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12-08-2009, 10:06 PM   #1
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Focus Question - New to Photography

Here's the situation, I just got my first tripod. I am trying to take a self portrait. And I set the timer to 12 sec. My question is lets say I press shoot, and then move to the desired position. How will the camera know to focus in to my position rather than then wall that way behind when I pressed shoot. I am new to photography and just got my K-x.

Thank You!

12-08-2009, 10:22 PM   #2
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The camera guesses. It has several points in the frame where it checks for high contrast, like the edge of something. (I forget how many points the K-x has, 9 or 11.) It looks at the data from each point, then uses some logic to pick a likely point. Then it tells the lens what to do to get that point in focus.

The lens will actually have a range of distances in focus depending on what aperture is chosen. It's never just one point. The larger the aperture number is, the greater the range that's in focus. Also, the greater the distance from camera to subject, the greater the range in focus. This is called depth of field, and a full discussion of it would cover at least a chapter in a book, so I'm just giving the high points here.

The camera also won't focus on most walls because they have no contrast. Try pointing the camera at a wall that's painted all one color with no texture. It will usually try and fail to focus.
12-08-2009, 10:42 PM   #3
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Thanks for the reply. I actually understand what you're saying. While I know the camera focuses when I hit the shoot button, does it refocus when I actually move to the desired area in front of the camera [this is on a 12 second timer] or does it stick to the initial focus point with me not in the picture.
12-08-2009, 10:44 PM   #4
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If the camera focuses when you trip the shutter, it will not refocus at the 12 second mark.

You may have to switch to manual focus to get a sharp picture.

12-08-2009, 10:47 PM   #5
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great, that is what I thought as I did not hear the focus motor running. Thank you guys for your help.
12-09-2009, 03:08 AM   #6
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QuoteOriginally posted by boodiespost Quote
great, that is what I thought as I did not hear the focus motor running. Thank you guys for your help.
What you can do is focus on the tripod hand-held from the spot you are going to stand at, then switch to manual focus mode and put the camera back on the tripod.
12-09-2009, 08:20 AM   #7
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Here's something that worked for me. I have a K7 so the big assumption here is that Kx has similar functionality. I think it does.

You can use a IR remote to take AF tripod self portrait. Just enable the AF with remote in the menus.

I don't have a Pentax IR remote but I do have a Palm with an IR sending capabilities. I found a Palm app here [URL="http://sourceforge.net/projects/prcf/"] that was developed for Pentax DSLRs and works with my Treo and other Palm devices. There maybe others out there as well.
12-09-2009, 10:31 AM   #8
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Yes, a remote is the way to go when tking self-portraits. There should be a custom option on the camera to control whether AF happens when you hit the button on the remote or not; you'd want to make sure it does.

12-09-2009, 12:09 PM   #9
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great, I already spent so much on the camera, bags, filter, batts, etc hahaha, I'll keep these info in mind thanks for all the help.
12-09-2009, 12:58 PM   #10
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Go to the store and return the filters - assuming you mean UV "protective" (as in, they protect the stores profit margin) filters, they were a waste of money. That should net you enough to buy the remote.
12-09-2009, 01:14 PM   #11
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AF-C

I haven't tried a self-portrait, but wouldn't AF-C (continuous AF) work? When the subject moves into the frame and sits down, the camera should re-focus, assuming that you sit in the portion of the frame that the camera is set to focus on?
12-09-2009, 09:55 PM   #12
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QuoteOriginally posted by Marc Sabatella Quote
Go to the store and return the filters - assuming you mean UV "protective" (as in, they protect the stores profit margin) filters, they were a waste of money. That should net you enough to buy the remote.
what about the protection of my kit lens? isn't that important? please let me know as I can still return it if I need to.



ps - i will try AFC and let you guys know
12-09-2009, 10:35 PM   #13
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This cheapie from DX works for me DealExtreme: $3.27 InfraRed IR Shutter Remote for Pentax/Nikon/Canon/Sony/Minolta/Konica Digital Cameras (1*CR2025)
12-09-2009, 11:13 PM   #14
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oh great, thanks for that. That is real cheap.

ps - what distance will that remote work from? a foot, 6 feet or 12 feet? etc..

Last edited by boodiespost; 12-09-2009 at 11:49 PM.
12-10-2009, 12:48 AM   #15
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Just gave it a try at about 30 feet and it worked fine
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