.8 w/ HSM is available at cameralensrentals.com, too:
CameraLensRentals.com - Sigma 70-200mm f/2.8 II EX APO Macro HSM Lens Rental

... hahahaha... That's the funniest way I've seen "put your money where your mouth is" in a while. But in Class A's defense, he has nothing to prove and years of historical behavior of the hardware on his side. If you were to disagree, I'd think it would be your task to execute the rental.

[K-9]

Let's keep in mind this is one website, and one sensor testing site only. If 4 others popped up, they could have 4 different results.

With that being said. The K-5 beat the D700 by only 2 points, but I would fully expect the upcoming D700 replacement will most likely pass over the K-5 on Dxo testing. As someone else pointed out, the K-5 just caught up and passed a camera that's been out over 2 years now.

[Pentaxor]

Let's keep in mind this is one website, and one sensor testing site only. If 4 others popped up, they could have 4 different results.

With that being said. The K-5 beat the D700 by only 2 points, but I would fully expect the upcoming D700 replacement will most likely pass over the K-5 on Dxo testing. As someone else pointed out, the K-5 just caught up and passed a camera that's been out over 2 years now.

atleast the sensors caught at some points rather than not. actually this is great news because it opened up a new set of possibilities. I remembered that 2 years ago, it as the end of the road for the APS-C size sensors with the MP wars reached way past 12MP. I'd say this have given the public options.

[ManWithCamera]

Let's keep in mind this is one website, and one sensor testing site only. If 4 others popped up, they could have 4 different results.

With that being said. The K-5 beat the D700 by only 2 points, but I would fully expect the upcoming D700 replacement will most likely pass over the K-5 on Dxo testing. As someone else pointed out, the K-5 just caught up and passed a camera that's been out over 2 years now.

Also, people should keep in mind that the D700 still beats the K-5 in terms of high-ISO performance (signal to noise ratio) up to ISO 6400. The K-5 wins in dynamic range and total score, but full frame still has the advantage in terms of noise (though, the gap is narrowing, when the latest DX is compared to two-year-old FX technology).

[rawr]

DX is compared to two-year-old FX technology

What's with all this 'DX' and 'FX' stuff I keep reading here? Those terms are Nikon branding terms that mean nothing to Pentax users, Canon users, Olly users, Sony users etc etc. If you want to be clear, stick to APS-C, FF, APS-H, 4/3 etc to indicate sensor formats. You don't see DXO describing sensor formats using those terms either.

Just as a refresher, these are the terms and dimensions...

[JohnBee]

Also, people should keep in mind that the D700 still beats the K-5 in terms of high-ISO performance (signal to noise ratio) up to ISO 6400. The K-5 wins in dynamic range and total score, but full frame still has the advantage in terms of noise (though, the gap is narrowing, when the latest DX is compared to two-year-old FX technology).

I agree, but... in my own research(its been a long week), I've found that the D700 holds no visible advantage over the K-5 anywhere under ISO5000. At which point, the K-5 begins applying(what we could call) heavy handed NR at the expense of detail.

Having said that, the D700 has somewhat of an advantage at or around ISO6400 at which point the K-5 seems to be at it's worst. And though I've managed to bi-pass NR, though close! ... it still doesn't seem to be enough to compensate for the D700's higher quality grain /detail retention.

What's even more interesting, is that passed this point, its a who it really does come down to a what is shittier affair. Which could be summarized by what ones prefers under the terms of detail losses.

Don't know how relevant to the cause this really is. But I thought it was interesting nonetheless.

However, I will go as far as saying that the K-5 is not only very good but even phenomenal at ISO3200. And if you're adventurous... you can bi-pass low level NR and shoot so close to nominal(in terms of IQ) that it would make your head spin. Okay... maybe not if you've handled a D700(that's would be expected), but from an APS-C perspective... absolutely stunning!

Okay I'm done.

[ManWithCamera]

What's with all this 'DX' and 'FX' stuff I keep reading here? Those terms are Nikon branding terms that mean nothing to Pentax users, Canon users, Olly users, Sony users etc etc. If you want to be clear, stick to APS-C, FF, APS-H, 4/3 etc to indicate sensor formats. You don't see DXO describing sensor formats using those terms either.

Just as a refresher, these are the terms and dimensions...

Ugh. Sorry, I didn't mean to be unclear. It's just that ever since the first time I heard Nikon's new FX/DX terminology, I wished the industry would adopt it. It's just so much easier to say (and especially easier to type). In addition, the term "FF" is not particularly accurate, either, since the medium format sensors are larger than "full-frame", yet are generally cropped versions of the film cameras they replace.

Thank you for the chart and I'll try to stick to saying "Aye Pee Ess Dash See" in the future.

[cbaytan]

What's with all this 'DX' and 'FX' stuff I keep reading here?

It figures, Nikki terms, when I saw Fx I thought he was talking about programmable button Fx.

[WerTicus]

the first time I heard Nikon's new FX/DX terminology, I wished the industry would adopt it.

You're one of those people that hovers their floor instead of vacuums it arnt you?

[Hypocorism]

In addition, the term "FF" is not particularly accurate, either, since the medium format sensors are larger than "full-frame", yet are generally cropped versions of the film cameras they replace.

?? You have me confused. Can you please explain what MF (Medium Format) has to do with 135 aka 35mm format -- the latter being what I thought "FF" full-frame was conceived to only apply to, and to no other.

Thank you for the chart and I'll try to stick to saying "Aye Pee Ess Dash See" in the future.

And while you're at it, please explain to me how APS-C "crop", typically 1.5 or very close (Pentax, Nikon, Sony, ...), is a totally different physical size in Canon lingo at only 1.6 FF ratio?

That is a huge difference, and I can smell motives like commercial advantage there.
So is Canon being an evil rogue who writes their own rules, or is APS-? just some dartboard at a piss-up party for any mfgr to flaunt as much and if they want?

.R.