circle of confusion charts

[jann1033]

i am posting this link since it has the circle of confusion for a bunch of cameras
http://www.dofmaster.com/digital_coc.html
which i asked about but no one told me so i stopped being lazy and found it the link to the reason for this is hyperfocal distance chart found here http://www.vividlight.com/articles/2314.htm
so it seems to me the chart for the d30 would work for present eos rebel and 40d cameras..anyone know that to be wrong please let me know

 

[handicap18]

That stuff gives me a Popsicle headache. Though I do like the hyperfocal chart. I have to pay more attention that stuff.

 

[Groucho]

We were just talking about the hyperfocal distance in the Learning Curve thread, if anyone wants to wade through my muddled explanation of it and see a few links, pictures, etc about it.

I'm still a little fuzzy on the whole circle of confusion thing, but I figure that it only makes sense, what with the "confusion" part.

 

[jann1033]

i find my own personal circle of confusion is much larger than my camera's
i have a tendency to forget about that thread so maybe i 'll check it out although right now i think i have the hyperfocal distance in my brain at least sort of right so maybe i'll just enjoy my ignorance for a little while till it try it and it doesn 't work

 

[seashoreCM]

Very vaguely speaking, the circle of confusion is the size of a blurry spot produced by a less than perfectly focused lens that you will still think is in focus. Looking at the overall picture, the human eye and brain are "confused" into thinking that the spot represents something still in focus.

To some extent it is subjective.

The charts mentioned above refer to the size of the spot (0.005mm or so) on the camera's sensor which could be as small as a quarter of an inch across. When the picture is enlarged to typical dimensions such as 4x6 inches or 8x10 inches or (on a movie screen) 4 feet across, the absolute size of a circle of confusion is much greater. Also roughly, the circle of confusion for most people is around 1/1000'th to 1/2000'th the diagonal of the picture seen at normal viewing distances.

For some cameras the pixels are so coarse (too few megapixels or film too grainy) or the lens is of such poor quality that nothing can be put in focus sharper than the circle of confusions as predicted in the aforementioned charts suggest.

For any camera, only subjects at a specific distance are realy in focus. If we take circle of confusion into account, those subjects whose tiny details are blurred no greater than the diameter of the circle of confusion are within a distance range (reflecting depth of field) as opposed to at one specific distance.

In adjusting a camera for the desired artistic result, the photographer wants certain material "in focus" and certain material (often a background) "out of focus". Often this can be done by experimenting and eyeballing (and with a camera that allows a lot of manual adjustments) without having to calculate circles of confusion.

Digital camera hints: http://members.aol.com/ajaynejr/digicam.htm

 

[boBQuincy]

Very vaguely speaking, the circle of confusion is the size of a spot produced by a less than perfectly focuses lens that you will still think is in focus.

To some extent it is subjective.

I think the subjectivity is the key, along with the change in how images are displayed and viewed. The typical output used to be 4" x 6" prints, now it is a monitor which is often closer to 8" x 10" or more. The range, contrast, luminosity , etc of a monitor vs a print is also very different and this could change how we view circles of confusion.

Unsharp masking probably figures in as well, most cameras perform that and a host of other algorithms on the image that was captured by the sensor before the image gets stored on the memory card.

It may be time to revisit COC and hyperfocal distance for digital, not so much for the changes in cameras but for the changes in what happens after the image is captured.