will the K3 iii autofocus fast with screwdrive lenses

Job.nl · 05-10-2021, 07:31 PM

I have some Limited lenses and was wondering if they are also really fast focusing on the K3 iii and are they useful for fast and accurate continuous shooting? And how would the Tamron 70-200 do it on this camera?

Ishpuini · 05-10-2021, 11:41 PM

My guess would be that it would be faster. Note that I still don't have the camera, so I'm just reasoning from a theoretical point-of-view.

The AF points being many more and much closer to each other, plus the AI for subject identification, would greatly improve the camera's capacity to keep track of the subject. In my experience, where the previous cameras lost out was not the actual speed with which the lens elements were moved, but the fact that AF lost track of the subject, resulting in the camera focusing on something nowhere near the subject. From that moment on, it was generally too far off to get the subject back into focus fast enough, simply because of the distance the lens elements had to move. So *if* the new AF is up to keeping track of the subject, my thinking is that the problem situation might be avoided... To be confirmed...

**StigVidar** · 05-11-2021, 12:12 AM

It also takes very little rotation to go from infinity to ~ 2-3 meters and can be done in a split of a second. My opinion is that lenses are fast enough and all depends on how accurate the camera body can maintain focus.

mtkeller · 05-11-2021, 04:54 AM

Yes. Here’s a gallery from the day after I got mine, and these are all shot with the Tamron 70–200 f/2.8 coupled to the HD DA 1.4x teleconverter. Some of the sequences don’t have 100% of the images tack sharp, but I chalk that up to operator error as I was trying to decide what setting to use for AF hold. The other thing I noticed is that I was able to pick up the camera to try to quickly grab a moment and could get the camera to successfully lock onto the subject in a way that would not have been possible before. Last night, I converted my DA*300mm that had glitchy SDM to screwdrive. Just took a few test shots in the backyard, but I was pleased with the speed at which it was able to focus, too.

SimplyCreativePhotography · 05-11-2021, 07:56 AM - **1 Like**

The AF was pretty snappy on my FA77 but AFC was quite annoying.

Ishpuini · 05-12-2021, 12:16 AM

Originally posted by SimplyCreativePhotography

The AF was pretty snappy on my FA77 but AFC was quite annoying.

Annoying in what sense?

SimplyCreativePhotography · 05-12-2021, 05:25 PM - **1 Like**

Originally posted by Ishpuini

Annoying in what sense?

Just noisy. AFC was so unreliable on my K-5 that I rarely used it, and likely never with my FA77. The K-3iii is much much better but for moving objects where it kept changing to keep them in focus (birds) I simply wasn't used to the constant noise. I suspect I won't use AFC often with my screw-drive lenses. It worked fine. I just found it distracting.

**Larrymc** · 05-12-2021, 06:06 PM - **1 Like**

Originally posted by SimplyCreativePhotography

Just noisy. AFC was so unreliable on my K-5 that I rarely used it, and likely never with my FA77. The K-3iii is much much better but for moving objects where it kept changing to keep them in focus (birds) I simply wasn't used to the constant noise. I suspect I won't use AFC often with my screw-drive lenses. It worked fine. I just found it distracting.

You didn't receive your complementary Pentax ear plugs,,,,HUH??

Ishpuini · 05-13-2021, 11:05 PM

Originally posted by SimplyCreativePhotography

Just noisy. AFC was so unreliable on my K-5 that I rarely used it, and likely never with my FA77. The K-3iii is much much better but for moving objects where it kept changing to keep them in focus (birds) I simply wasn't used to the constant noise. I suspect I won't use AFC often with my screw-drive lenses. It worked fine. I just found it distracting.

Ah yes, screw drive lenses are noisy indeed. And I can imagine with increasing speed the noise would increase as well. I remember noticing this especially if my FA*300, when I returned to it a few times when needing a more correct telelens. I'm used to the DFA150-450 now.

SimplyCreativePhotography · 05-14-2021, 05:59 AM

Originally posted by Ishpuini

Ah yes, screw drive lenses are noisy indeed. And I can imagine with increasing speed the noise would increase as well. I remember noticing this especially if my FA*300, when I returned to it a few times when needing a more correct telelens. I'm used to the DFA150-450 now.

But I also love using them. I think it's just a matter of sticking with AFS.

In other news, my 16-50SDM doesn't seem to have made the transition to the K3-iii as nicely as the 50-135. Hopefully not another SDM issue. (repaired once already). It was working fine on my K-5 up until I got my new camera. More testing to do before I can be sure.

Ishpuini · 05-15-2021, 06:22 AM

Originally posted by SimplyCreativePhotography

But I also love using them. I think it's just a matter of sticking with AFS.

In other news, my 16-50SDM doesn't seem to have made the transition to the K3-iii as nicely as the 50-135. Hopefully not another SDM issue. (repaired once already). It was working fine on my K-5 up until I got my new camera. More testing to do before I can be sure.

Hope your 16-50's SDM will recover. If it doesn't, make sure to use your K-5 to convert it to screw drive. I had to borrow a friend's because debug mode in the later flagships wasn't documented. Mine was repaired twice before I converted it.

SimplyCreativePhotography · 05-17-2021, 05:16 PM

Originally posted by Ishpuini

Hope your 16-50's SDM will recover. If it doesn't, make sure to use your K-5 to convert it to screw drive. I had to borrow a friend's because debug mode in the later flagships wasn't documented. Mine was repaired twice before I converted it.

I'll see where it goes. Likewise for me after the first repair I played with the screw drive version for a bit but eventually sent it in for a second repair. I just took it for a walk outside and everything seemed fine so hopefully I'll be ok.

05-10-2021, 07:31 PM	#1
Job.nl New Member Join Date: Jun 2016 Posts: 5	will the K3 iii autofocus fast with screwdrive lenses I have some Limited lenses and was wondering if they are also really fast focusing on the K3 iii and are they useful for fast and accurate continuous shooting? And how would the Tamron 70-200 do it on this camera?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Comparison K3 III versus Sony A7 III	bwgv001	Pentax DSLR Discussion	51	04-30-2021 01:20 PM
Power of K3 Screwdrive motor	Joshua A	Pentax DSLR Discussion	23	08-19-2014 02:19 PM
Autofocus systems may be about to get extremely FAST! like 10 miliseconds fast	photoleet	Photographic Technique	26	01-26-2012 03:15 PM
Autofocus: SDM vs Screwdrive question	geezer52	Pentax SLR Lens Discussion	6	11-30-2011 06:47 PM
Autofocus (Screwdrive) Gets Stuck at a Particular Close Focus Range?	paperbag846	Pentax SLR Lens Discussion	5	06-21-2011 09:07 AM

05-10-2021, 11:41 PM	#2
Ishpuini Veteran Member Join Date: Sep 2006 Location: Antwerp, Belgium Photos: Gallery Posts: 1,727	My guess would be that it would be faster. Note that I still don't have the camera, so I'm just reasoning from a theoretical point-of-view. The AF points being many more and much closer to each other, plus the AI for subject identification, would greatly improve the camera's capacity to keep track of the subject. In my experience, where the previous cameras lost out was not the actual speed with which the lens elements were moved, but the fact that AF lost track of the subject, resulting in the camera focusing on something nowhere near the subject. From that moment on, it was generally too far off to get the subject back into focus fast enough, simply because of the distance the lens elements had to move. So if the new AF is up to keeping track of the subject, my thinking is that the problem situation might be avoided... To be confirmed...

05-11-2021, 12:12 AM	#3
StigVidar Site Supporter Join Date: Nov 2006 Location: Norway Photos: Gallery \| Albums Posts: 705	It also takes very little rotation to go from infinity to ~ 2-3 meters and can be done in a split of a second. My opinion is that lenses are fast enough and all depends on how accurate the camera body can maintain focus.

05-11-2021, 04:54 AM	#4
mtkeller Veteran Member Join Date: Feb 2019 Location: Sioux City, IA Photos: Gallery Posts: 938	Yes. Here’s a gallery from the day after I got mine, and these are all shot with the Tamron 70–200 f/2.8 coupled to the HD DA 1.4x teleconverter. Some of the sequences don’t have 100% of the images tack sharp, but I chalk that up to operator error as I was trying to decide what setting to use for AF hold. The other thing I noticed is that I was able to pick up the camera to try to quickly grab a moment and could get the camera to successfully lock onto the subject in a way that would not have been possible before. Last night, I converted my DA*300mm that had glitchy SDM to screwdrive. Just took a few test shots in the backyard, but I was pleased with the speed at which it was able to focus, too.

05-11-2021, 07:56 AM - 1 Like	#5
SimplyCreativePhotography Senior Member Join Date: Apr 2009 Location: Drayton, Ontario, Canada Photos: Albums Posts: 264	The AF was pretty snappy on my FA77 but AFC was quite annoying.

05-12-2021, 12:16 AM	#6
Ishpuini Veteran Member Join Date: Sep 2006 Location: Antwerp, Belgium Photos: Gallery Posts: 1,727	Originally posted by SimplyCreativePhotography The AF was pretty snappy on my FA77 but AFC was quite annoying. Annoying in what sense?

05-12-2021, 05:25 PM - 1 Like	#7
SimplyCreativePhotography Senior Member Join Date: Apr 2009 Location: Drayton, Ontario, Canada Photos: Albums Posts: 264	Originally posted by Ishpuini Annoying in what sense? Just noisy. AFC was so unreliable on my K-5 that I rarely used it, and likely never with my FA77. The K-3iii is much much better but for moving objects where it kept changing to keep them in focus (birds) I simply wasn't used to the constant noise. I suspect I won't use AFC often with my screw-drive lenses. It worked fine. I just found it distracting.

05-12-2021, 06:06 PM - 1 Like	#8
Larrymc Site Supporter Join Date: Jun 2014 Location: Mississippi, USA Posts: 5,252	Originally posted by SimplyCreativePhotography Just noisy. AFC was so unreliable on my K-5 that I rarely used it, and likely never with my FA77. The K-3iii is much much better but for moving objects where it kept changing to keep them in focus (birds) I simply wasn't used to the constant noise. I suspect I won't use AFC often with my screw-drive lenses. It worked fine. I just found it distracting. You didn't receive your complementary Pentax ear plugs,,,,HUH??

05-13-2021, 11:05 PM	#9
Ishpuini Veteran Member Join Date: Sep 2006 Location: Antwerp, Belgium Photos: Gallery Posts: 1,727	Originally posted by SimplyCreativePhotography Just noisy. AFC was so unreliable on my K-5 that I rarely used it, and likely never with my FA77. The K-3iii is much much better but for moving objects where it kept changing to keep them in focus (birds) I simply wasn't used to the constant noise. I suspect I won't use AFC often with my screw-drive lenses. It worked fine. I just found it distracting. Ah yes, screw drive lenses are noisy indeed. And I can imagine with increasing speed the noise would increase as well. I remember noticing this especially if my FA*300, when I returned to it a few times when needing a more correct telelens. I'm used to the DFA150-450 now.

05-14-2021, 05:59 AM	#10
SimplyCreativePhotography Senior Member Join Date: Apr 2009 Location: Drayton, Ontario, Canada Photos: Albums Posts: 264	Originally posted by Ishpuini Ah yes, screw drive lenses are noisy indeed. And I can imagine with increasing speed the noise would increase as well. I remember noticing this especially if my FA*300, when I returned to it a few times when needing a more correct telelens. I'm used to the DFA150-450 now. But I also love using them. I think it's just a matter of sticking with AFS. In other news, my 16-50SDM doesn't seem to have made the transition to the K3-iii as nicely as the 50-135. Hopefully not another SDM issue. (repaired once already). It was working fine on my K-5 up until I got my new camera. More testing to do before I can be sure.

05-15-2021, 06:22 AM	#11
Ishpuini Veteran Member Join Date: Sep 2006 Location: Antwerp, Belgium Photos: Gallery Posts: 1,727	Originally posted by SimplyCreativePhotography But I also love using them. I think it's just a matter of sticking with AFS. In other news, my 16-50SDM doesn't seem to have made the transition to the K3-iii as nicely as the 50-135. Hopefully not another SDM issue. (repaired once already). It was working fine on my K-5 up until I got my new camera. More testing to do before I can be sure. Hope your 16-50's SDM will recover. If it doesn't, make sure to use your K-5 to convert it to screw drive. I had to borrow a friend's because debug mode in the later flagships wasn't documented. Mine was repaired twice before I converted it.

05-17-2021, 05:16 PM	#12
SimplyCreativePhotography Senior Member Join Date: Apr 2009 Location: Drayton, Ontario, Canada Photos: Albums Posts: 264	Originally posted by Ishpuini Hope your 16-50's SDM will recover. If it doesn't, make sure to use your K-5 to convert it to screw drive. I had to borrow a friend's because debug mode in the later flagships wasn't documented. Mine was repaired twice before I converted it. I'll see where it goes. Likewise for me after the first repair I played with the screw drive version for a bit but eventually sent it in for a second repair. I just took it for a walk outside and everything seemed fine so hopefully I'll be ok.