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04-09-2015, 07:51 AM   #571
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QuoteOriginally posted by kenspo Quote
.i will have other cameras to test on soon.
oh? which one?

04-09-2015, 07:52 AM - 1 Like   #572
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QuoteOriginally posted by Franc Quote
oh? which one?
Haha..i can't tell..not yet..but many things happening at the moment
04-09-2015, 08:04 AM   #573
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QuoteOriginally posted by kenspo Quote
Hmm..its hard for me to answer this 100%..Since im still pretty new to Pentax, and never used anything beside K-3 and 645Z..So it is maybe more a feeling i have..i will have other cameras to test on soon (new ones, not older ones), then i'll see if i was correct or not.
Thanks for answering... I'm just hoping someone will jump in here and tell me how wrong I am...
04-09-2015, 09:07 AM   #574
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Are the lenses delayed at this point? I know the pre-orders have been out for a while, is there a shipping date or are they still working on the lens?

04-09-2015, 09:42 AM   #575
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QuoteOriginally posted by normhead Quote
the lens to move so quickly that the lens moves past the focus point without registering that it was in focus, and then having to come back
The camera's processor is much faster than any lens motor. But it is likely to be programmed to take short cuts, based on the average speed of lens motors, in order to get close to focus quickly. The slowest part of the entire system is the lens motor, so programming tricks that compensate for slow lens motors will undoubtedly be used, and significantly faster lens motors could end up overshooting.
QuoteOriginally posted by normhead Quote
The only factor that could be different would be the camera's ability to recognize when the image is in focus
I don't think the Prime III processor in the K-3 is significantly slower than the competition's. But with fewer AF points to process data from, the K-3 will have a limitation that can't be completely overcome with firmware upgrades. On the other hand, if the PDAF sensors are equally sensitive, then smarter programming could compensate for fewer AF points, especially combined with behavioral compensation by the photographer. I seriously think the main difference is the focusing systems in the lenses themselves; the length of throw, mass of the lens and speed, power and precision of the motor.
QuoteOriginally posted by normhead Quote
Am I missing something?
You probably know more about camera design than I do, and I'm sure there are far more knowledgeable people on this forum than either one of us, but I think the only part you have headed the wrong way on is thinking that the camera has to recognize focus quicker. The other thing I want to throw in is that different lens motors have different levels of precision, and the camera's processor has to be programmed to make a decision to keep moving the lens to get more accurate focus, or to accept "close enough" in order to release the shutter sooner.
04-09-2015, 10:10 AM   #576
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QuoteOriginally posted by totsmuyco Quote
Well I hope Pentax will not forget the APS-C lines despite their intention to compete with the pro line.
They won't (well, I can't be that definitive because I don't work for Ricoh. Folks on the 'net like to use absolutes even when they are in no position to make that judgement, so I like to be skeptical when I see that kind of language).

Anyway, the APS-C market is still MUCH larger than the FF market. Neglecting it would be foolish. Especially when the "Pro" APS-C DSLR market is so under served.
Right now, there are only 2 modern Pro APS-C bodies in the entire sea of DSLRs, the K-3 and the 7DII.
04-09-2015, 10:28 AM   #577
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QuoteOriginally posted by harrisonww Quote
Are the lenses delayed at this point? I know the pre-orders have been out for a while, is there a shipping date or are they still working on the lens?
No and no. Will start shipping very soon.
04-09-2015, 11:36 AM   #578
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QuoteOriginally posted by normhead Quote
Hopefully the FF will. But if the K-3 doesn't make full use of the new lenses, I would expect the lens to move so quickly that the lens moves past the focus point without registering that it was in focus, and then having to come back. You see this in old screw drive lenses that are 6.3 or slower, the speed of focus is geared up but there isn't enough light to look focus at that speed and the lens hunts.. SO, I'm wondering if you're seeing anything like that that would indicate the speed of focus is stressing the AF system?

I guess in the FF system they could bump the voltage to the new lenses to make them faster and have a recognition chip so the it doesn't fry the SDM lenses, but apart from more power to the motors, I'm not sure how the lens would focus faster than it does now. The only factor that could be different would be the camera's ability to recognize when the image is in focus. If it's not missing focus and hunting, I'm not sure how it could be any different. The .1 second focus speed on a D610 is based on a very short movement when focussing the lens. The .5 second focus speed on a K-3 is in part based on a much longer distance. There are only two ways around the slow focus speed. Move the lens element faster, or shorten the distance it has to move to get from close to infinity. Am I missing something?

In both cases the AF system has less time to recognize that the desired point is in focus. But just improving the AF focus lock system in the camera can't make up for slow focussing lenses.

Or in other words, unless Pentax starts making lenses designed with higher gearing or less distance to travel in focusing, I'm not sure how any improvement in the AF module is going to help. Most of the time, the AF system is waiting for the lens to get to the point where things are in focus. That's what I'd like to see improved i these lenses. If it takes the AF system a few years to catch up that's fine with me. To me, seeing a bit of hunting out the gate would be good thing. It would mean the lens focusses quickly.. and the cameras AF could be improved to make it lock focus more reliably in the future.

If the K-3 doesn't hunt, and you're still dealing with a slow focusing lens... how is there going to be improvement? It doesn't make any sense to me to release an "improved lens" that focusses at 1/5th the speed of the competition.
The whole point of PDAF is that you can detect directly where exactly the focus should be put on and give the order. There no need to reread the focus position. At the basic there no feedback loop where the AF check again and give a new correction order with hunting. That's why you can have back/front focussing: there play in the mechanics and so own and so in the end the focus is not exactly where it should be. The hunt is the camera that discover there was an error and try to correct... or even maybe that known that its initial computation was not very precise and try to correct it.

On advenced lenses, the lense monitor himself the execution of the new focus position. It is then able to detect that if there a "long move" to do it can accelerate at full speed... and slow down to stop exactly where needed. This feedback loop also help make the most advenced lenses much more precise. The concept is a bit like when you want to grab something with your hands: if you uses you eyes to track the movement you are much more precise than if you just given the order eyes closed and execute it. You can't correct any devition from it.

As for the power limitation, without knowing the protocol of the mount and it latest evolutions, it is simply impossible to conclude what the limitation is, how the negociation is made with the camera if the voltage stay always the same and the motor can just consume as much intensity as it needs. Anyway this is very basic eletricity. If a 5$ USB charger can plug to a power plug and give exactly the form of energy the USB device need including transforming the voltage I guess a 2000$ camera + 2000$+ lense should be able to solve the issue... The only limitation really would be battery power. And there even Pentax could use a more advenced model if needed. They just need to use the latest advencement made on battery gear for smartphone, laptops and other very power hungry mobile devices.

Last but not least, there almost never such a need to focus fast. To go from minimal focus distance to infinite instantly. Most often what is needed is to move slightly the focus. So the lense more than being fast, should be reactive, have minimal latency and be precise.

On the camera side the issue is that moving objects continue to move when the mirror is up to take the photo and so the AF-C doesn't work anymore. Advanced algorithms continuouly evaluate what is the object the photographer want to focus on by using both the AF sensor (to evaluate the distance and get a deph map) and also the metering sensor to get a low resolution picture of the scene. Using theses both information is it possible to follow the object moving lateraly or vertically in the frame and with AF sensor to follow the deph change. All of this finally allow to estimate the current speed, direction, trajectory of the object in focus an predict exactly where it will be when the photo will be taken and to ask the lense to move to this focus position just in due time.

This is by combining everything that you get the best results. A modern lense with advenced feedback look mechanism and very precise high quality mechanics. A powerfull enough motor, a good optical design that allow to move fast enough the focussing lenses, a good AF support from the camera and even machine learning and IA algortihms to recognize subject, predict trajectories, give the orders so that the focussing will be just fine at the time the picture is taken.

04-09-2015, 12:07 PM   #579
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QuoteOriginally posted by RGlasel Quote
I don't think the Prime III processor in the K-3 is significantly slower than the competition's.
It's almost the same Milbeaut Nikon called EXPEED 4.
04-09-2015, 12:42 PM   #580
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QuoteOriginally posted by jaad75 Quote
It's almost the same Milbeaut Nikon called EXPEED 4.
The software on it and its optimization play a huge role too. I don't think Pentax has the same focussing software as Nikon has... otherwise the AF efficiency would be quite different. I also think that part of the processing is done by the hardware that control the PDAF directly.
04-09-2015, 02:14 PM   #581
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QuoteOriginally posted by Nicolas06 Quote
The software on it and its optimization play a huge role too. I don't think Pentax has the same focussing software as Nikon has... otherwise the AF efficiency would be quite different. I also think that part of the processing is done by the hardware that control the PDAF directly.
AFAIK the Milbeaut has not much if at all to do with PDAF.
04-09-2015, 08:21 PM   #582
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QuoteOriginally posted by kenspo Quote
Haha..i can't tell..not yet..but many things happening at the moment
Wink if a new Pentax 300mm f2.8 will be coming out soon....
04-10-2015, 12:23 AM   #583
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QuoteOriginally posted by Stavri Quote
Wink if a new Pentax 300mm f2.8 will be coming out soon....
<-- both eyes closed I dont know which prime is coming when..yet zooms and camera house is first..
04-10-2015, 01:44 AM   #584
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QuoteOriginally posted by kenspo Quote
<-- both eyes closed I dont know which prime is coming when..yet zooms and camera house is first..




So wink for us if the camera house is Jun/Jul.
04-10-2015, 01:48 AM   #585
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QuoteOriginally posted by vcollerp Quote
So wink for us if the camera house is Jun/Jul.
There might be something happening before that time too
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