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12-28-2008, 01:09 AM   #16
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QuoteOriginally posted by drabina Quote
I did play with Nikon D40 at the store trying to focus on people moving and it looked like it was spot on. I had a feeling that AF knew which way to turn so I never had any back and forth AF action.
I think you know the answer already. None of the existing Pentax DSLRs has predictive AF, together with slower AF in dim environment, Pentax is unable to follow any moving target in less than ideal lighting environment, and gets much worse as the EV drops further. No fancy lens can save Pentax from this issue, yet. Also, as the subject distance is less, AF has to work harder to follow the subject (for any system). There is a huge practical difference between shooting moving target from far far away and shooting at less than 3 metres (typical for family shots), or filling the whole frame with the subject than the subject as small as a peanut in the picture (most examples being post in the forums). But it is safe to say, if AF tracking, low light AF and more dependable TTL flash are what you needed the most, Canon & Nikon are miles ahead of Pentax. For anything else, Pentax is okay.

12-29-2008, 12:21 AM   #17
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I note an earlier poster commented that the Sigma 70-200 f2.8II HSM is fast, accurate and quiet. I recently purchased this lens for use shooting motorcycle racing. The lens I used previoulsy was the Tamron 70-300 Di LD.

Problems I had with the Tamron were AF-C was not effective with this lens, and panning was hit and miss. Essentially the only way to ensure consistent results was to use a manual focus trap.

With the Sigma I can succesfully pan, use AF-C and achieve very sharp images. The lens locks onto the bikes quickly (no hunting) and accurately. I have replicated outstanding (my impression of the results) images that I could never achieve using the Tamron.

Unfair comparison maybe (no doubt actually!). It would be useful to compare similar SDM and HSM lenses, but they don't exist in Pentax mount. Also am I incorrect in stating that HSM is different to SDM?

Anyway here is a sample:



more here: http://www.flashpixx.net/
12-29-2008, 06:47 AM   #18
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Thanks for all replies. It looks like move to the SDM lens wouldn't help that much.

D60 with kit lens is less than $500 at Amazon.com so I may just order it and try it out. If I like it, I will keep it, if it is not that better (in AF) than my K10D, then I keep Pentax.
12-29-2008, 07:21 AM   #19
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QuoteOriginally posted by flash1100 Quote
am I incorrect in stating that HSM is different to SDM?
That is correct for now.
HSM = ring motor in lens
SDM = little motor driving effectively an in-lens screw

Ring motors are faster and more precise generally. It's ironic that a 3rd party released a ring motor lens before Pentax
I think the 60-250 is supposed to be the first Pentax ring motor lens...

12-29-2008, 11:32 AM   #20
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I see all these comments comparing Nikon, Canon, Pentax dSLR's, and I don't disagree with any remarks. I've thought out loud like Vagrant10, and utilize some of the same logic trying for the largest depth of field possible and counting on cropping as needed to get a better shot.

However, I've also noticed that with a could compact p&s camera, I can get fairly consistent shots with less effort than any dSLR. This isn't to say these cameras are better, but they are for the situation. Their small lenses require almost no focusing issues with the camera and if you get one that performs well enough in low light, the wild children shots just come out better vs. the effort put in. I have been surprised by the adequacy of the low light performance on the point and shoot cameras of the past couple of years.

Of course, given the time and a still kid, the dSLR is still king, but I know that once I get to having my own kids, I won't hesitate to get a secondary camera that is the top of the line point and shoot just for those occasions.
12-29-2008, 11:38 AM   #21
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QuoteOriginally posted by kenyee Quote
That is correct for now.
HSM = ring motor in lens
SDM = little motor driving effectively an in-lens screw

Ring motors are faster and more precise generally. It's ironic that a 3rd party released a ring motor lens before Pentax
I think the 60-250 is supposed to be the first Pentax ring motor lens...
won't the 55/1.4 be the first?
12-29-2008, 11:58 AM   #22
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QuoteOriginally posted by kristoffon Quote
won't the 55/1.4 be the first?
The ring motors make the most difference in heavier lenses (zooms, etc.)...that's why Pentax said they'd implement it in "high performance" lenses.
A 55/1.4 wouldn't need it...
12-30-2008, 05:08 PM   #23
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QuoteOriginally posted by nostatic Quote
what he said. SDM is dead quiet, but I don't notice it is any faster. This is on a K20d though, and I'm usually comparing a 50-135* to ltd primes.
The 50-135 is probably the slowest AF lens I ever owned. The SDM motor in conjunction with the long focus throw makes it a poor comparison to primes.

My FA 135f2.8 smoked it (with a longer focus throw), my FA 200f2.8 smoked it, and I am not even speaking of the 70-200f4 USM...

12-30-2008, 05:14 PM   #24
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QuoteOriginally posted by Frogroast Quote
Yep - light hum/whir is all you hear with SDM.

I'm not sure any lens you add to any camera system should make AF purely faster as long as the body is doing the focusing. In the Pentax system they're nearly if not close to the same (no measurebation, just recall).

Something else you also need to consider: If the AF is "having trouble keeping up" with a 2 year old, is it an AF speed issue (by the time it focuses, the subject is gone), or is it actually a focus-lock issue (can't lock, no picture is taken). You could argue either way, however my personal experience with the K10 seems to indicate it just can't lock, so speed is rarely the issue :-)

If your 2 yr old is up to par with sport stars and race cars, then a higher-end Nikon or Canon would do you well. However, before you go jumping systems, do your research and you will find there can be issues with all systems - here's a case in point - AF problems with Canon's nearly $5,000 body only flagship as reported back in August:

"In our view, there's more work to be done. In bright conditions, the EOS-1D Mark III still doesn't match the EOS-1D Mark II N; at times the two are close, and at other times the EOS-1D Mark III's autofocus performance is below what we consider acceptable," Galbraith said. "The culprit that continues to cramp the EOS-1D Mark III's autofocus style is bright sunlight."

So if bright sunlight cramps up arguably one of the most used bodies in sports photography, imagine what those guys think after dropping that kind of money on their jewels .
No doubt Canon had some hard time with their 1DMkIII... but we are talking tracking focus at 11fps... pretty far from Pentax's territory...

IMHO the K20 marked a significant step up from the previous Pentax DSLRs when it comes to tracking at 3fps, I really had no major problems with it in bright sunlight. The K10 was almost always a miss on this item.
12-30-2008, 05:18 PM   #25
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F

QuoteOriginally posted by kenyee Quote
That is correct for now.
HSM = ring motor in lens
SDM = little motor driving effectively an in-lens screw

Ring motors are faster and more precise generally. It's ironic that a 3rd party released a ring motor lens before Pentax
I think the 60-250 is supposed to be the first Pentax ring motor lens...
Where did you see this?

I thought the 60_250 was still supposed to be SDM+screw dual AF mechanism (hence no ring SDM)?

The one I tried in october sure didn't feel any faster than the 50-135...
12-30-2008, 07:19 PM   #26
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QuoteOriginally posted by lol101 Quote
Where did you see this?
I thought the 60_250 was still supposed to be SDM+screw dual AF mechanism (hence no ring SDM)?.
I did not see it specified by Pentax anywhere.

Pentax said they're use ring motors for "high performance lenses". Ring motors work better for heavier lenses. The 60-250 is a heavy lens and is DA* so it should be high performance. So the logical thing to do is stick a ring motor on it since it's taking so bloody long to release it...but Pentax isn't always logical
12-31-2008, 12:01 AM   #27
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QuoteOriginally posted by kenyee Quote
I did not see it specified by Pentax anywhere.

Pentax said they're use ring motors for "high performance lenses". Ring motors work better for heavier lenses. The 60-250 is a heavy lens and is DA* so it should be high performance. So the logical thing to do is stick a ring motor on it since it's taking so bloody long to release it...but Pentax isn't always logical
I agree, it "should be" ring SDM... but most probably won't... :ugh:

But let's wait some more (we don't really have a choice anyway), after all, they may change it before the actual release (in spring... of some year!).
01-02-2009, 09:42 PM   #28
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QuoteOriginally posted by emalvick Quote
I see all these comments comparing Nikon, Canon, Pentax dSLR's, and I don't disagree with any remarks. I've thought out loud like Vagrant10, and utilize some of the same logic trying for the largest depth of field possible and counting on cropping as needed to get a better shot.

However, I've also noticed that with a could compact p&s camera, I can get fairly consistent shots with less effort than any dSLR. This isn't to say these cameras are better, but they are for the situation. Their small lenses require almost no focusing issues with the camera and if you get one that performs well enough in low light, the wild children shots just come out better vs. the effort put in. I have been surprised by the adequacy of the low light performance on the point and shoot cameras of the past couple of years.

Of course, given the time and a still kid, the dSLR is still king, but I know that once I get to having my own kids, I won't hesitate to get a secondary camera that is the top of the line point and shoot just for those occasions.
Congratulations, a very practical solution to the chronic problem of catching kids in motion.. Part of the problem in catching kids is leaving the DSLR around where its handy to take the photo, thus also risking damage from the subject perhaps pulling the camera onto the floor. This recently happened to my nephew's camera with his child. Its a lot less traumatic if that camera hitting the floor is a PS, IMHO.

There is no perfect DSLR camera that is a great value, has pancake lenses :-), and that is also good for every application. It helps to identify specifically what one wants that DSLR for. I bought my first DSLR because i was convinced i wanted to do BIF. My first audobon meeting convinced me i wasn't really interested in BIF for the long term. Now i'm doing long exposures, landscapes, and some street photos and find the Pentax very well suited for that.

Interesting stuff posters are bringing up about HSM and SDM. I like the SDM on my DA 300, but hey, if Pentax has to go with a ring motor, i hope they license Sigma's system rather than inventing something brand new and non-standard.
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