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Archive 2012 · establishing hyperfocal distance..
  
 
rolei
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p.2 #1 · establishing hyperfocal distance..


all images are done with rmote controle on tripod


Nov 11, 2012 at 11:57 AM
gdanmitchell
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p.2 #2 · establishing hyperfocal distance..


willis wrote:
I think 'acceptable sharpness' is conventionally what appears sharp in an 8"x10" print at 25cm for someone with good vision. This is very different to close inspection of and A3+ print. Don't expect 7D images to look sharp at infinity when viewed at 100% on screen using the usual hyperfocal calculations.


The traditional "calculations" were also based, if I recall correctly, on shooting with 35mm film. Thus, they fail on that basis as well with other formats.

I'm of the opinion that the world would be a better place if "DOF calculators" and the like suddenly disappeared and we were left to think more carefully about how aperture choices affect our own photographs instead of looking for (false) formulas to do our thinking for us.

Dan



Nov 11, 2012 at 05:21 PM
gdanmitchell
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p.2 #3 · establishing hyperfocal distance..


RobDickinson wrote:
Hyperfocal is a great way to get everything in the plane of focus but everything may not be critically sharp.

Sometimes its better to focus on the near object of interest and stop down till you have the background acceptable. You may run into diffraction but this is often less of a problem than an overall fuzziness from hyperfocal.


Here is what some think DOF/hyperfocal distance implies: By focusing at the hyperfocal distance, all objects within the depth of field range will be in focus.

Here is what it really means: There is a plane (more or less) perpendicular to the sensor/film that is optimally in focus. Objects in front of or behind (unless you focus "at infinity") are "out of focus" relative to this plane and become less and less in focus as they are further from the plane. The rate at which the "out of focus-ness" increases is greater with large apertures than with small apertures. Depending upon your expectations, the size of the print you will produce, the format of your film/sensor, and other factors, the point at which the "out of focus-ness" becomes visible or a problem can vary a great deal. And aperture choice and the resulting DOF cannot be manipulated in a vacuum. For example, using a smaller aperture to increase DOF may improve resolution in the corners of the frame while at the same time diminishing resolution in the center due to diffraction blur - either of which may or may not matter depending upon a host of other factors.

Sorry, but that's the reality of DOF. :-)

Dan



Nov 11, 2012 at 05:28 PM
Lars Johnsson
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p.2 #4 · establishing hyperfocal distance..


gdanmitchell wrote:
The traditional "calculations" were also based, if I recall correctly, on shooting with 35mm film. Thus, they fail on that basis as well with other formats.

I'm of the opinion that the world would be a better place if "DOF calculators" and the like suddenly disappeared and we were left to think more carefully about how aperture choices affect our own photographs instead of looking for (false) formulas to do our thinking for us.

Dan


In every decent DOF calculator you can choose what kind of format or what camera you are using. So that's no problem. But I don't like or use them.



Nov 11, 2012 at 06:02 PM
 

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Monito
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p.2 #5 · establishing hyperfocal distance..


Lars Johnsson wrote:
In every decent DOF calculator you can choose what kind of format or what camera you are using. So that's no problem. But I don't like or use them.


Yeah, and you can choose viewing distance and print size too, or allow the default viewing distance and print size (8x10 inch).

Once you've fixed (made non-variable) all those values, then you can get an accurate DoF that applies to a very restricted set of conditions.

If viewing distance or print size or both or might change, then your calculations are useless.



Nov 11, 2012 at 06:56 PM
BrianO
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p.2 #6 · establishing hyperfocal distance..


rolei wrote:
all images [were] done with rmote controle on tripod


Then unless you had a very flimsy tripod, I suspect that the lens was the problem. Having one shot where one side of the frame is blurred and the other side is sharp, at the same distance, isn't normal. It's not likely that yours was a case of "operator error." Something was wrong with the equipment.

I don't mean to sound impolite, but...why did you put a really cheap lens on an expensive camera? I'm pretty sure that the problem lies there.



Nov 11, 2012 at 09:10 PM
jcolwell
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p.2 #7 · establishing hyperfocal distance..



Monito wrote:
If viewing distance or print size or both or might change, then your calculations are useless.


True.

OTOH, even if all of the shooting and viewing parameters are correctly defined to produce a "within DOF" image, you can still blow it all away with a quick peek at 100%, before rendering the final viewing format. Stupid 100%!



Nov 11, 2012 at 09:29 PM
rolei
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p.2 #8 · establishing hyperfocal distance..


next week i am getting new lens finally and will do the test again and post it!


Nov 11, 2012 at 09:30 PM
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