Weird focus issue.

dwinnert · 05-22-2007, 01:21 PM

I am new to the K10D so bare with me.

I am using the 40 Limited .

If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using.

If I manually choose the focus point...it is tack sharp.

This only seems to be an issue when I am in the 3-4' range. Farther shots always seem to properly focus on the auto chosen focus point.

Anyone else see this?

Thanks.

pschlute · 05-22-2007, 01:51 PM

I have the DS and have the same with the 40mm and other lenses. Close up they all seem to bf or ff sometimes, and pick perfect focus other times.

I have been down the route of the focus test chart and adjusting focus through the debug menu, and to be honest...dont bother. It is apparent to me that the autofocus is a bit wayward close up and varies per lens. To test this put your camera on a tripod in front of a clear contrasty subject and keep getting it to autofocus while you watch the lens distance markings. You will be surprised at the variance.

The secret is to manually focus close up....the quick focus system was not invented for nought.

You will not notice the misfocus (if it exists) on longer distances as the depth of field will bet hat much greater.

benjikan · 05-22-2007, 01:53 PM

Originally posted by dwinnert

I am new to the K10D so bare with me.

I am using the 40 Limited .

If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using.

If I manually choose the focus point...it is tack sharp.

This only seems to be an issue when I am in the 3-4' range. Farther shots always seem to properly focus on the auto chosen focus point.

Anyone else see this?

Thanks.

I haven't had a problem with my 40. But I am on my third 21mm Limited and I do have a sililar problem with it. Whe MF it is fine...

blende8 · 05-23-2007, 12:24 AM

Originally posted by dwinnert

If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using.

One thing you have to keep in mind is that the actual AF sensors are much larger than the little red squares. So, if there is something close by with good contrast, perhaps the camera focusses there.

dwinnert · 05-23-2007, 07:14 AM

That actually makes since. Have you ever come across a drawing or picture showing the true focus pattern?

Thanks

Dave

Originally posted by blende8

One thing you have to keep in mind is that the actual AF sensors are much larger than the little red squares. So, if there is something close by with good contrast, perhaps the camera focusses there.

blende8 · 05-23-2007, 08:28 AM

This is of the ist*, but the K10D is similar:
(taken from a German advertisement)

BigMac · 05-23-2007, 11:32 PM

Originally posted by dwinnert

I am new to the K10D so bare with me.

I am using the 40 Limited .

If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using.

If I manually choose the focus point...it is tack sharp.

This only seems to be an issue when I am in the 3-4' range. Farther shots always seem to properly focus on the auto chosen focus point.

Anyone else see this?

Thanks.

Hi dwinnert,

I assume you were doing your indoor shooting, the camera's green full auto focusing system is difficult to focus under indoor low light, I suggest that you turn the focus selection gear dial to SEL, then select the center focus point or any focus point you wish by pressing any of the 4 arrows, it will focus much quicker for you because you force the camera to focus where you want it to. If the indoor lighting is extremely uneven, like some ballroom or banquet room, I turned the metering ring to center metering, force the camera only meter at the center where I want it to meter, smaller metering area, less confusion.

I like to leave it at the center after I moved to SEL, because if I need to recompose, all I have to do just keep my finger halfway press after focus locked, then move the camera a little to the left or right, then shoot, it works perfectly for me. But you need to go to the menu camera setting section, there are 6 pages there, select page 2 or 2nd screen, select ON at the "AE-L with AF Locked" line, by default Pentax sets it OFF. IF you don't change the setting, you'll have difficult time to recompose your shot, the view finder will blink because the AE is not locked with focus.

Well, I hope it works for you, like one of those commercial...."Try it, you will like it". If you start thinking about it, that is why the K10D comes with 2 easy access metering dial and focus dial where your right thumb and left finger can reach easily.... That is another reason I bought mine other than ATV mode and SR.

blende8 · 05-23-2007, 11:45 PM

Originally posted by BigMac

I like to leave it at the center after I moved to SEL, because if I need to recompose, all I have to do just keep my finger halfway press after focus locked, then move the camera a little to the left or right, then shoot, it works perfectly for me.

This does not work, because by recomposing you are changing the distance, normally.
Check here:
Kamera-Digital.com :: Indonesia Digital Camera :: Tips & Tricks :: Why recomposing with AF cameras is a bad idea

and here, for an explanatory image:
Don't recompose!
(text German, but image is self-explanatory)

BigMac · 05-24-2007, 12:25 AM

Originally posted by blende8

This does not work, because by recomposing you are changing the distance, normally.
Check here:
Kamera-Digital.com :: Indonesia Digital Camera :: Tips & Tricks :: Why recomposing with AF cameras is a bad idea

and here, for an explanatory image:
Don't recompose!
(text German, but image is self-explanatory)

The website that you showing us is a fine example, but, in real world, an experience photographer would not recompose like the website was demonstrating, we would "Move" the camera a hair to the left or the right, so the subject would not be at the boring dead center. Not "Turn" the camera like the website was demonstrating. There is a big difference by "Moving" or "Turning" the camera. By moving a few hair, you keep the same distance, only need to lock the exposure, even if the distance is slightly off, it is not noticeable, you can always fine tune it with software. By "Turning", you distance is off... Way off. Focus will be OFF like the website demonstrated. I'm glad that you brought it up though, it is a very good advise for all of us. So we all can improve our skill.

05-22-2007, 01:21 PM	#1
dwinnert Senior Member Join Date: May 2007 Posts: 107	Weird focus issue. I am new to the K10D so bare with me. I am using the 40 Limited . If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using. If I manually choose the focus point...it is tack sharp. This only seems to be an issue when I am in the 3-4' range. Farther shots always seem to properly focus on the auto chosen focus point. Anyone else see this? Thanks.

05-22-2007, 01:51 PM	#2
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,210	Focus I have the DS and have the same with the 40mm and other lenses. Close up they all seem to bf or ff sometimes, and pick perfect focus other times. I have been down the route of the focus test chart and adjusting focus through the debug menu, and to be honest...dont bother. It is apparent to me that the autofocus is a bit wayward close up and varies per lens. To test this put your camera on a tripod in front of a clear contrasty subject and keep getting it to autofocus while you watch the lens distance markings. You will be surprised at the variance. The secret is to manually focus close up....the quick focus system was not invented for nought. You will not notice the misfocus (if it exists) on longer distances as the depth of field will bet hat much greater.

05-22-2007, 01:53 PM	#3
benjikan Veteran Member Join Date: Jan 2007 Location: Paris, France Photos: Gallery Posts: 4,308	21 Limited Originally posted by dwinnert I am new to the K10D so bare with me. I am using the 40 Limited . If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using. If I manually choose the focus point...it is tack sharp. This only seems to be an issue when I am in the 3-4' range. Farther shots always seem to properly focus on the auto chosen focus point. Anyone else see this? Thanks. I haven't had a problem with my 40. But I am on my third 21mm Limited and I do have a sililar problem with it. Whe MF it is fine...

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05-23-2007, 12:24 AM	#4
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	Originally posted by dwinnert If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using. One thing you have to keep in mind is that the actual AF sensors are much larger than the little red squares. So, if there is something close by with good contrast, perhaps the camera focusses there.

05-23-2007, 07:14 AM	#5
dwinnert Senior Member Join Date: May 2007 Posts: 107 Original Poster	That actually makes since. Have you ever come across a drawing or picture showing the true focus pattern? Thanks Dave Originally posted by blende8 One thing you have to keep in mind is that the actual AF sensors are much larger than the little red squares. So, if there is something close by with good contrast, perhaps the camera focusses there.

05-23-2007, 08:28 AM	#6
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	This is of the ist*, but the K10D is similar: (taken from a German advertisement)

05-23-2007, 11:32 PM	#7
BigMac New Member Join Date: May 2007 Location: Las Vegas, NV Posts: 17	Originally posted by dwinnert I am new to the K10D so bare with me. I am using the 40 Limited . If I choose auto focus point and it selects an area to focus on, it never seems to be spot on with it's chosen focus point. Almost like there is a little BF/FF or the highlighted focus point is really not the one the camera is using. If I manually choose the focus point...it is tack sharp. This only seems to be an issue when I am in the 3-4' range. Farther shots always seem to properly focus on the auto chosen focus point. Anyone else see this? Thanks. Hi dwinnert, I assume you were doing your indoor shooting, the camera's green full auto focusing system is difficult to focus under indoor low light, I suggest that you turn the focus selection gear dial to SEL, then select the center focus point or any focus point you wish by pressing any of the 4 arrows, it will focus much quicker for you because you force the camera to focus where you want it to. If the indoor lighting is extremely uneven, like some ballroom or banquet room, I turned the metering ring to center metering, force the camera only meter at the center where I want it to meter, smaller metering area, less confusion. I like to leave it at the center after I moved to SEL, because if I need to recompose, all I have to do just keep my finger halfway press after focus locked, then move the camera a little to the left or right, then shoot, it works perfectly for me. But you need to go to the menu camera setting section, there are 6 pages there, select page 2 or 2nd screen, select ON at the "AE-L with AF Locked" line, by default Pentax sets it OFF. IF you don't change the setting, you'll have difficult time to recompose your shot, the view finder will blink because the AE is not locked with focus. Well, I hope it works for you, like one of those commercial...."Try it, you will like it". If you start thinking about it, that is why the K10D comes with 2 easy access metering dial and focus dial where your right thumb and left finger can reach easily.... That is another reason I bought mine other than ATV mode and SR.

05-23-2007, 11:45 PM	#8
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	Originally posted by BigMac I like to leave it at the center after I moved to SEL, because if I need to recompose, all I have to do just keep my finger halfway press after focus locked, then move the camera a little to the left or right, then shoot, it works perfectly for me. This does not work, because by recomposing you are changing the distance, normally. Check here: Kamera-Digital.com :: Indonesia Digital Camera :: Tips & Tricks :: Why recomposing with AF cameras is a bad idea and here, for an explanatory image: Don't recompose! (text German, but image is self-explanatory)

05-24-2007, 12:25 AM	#9
BigMac New Member Join Date: May 2007 Location: Las Vegas, NV Posts: 17	Originally posted by blende8 This does not work, because by recomposing you are changing the distance, normally. Check here: Kamera-Digital.com :: Indonesia Digital Camera :: Tips & Tricks :: Why recomposing with AF cameras is a bad idea and here, for an explanatory image: Don't recompose! (text German, but image is self-explanatory) The website that you showing us is a fine example, but, in real world, an experience photographer would not recompose like the website was demonstrating, we would "Move" the camera a hair to the left or the right, so the subject would not be at the boring dead center. Not "Turn" the camera like the website was demonstrating. There is a big difference by "Moving" or "Turning" the camera. By moving a few hair, you keep the same distance, only need to lock the exposure, even if the distance is slightly off, it is not noticeable, you can always fine tune it with software. By "Turning", you distance is off... Way off. Focus will be OFF like the website demonstrated. I'm glad that you brought it up though, it is a very good advise for all of us. So we all can improve our skill.