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09-05-2009, 04:57 AM   #61
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QuoteOriginally posted by PDL Quote
So each time you pushed the shutter button the camera tries to focus? On the "hand off" just why not focus on the groom and blast away -- after de-coupling AF from the shutter button.

With de-coupling -- you decide when the camera will focus - not the other way around. With Pentax lenses you can use manual focus function and just blast away.

AF-C will not allow the camera to shoot without shutter button (or AF button) confirmation. However, once I let got of the AF button (OK button on the *istDs) and I push the shutter - the camera captures an image. I decide when the camera shoots - not the AF function.

Do those people really move that much that the system would have to refocus the entire image?
Good tips, duly noted
QuoteOriginally posted by PDL Quote
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.



QuoteOriginally posted by jbinpg Quote
I have gone both ways on the AF button on my K20. I started with the AF on the shutter button then went to the AF button to focus for a while. I eventually returned to the shutter button with the AF button to disable AF. For those times when the camera refuses to lock focus, I just hit the AF kill button and focus manually. Better than missing a shot.
I'll try this one as well. Need to experiment some more


QuoteOriginally posted by stevebrot Quote
This is one of the best tricks available on the Pentax cameras...a bit of a hack, but a neat trick even though.

I was about three lines into Wheatfield's original message when I figured out what the core of the rant was going to be. In my opinion, missed focus/missed shot is the "dirty little secret" of AF photography. I have brought the issue up to various photographers and most have sheepishly admitted to using manual focus when they could not risk missing the shot. This is the case regardless of the brand of camera used.

The matter also came up at the K7 road trip stop here in Portland. The guy behind me asked Mark Dimalanta whether he used AF for his surfing and other sports shots. The answer? Often not. Don't quote me, but I also believe that he said that he uses Russel's trick for fast breaking action (AF-S to lock focus followed by burst exposures).

The comment about having a back-up shooter is also well-taken. I have been at several weddings and receptions where more than one camera/shooter was used for "can't mess up" shots such as the toast.
Thanks, good info



Thanks for the links




To the OP :
The 31 limited doesn’t have the fastest focus. So not surprised how it could act up. But a shame to hear that the DA* 55/1.4 was causing trouble.
In any case; I’ve also read of wedding and ceremonies, where a team of 3-4 photographers covers the event. So even if one doesn’t nail the shot, others might have gotten it

09-05-2009, 01:50 PM   #62
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QuoteOriginally posted by jbinpg Quote
I have gone both ways on the AF button on my K20. I started with the AF on the shutter button then went to the AF button to focus for a while. I eventually returned to the shutter button with the AF button to disable AF. For those times when the camera refuses to lock focus, I just hit the AF kill button and focus manually. Better than missing a shot.
What lenses are you using here?
If I set my K20D up like this with the FA LTDs, using the AF button to disable focus does not decouple the screw drive, I still can't manually focus the lens without resetting the switch to MF, or am I missing something? With the DA lenses with quick shift I just use the AF button to auto focus or not to manually focus. I don't see the purpose here.
09-05-2009, 02:28 PM   #63
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QuoteOriginally posted by Eaglerapids Quote
What lenses are you using here?
using the AF button to disable focus does not decouple the screw drive
On my K10D no button can decouple screw drive from the lens, its a mechanical operation done with the AF/MF switch.

Dont think its different on other bodies.
09-05-2009, 03:16 PM   #64
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I realize this ilya and that's why I'm wondering what jbinpg's reasons are for setting his camera up like that. I may very well be missing something here but I don't know what:-). Why kill AF with the AF button when at least with FA lenses you can't manually focus them without changing the mechanical switch which would be a major pain to do in the heat of the moment like Wheatfield found himself in. I haven't come across this problem but if we were using a DA lens with quick shift and the focus refused to lock automatically, I would think we could manual focus with the lens and achieve lock without killing the AF with the AF button. On the other hand I can see someone setting their camera up with a half press of the shutter button to focus and then killing it with the AF button if for instance they wanted to manually focus on someplace different than where the camera set focus, like a bird behind some branches in a tree. But that's a bit different scenario than Wheatfield's, he couldn't achieve focus lock. But, my point and original question, how would killing AF with the AF button help to manual focus a FA lens in Wheatfield's case?

Well, ok, if we were using a DA lens with quich shift and we changed focus and then went to take the picture, I suppose the camera could try to refocus since in this instance we have AF set to half press of the shutter button. BUT, if we achieved focus lock with the quick shift the camera shouldn't try to change focus when we hit the shutter button.

Another thing. I must say this highlights a disadvantage of the FA lenses, especially the FA Limiteds compared to the DA Limiteds or probably a better way to state it, the one big advantage of the DA line of lenses.....quick shift. It is pretty cool. I personally have spent a lot of money on focusing screens and have practiced a LOT on my manual focus abilities because I just naturally prefer to manual focus, but that's me and how I like to do things. But there are times when you need autofocus and you need it now and it's a big disappointment if it lets you down. On the other hand, I can imagine the shot Wheatfield had with his 31Ltd on the camera and I can't think of any other lens I would have prefered other than it. We aren't perfect, neither is our equipment. Shots will be missed. But when you get one with the 31 you know there isn't another lens around that would have done the job better.


Last edited by Eaglerapids; 09-05-2009 at 03:40 PM.
09-05-2009, 03:16 PM   #65
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Sorry, I should have specified: Hitting the AF button to cancel AF works with my DA* 300/4 with the SDM AF. However, this thread has led me to go back to decoupling the shutter button from AF and using the AF button to focus again. This method certainly has its advantages.

Jack
09-05-2009, 03:53 PM   #66
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QuoteOriginally posted by Eaglerapids Quote
I realize this ilya and that's why I'm wondering what jbinpg's reasons are for setting his camera up like that. I may very well be missing something here but I don't know what:-).
It can be very useful in AF.C mode, to stop the AF from changing if you want to recompose, for instance.
09-05-2009, 05:02 PM   #67
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QuoteOriginally posted by ilya80 Quote
On my K10D no button can decouple screw drive from the lens
Wrong answer. There is one button that will do it. Not very obvious, but pushing the lens release button will decouple the screw drive and allow you to manually focus. You still have to be careful so you don't remove the lens, but it works.
09-05-2009, 11:45 PM   #68
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QuoteOriginally posted by ilya80 Quote
On my K10D no button can decouple screw drive from the lens, its a mechanical operation done with the AF/MF switch.

Dont think its different on other bodies.
True, but lenses with Quick-shift act like the AF is decoupled when focus is not moving.

09-05-2009, 11:52 PM   #69
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QuoteOriginally posted by Wheatfield Quote
I tried AF-C during the processional (it was VERY slow moving so I was able to make adjustments to the camera, something I try to avoid), but found that the camera wasn't following the subject accurately.
I should have just switched the AF off completely.
Live and learn.
Fortunately, I don't shoot weddings very often.

Pentax has a way to go in the AF department still. This isn't really surprising, they are still using what is essentially an 8 year old AF system.
I know you're already under the hammer here, but you really shouldn't be testing things out at the event. You should be aware of the camera's performance in the situation and prepare for it, I'm surprised you didn't know the K20D was not a stellar performer indoors.

I've experienced the green light blinking/lighting up to confirm focus but not firing the shot on the K100D, but it comes without the beep.

Btw, AF in the K7 is greatly improved vs K10/20, I'm guessing you'd have noticed that too.
09-06-2009, 05:17 PM   #70
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QuoteOriginally posted by RBellavance Quote
It can be very useful in AF.C mode, to stop the AF from changing if you want to recompose, for instance.
I hadn't thought of that, good one.
09-08-2009, 09:46 PM   #71
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QuoteOriginally posted by rparmar Quote
Good lord, man, that's not a knob, it's a rotary potentiometer!



P.S. I use MF when the going gets tough. Best thing Pentax could do for me would be to provide a setting for catch-in-focus when using AF lenses.
They introduced it with the K20 - leave the body in AF.S and turn the lens to MF. I wish they could back firmware my K10 to work like that. I would love CIF with the 50-135. I used the 70-210 and AF.S with the MZ-S for years.
09-08-2009, 11:35 PM   #72
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QuoteOriginally posted by flyer Quote
Wrong answer. There is one button that will do it. Not very obvious, but pushing the lens release button will decouple the screw drive and allow you to manually focus. You still have to be careful so you don't remove the lens, but it works.
o_O
Best trick ever, I'll keep it in mind, thank you!
09-09-2009, 04:46 AM   #73
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QuoteOriginally posted by Canada_Rockies Quote
They introduced it with the K20 - leave the body in AF.S and turn the lens to MF.
I have many lenses but none that turn to MF.
09-09-2009, 02:44 PM   #74
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QuoteOriginally posted by flyer Quote
Wrong answer. There is one button that will do it. Not very obvious, but pushing the lens release button will decouple the screw drive and allow you to manually focus. You still have to be careful so you don't remove the lens, but it works.
Be careful using this technique panning a fast car or the like - I can just see the lens being flung off the camera as fast as the car flies past...
09-20-2009, 06:56 PM   #75
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QuoteOriginally posted by rparmar Quote
I have many lenses but none that turn to MF.
The DA* 300/4 has a mf/af switch on it and now I'm beginning to understand why.
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