Focussing - when your lens hits 'infinity' what happens to the rangefinder?

[SJP]

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Focallength: 50mm

f-Stop: f8

 

Subject distance 10 m

 

Depth of field

Near limit 9.69 m

Far limit 10.3 m

Total 0.64 m

 

In front of subject 0.31 m (48%)

Behind subject 0.33 m (52%)

 

Hyperfocal distance 312.6 m

Circle of confusion 0.001 mm

 

just an example with a custom (very strict) CoC.

Which shows that on paper you can take values outside the realm of physics. The CoC you use is 1 micron (Jaap, indeed not 10 micron!) which is about 7 times smaller than the pixels on a M8 sensor and 31x smaller than the industry standard. Using the above example of a 50 mm lens at f/8 if for sake of argument we would take 7 micron as the CoC (sensor limited value) then we find that the hyperfocal distance is about 30 metres. A more realistic sensor limited CoC is 14 micron, via the Nyquist criterion, and then we get a hyperfocal distance of 20 metres.

 

So you can use the concept of hyperfocal setting at infinity with the M8. As with any other camera. Nothing fundamental has changed since 1920.

 

EDIT: @ Steve Ash, the new noctilux DoF data seems to based on a CoC of 28 micron instead of the standard 31 micron. This is interesting maybe they are slowly pulling in the reigns?

Edited July 5, 2009 by SJP

[Nicoleica]

Not wishing to interrupt this theoretical orgy, but aren't we getting into the regions whereby you need to start taking photographs in space here? Surely the effects of atmospheric dispersion are going to have a greater effect than any slight focussing error at these levels?

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[SJP]

Not wishing to interrupt this theoretical orgy, but aren't we getting into the regions whereby you need to start taking photographs in space here? Surely the effects of atmospheric dispersion are going to have a greater effect than any slight focussing error at these levels?

+ 1

 

The original concepts are fine & there is no need to completely rethink the basics. As mentioned before a 0.001 mm circle of confusion is outside the realm of physics even in outer space, unless you have x-ray eyes

[el.nino]

+ 1

 

The original concepts are fine & there is no need to completely rethink the basics. As mentioned before a 0.001 mm circle of confusion is outside the realm of physics even in outer space, unless you have x-ray eyes

 

you are right. i just wanted to exaggerate my point and just chose the smallest CoC available on the calculator (didn't even think about its meaning).

but, as most of my photographs are in the infinity-area (land- and cityscapes) i tested many focussing-concepts and only the infinity-concept gave me the results i wanted (and a lot of users around the web are reporting the same).

 

there is also a nice video about different focussing-techniques (especially on a rangefinder): Focus and Depth of Field The Figital Revolution