EV corelation with f-stop and ASA

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This is a supplement "to taking xray pictures" question of 2-10-99. I have been using a Nikon FG-20 film camera with macro lens mounted on a tripod at present. I find that I need 1/4 sec exposure with ISO 100 slide film with f5.6. Can you help with tanslating this so I can decide which digital cameras may be able to handle this. You can explain as much as you wish about EV and I will be glad to listen. Or refer me to a source. Thank Joe Parravano University of Nevada

-- joseph parravano (parravano@iname.com), February 11, 1999

Answers

'Got out my trusty old Gossen Luna Pro (vintage ~1970), and it translates your exposure specs (1/4 at f5.6 for ISO 100) to EV 12. (Which interestingly enough, is exactly the light level for our "indoor model" test shots - a bright residential interior.) For reference, at the other end of the scale, the "sunny 16 rule" (use shutter speed of 1/ISO at f16 in bright sunlight) translates to EV 20.

Most digicams should be able to handle that light level - They all typically have an ISO rating of ~100, and just about all go down to 1/ 4 second, pretty much all have lenses faster than f5.6. OTOH, some handle it better than others. Looking at the indoor model shots in the Comparometer on this site would give you a pretty good idea of how the various models would handle your situation. (The Comparometer can be found at http://www.imaging-resource.com/IMCOMP/COMPS01.HTM)

-- Dave Etchells (web@imaging-resource.com), February 13, 1999.


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