Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Nov 26, 2010, 6:32 PM   #1
Senior Member
 
Join Date: Jan 2010
Location: Western Ma. USA
Posts: 795
Default Am I asking for the best of both worlds?

I have the Pentax K-r.

My situation:

I usually have the camera set to AF-A (which is usually set to AF-S). I also usually have the AF point set to center (so that i can manually choose what i want in focus). Then, I will re-frame the subject after gaining the proper focus point. That is my preference.

My question:
Is it possible (probably with another setting) to still use the center focus point only, then have the camera "lock" into that subject point so when i re-frame the camera, focus will stay on what i had pre-selected even if the subject changes distances?

What i am most interested in this function for is taking photos of people. I pre-focus on their eyes, then i re-frame properly, and take the photo. But if they move even slightly forwards or backwards, the focus point changes and everything is wrong. For people photos, i am mostly using my 50mm f1.4 set at the top 2-3 stops. So a small change in distance will obviously change the focus a lot.

Any help would be appreciated. I am afraid of the answer though.
__________________
ewheeler20 is offline   Reply With Quote
Sponsored Links
Old Nov 26, 2010, 6:38 PM   #2
Senior Member
 
MadMikeSS's Avatar
 
Join Date: Jul 2006
Location: Kenmore, NY
Posts: 743
Default

I'm assuming since it's the K-r, being the more entry level model, that you don't have a setting to select your AF point. My K20D has the option, so you just select the focus point closest to where you want to focus on and instead of having to recompose you can just fire off the shot and it'll keep the point on the target the whole time... But if you don't have that option with the K-r then recompose may be your only hope...
__________________
~MadMikeSS~
PPG Page
MadMikeSS is offline   Reply With Quote
Old Nov 26, 2010, 6:56 PM   #3
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,234
Default

According to the spec sheet, the camera does have selectable AF points, so, if you have the time (portrait work, I'm guessing), you should be able to select the AF point nearest the subject's eyes, and use that.

brian
VTphotog is offline   Reply With Quote
Old Nov 26, 2010, 10:19 PM   #4
Senior Member
 
snostorm's Avatar
 
Join Date: Jan 2004
Location: Chicago Suburb, IL, USA
Posts: 2,770
Default

Hi ewheeler20,

As Brian stated, the K-r has 11 selectable focus points, and it also has the LED overlay indicators that light up to show which one that has been selected. The full 11 focusing points are only available for the F and FA 50 f1.4 (Auto Focus) lens models though, so if yours is a manual focus only lens, you can only use the Center Point te get an automatic focus confirmation.

As you mentioned, at wide apertures this might not be accurate enough using ceter point focus and recompose.

Scott
snostorm is offline   Reply With Quote
Old Nov 26, 2010, 10:59 PM   #5
Senior Member
 
Join Date: Jan 2010
Location: Western Ma. USA
Posts: 795
Default

thanks for the responses, but i did already know about the selectable AF points. Unfortunately its not really a 'fast enough' solution for what i need. I am not shooting studio style portraits, i am shooting family get-together shots as people mingle and move around.

So the composition is not consistent enough, which would result in my choosing a different AF point between each shot... but the odds are, in that time the person as probably already moved. (we're fast).

I was really just hoping i had missed a setting on my menu, lol.
__________________
ewheeler20 is offline   Reply With Quote
Old Nov 27, 2010, 12:43 AM   #6
Senior Member
 
snostorm's Avatar
 
Join Date: Jan 2004
Location: Chicago Suburb, IL, USA
Posts: 2,770
Default

Hi ewheeler,

Everything like this is a matter of developing technique, IMO.

In the old days, for example, street shooters would eyeball lighting conditions, set the aperture and shutter speed while bringing the camera up to their eye, and only have to make minor focus corrections because they had already set up the focus by approximating the distance -- this was with fully manual cameras and lenses. The camera would be ready to take the shot almost instantaneously, and all the photographer had to do was frame the shot. . .I was always amazed at the guys who could do this. . .

With the K-r, you can program the green button to reset your selectable focus point to the center, then you can preset the focus point by feel, pushing the buttons as you bring the camera up to your eye. From the center point, it only takes a max of two button presses to go to any other focus point on the grid. It's really a matter of developing a drill where you automatically return to center after any series of shots, then get used to using the direction buttons without looking through the viewfinder.

Scott
snostorm is offline   Reply With Quote
Old Nov 28, 2010, 6:11 PM   #7
Senior Member
 
thkn777's Avatar
 
Join Date: Jun 2004
Location: Germany
Posts: 1,831
Default

Errm, can't you just press the shutter half-way, thus getting focus where you want, then - while still pressing the shutter half way down - reframe/compose and then take the image by pressing the shutter fully?

I might miss something very basic here, but with your settings (AF-S and NOT(!) AF-C) this should be possible. As for speed - well, it might get more than one attempt and practise helps, too!

Afaik there is no other lock-focus-thingie that works the way you describe. Saw such a function for slow moving subjects in recent camera mobile phones, though.

Regards,
Th.

Last edited by thkn777; Nov 28, 2010 at 6:17 PM.
thkn777 is offline   Reply With Quote
Old Nov 28, 2010, 7:03 PM   #8
Senior Member
 
Join Date: Jan 2010
Location: Western Ma. USA
Posts: 795
Default

Quote:
Originally Posted by thkn777 View Post
Errm, can't you just press the shutter half-way, thus getting focus where you want, then - while still pressing the shutter half way down - reframe/compose and then take the image by pressing the shutter fully?
yes, and that is what i do now.... but if your subject that you had pre-focused on while reframing, moved towards or away from you slightly, the focus will be WRONG.
That is why i asked if my camera had some hidden function that i missed that would continually refocus on the subject that i had pre-focused on. That is DIFFERENT from the 11-point AF spots, and that is DIFFERENT from the AP-C setting.
__________________
ewheeler20 is offline   Reply With Quote
Old Nov 28, 2010, 8:00 PM   #9
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,234
Default

You could adapt the gun camera from an F-16. Other than that, I don't think cameras have developed to that point yet. brian
VTphotog is offline   Reply With Quote
Old Nov 28, 2010, 11:33 PM   #10
Senior Member
 
VTphotog's Avatar
 
Join Date: Mar 2005
Location: Extreme Northeastern Vermont, USA
Posts: 4,234
Default

You could probably do what you want with the K-5. It has Face Recognition, which might work with AF-C, though I don't think it can really tell one face from another. brian
VTphotog is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 6:38 AM.