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08-23-2009, 05:43 PM   #31
PDL
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what?

QuoteOriginally posted by Russell-Evans Quote
You missed AF -> Shutter ==> the human
Sorry, I do not get this one, in order for AF to start - either you have to turn the camera on, or run your finger over the shutter button. Once the device is alive, focus as you wish.

QuoteOriginally posted by Russell-Evans Quote
Once you get used to using it, it is not much different than having AF on the AF button. With the grip on the K10/20D, hitting the AF button is pretty impossible for me. AF on the shutter is the only option. At least the K-7 addressed the missing AF button on the grip.
I do not have a grip - so to speak - so issues with the AF button and the grip are not an issue with my method of shooting.

QuoteOriginally posted by Russell-Evans Quote
I really wish the K10D and K20D had the focus switch of the K100 series. I'm always worried about the switch unless I flip the camera over to look at it.
Here is the what? part. There is the same focus swithc AF-S, AF-C, M on all of my Pentax DSLR's. What switch are you talking about.
*istDS
K10D
K20D

As for Wheatfield - The last time I shot a wedding it was back in the 70's. No magic flash (6 second recharge time - manual f/stop adjustment based on the distance scale on the flash), manual focus, 1/60th X sync, ASA 200 film with some ASA 160 slides. I did manage to get the required shots. Set the shot up and waited for the people to walk into the distance I had preset and boom - they were blind for three seconds. By de-coupling AF from the shutter button and using the AF/OK button - the same thing happens. Two things that are nice with Pentax. Use the focus select switch set to manual - with de-coupled AF - manual focus with the AF button pressed and the green hexagon still works (do this with my manual lens). Or use AF button to focus on the spot - wait for the object to get into focus, release the AF button and press the shutter button as many times as you require.

I have atteded two photo workshops sponsored by National Geographic. At each one the guy(s) from NG have de-coupled AF from the shutter button - so THEY decide when the object is in focus - not the camera. In fact, one of them (Michael Melford) said that on his Canon MkIII something or another - the only two custom functions he sets up are to display the histogram on the LCD and to de-couple AF. He has at least 5 covers.

Again - shoot how you want - but technique does count, I prefer to rely on me not the camera - the camera does not (hopefully) know as much as I do. Oh - I use AF - recompose - shoot 99.9% of the time

The Elitist - formerly known as PDL

08-23-2009, 06:34 PM   #32
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QuoteOriginally posted by PDL Quote
Here is the what? part. There is the same focus swithc AF-S, AF-C, M on all of my Pentax DSLR's. What switch are you talking about.
*istDS
K10D
K20D
The K100D has a slide switch for AF/MF. The K20D has a rotating switch that does AF.S, AF.C, and MF.
08-23-2009, 07:44 PM   #33
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I've definitely run up against these issues in my concert shooting. As you can imagine, any AF issue is made much worse in low light, and without an SDM or quick-release focus lens, I end up missing way too many shots.

A stupid simple workaround would be something I think I first saw suggested on TOP: A custom function setting that says, in effect "Regardless of what other settings say, always release the shutter when it is depressed all the way (even if focus hasn't been acquired)"

I think manufacturers are too worried about people complaining about out of focus shots (due to misunderstanding this function) to put it in anything but those bodies relegated by their pricetag to pros.
08-23-2009, 07:50 PM   #34
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Original Poster
QuoteOriginally posted by alohadave Quote
Correction: This is an issue if you are using non-QSF lenses.
Fair enough. Until Pentax comes out with a decently fast DA normal prime for their DSLR line-up, I'm stuck with the 31mm, which is non QSF,

QuoteQuote:
If you know that it's a critical situation, why not modify your setup to ensure you get the shot, rather than ranting when it doesn't work the way you want?
Absolutely, and I've learned that for next time. For some reason I thought that the AF would work in a well lit room with relatively stationary subjects. My mistake for presuming that the equipment would do what it should do.

QuoteQuote:
And her camera has never, ever done anything wrong? No camera is perfect, and her anecdote doesn't prove anything about the reliability of Nikon cameras, nor does your experience prove anything about the reliability of Pentax cameras.
Apparently it hasn't not taken a picture when she wants it to. Whatever other faults it may have, it works as advertised.

QuoteOriginally posted by WalterGA Quote
I figured out some time ago, that, if I HAD to get a shot, I'd let the camera AF, then I'd flip to manual. Works every time. It's called "thinking in advance."
Yup. I do find it annoying that 25 years after AF was invented, Pentax still doesn't have one that works reliably.

QuoteOriginally posted by creampuff Quote
Sorry but I'm wondering how is the camera to blame?
The camera didn't do what it was supposed to do in conditions that should have been no problem for it to do what it was supposed to do. My available light stuff was shot at f/2.8 for 1/30 at ISO 400.
QuoteQuote:
Isn't it the responsibility of a working pro to know the ins and outs of the cameras beforehand? There no reason in my view why the shutter can't be released once the AF has locked.
I didn't realize that this would be pushing the camera's envelope to the point of causing it to fail. Having said that, and knowing full well that I should have known it, it is still really crappy AF performance. There is no reason in my view that the shutter shouldn't release either once the AF has locked, but it did exactly that, and that, my dear friend, is the camera's failure to perform.

08-23-2009, 08:54 PM   #35
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QuoteOriginally posted by Wheatfield Quote

Yup. I do find it annoying that 25 years after AF was invented, Pentax still doesn't have one that works reliably.
......Having said that, and knowing full well that I should have known it, it is still really crappy AF performance. There is no reason in my view that the shutter shouldn't release either once the AF has locked, but it did exactly that, and that, my dear friend, is the camera's failure to perform.
I hope you take this positively, because I'm sure others are interested in what may have gone wrong, to avoid a recurrence.

I'm sorry, I'm still not satisfied with "the camera failed to perform" explanation.

From my experience, 3,000 photos on the K-7, some 30,000 shots on the K100D, easily 20% of them with P-TTL flash, once the AF-confirmation lights up, the AF - slow, crappy as it may be, is no longer holding you back from taking the shot. The "slow" portion happens before the AF-confirmation Light and Beep comes up, not after.

There may be some other setting, interlock or limitation holding you back. You may even have set it accidentally without realising it.

The rare occasions I've had where the object was in focus, but the shutter wouldn't trigger have all been Flash related.
With on-board flash, the default setting is shutter will only trigger once the flash is ready. With external flash, the shutter will still trigger regardless, but I've noticed a delay compared with No Flash or Flash Ready.
If the flash had powered down in power saving mode, half-pressing the shutter will "wake up" the flash, but there may be a delay in shutter trigger as the camera communicates with the flash. For important occasions, I make sure the power is back on first.

With P-TTL flash, I'm familiar with a few other built-in delays after the shutter button is pressed e.g. Red-Eye reduction, P-TTL pre-flash, but since you are using a Manual flash, that doesn't apply.

Another delay may be a flash-camera communication problem. There is some minimum interaction even with a Manual flash.

Just trying to walk through the possibilities to diagnose the problem. "Camera failed to perform" doesn't look the right explanation to me.

Last edited by kittykat46; 08-23-2009 at 09:04 PM.
08-23-2009, 09:13 PM   #36
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I'm not going to read all the posts in this thread but I already got the idea some one is saying Pentaxes af is bad and so is pttl.

Well now that I am shooting with a 5d mk2 and now have some experience with the nikon D300 let me say,

Yes Pentax needs to up their game with AF but it's not as bad as your making it sound, With the K7 it was on par with other apsc camera ( ok not the d300 but it is closing the gap ).

What really is slow is the lenses speed, the limited lenses af as fast as any usm lens, as does the old 16-45 but the sdm lenses are jsut slow, fix that and the gap closes even more.

Next with the mk2 in ai focus, the damn thing is hyper active and I'm missing shots due to this, servo is only good for sports and the mk2 is not a sports shooter. The Pentax actually does well with afc and single shot, more accurate than most other apsc cameras for stuff like stage shows and fashion events I shoot, the slow af actually nails those shots accurately, the mk2 does as well but I was expecting af light years a head on it and the 50d, not just a little better. Low light is where the Pentax falls over but then again Nikon uses a spot light to help their camera focus and canon wants you to by a speed light and use the spot beam, spot beam vs spot beam no difference ( k7 vs others that is ).

Now for Pttl, ya it sucks with pentax flashes but add a metz and it makes sense, it's very accurate with the metz, better than canon imo as I'm always dialing the canon down 1/3 a stop. The canons are better in higlights so the metter seems bias 1/3 to 2/3 stops higher than pentaxes but with flash it loves to blow everything away, either that or I need a new 580 as this thing is very banged up.

Now as I've said Pentax does need to catch up and the k7 is a step closer, the lenses af speed needs to be fixed now with an af upgrade and they'll be as good. Until then I will still be using my k20D, to back up the mk2.
08-23-2009, 09:24 PM   #37
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Why can't it? FWIW Wheatfield might have received a lemon. It happens to all brands.

I've never had a body locked and then refused to shoot. Once it's locked, even if you point it totally at some random direction, it never "loses" the lock (Unless in AF-C, but then you would be able to fire at any time in AF-C).

As to the use of AF button, it's all personal preference. I still find myself 100% in control even if I set to AF with the shutter button half-pressed and AF button set to disable AF, although I prefer using the AF button, for the sole reason of not having to "press and hold" any button, which I hate to do (in my opinion, any operation that requires holding a button is a design flaw, because fingers get tired)


QuoteOriginally posted by kittykat46 Quote
I hope you take this positively, because I'm sure others are interested in what may have gone wrong, to avoid a recurrence.

I'm sorry, I'm still not satisfied with "the camera failed to perform" explanation.

From my experience, 3,000 photos on the K-7, some 30,000 shots on the K100D, easily 20% of them with P-TTL flash, once the AF-confirmation lights up, the AF - slow, crappy as it may be, is no longer holding you back from taking the shot. The "slow" portion happens before the AF-confirmation Light and Beep comes up, not after.

There may be some other setting, interlock or limitation holding you back. You may even have set it accidentally without realising it.

The rare occasions I've had where the object was in focus, but the shutter wouldn't trigger have all been Flash related.
With on-board flash, the default setting is shutter will only trigger once the flash is ready. With external flash, the shutter will still trigger regardless, but I've noticed a delay compared with No Flash or Flash Ready.
If the flash had powered down in power saving mode, half-pressing the shutter will "wake up" the flash, but there may be a delay in shutter trigger as the camera communicates with the flash. For important occasions, I make sure the power is back on first.

With P-TTL flash, I'm familiar with a few other built-in delays after the shutter button is pressed e.g. Red-Eye reduction, P-TTL pre-flash, but since you are using a Manual flash, that doesn't apply.

Another delay may be a flash-camera communication problem. There is some minimum interaction even with a Manual flash.

Just trying to walk through the possibilities to diagnose the problem. "Camera failed to perform" doesn't look the right explanation to me.
08-23-2009, 09:48 PM   #38
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Surprising that the cameras failed to perform under those conditions. Not had a problem with the K200 as of yet, but I'll surely be watching for it.

Wheatfield, I'm sorry you've experienced these issues, and I want to thank you for sharing your experience. These situations may be something the rest of us will NEED to be aware of in the future.

Having upgraded from the K1000 straight to digital gives me an advantage here. I'm accustomed to manual focus on-the-fly from my newspaper days.

08-23-2009, 09:58 PM   #39
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I have experienced what Wheatfield has described while using AF. K10/20 both will do the same thing. Trying to lock focus at times either camera will focus to infinity then close back and forth never locking focus. When you do get it to finally lock on something the shutter will not fire. I do not use AF that often but I have been in the same boat.

What I have always attributed the cause for this to happen was having the shutter button doing to many functions at once. I have only recently turned off the link between the shutter button and the AF. I can not say for certain but so far I haven't been able to reproduce the problem after freeing up the shutter button from autofocus duties. Using the AF button seems to work much better.
08-24-2009, 12:57 AM   #40
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QuoteOriginally posted by PDL Quote
Here is the what? part. There is the same focus swithc AF-S, AF-C, M on all of my Pentax DSLR's. What switch are you talking about.
*istDS
K10D
K20D
The button slides, not twist. I think this would be much more convenient. Yes, it would need to be a three position switch to account for MF, AF-C, and AF-S.



Thank you
Russell
08-24-2009, 01:33 AM   #41
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like the *istD.






QuoteOriginally posted by Russell-Evans Quote
The button slides, not twist. I think this would be much more convenient. Yes, it would need to be a three position switch to account for MF, AF-C, and AF-S.



Thank you
Russell
08-24-2009, 02:10 AM   #42
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Sliding and twisting buttons are both sucky. This kind of knob would be much more usable:


Like synthesizer filter knob but with three steps. Digital cameras are boring because there are not enough knobs to turn.
08-24-2009, 02:24 AM   #43
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QuoteOriginally posted by séamuis Quote
like the *istD.

That would be the ticket.

Thank you
Russell
08-24-2009, 02:25 AM   #44
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QuoteOriginally posted by Maffer Quote
Sliding and twisting buttons are both sucky. This kind of knob would be much more usable:


Like synthesizer filter knob but with three steps. Digital cameras are boring because there are not enough knobs to turn.

Mine would go up to eleven.

Thank you
Russell
08-24-2009, 03:04 AM   #45
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Wheatfield, I can certainly relate to your issue as I've had my cameras do this to me multiple times. This is indeed an annoying issue but after rolling my K20 and K10 counters multiple times, I've learned to quickly force the camera to relock AF by repressing the shutter halfway down and to pre-focus to the closest spot then refocus on the intended target.

It doesn't always work, but it has certainly made it less frequent of an issue, particularly at weddings where most ceremonies are predictable/planned in advance.

Do you have catch in-focus on? It can help, though this as well can be a PITA in low-light.

I've debated on adding an LED light to my cameras, somehow attached to my flash unit, though I haven't found one that doesn't look like a coal-miner's attachment.
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