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12-09-2013, 05:21 AM   #1
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Possible Dumb Question

I have a question (hopefully it's not too dumb of a question) about my Pentax K1000SE. I know that if you want to maximize your depth of field, you should focus one-third of the way into a scene. How exactly would you go about doing this with the K1000SE since the focusing thingamabob (I know...not a technical term) is directly in the middle of the viewfinder when you look through it? Would you have to use the focus-and-recompose method?

12-09-2013, 05:38 AM   #2
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Wait wait wait. About manual focus:
a) You should always try to focus exactly on the subject. (either a person's eyes, or the mountain range in landscape, etc.)
b) Many older cameras have a big viewfinder (bigger than modern DSLR cameras) so MF is easier. They might also have a focus screen (microprism, split, matte, there are many kinds) - this emphasizes the out of focus character, and makes it easier to see when something is in-focus. This is a focus aid and can be useful, but you shouldnt let it limit you.
c) There are focus techniques like zone focusing. Zone focusing takes into account the Depth of field. The depth of field is the field that appears to be sharp and in-focus. The DoF gets wider when you have a higher f-number (narrower aperture). Many older lenses have DoF scales on the focus ring, so you can actually check your depth of field. A clever use of zone focusing is when you set the focus such that "the most" stuff is in-focus. This depends on the aperture you selected, and its called hyperfocal focusing. I think this is where the "focus one third in" comes from - it is a rule of thumb, but not super accurate.
d) Focus and recompose is a good technique, but may not be super accurate, since tilting the camera can change where the DoF is. It takes a lot of practice to get this technique right.

If you use AF, there are some focus points that the camera uses. The center one is usually the most accurate. Some cameras have viewfinder overlays to show you approximately where the AF point is, others do not. Cameras also have different numbers and types of focusing points. You can use this to AF, then lock focus and recompose and take the shot. But the same as d) applies here.

I mentioned a bunch of things related to focusing, and i hope that some of these will help you out. Not sure what exactly your question was, though. You can also find manuals and books on how to achieve focus (even video tutorials for hyperfocal focusing). Focus is very important in photography, so take the time
12-09-2013, 06:24 AM   #3
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Thank your for your help. I'll have to try out some of the things that you have suggested. I'm not used to dealing with a camera that does not have actual focus points and a camera with a viewfinder that you can only see part of a scene in. My other two cameras (Canon EOS Elan IIe and Canon EOS Rebel XSi) focuses differently than the K1000SE. Of course, I just bought the K1000SE so I haven't actually tried it out yet. Hopefully, once I start shooting with this camera, I'll get the hang of how to use it. It will just take a little time.
12-09-2013, 08:03 AM   #4
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I think you have two things mixed up here. Correct me if I'm wrong, but by "focusing a third of the way" do you mean from left to right in the viewfinder? Or a third of the way from you to infinity?

12-09-2013, 09:43 AM   #5
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QuoteOriginally posted by photographyguy74 Quote
I know that if you want to maximize your depth of field, you should focus one-third of the way into a scene.
This technique is usually used for landscape images where you want as much of the scene in focus as you can. It is a "rule of thumb" or general guide but often works well. It works because the area in focus extends both in front and to the rear of the plane you focus on. How far it extends depends on the aperture, the lens focal length and the distance to your subject.

So if you have a landscape image in mind pick a point about 1/3 of the way into the scene and focus on that. The aperture and focal length will then determine how much of the scene will be in focus. On older lenses there are markings that help show you the near and far distance to the edges of the in focus area.

Take a look at this calculator it might help explain things: Online Depth of Field Calculator
12-10-2013, 12:46 AM   #6
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And there is no such thing as a dumb question
12-10-2013, 06:00 AM   #7
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Actually there are a lot of things confused in this thread

First of all, the point of perfect focus, at long distances places acceptable depth of field at 1/3 in front 2/3 behind. This is the concept, in the extreme of hyper focal distance, which puts the 2/3 point at the infinity mark on the lens. You preset this it is not something you do in the viewfinder, and it really only applies for an 8x10 print.

Second this behaviour is at infinity , the closer you get to the subject, the more this shifts to 50/50 in front and behind.

As for focusing through the viewfinder, unless you are doing something special focus and focus lock at what you want in focus. Nothing mode nothing less.

The viewfinder shows only the focus plane, I.s. A single slightly curved plane at right angles to the lens axis. I say slightly curved, because unless you have a true macro lens or a rectalinear ultra wide angle lens focus is normally on the edge of a sphere because this is an acceptable approximation at longer focal lengths to a plane
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