[GoremanX]

both Nikon and Canon have better AF than Pentax, I suspect Canon has the edge on this one.
Note that you need to be into the upper end bodies to see these advantages.

Is the D90 considered an "upper end" body? I'm not sure where it rates on the scale, but I vaguely remember it costing more than a K-7 and less than a D300s. When I was comparing the D90 and K-7 side-by-side using a VR 70-300mm F4.5-5.6 and a DA* 50-135mm F2.8, I found that the Nikon was auto-focusing much faster and more reliably, especially in low-light conditions. I wasted over an hour of my life comparing the 2 while I waited for my single 4x6 to be printed at Ritz Camera. Of course, the speed difference could be chalked up to SDM, which is inherently slow, but the low-light performance surprised me a bit. I was using an F2.8 lens, and the largest aperture on the Nikon lens was only F4.5. Yet the Nikon would consistently find focus even under the worst conditions, while my Pentax would just hunt and hunt. The Nikon version of "hunting" is laughable, it essentially consists of the lens sweeping through its range once before coming back and finding focus. The Pentax version of "hunting" involves the lens sweeping through its range twice and then giving up. It's pretty frustrating.

Having said that, I was recently amazed at my K-7's low light focusing accuracy when using the FA 31mm Limited. I was able to take pictures in light that I could barely see by. I guess an F1.8 lens tends to help a lot. When I took this shot, I had to strain to make sure I was aiming the right way:

1/8 shutter speed, F2.2, ISO800

[the swede]

The K-7 focuses faster and better in both low light and "normal" light than previous cameras.

There are som unscientiffic yet reliable video clips on youtube showing the differences.

The screwdriven AF with K-7 and lenses like 18-55 and 16-45 is a blast. They are realy fast, and realy reliable in good light. The 18-55 focuses faster than Nikons 16-85 from nl to inf, but i know thats not an fair comparison due to the very short focus path of the 18-55 and 16-45.

I would like to give cudos to Pentax for their lenses, because the are a lot faster than Sigmas and Tamrons screwdriven lenses! For example the Tamron 17-50 is much slower than DA18-55 and DA16-45, even though its short focus path.

But, all this doesnt compare to the silent and fast AF from Canikon. Because they are faster, quieter and much more reliable. I've been a Canon user before i went Pentax and i strongly feel Pentax is behind. But i knew that when i made the switch, so this is not a biggie for me.

What Pentax should do is release new SDM lenses (the SDM that they've secretly updated, or whatever). I hope they bought new motors even if they still name them SDM.

And they should build a completely new line of midlevel lenses to with focus motors! They could use the entire DA line and remake them with motors! That would be realy nice.

Imagine 16-45 F4 WR SDM, 55-300 WR SDM, DA 12-24 F4 WR SDM.....

Thats enough "bla bla bla" from me

Change system if you dont like Pentax AF and if its the most important thing to you. Thats the best thing to do! Canikon isnt bad! They're great. But it will cost more in comparison to get the same, as someone mentioned.

[kent]

today my k200d just hunted a lot in low light without succesion and whereas my firiend with Canon 500d could achieve focus without hunting at all. Well that was a bit frustrating

[SteveB]

today my k200d just hunted a lot in low light without succesion and whereas my firiend with Canon 500d could achieve focus without hunting at all. Well that was a bit frustrating

I've got a magazine review that included the Canon 500D Pentax Kx and Nikon D90. The worst for AF accuracy was the 500D, being quite unacceptable most of the time with the kit lens and a 50mm prime, they only got a sharp focus with it occasionally. The Kx was rated almost as good as the D90. This is for accuracy, not speed, but they had no complaints about the Kx speed.
The 500D performance could be a one off I suppose.

[AVANT]

I want to point out that we shouldn't link focus systems to a brand, we should link them to a model.

Pentax's current generation of cameras have much improved focusing compared to earlier generations. Where as Canon and Nikon made these improvements several generation ago, because Pentax is late to the game for focus improvement, you really shouldn't compare say a K10/K20 to a D80/D90 or 30D/40D in this arena.

The focus on my K10D and K7 are very very different. The K7 has improved drastically in this area. It does much less low light hunting and much quicker to confirm focus. Note that I use this on my DA*s and FA50, I have never connected my kit lenses to see if the focus improvements are dampened. I honestly feel that my K7's focus is now comparable to its competitors with only a very slight edge to the Canon and Nikon equivalents. It's not until I compare with the full frame big boys that I feel my K7 is inadequate.

[zackspeed]

Anybody tried the K-7 on Sigma 2,8 70-200 HSM?
No?
Do it,you will see what the K-7 wants to do with Pentax lenses
Hope for a new,faster sdm in near future.

[knoxploration]

Also, my understanding is that the "+" is for the light-color aware sensor that corrects for front-focusing under tungsten light, and not for the AF assist lamp.

You're correct in that understanding.

[robgo2]

AF on the K-x is not up to the level of the K-7. AF on the K-7 is not up to the level of the D300s or 7D, but it is very close and should be more than adequate for the purpose of wedding photography. It focuses very well in low light. But you have a K-x, and I truly do not know if it is up to the task, at least in your hands. I would suggest that you practice in lighting conditions similar to those you will encounter at the wedding shoot. Get yourself invited to someone else's wedding and bring your camera. Practice with moving targets, and use your flash. That should tell you if you will be able to pull it off with your current equipment.

Rob

[robgo2]

Is the D90 considered an "upper end" body? I'm not sure where it rates on the scale, but I vaguely remember it costing more than a K-7 and less than a D300s. When I was comparing the D90 and K-7 side-by-side using a VR 70-300mm F4.5-5.6 and a DA* 50-135mm F2.8, I found that the Nikon was auto-focusing much faster and more reliably, especially in low-light conditions. I wasted over an hour of my life comparing the 2 while I waited for my single 4x6 to be printed at Ritz Camera. Of course, the speed difference could be chalked up to SDM, which is inherently slow, but the low-light performance surprised me a bit. I was using an F2.8 lens, and the largest aperture on the Nikon lens was only F4.5. Yet the Nikon would consistently find focus even under the worst conditions, while my Pentax would just hunt and hunt. The Nikon version of "hunting" is laughable, it essentially consists of the lens sweeping through its range once before coming back and finding focus. The Pentax version of "hunting" involves the lens sweeping through its range twice and then giving up. It's pretty frustrating.

Having said that, I was recently amazed at my K-7's low light focusing accuracy when using the FA 31mm Limited. I was able to take pictures in light that I could barely see by. I guess an F1.8 lens tends to help a lot. When I took this shot, I had to strain to make sure I was aiming the right way:

1/8 shutter speed, F2.2, ISO800
Attachment 57896

Goreman.

Another thing that your photo demonstrates is how effective the SR is on the K-7. There is no way that you should have been able to get that shot at 1/8 sec. SR allowed you to shoot at ISO 800 rather than ISO 3200. In-camera SR is one of the most valuable features of the Pentax system, something that is frequently overlooked (deliberately) by reviewers and users of certain other brands.

Rob

[Parallax]

There were bazillions of really great photographs taken over the years prior to the advent of AF. Some of them were even taken at weddings. I think it is natural that the more technology progresses, the more we tend to rely on it. That doesn't mean that better technology doesn't contribute to better pictures. Software and hardware can both make a difference, but ultimately it comes down to the skill and artistic ability of the photographer. To put it another way; the most critical piece of hardware is the nut behind the viewfinder.
No matter what camera or lens you have there are always going to be shots that just don't come out right that maybe would have if you had a different one.

Pick the system that best meets your needs and learn to capitalize on it's strengths and compensate for it's shortcomings. They all have both.

[Urkeldaedalus]

Giggli G,

You are actually asking two questions in your post as far as I can see.

1. When will Pentax get better low light autofocus performance than your K-x?
2. Should you stay with Pentax, especially considering your wedding gig coming up?

The answer to question number one is that the K-7 already is better at autofocusing in lowlight than your k-x, and in future cameras from Pentax I would expect that only to get better.

The answer to number two is more personal to you. If your girlfriend favors another brand for her camera and you don't mind switching to this, I don't think any brand really destroys another in autofocus performance at your price range, so it's really more what appeals to you. For the wedding, it will make more difference if you have two camera bodies and lenses that can get the job done than what the name says on the front of the camera. Is your girlfriend helping you shoot the wedding?

K-7 Portrait by candle light

[dylansalt]

Too be quite honest you can purchase a lightly used Nikon D90 with the 18-105 VR (very sharp & fast focusing) for about the same $ as the Kx.

The D90 rates very highly with DXO & has flash capability regarded as the best.

You will never have to second guess flash exposure.

Why mess around - the D90 has excellent IQ up to 3200 and too be quite honest much nicer to hold & use than the Kx

[GoremanX]

Too be quite honest you can purchase a lightly used Nikon D90 with the 18-105 VR (very sharp & fast focusing) for about the same $ as the Kx.

What the heck are you talking about?!? The D90 w/ that lens currently costs $1,399.90!!! And that's AFTER a $250 instant rebate!!! That's over 2x as much as a K-x with TWO kit lenses!

[knoxploration]

What the heck are you talking about?!? The D90 w/ that lens currently costs $1,399.90!!! And that's AFTER a $250 instant rebate!!! That's over 2x as much as a K-x with TWO kit lenses!

He's suggesting buying used (although I'd guess it'd have to be quite a lot more than "lightly" used to get the prices he's suggesting in most markets).

Note though that he's in South Africa, and their pricing for Pentax seems (from what I recall from past threads) to be totally out of whack with the rest of the world.

Which means unless Giggli G is in SA too, the post is likely of no relevance to him/her.

[GoremanX]

He's suggesting buying used (although I'd guess it'd have to be quite a lot more than "lightly" used to get the prices he's suggesting in most markets).

To have it cost as much as a K-x, it would have to be SEVERELY used. As far as I can tell, if a current camera still operates as it should, it tends to sell for almost the same amount used as new. Just look at what people are asking for K-7's in the marketplace of this forum. Same goes with lenses.

Note though that he's in South Africa, and their pricing for Pentax seems (from what I recall from past threads) to be totally out of whack with the rest of the world.

They'd have to be for the D90 to cost as much as a K-x. Not even in the same class...