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06-23-2018, 02:18 PM   #16
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QuoteOriginally posted by MightyMike Quote
*snip*

I know you're having fun but lets expend on that. Lets take skill at a few simple levels, can you hold the center of the viewfinder on the subject? or more simply hold a telephoto lens steady?. Can you do this while following the subject and zooming at the same time for framing? Can you anticipate the subject and how the camera may behave to maximize the results? just because the camera can offload the focusing requirement from the user doesn't mean the user can offload all skill to the camera.

*snip*
Hey hey hold your horses... while the K-01 is supposed to have AF-C, in practice I couldn't make it work even tracking a picture on my TV moving one step at a time...
I have a K-30 since September, but I've only had one chance to try AF-C (at a historical car race), and, while it was with a wide-ish lens, I've been pleased with what I saw. I mean... to a MF guy all this looks like a miracle!
I'm trying it again with a longer lens as soon as I get the chance though, so your tips will be invaluable.

06-23-2018, 02:23 PM - 1 Like   #17
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QuoteOriginally posted by LensBeginner Quote
Hey hey hold your horses... while the K-01 is supposed to have AF-C, in practice I couldn't make it work even tracking a picture on my TV moving one step at a time...
I have a K-30 since September, but I've only had one chance to try AF-C (at a historical car race), and, while it was with a wide-ish lens, I've been pleased with what I saw. I mean... to a MF guy all this looks like a miracle!
I'm trying it again with a longer lens as soon as I get the chance though, so your tips will be invaluable.
Those of us, me included who don't mind MF have to give serious consideration to the use of focus trap (therefore semi-AF). I did this years ago with an 800mm F8.0 mirror lens at the red bull air races, the results weren't perfect but I most certainly got worthy results! You maintain the control of MF but the camera will snap when something is in focus, in most cases only on the center AF point so forget framing.

Last edited by MightyMike; 06-23-2018 at 04:10 PM.
06-23-2018, 02:30 PM   #18
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QuoteOriginally posted by MightyMike Quote
Those of us, me included who don't mind MF have to give serious consideration to the use of focus trap (therefore semi-AF). I did this years ago with an 800mm F8.0 mirror lens at the red bull air races, the results were perfect but I most certainly got worthy results! You maintain the control of MF but the camera will snap when something is in focus, in most cases only on the center AF point so forget framing.
Center point with AF-S (duh!) is the only choice you have for CIF.


Steve
06-23-2018, 02:34 PM - 1 Like   #19
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QuoteOriginally posted by stevebrot Quote
Center point with AF-S (duh!) is the only choice you have for CIF.


Steve
I remember (unless I'm remembering wrong) someone once showed how with modern SDM and HSM lenses one could CIF with other points. I haven't tried this to be certain.

06-23-2018, 02:56 PM - 1 Like   #20
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QuoteOriginally posted by normhead Quote
That's nice but without comparison's from Nikon , Canon and Sony cameras, we have no idea what those numbers mean. I've heard Canon AF called fast but inaccurate, so, I wouldn't in any way concede that Pentax AF is poorer than anyone else's without direct comparisons.
I also might add that people need to know what the AF type and design is intended to do. Some AF is designed for general all around use. Not all cameras are sports cameras. Not all cameras shoot 10 frames a second. Yet, it seems like the ONLY metric people want to use is super high end sports use with some kind of tracking mode that would rival an F16.


Well, what if I never shoot sports, or if I do it's maybe once a year?


Would it matter to me then?


Truth be told I could get better pictures and better keeper rates by not using AF at all in a lot of high speed situations. AF is a convenience feature as far as I am concerned. That said people are trying to take that to an extreme. All this camera marketing is making people dependent.


Given I have never used any other systems before, but having upgraded from a K-5 to a K-3 and now a K-1 having better AF particularly in low light is kind of nice.


On the flip side of that I want to hear what people would do if they go on an expensive trip halfway around the world and are in a once in a lifetime moment and their AF stops working. What do they do then? Most would just cry and put their cameras up claiming they could never take another photo and probably wind up switching camera gear.


"Sorry guys! I can't take photos of this international summit and a historic handshake because my AF quit working this morning". Unfortunately this is how a lot of people actually think now. It's sort of like having your butler go on vacation and because of that you wear dirty underwear for the next month until he gets back.


A true professional though would just keep on shooting and would know how to make it work. Taking photos is about capturing the moment and image. How you get from point A to point B is a question very few will ask.
06-23-2018, 03:02 PM - 2 Likes   #21
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QuoteOriginally posted by stevebrot Quote
I did but came up with nothing. I also consulted the ExifTool Pentax makernotes Tag reference with the same result.
ExifTool | Pentax Tag Reference
Copy paste of an EXIF report with the pertinent fields highlighted along with a note of what tool was used would be helpful.*


Steve

* Tag names for the makernotes section are arbitrary for any software that supports them. That is why it is helpful to identify the tool. ExifTool is fairly authoritative and exhaustive, but that doesn't mean it is without fault.
It's called AFIntegrationTime and seems to be an 8-bit integer recording the time in msec (although values of less than 2 msec recorded as zero).

See ExifTool | Pentax Tag Reference | AFInfo Tags
06-23-2018, 03:07 PM   #22
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QuoteOriginally posted by MightyMike Quote
I remember (unless I'm remembering wrong) someone once showed how with modern SDM and HSM lenses one could CIF with other points. I haven't tried this to be certain.
I just tried it and you are correct! This is a new one for me. I knew it was possible to do CIF with AF lenses having AF/MF switches on the lens, but did not know until today that one could select AF point for CIF with these lenses. The feature is undocumented on the K-3, but is explicit on the KP and K-1. What's more, focus point selection appears to be available for non-AF lenses too on those cameras, based on the user guide description. I guess today must be my day to learn something new.


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06-23-2018, 03:08 PM   #23
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QuoteOriginally posted by alamo5000 Quote
I also might add that people need to know what the AF type and design is intended to do. Some AF is designed for general all around use. Not all cameras are sports cameras. Not all cameras shoot 10 frames a second. Yet, it seems like the ONLY metric people want to use is super high end sports use with some kind of tracking mode that would rival an F16.


Well, what if I never shoot sports, or if I do it's maybe once a year?


Would it matter to me then?
Then don't worry about it, why would you be concerned about AF if its not something you care to use often? Those who use AF is extreme situations certainly should be interested to know if it can be effective in such situations. When it comes to static objects and low light the vast majority of cameras are perfectly fine so one doesn't care to test those metrics. That said if the AF can handle the extremes its highly likely it can handle the other metrics.

QuoteOriginally posted by alamo5000 Quote
On the flip side of that I want to hear what people would do if they go on an expensive trip halfway around the world and are in a once in a lifetime moment and their AF stops working. What do they do then? Most would just cry and put their cameras up claiming they could never take another photo and probably wind up switching camera gear.
Given that I use MF (ok I admit with CIF assist) in some sports I think I can get by manually focusing on trips, in fact on the last could of trips I've had 2 MF lenses with me along with AF lenses.


QuoteOriginally posted by alamo5000 Quote
"Sorry guys! I can't take photos of this international summit and a historic handshake because my AF quit working this morning". Unfortunately this is how a lot of people actually think now. It's sort of like having your butler go on vacation and because of that you wear dirty underwear for the next month until he gets back.


A true professional though would just keep on shooting and would know how to make it work. Taking photos is about capturing the moment and image. How you get from point A to point B is a question very few will ask.
Who said anything about being professional except you! Taking a photo isn't always about capturing (the or a) moment that is merely just one genre of photography, perhaps a common one but one of many none the less.

---------- Post added 06-23-18 at 06:14 PM ----------

QuoteOriginally posted by photoptimist Quote
It's called AFIntegrationTime and seems to be an 8-bit integer recording the time in msec (although values of less than 2 msec recorded as zero).

See ExifTool | Pentax Tag Reference | AFInfo Tags
I always thought that was a metric related specifically to how long it took from the camera being told to focus to when it acquired focus, its extremely variable in that the lenses out of focus position and the position of the target can be completely different shot to shot, sometimes its short and sometimes its longer but as far as I'm concerned its never as long as the gap between photos regardless of any Pentax burst speeds. So I can't see it as having any bearing on the results. It would have more of a bearing if you wanted to test how long the system takes to acquire focus when its well out of focus rather then when its already supposed to be tracking a subject.

Now am I wrong in my understanding of this value?

---------- Post added 06-23-18 at 06:15 PM ----------

QuoteOriginally posted by stevebrot Quote
I just tried it and you are correct! This is a new one for me. I knew it was possible to do CIF with AF lenses having AF/MF switches on the lens, but did not know until today that one could select AF point for CIF with these lenses. The feature is undocumented on the K-3, but is explicit on the KP and K-1. What's more, focus point selection appears to be available for non-AF lenses too on those cameras, based on the user guide description. I guess today must be my day to learn something new.


Steve
Great, I'm glad I was able to pass along that information even if I couldn't remember it fully

06-23-2018, 03:26 PM   #24
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QuoteOriginally posted by MightyMike Quote
I always thought that was a metric related specifically to how long it took from the camera being told to focus to when it acquired focus, its extremely variable in that the lenses out of focus position and the position of the target can be completely different shot to shot, sometimes its short and sometimes its longer but as far as I'm concerned its never as long as the gap between photos regardless of any Pentax burst speeds. So I can't see it as having any bearing on the results. It would have more of a bearing if you wanted to test how long the system takes to acquire focus when its well out of focus rather then when its already supposed to be tracking a subject.

Now am I wrong in my understanding of this value?
The various online discussions I've seen all suggest that small values occur in bright sun and large values occur in dim light.

The AF module uses a photodiode array and in dim light (or with lenses with narrower wide-open apertures), those photodiodes take a little longer to gather a sufficient signal. You mentioned that the 1/2000 second shutter speed was not fast enough to stop motion of the dogs and that same blurring issue would affect the AF module.
06-23-2018, 03:32 PM   #25
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QuoteOriginally posted by MightyMike Quote
Then don't worry about it, why would you be concerned about AF if its not something you care to use often? Those who use AF is extreme situations certainly should be interested to know if it can be effective in such situations. When it comes to static objects and low light the vast majority of cameras are perfectly fine so one doesn't care to test those metrics. That said if the AF can handle the extremes its highly likely it can handle the other metrics.
I use AF all the time. Constantly in fact. That said you bring up an interesting point. Knowing what your camera is designed for is important. Knowing where the limitations are is important. That is actually valuable information. It is not however the be all and end all of photography. When AF stops working, go to plan B.


Considering that for most relatively slow moving and especially static objects the AF in a point and shoot will work just fine. Considering what the photographer intends to do makes the AF discussion more or less important depending on the answer. That would apply equally as much to camera bodies too. A 3 fps clunker might be the cat's meow for everything---except Formula One.


It boils down to the right tool for the right job. Even the 645z or even some expensive Hassleblad, however awesome those cameras are, they are not intended to be high speed.


Really at the end of the day, like I said, AF tests are often only used to measure a single metric or even a single type of photography. Comparing a 12fps with F16 Strike Eagle AF tracking modes to a Hassleblad medium format is comparing apples to oranges... If we measure strictly by which one has the best 'hummingbird in flight' tracking ability, then by all means 'Hassleblad's system sucks too'.


Yet, people persist in proclaiming what is or isn't the 'number one' or 'best' AF. Again it begs the question, 'the best AF for what'?


QuoteOriginally posted by MightyMike Quote
Who said anything about being professional except you! Taking a photo isn't always about capturing (the or a) moment that is merely just one genre of photography, perhaps a common one but one of many none the less.
I'm far from a professional. I've never been paid a nickel for a picture. I'm just a layman like 95% of the people here. That said professional or not, layman or not, the object is to take and capture photos. I am kind of in a 'no excuses' mood right now so the whole "I didn't get the shot because my AF..." doesn't fly.


Amateur or professional alike, the question remains. Do you want good pictures or not? That's a yes or no question. If the answer is yes, and this is not at all detracting from good AF system at all, but if one wants good pictures they need to know how to get them in all kinds of situations, including not having AF at all.
06-23-2018, 03:37 PM   #26
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On a side note, I rarely, if ever get involved in any of these 'technology' or 'technical' related threads. I am here just stirring the pot to help us get to 100% so somebody can get a free K-1.
06-23-2018, 03:54 PM   #27
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QuoteOriginally posted by stevebrot Quote
What's more, focus point selection appears to be available for non-AF lenses too on those cameras, based on the user guide description. I guess today must be my day to learn something new.


Steve
From this i would think manual lenses don't need center point only for focus confirmation? Just tried on my k-s2 sigma 70 on manual has all points but A 50 is limited to spot.
06-23-2018, 04:05 PM - 1 Like   #28
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QuoteOriginally posted by alamo5000 Quote
I use AF all the time. Constantly in fact. That said you bring up an interesting point. Knowing what your camera is designed for is important. Knowing where the limitations are is important. That is actually valuable information. It is not however the be all and end all of photography. When AF stops working, go to plan B.
I never said and never wanted to infer that it was the be all and end all of photography.


QuoteOriginally posted by alamo5000 Quote
Considering that for most relatively slow moving and especially static objects the AF in a point and shoot will work just fine. Considering what the photographer intends to do makes the AF discussion more or less important depending on the answer. That would apply equally as much to camera bodies too. A 3 fps clunker might be the cat's meow for everything---except Formula One.
This also depends on what the photographer wants out of the camera, after all formula 1 can be covered without burst if one wants to, albeit in a spectacular crash situation the more fps the better. If you're not a profession photographer and are just there to enjoy the event and take back some photos then just about anything is good enough in just about any situation


QuoteOriginally posted by alamo5000 Quote
It boils down to the right tool for the right job. Even the 645z or even some expensive Hassleblad, however awesome those cameras are, they are not intended to be high speed.
Not intended for doesn't mean not possible depending on your definition of possible

QuoteOriginally posted by alamo5000 Quote
Really at the end of the day, like I said, AF tests are often only used to measure a single metric or even a single type of photography. Comparing a 12fps with F16 Strike Eagle AF tracking modes to a Hassleblad medium format is comparing apples to oranges... If we measure strictly by which one has the best 'hummingbird in flight' tracking ability, then by all means 'Hassleblad's system sucks too'.
Be careful as one can take this too far in that any 2 items that aren't the saem can be considered apples to oranges, one must draw a line and allow for differences otherwise comparisons would be impossible.


QuoteOriginally posted by alamo5000 Quote
Yet, people persist in proclaiming what is or isn't the 'number one' or 'best' AF. Again it begs the question, 'the best AF for what'?
I proclaim the other guys have better AF overall for action tracking, can you make a validated counter claim that shows Pentax has an advantage in this area?


QuoteOriginally posted by alamo5000 Quote
I'm far from a professional. I've never been paid a nickel for a picture. I'm just a layman like 95% of the people here. That said professional or not, layman or not, the object is to take and capture photos. I am kind of in a 'no excuses' mood right now so the whole "I didn't get the shot because my AF..." doesn't fly.
I'm pretty sure I made it clear in the original post that skill plays a huge role in whether or not one gets the photo, I agree many too often are quick to blame the camera, I always look for user error and other things that excuse the camera for a failed photo.


QuoteOriginally posted by alamo5000 Quote
Amateur or professional alike, the question remains. Do you want good pictures or not? That's a yes or no question. If the answer is yes, and this is not at all detracting from good AF system at all, but if one wants good pictures they need to know how to get them in all kinds of situations, including not having AF at all.
Of course, re-read the opening to my report, I clearly mention skill as being important.

---------- Post added 06-23-18 at 07:06 PM ----------

QuoteOriginally posted by alamo5000 Quote
On a side note, I rarely, if ever get involved in any of these 'technology' or 'technical' related threads. I am here just stirring the pot to help us get to 100% so somebody can get a free K-1.
I was hoping this report and my first report on the K-1 II's AF would do just the same, get responses so someone can win a camera, it need not be be but I won't say no either.

---------- Post added 06-23-18 at 07:08 PM ----------

QuoteOriginally posted by swanlefitte Quote
From this i would think manual lenses don't need center point only for focus confirmation? Just tried on my k-s2 sigma 70 on manual has all points but A 50 is limited to spot.
I too haven't found an MF lens that offers more than center point
06-23-2018, 04:43 PM   #29
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QuoteOriginally posted by photoptimist Quote
It's called AFIntegrationTime and seems to be an 8-bit integer recording the time in msec (although values of less than 2 msec recorded as zero).

See ExifTool | Pentax Tag Reference | AFInfo Tags
Interesting. Today is the first time I have read of that value being the setting of a shutter of sorts. It had been my understanding that it was a report of the measured time to attain focus after the AF point was determined (the gap between red dot and green hexagon) rather than the settings value for an AF time window.

Google was no help, so I grabbed my K-3 and did a series of shots of similar low complexity subjects (light switch and edge of window molding) at both f/4 and f/11 at both LV 4 and LV 15. All four cases resulted in AFIntegrationTime = 4ms. I then looked at a photo taken yesterday of a high contrast subject (variegated iris bloom) at f/5.6 and LV 12 and found the AFIntegrationTime to be 0ms. Hmmmm...does not seem to be related of LV or aperture.

I downloaded the ExifTool Perl module for Pentax and found the source code comment:
"# effective exposure time for AF sensors in 2 ms increments
OK...that is clear as mud, though it does sound like some type of timing window. Went back to the camera and tried AF-C with various slower-focus AF lenses and still got values of either 0ms or 4ms.

Whatever...


Steve

(...AFIntegrationTime goes back at least to the K10D and maybe further...)

Last edited by stevebrot; 06-23-2018 at 04:54 PM.
06-23-2018, 04:59 PM   #30
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QuoteOriginally posted by stevebrot Quote
Interesting. Today is the first time I have read of that value being the setting of a shutter of sorts. It had been my understanding that it was a report of the measured time to attain focus after the AF point was determined (the gap between red dot and green hexagon) rather than the settings value for an AF time window.

Google was no help, so I grabbed my K-3 and did a series of shots of similar low complexity subjects (light switch and edge of window molding) at both f/4 and f/11 at both LV 4 and LV 15. All four cases resulted in AFIntegrationTime = 4ms. I then looked at a photo taken yesterday of a high contrast subject (variegated iris bloom) at f/5.6 and LV 12 and found the AFIntegrationTime to be 0ms. Hmmmm...does not seem to be related of LV or aperture.

I downloaded the ExifTool Perl module for Pentax and found the source code comment:
"# effective exposure time for AF sensors in 2 ms increments
OK...that is clear as mud, though it does sound like some type of timing window. Went back to the camera and tried AF-C with various slower-focus AF lenses and still got values of either 0ms or 4ms.

Whatever...


Steve

(...AFIntegrationTime goes back at least to the K10D and maybe further...)
I appreciate that you took time to test it, I can't wait to hear more on the subject from someone who knows or who knows how to test it to determine its actual meaning
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