If I were testing the meters, I'd do the following:
1. Be sure to compare both meters in spot metering mode. You probably
did this but just in case...
2. Verify what the 'spot' in the spot metering is. Put a small saucer
sized white paper plate on a piece of black foam core. With the K5 -
fill the frame with the plate and then slowly walk away from it, letting
the black foam core start to fill the frame. Keep the paper plate
centered in the finder - you will see the meter reading stay steady and
then rapidly change as the plate gets smaller than the area being
metered. You can verify that the "spot" being measured correlates the to
the circle in the center of the frame. You could do that with the
Sekonic as well.
3. Test both the K5 and Sekonic on a gray card, using your knowledge of
the size of the spots to be sure that you are only metering off the grey
card.
4. If there is a material difference in the readings off the gray card,
then test the meters off a gray card in direct noon sunlight and compare
to the sunny 16 rule. Hopefully one of the meters will comply with that.
5. Use the meter that complies with sunny 16 to work up an adjustment
factor for the other.
6. Spot meter off various colored items and see if the meters perform
consistently. If they vary, they may be more or less sensitive to
different colors. This can be a bugger because you have no control
point. One meter may be more sensitive to green, another to red, you
can't use one to calibrate the other. You can try the sunny 16 rule with
different colors, of course..
Are you shooting slide film, color neg, or silver B&W?
If B&W, I'd just go out and shoot, take notes (mental or otherwise) and
compensate the workflow. That means tweaking your metering / film ISO
setting (same thing), your development times and agitation regimen. Use
the data printed along the edge of the film as a control point for
developing. If you are shooting slide film you have to be more careful
with metering.
Here's a story about metering and slide film:
I visited the beach with a friend of mine one day, and we both shot this
lighthouse:
http://www.markcassino.com/newsite/portfolios/lighthouses/pages/0204l07.htm
He had a Nikon F5 with a super sophisticated evaluative / color
corrected metering system that he relied on. I had a Pz-1p. I spot
metered off the black metal frame, did some quick zone calcs in my head,
and set the exposure manually. We both shot ISO 100 slide film (him
Provia, me E100S.) My shots came out very well - maybe 1/4 to 1/2 stop
over exposed, but very usable. His were a mess. SO taking control of
metering with film is important.
Good luck!
MCC
On 5/21/2012 8:27 PM, Kenton Brede wrote:
I'm making a foray into film and decided I should get a light meter.
I bought a used Sekonic L-508 which has both incident and spot
metering. Messing around with the K-5 and Sekonic, I found the
readings didn't really match up. So I took a picture of the blue sky,
the histogram was spiked in the center. I then spot metered the sky.
I used the compensation function to dial in 3AV to bring the meter in
line with the K-5's shutter, ISO and aperture. I used a gray card in
the shade to meter off of with the K-5, and then matched those
settings on the Sekonic by dialing in a -1AV for the incident reading.
Does this sound like a decent calibration method?
I went around metering things and taking shots with the K-5. I found
that if I spot metered off a shaded green bush, I needed to speed up
the shutter 2 stops to bring the histogram near center. When metering
off a gray cloud, with silver lining, I sped up the shutter a couple
stops to bring the histogram to center. The incident meter seemed to
get the K-5 in the ballpark when metering in front of a tan shed,
while the meter was facing the direction the sun. In shade, facing
away from the sun, I generally had to slow the shutter down a couple
stops.
Does this sound like the way an accurate light meter works? I've
never used one.
Any thoughts appreciated. I realize all this hinges on the K-5 being
accurate, and assuming the film cameras will work with the same meter
readout as the K-5. I probably should have just purchased a new
model, but good ones are expensive!
Thanks,
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