LoneRangeFinder Loc: Left field

I realize that most of the Macros shooters have this calculation down for their specific set-ups. Here's what I do to get a starting point:

After setting the ISO, f/stop and shutter duration, I set my flash to Manual (using the camera control). I then shoot a gray card and then adjust using the histogram, usually the flash output. Other than trial and error, what do others use? I find this useful as I get accustomed to different combinations of extension. Thoughts?

Nikonian72 Loc: Chico CA

Having used my SB-600/O-Flash combination for a few years, I know that my settings will start at ISO 400, 1/200-sec at f/22 for an average-toned subject at about 7-inch Working Distance. Lighter-colored subjects require less exposure, and darker-colored subjects require more exposure. Making adjustments is easy.

Blurryeyed Loc: NC Mountains.

I agree with Douglass, there is no one setting that is going to work for all situations, a lighter subject requires less flash than a darker subject with other variables remaining constant. Your gray card idea sounds pretty good for initial setup, but I am not even sure how you go about that. For me I have a little fake plant in the living room that I will shoot before going out in the field just to confirm that I am somewhere near where I need to be before going out into the field. I really like reduced flash power so before I go any higher than 1/8th power on my flash I will consider changing the ISO, that can be a trade off too as I consider the camera that I use for macro to be a little noisy, but that could sometimes be caused by underexposure, I may be a bit unforgiving to my camera... it may be more me than the camera.

martinfisherphoto Loc: Lake Placid Florida

I always keep my ISO at 320 shutter at 1/200 and only change my aperture 4 stops total for the most part. I just look at scene, set flash and fire. will check once and adjust if I have to. I also use Spot metering on all my shots. Total black subjects is the only time I will miss an exposure as I have to crank up the flash more than I like to.

LoneRangeFinder Loc: Left field

I'm still trying new diffusers and I'm still learning how much increase the tubes take. I just use it as a start point. I'm going to go back to removing the flash from the hot shoe. I bought a few pieces of hardware today-- but essentially I'm returning to one of my earlier set-ups. It has the option of adding a supplemental flash-- which I've not tried with digital.

I agree with upping the ISO rather than changing the manual lighting ratio. I may never use TTL again.

Nikonian72 Loc: Chico CA

I use ISO 400, which synchronizes background exposure at 1/200-sec at f/16, with speedlight illuminated subject.

LoneRangeFinder Loc: Left field

You raise an important point: balancing flash illumination with daylight exposure.
There are many days here in Portland where we toss the sunny-16 "rule".