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06-22-2010, 05:22 AM   #1
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Newbie question on zooms



Can someone tell me what these red and white lines and arcs represent, and how to interpret them?

06-22-2010, 05:46 AM   #2
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QuoteOriginally posted by bkhl Quote

Can someone tell me what these red and white lines and arcs represent, and how to interpret them?
I'm assuming that the lens is a zom lens. And, it looks like a "one touch" zoom.

The Red and White lines are Depth of Field indicators.

You have a line that corresponds to each f-stop. You have, for example, a marking of 5.6 on either side of center. On your focus ring, you have distances from the minimum to infinity. The area between those line, at each give f-stop, is the area that should be in focus. And, the shorter the focal length, the wider the DOF.

If you do a Google search on "Depth of Field", you'll probably find a great deal of information that will answer your question a lot better than I have.

here's a link for you. http://www.great-landscape-photography.com/hyperfocal.html



edit: the curved Red line is the center focus point if you are using "Infra-Red" Film. I'm sure someone will correct me if that's wrong.

This post should probably have been put in the "SLR Lens discussion" or "Beginners Corner"

Last edited by Ed n Georgia; 06-22-2010 at 06:02 AM.
06-22-2010, 05:53 AM   #3
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These are probably hyperfocus marks. The white line directly right of the middle straight red line is the in focus distance for f5.6, the white line to the right of that is for f11, line to the right of that is for f16 and so on.

Google hyperfocus distance and you'll get a good idea of what it is.
06-22-2010, 05:58 AM   #4
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Those lines are used for estimating depth of field.

If you don't know what depth of field is - google it first or it'll get confusing

If you want to use those lines, here's how it works.

If you count from the center, there are 5 pairs of lines, the middle pair is orange.
Below the lines, there are several aperture markings, also in pairs except for the middle one - the rhombus, which represents aperture of f/3.5 (the largest aperture of your lens). Each pair of lines corresponds to a pair of aperture markings, except for the innermost orange pair, which corresponds to the rhombus. The second innermost pair of lines correspond to aperture f/5.6, the third innermost pair corresponds to f/11, the next pair corresponds to f/16, and the outermost pair of lines corresponds to f/22. (it's kind of hard to explain but really easy once you get it )

Now, say, you're using your lens at some aperture and you want to know what depth of field the lens will give you - without actually taking a picture. To estimate the depth of field, you just look at where the pair of lines that correspond to the aperture you've selected point on the distance scale (top of the picture).

For example, if you're using f/3.5, you would just check the innermost orange lines - which right now point at 3m and somewhere between 3m and infinity. If you take a picture with aperture at f/3.5, everything from 3 meters to somewhere between 3 meters and infinity (distance from camera sensor) will be in sharp focus.
Say, you now want to use f/22, and want to guesstimate the depth of field. Now, you would check the outermost lines - which point at 1.2m and past infinity. This means that, if you take a picture at f/22, everything from 1.2m and onward to infinity (again, distance from camera sensor) would be in sharp focus.

06-22-2010, 09:23 AM   #5
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QuoteOriginally posted by Ed n Georgia Quote
This post should probably have been put in the "SLR Lens discussion" or "Beginners Corner"
I think so too. The question has been accurately answered, but I'll move it to the beginners corner for others that may have the same question to see.
06-22-2010, 12:47 PM   #6
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Thanks everyone.
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