Precision focusing - Possible?

HOLLYW00D · 12-01-2013, 01:26 PM

Howdy, I'm having an issue focusing on the exact spot I'd like. I am using Spot as my AF selection, and it seems like the camera/lens rarely wants to focus on what the AF indicator is on. Instead, it generally focuses on something else, within the ( ) etchings on the screen. This is more pronounced when using a shorter focal length lens shooting subject farther than ten feet away, since the desired point of focus gets smaller within the ( ) area. Am I wrong to think that the exact focus point should be within the red rectangular indicator in the viewfinder? Thanks in advance.

i83N · 12-01-2013, 02:05 PM

I think you talk about two separate things. first "spot" is metering, metering nob located under program selector on K5, AF point selector is under your right hand thumb. Second I think you having front and back focus problems.

**jatrax** · 12-01-2013, 02:22 PM

Originally posted by HOLLYW00D

Am I wrong to think that the exact focus point should be within the red rectangular indicator in the viewfinder?

The red dot (or square) is just an indicator for which AF area is being used. It is NOT the size of the AF area. I think people get confused because it is called a point but it is not, it is an area. And the camera can focus on anything within that area. On the k-5 it is generally recognized that anything within the () brackets is fair game for the center point sensor. Not ideal and one of the things most disliked about the k-5, but it is what it is.

HOLLYW00D · 12-01-2013, 02:34 PM

Does anyone know of a camera body, from any manufacturer, that would give me the precise focus "point" I long for? You can PM me if you don't want to blaspheme the names of other camera manufacturers.

**Miguel** · 12-01-2013, 03:01 PM

Originally posted by HOLLYW00D

Does anyone know of a camera body, from any manufacturer, that would give me the precise focus "point" I long for? You can PM me if you don't want to blaspheme the names of other camera manufacturers.

Well, my Canon 7D (and I assume most newer higher-end Canon bodies) has Spot-AF points that covers a smaller area to focus upon than the normal AF points. They don't have to be at the center of the frame. Very useful for macro work. This is an area where Pentax still lags.

M

HOLLYW00D · 12-01-2013, 03:42 PM

How do you guys "deal" with this behavior? Can I tweak my technique in a way to help mitigate this? Shoot at a higher (in number) aperture?

**Miguel** · 12-01-2013, 03:50 PM

Originally posted by HOLLYW00D

How do you guys "deal" with this behavior? Can I tweak my technique in a way to help mitigate this? Shoot at a higher (in number) aperture?

I'd suggest performing AF testing on each of them and fine-tune their performance with the in-body controls. That puts everything on a baseline.

M

HOLLYW00D · 12-01-2013, 05:22 PM

I feel like the lenses/camera are where they should be, it's just that I am (was? ...cooling off now) ready to throw in the towel. Below are a couple of samples where the images are sharp where I want them to be, but if the subjects were farther away, trying to select a focus point using the center indicator, is futile.

**jatrax** · 12-01-2013, 08:07 PM

Originally posted by HOLLYW00D

How do you guys "deal" with this behavior? Can I tweak my technique in a way to help mitigate this? Shoot at a higher (in number) aperture?

Higher aperture number (smaller aperture) will give you more depth of focus and make it easier to hit focus, but that may not be what you want. I generally use manual focus when I want it right, you cannot expect the camera to know what you are focusing on when the depth of focus is so thin.

Another method is to use live view and zoom in. Put the camera on a tripod and using live view you can nail the focus wherever you want. Slower, but effective.

HOLLYW00D · 12-01-2013, 10:21 PM

Thank you all for the suggestions. You've definitely helped settle my uneasiness.

Wired · 12-19-2013, 06:11 PM

you could also try the technique I've outlined here:

https://www.pentaxforums.com/forums/38-photographic-technique/236970-perfect-...ml#post2508511

however, for this specific situation, manual focus would be my suggested focusing method.

**TER-OR** · 12-20-2013, 08:45 AM

learn how the focus points behave, keep your aperture stopped down for most purposes. When there's enough light, that's easy....

adwb · 12-21-2013, 12:35 AM

Can I suggest you take a sheet of blank paper draw a small round or square mark on it and preferably with the camera on a tripod try to see how far away from the Mark you made the red spot is before it stops locking the focus on the spot? You will soon see that you can be some distance away and that's why we get focus problems.

It is in the end a AUTO function and no one claims them to be perfect just like the AUTO exposure settings.

All is not lost however , there is a almost forgotten technique you can use, it is often as fast as the auto but does need good eyesight and to have the viewfinder diopter adjustment carefully set so the etched lines are absolutely sharp.

What you then do is use MANUAL focus

12-01-2013, 01:26 PM	#1
HOLLYW00D New Member Join Date: May 2011 Location: Wisconsin Posts: 17	Precision focusing - Possible? Howdy, I'm having an issue focusing on the exact spot I'd like. I am using Spot as my AF selection, and it seems like the camera/lens rarely wants to focus on what the AF indicator is on. Instead, it generally focuses on something else, within the ( ) etchings on the screen. This is more pronounced when using a shorter focal length lens shooting subject farther than ten feet away, since the desired point of focus gets smaller within the ( ) area. Am I wrong to think that the exact focus point should be within the red rectangular indicator in the viewfinder? Thanks in advance.

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12-01-2013, 02:05 PM	#2
i83N Veteran Member Join Date: Mar 2009 Location: Lithuania Photos: Gallery Posts: 1,203	I think you talk about two separate things. first "spot" is metering, metering nob located under program selector on K5, AF point selector is under your right hand thumb. Second I think you having front and back focus problems.

12-01-2013, 02:22 PM	#3
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by HOLLYW00D Am I wrong to think that the exact focus point should be within the red rectangular indicator in the viewfinder? The red dot (or square) is just an indicator for which AF area is being used. It is NOT the size of the AF area. I think people get confused because it is called a point but it is not, it is an area. And the camera can focus on anything within that area. On the k-5 it is generally recognized that anything within the () brackets is fair game for the center point sensor. Not ideal and one of the things most disliked about the k-5, but it is what it is.

12-01-2013, 02:34 PM	#4
HOLLYW00D New Member Join Date: May 2011 Location: Wisconsin Posts: 17 Original Poster	Does anyone know of a camera body, from any manufacturer, that would give me the precise focus "point" I long for? You can PM me if you don't want to blaspheme the names of other camera manufacturers.

12-01-2013, 03:01 PM	#5
Miguel Site Supporter Join Date: Sep 2007 Location: Near Seattle Photos: Gallery Posts: 2,743	Originally posted by HOLLYW00D Does anyone know of a camera body, from any manufacturer, that would give me the precise focus "point" I long for? You can PM me if you don't want to blaspheme the names of other camera manufacturers. Well, my Canon 7D (and I assume most newer higher-end Canon bodies) has Spot-AF points that covers a smaller area to focus upon than the normal AF points. They don't have to be at the center of the frame. Very useful for macro work. This is an area where Pentax still lags. M

12-01-2013, 03:42 PM	#6
HOLLYW00D New Member Join Date: May 2011 Location: Wisconsin Posts: 17 Original Poster	How do you guys "deal" with this behavior? Can I tweak my technique in a way to help mitigate this? Shoot at a higher (in number) aperture?

12-01-2013, 03:50 PM	#7
Miguel Site Supporter Join Date: Sep 2007 Location: Near Seattle Photos: Gallery Posts: 2,743	Originally posted by HOLLYW00D How do you guys "deal" with this behavior? Can I tweak my technique in a way to help mitigate this? Shoot at a higher (in number) aperture? I'd suggest performing AF testing on each of them and fine-tune their performance with the in-body controls. That puts everything on a baseline. M

12-01-2013, 05:22 PM	#8
HOLLYW00D New Member Join Date: May 2011 Location: Wisconsin Posts: 17 Original Poster	I feel like the lenses/camera are where they should be, it's just that I am (was? ...cooling off now) ready to throw in the towel. Below are a couple of samples where the images are sharp where I want them to be, but if the subjects were farther away, trying to select a focus point using the center indicator, is futile.

12-01-2013, 08:07 PM	#9
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by HOLLYW00D How do you guys "deal" with this behavior? Can I tweak my technique in a way to help mitigate this? Shoot at a higher (in number) aperture? Higher aperture number (smaller aperture) will give you more depth of focus and make it easier to hit focus, but that may not be what you want. I generally use manual focus when I want it right, you cannot expect the camera to know what you are focusing on when the depth of focus is so thin. Another method is to use live view and zoom in. Put the camera on a tripod and using live view you can nail the focus wherever you want. Slower, but effective.

12-01-2013, 10:21 PM	#10
HOLLYW00D New Member Join Date: May 2011 Location: Wisconsin Posts: 17 Original Poster	Thank you all for the suggestions. You've definitely helped settle my uneasiness.

12-19-2013, 06:11 PM	#11
Wired Veteran Member Join Date: Aug 2009 Location: Edmonton, AB Photos: Gallery \| Albums Posts: 2,519	you could also try the technique I've outlined here: https://www.pentaxforums.com/forums/38-photographic-technique/236970-perfect-...ml#post2508511 however, for this specific situation, manual focus would be my suggested focusing method.

12-20-2013, 08:45 AM	#12
TER-OR Site Supporter Join Date: Apr 2009 Location: Dundee, IL Photos: Gallery \| Albums Posts: 6,699	learn how the focus points behave, keep your aperture stopped down for most purposes. When there's enough light, that's easy....

12-21-2013, 12:35 AM	#13
adwb Veteran Member Join Date: Sep 2009 Location: Bristol UK Photos: Gallery Posts: 1,636	Can I suggest you take a sheet of blank paper draw a small round or square mark on it and preferably with the camera on a tripod try to see how far away from the Mark you made the red spot is before it stops locking the focus on the spot? You will soon see that you can be some distance away and that's why we get focus problems. It is in the end a AUTO function and no one claims them to be perfect just like the AUTO exposure settings. All is not lost however , there is a almost forgotten technique you can use, it is often as fast as the auto but does need good eyesight and to have the viewfinder diopter adjustment carefully set so the etched lines are absolutely sharp. What you then do is use MANUAL focus