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hyperfocal distance and my SX100

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Offline waterwingz

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Re: hyperfocal distance and my SX100
« Reply #20 on: 07 / November / 2018, 10:21:40 »
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Quote from: shinnen on 07 / November / 2018, 09:16:39
Will the DOF readouts be helpful wrt to macros?
Sorry, I'm not really sure what you are trying to do?  Can you elaborate on what you mean by "macros" and "readout" and how that's related to DOF?
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Offline reyalp

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Re: hyperfocal distance and my SX100
« Reply #21 on: 07 / November / 2018, 23:44:18 »
Quote from: shinnen on 07 / November / 2018, 09:16:39
Hi again,
       Will the DOF readouts be helpful wrt to macros?
Assuming you mean the DOF calculator OSD, it's up to you whether you find those values useful, but I doubt they'll be a big help for general macro shooting.

Seeing how zoom and aperture affect DOF might be of some value, but you can probably see that in the live view.

If you have a setup where your subjects are always at exactly the same distance, then the subject distance value might help you use consistent settings.
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #22 on: 08 / November / 2018, 11:16:12 »
Hi waterwingz/reyalp,
      Maybe I'm asking the wrong question. Recently I tried to photograph some large mushrooms, having a DOF in the order of 3 or 4 inches, and I could not get them all in focus. So, I was thinking that the hyperfocal setting, or the DOF, might be somehow applicable to macros.
..... john
« Last Edit: 08 / November / 2018, 11:19:23 by shinnen »
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Offline waterwingz

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Re: hyperfocal distance and my SX100
« Reply #23 on: 08 / November / 2018, 11:31:34 »
Quote from: shinnen on 08 / November / 2018, 11:16:12
Hi waterwingz/reyalp,
      Maybe I'm asking the wrong question. Recently I tried to photograph some large mushrooms, having a DOF in the order of 3 or 4 inches, and I could not get them all in focus. So, I was thinking that the hyperfocal setting, or the DOF, might be somehow applicable to macros.
..... john
Sorry - had my software hat on when I read the word "macros" - kind of means the same thing as "script".  You mean macro photography - otherwise known as extreme closeups.

As reyalp pointed out, the CHDK OSD should give you some idea of the DOF via the near limit & far limit values.  I'm not sure how accurate those will actually be however.

From a picture taking point of view,  you can control the point of actual focus (MF),  the aperture (which determines depth of field in addition to exposure), and the zoom position (which changes the aperture and DOF).   So you don't get to set the DOF directly - you set your focus to the mid-point of what you want to take a picture of,  adjust your aperture to change the DOF around that point,  and maybe physically move the camera closer or farther away so that you can adjust the zoom position for different DOF with the same framing.
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Offline reyalp

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Re: hyperfocal distance and my SX100
« Reply #24 on: 08 / November / 2018, 13:24:48 »
Quote from: shinnen on 08 / November / 2018, 11:16:12
So, I was thinking that the hyperfocal setting, or the DOF, might be somehow applicable to macros.
..... john
Hyperfocal is (quoting wikipedia) a distance beyond which all objects can be brought into an "acceptable" focus. So it's relevant when you want to capture relatively near stuff out to infinity (think landscape or maybe a street scene), but not for normal macro shooting where everything is much closer than infinity.

DOF is a product of aperture and zoom. The DOF calculator will show you near / far limits, but you are probably better off evaluating these from the live view or test shots. The specific distances in the DOF calculator may or may not be accurate, and in any case, you probably aren't measuring the distances.

With CHDK, you can often get slightly more DOF by overriding the aperture beyond the normal Canon value, i.e. f/11 instead of f/8 at wide angle, or f/16 zoomed. This may hurt image quality a bit overall due to diffraction. It will also longer exposure, and you will need to set all the exposure parameters manually because the Canon firmware is not aware of the override value.

If you want even more DOF for close up shots, you probably have to resort to focus stacking
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #25 on: 08 / November / 2018, 19:30:37 »
Thanks again reyalp/waterwingz. I'm going to have to work on those suggestions.
I appreciate the help.
..... john
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #26 on: 09 / November / 2018, 18:24:55 »
I suspect that this is a dopey question, but I'll ask it anyway.
Can I assume, that if I were to focus my camera on an object, which is the hyperfocal distance away (i.e. 2.51 meters), that everything from 1.25 meters to infinity should be in focus?
...... john
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Offline waterwingz

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Re: hyperfocal distance and my SX100
« Reply #27 on: 09 / November / 2018, 18:25:55 »
Quote from: shinnen on 09 / November / 2018, 18:24:55
Can I assume, that if I were to focus my camera on an object, which is the hyperfocal distance away (i.e. 2.51 meters), that everything from 1.25 meters to infinity should be in focus?
yes
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Offline shinnen

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Re: hyperfocal distance and my SX100
« Reply #28 on: 10 / November / 2018, 09:09:02 »
Quote from: waterwingz on 09 / November / 2018, 18:25:55
Quote from: shinnen on 09 / November / 2018, 18:24:55
Can I assume, that if I were to focus my camera on an object, which is the hyperfocal distance away (i.e. 2.51 meters), that everything from 1.25 meters to infinity should be in focus?
yes
And by the same token, if I focus on a subject 5 meters away, should I expect everything from 2.5 meters to infinity be in focus?
.... john
« Last Edit: 10 / November / 2018, 09:15:22 by shinnen »
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Offline waterwingz

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Re: hyperfocal distance and my SX100
« Reply #29 on: 10 / November / 2018, 10:13:41 »
Quote from: shinnen on 10 / November / 2018, 09:09:02
And by the same token, if I focus on a subject 5 meters away, should I expect everything from 2.5 meters to infinity be in focus?
I'm going to say "not necessarily" but before we get too deep into my lack of knowledge, I did some googling.  Here's a more official definition of hyperfocal distance from the first reference I link below :

"The technical definition is the closest focusing distance that allows objects at infinity to be acceptably sharp.  It is important to note that, if you focus at the hyperfocal distance, your photo will be sharp from half that point out to infinity."

A quick google turns up lots of hits - here's the first couple of good ones :

link>  Hyperfocal Distance Explained
link>  Cambridge in Color Tutorials : Hyperfocal Distance
link>  Wikipedia : Hyperfocal Distance

HTH!
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