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03-03-2019, 09:33 AM - 1 Like   #1
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Does the number of focus points improve focus speeds?

Iím starting to see all these posts again about what the K-3II replacement should have. The number one thing seems to be more sensor points and faster and more accurate focus. This lead me to thinking about focus speed and accuracy. Isnít it the lens that is responsible for focus speed. I can see that the body would be responsible for the accuracy of auto focus but not the speed. Also the main recommendation I see for photo focusing is spot focusing. Not being an expert on this I assume that this would use only a few sensors max. So what good would more sensors provide for taking photos other than I hav more sensors than you. I can see where more sensors would be useful for continuous focus for moving objects and video. But I think that once you get above a certain number itís just a gimmick and no longer provides any advantage. Regarding focus accuracy I would guess that is more the algorithms used and light to determine focus accuracy than hundreds of sensor points. So maybe all Pentax needs are better focus algorithms in their software.

Just wondering if Im looking at this correctly or if my thinking is flawed.

03-03-2019, 09:49 AM - 2 Likes   #2
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There is a reason DSLRs have little illuminated points on the focus screen that light up when focus lock is achieved. It is so that the person behind the camera can see if the camera has got it right.

First thing I do with a new camera is to change the focus points settiing to central 9. i dont go in for the "blunderbus" approach.
03-03-2019, 09:57 AM - 1 Like   #3
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Of course the lens plays a role in the focus process but it is the microchips in the camera that determine speed and accuracy, just like it was the photographer before AF came into existence.
03-03-2019, 09:59 AM   #4
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QuoteOriginally posted by pschlute Quote
There is a reason DSLRs have little illuminated points on the focus screen that light up when focus lock is achieved. It is so that the person behind the camera can see if the camera has got it right.

First thing I do with a new camera is to change the focus points settiing to central 9. i dont go in for the "blunderbus" approach.
So my thinking is not totally flawed?

---------- Post added 03-03-19 at 10:05 AM ----------

QuoteOriginally posted by Docrwm Quote
Of course the lens plays a role in the focus process but it is the microchips in the camera that determine speed and accuracy, just like it was the photographer before AF came into existence.
What got me going on this is my newer Pentax lenses like the 18-135 and 16-85 plus some Sigma hsm lenses seem to focus as fast as a Canon 80d I played with at Best Buy. I personally think that the main issue I have with focus and Pentax is accuracy rather than speed.

03-03-2019, 10:10 AM   #5
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QuoteOriginally posted by steve_k Quote
So my thinking is not totally flawed?

---------- Post added 03-03-19 at 10:05 AM ----------


What got me going on this is my newer Pentax lenses like the 18-135 and 16-85 plus some Sigma hsm lenses seem to focus as fast as a Canon 80d I played with at Best Buy. I personally think that the main issue I have with focus and Pentax is accuracy rather than speed.
The motors in the lenses are not the issue - they are generally fine speed-wise. It's the speed of lock on and the speed of relock with moving subjects. It's not just sports like many assert, its also toddlers, and event photography when the subjects are not posing.
03-03-2019, 11:07 AM - 1 Like   #6
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QuoteOriginally posted by Docrwm Quote
The motors in the lenses are not the issue - they are generally fine speed-wise. It's the speed of lock on and the speed of relock with moving subjects. It's not just sports like many assert, its also toddlers, and event photography when the subjects are not posing.
Anyone with a DA 55-300 PLM might not agree with that analysis. The PLM defines what is possible with current Pentax AF, and it's impressive.

---------- Post added 03-03-19 at 01:08 PM ----------

QuoteOriginally posted by steve_k Quote
I have with focus and Pentax is accuracy rather than speed.
The idea that Pentax focusses on accuracy rather than speed has long been a thing. So, I need to see some numbers here.

Only a few systems in the over $4000 range can lock focus as quickly as a Pentax in AF.s The case could certainly be made that multi-point focussing slows down focus lock. I'm sure you can find evidence for the opposing viewpoint as well. But none of us know what really goes on in these systems and what affects them so it's all guesswork.

Last edited by normhead; 03-03-2019 at 11:12 AM.
03-03-2019, 11:35 AM   #7
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QuoteOriginally posted by normhead Quote
Anyone with a DA 55-300 PLM might not agree with that analysis. The PLM defines what is possible with current Pentax AF, and it's impressive.

---------- Post added 03-03-19 at 01:08 PM ----------



The idea that Pentax focusses on accuracy rather than speed has long been a thing. So, I need to see some numbers here.

Only a few systems in the over $4000 range can lock focus as quickly as a Pentax in AF.s The case could certainly be made that multi-point focussing slows down focus lock. I'm sure you can find evidence for the opposing viewpoint as well. But none of us know what really goes on in these systems and what affects them so it's all guesswork.
Sorry, but you can have the fastest, most reliable, motor in the world but you pair it with slow, quirky, and unreliable microchips and it fails more than old motors with great AF microchips. The motors are NOT the issue, merely window dressing and while a nice improvement in some instances they are not the solution to the ages old complaint about AF in the Pentax platform.
03-03-2019, 11:55 AM - 2 Likes   #8
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QuoteOriginally posted by Docrwm Quote
Sorry, but you can have the fastest, most reliable, motor in the world but you pair it with slow, quirky, and unreliable microchips and it fails more than old motors with great AF microchips. The motors are NOT the issue, merely window dressing and while a nice improvement in some instances they are not the solution to the ages old complaint about AF in the Pentax platform.
Funny, cause the 55-300 solved a lot of my Pentax AF issues. I came at it a different way. I argued Pentax has always built lenses for the cameras they produced. The older slower AF lenses optimized for a K20D or older simply can't compare to a DA 55-PLM on a K-3 or later. Older lenses like the older DA*s were not even designed for AF as fast as the K-3/K-1 lenses.

Try out a DA 55-300 PLM and get back to me. We are talking about practical observations as opposed to theoretical constructs and assumptions. As I said, you don't know how good Pentax AF is until you try a DA 55-300 PLM on a K-P. Before that time, you're not even qualified to comment on the current state of Pentax and AF.

03-03-2019, 11:59 AM   #9
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QuoteOriginally posted by normhead Quote
Funny, cause the 55-300 solved a lot of my Pentax AF issues. I came at it a different way. I argued Pentax has always built lenses for the cameras they produced. The older slower AF lenses optimized for a K20D or older simply can't compare to a DA 55-PLM on a K-3 or later. Older lenses like the older DA*s were not even designed for AF as fast as the K-3/K-1 lenses.

Try out a DA 55-300 PLM and get back to me. We are talking about practical observations as opposed to theoretical constructs and assumptions. As I said, you don't know how good Pentax AF is until you try a DA 55-300 PLM on a K-P. Before that time, you're not even qualified to comment on the current state of Pentax and AF.

Sometimes its the photographer. I do own many electrically motored lenses and still find that ITS NOT THE LENSES. Again, sorry but I'm not buying the PLM for an array of reasons - even to satisfy you and your need for Pentax to be as good as other systems when it comes to AF. Bottom line, Pentax, by all non-fanboy accounts, still lags far behind in AF. My experience with working with Canon and Nikon shooters supports that contention.
03-03-2019, 12:19 PM - 1 Like   #10
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QuoteOriginally posted by steve_k Quote
I’m starting to see all these posts again about what the K-3II replacement should have. The number one thing seems to be more sensor points and faster and more accurate focus. This lead me to thinking about focus speed and accuracy. Isn’t it the lens that is responsible for focus speed. I can see that the body would be responsible for the accuracy of auto focus but not the speed. Also the main recommendation I see for photo focusing is spot focusing. Not being an expert on this I assume that this would use only a few sensors max. So what good would more sensors provide for taking photos other than I hav more sensors than you. I can see where more sensors would be useful for continuous focus for moving objects and video. But I think that once you get above a certain number it’s just a gimmick and no longer provides any advantage. Regarding focus accuracy I would guess that is more the algorithms used and light to determine focus accuracy than hundreds of sensor points. So maybe all Pentax needs are better focus algorithms in their software.

Just wondering if Im looking at this correctly or if my thinking is flawed.
It improves the tracking capability but not speed if everything else is equal. Tho both speed and af tracking capability depends on processing speed and software algorithms and lens used.

Last edited by Trickortreat; 03-04-2019 at 03:30 AM.
03-03-2019, 12:23 PM - 4 Likes   #11
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QuoteOriginally posted by Docrwm Quote
Sometimes its the photographer. I do own many electrically motored lenses and still find that ITS NOT THE LENSES. Again, sorry but I'm not buying the PLM for an array of reasons - even to satisfy you and your need for Pentax to be as good as other systems when it comes to AF. Bottom line, Pentax, by all non-fanboy accounts, still lags far behind in AF. My experience with working with Canon and Nikon shooters supports that contention.
Name calling rarely accomplishes anything. But Believe what you want....


QuoteQuote:
Pentax, by all non-fanboy accounts, still lags far behind in AF.
Some actual facts for you

Full auto-focus Single area AF Pentax K-1 .09s

Canon 1Dx
Full auto-focus Single area AF .085s

Canon 5d mk4
Full auto-focus Single area AF .165s

Nikon D850
Full Autofocus Single Point(Center) AF-S .076s

NIkon 5D
Full Autofocus Single Point (Center) AF-S .132s

Sony A9
Full Autofocus Single Point (Center) AF-S .216s

Sony A7rIII
Full Autofocus Single Point (Center) AF-S .212s

All taken from Imaging Resources' Performance stats. No doubt, Pentax fan boys.

Only the best of the rest matches what i do much of the time, and many fall behind.

Educate yourself try out a K-P and 55-300 PLM. By the way we also have testimonials from at least one former Nikon user that this information is accurate.

So am I the Pentax fanboy, or are you the "any AF but Pentax" fanboy?
Your opinion is important to us.

Who's AF is best depends on how you use your camera. I regularly shoot beside Canon, Nikon and Sony shooters, and after a change in pose by the wildlife, I often get off the first shot off, the speed of Pentax AF.s in focus confirmation makes up for my 70 year old reflexes. I also find most of them so brainwashed by the same internet hogwash you've fallen prey to my camera turns their heads and leaves them groping for explanations.

But, if you want to present some actual facts to prove your case, I'll be happy to look them over.

Given a choice between someone who has actually used cameras from both systems extensively, I'm not really interested in anecdotal comparisons. Some guy saying "my camera is better than yours" doesn't make it true. Especially when they use one system full time and have just fooled around with the other a few times.

Please don't try and pull this B.S. on me (us) again.
Pentax is severely limited in tracking AF, though there are youtube demonstrations that it doesn't lag that far behind even there as Canikon people like to make out it does. IN AF.s it has an advantage over all but the most expensive systems. There's no comparably priced system that comes close to a K-3, which is now 6 years old. Different philosophies of AF design, with strengths in different areas. Don't mistake that as "one is better than the other."

I've learned how to get the most out of my system. It stacks up with the best in almost every situation I've used it, I don't listen much to people who claim I can't do things I do. Why would I?

Last edited by normhead; 03-03-2019 at 12:41 PM.
03-03-2019, 01:40 PM - 1 Like   #12
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QuoteOriginally posted by Docrwm Quote
Sometimes its the photographer. I do own many electrically motored lenses and still find that ITS NOT THE LENSES. Again, sorry but I'm not buying the PLM for an array of reasons - even to satisfy you and your need for Pentax to be as good as other systems when it comes to AF. Bottom line, Pentax, by all non-fanboy accounts, still lags far behind in AF. My experience with working with Canon and Nikon shooters supports that contention.
Recently I accidentally mounted the older DA 55-300 on my KP instead of the PLM variant. I didn't measure anything, but it certainly felt slower to me. The PLM variant is much closer to the performance I remember from my years as a Canon user.
03-03-2019, 02:19 PM   #13
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Adding auto focus points mainly helps with tracking.

Auto focus issues can be related to a number of things. Screw driven lenses actually can focus very quickly. The FA 135 and DA 40 are some of the fastest focusing lenses I own, due to their short focus throw. SDM lenses tend to be very slow and are pretty useless when it comes to tracking. The DA *55 and DA *50-135 are particularly difficult in that respect. Optically great, but just don't get anywhere very fast. Newer DC motor lenses and the new DFA zooms and primes are pretty speedy.

Camera bodies do make a difference and newer ones do better with regard to focus acquisition, but the lens component should not be ignored as SDM lenses are going to struggle in most auto focus tests, regardless of the camera body they are mounted on.
03-03-2019, 03:17 PM   #14
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Lens motor is important. In-body motor is important. Auto focus sensor is important. Processor calculating the focus corrections is important. The auto focus algorithms are important. Data transfer rate is important (not speaking about SD-card now). Battery charge level is important. Every bit and piece in the chain of focusing is important - not least the photographer.
Pentax autofocus in AF-S is fast and reliable - especially if you have SPOT mode selected.
AF-C lags behind others and it's also making unnecessary corrections after getting it right.

Important thing to do is to knowledge the good and the bad and know how to get best possible results with what you have (I got quite a few keepers of surfers yesterday).
03-03-2019, 03:29 PM   #15
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The lens makes a huge difference in low light situations. I have shot enough weddings and events to know this is true. When I shoot an event I don't have Canon, Nikon or Sony shooters next to me. Pentax AF with 2.8 or faster lens works great for me and most importantly my clients.
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