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-   -   Hyperfocal distance on 1.5x crop? (https://forums.steves-digicams.com/sony-alpha-dslr-konica-minolta-dslr-sony-slt-77/hyperfocal-distance-1-5x-crop-99347/)

maxxum7d Aug 28, 2006 1:35 PM

Does anyone know how the hyperfocal distance is affected when using the 7D?

NHL Aug 28, 2006 2:23 PM

Yes - they do, you can calculate it here: http://www.outsight.com/hyperfocal.html#digital

tmoreau Aug 28, 2006 2:27 PM

Interesting question.

If you cut a little off the sides of your film negative, does it go out of focus?

Of course not, but if you then make a 8x10 print from it your effectively enlarging it more than before you cropped it. Therefore, you need to be more critical of sharpness. Technically, your circle of confusion just changed.


Using http://www.dofmaster.com/dofjs.html:

35mm film, 50mm lens, f/2.8, focused at 10 feet = dof 2.06 feet
hyperfocal distance 96.8 feet

(same lens on digital)
1.53x crop, 50mm lens, f/2.8, focused at 10 feet = dof 1.36 feet
hyperfocal distance 145.2 feet

(same field of view on digital)
1.53x crop, 35mm lens, f/2.8 focused at 10 feet = dof 2.84 feet
hyperfocal distance 71.2 feet

So yes, hyperfocal distance IS different. That chart on your lenses isnt quite as accurate anymore. I'd sugest using that calculator and comparing the results to whats printed on your lens and making some notes. A couple tests should confirm if you need to make adjustments or not. Your APS dslr actually has more dof than film IN A SIMILAR COMPOSITION, because your using a different focal length.

When I set hyperfocal distance, I use the next smaller aperture. If I'm shooting f/11 I'll set the infinity mark on f/8 instead, or I'll focus even closer to infinity if conditions allow.


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