cgardner Offline Dedicated FM Upload & Sell: Off
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Daan B wrote:
I just got a Sekonix L-358... works everytime... spot on metering. It doesn't have spot metering (although you could buy a very expensive adapter for that) and it can't be calibrated... two features I don't really care for 
It can be "compenstated" to the camera and in fact its usually necessary to do that to ensure accurate readings with the recommended metering technique for exposure: pointing the dome back at the camera.
Use a textured white object like a terry towel as a target under consistent lighting, after setting custom WB in the camera off a gray card to ensure all channels will clip at the same time'
Take a meter reading, as specified in the L-358 user guide, dome at carmera. Lets assume the reading was f/8. Now make a series of bracketed exposures in 1/3 increments from f/5.6 to f/11 resulting in 7 files.
Open the seven files in your normal RAW workflow (i.e. DPP, ACR) and look at the detail in the towel to find the point just below where overexposure starts to erode the subtle variation in tone in the terry cloth - why a towel not a card is used.
Odds are that the file which looks the best is not the one shot at f/8. If you shoot with Canon more likely the shot at f/9 will be more optimally exposed: Canon cameras have true ISOs closer to 120-125 per ANSI standard.
Once you find the delta between what your meter predicts and what the camera actually produces, turn on the meter, press both ISO buttons at the same time and enter the delta as the exposure compensation factor (e.g. Adj 0.3).
While setting the meter to read in 1/10 stops is more accurate, changing the meter readout via the DIP switch to read in 1/3 stops like the camera is more practical. So in this example of you metered f/8 but found f/9 yielded better exposure and entered an EC of .3 on the meter the meter reading in the same light will now read f/9 matching meter to the camera. A black rectangle with a -/+ will appear on the display to remind you that EC is dialed in, but the amount is not shown.
Once compensated the factor will be applied to all ISO speeds. But since each camera body may differ you'd need to repeat the test for each.
Take care to make the compensation only after the meter is turned on. The procedure for changing the factory CALIBRATION uses the same controls, but with the ISO buttons pushed before the meter is turned on. If you change the calibration the only way to get it back to ANSI standards would be to send it into Sekonic for service.
Of course you can learn all that yourself by reading the user guide 
Chuck
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