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06-15-2012, 08:33 AM   #1
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P-ttl settings, (Camera) K10D

Just curious as to camera settings to use with a Metz AF-50. Should I be in "Program Mode", with multi segmented metering? If I use X sync, and set my flash to manual, I can get good results, but tomorrow, (6-16) I have a really limited time to play "trial and error". I will have some time to experiment prior to the BIG event, under the exact same conditions. It will be indoors, very high ceilings, and I will be no farther away than 50' from my (subjects). I really want to do a good job for my club. Or, will accept other options.

06-15-2012, 12:28 PM   #2
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15 meters (50 feet) is a long distance to cover with a flash unless you crank up the ISO and can use fast glass. Bouncing or a diffuser will make the situation worse. Get closer if you can.

Don't forget that your flash has a zoom head and the specified guide number of 50 will only apply at longer focal length; at 18mm it is 26 (see the manual).

Wiith ISO 400, 18mm position of the kit lens, aperture of 3.5, you will just cover the 15m distance (direct flash).

I would use Av or M (shutter speed 1/180 or slower). ISO 400 to begin with and an aperture that's wide enough to cover the most common distance that you expect to shoot and the focal length of the lens. pTTL will take care of the rest.

Check the results to get a feel for what will work.

This is with direct flash; bouncing will cost you at least one stop (or in other words it will decrease the reach with a factor1.4). To compensate, ISO from from 400 to 800 or aperture one stop wider open.

Use a fixed ISO; don't let the camera decide !!
Don't forget spare batteries and good luck.
06-15-2012, 01:17 PM   #3
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don't forget that GN of 50 in meters is 50 meters distance at ISO 100 and F1.0
to start with

GN(iso=100) = distance f-number

to compensate for ISO, you need to take the square root of the change in ISO, or

GN = distance x f-number x square root (ISO/100)

reworking this for distance gives you

distance = GN(iso =100) x root (ISO/100) / F number

shooting a GN=50 flash at ISO 400 doubles the guide number but even this when you consider a lens typically is F2.8 or slower will not give you the 50meters you want.

you would really need consider setting ISO to 1600 and shooting at F4 to reach out to 50 meters.
06-15-2012, 08:32 PM   #4
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Original Poster
Did the same shoot last year with the in camera flash only, I set the ISO quite high, (I believe 800) and the noise was really really bad. I'll give your suggestions a try, prior to the "live" shoot. Maybe I'll take my laptop to review the test images. I gave 50' at the extreme length, but I will force my way in much closer, 25' to 10'. I got the extra batteries, for flash and camera charged and ready

Last edited by jcamero; 06-15-2012 at 08:35 PM. Reason: Adding 1 sentence.

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