Maximizing settings

I'm using a Pentax K10D and a Sigma EF-500 DG Super. I recently upgraded from

the *ist DS. I noticed that with the DS, I generally had to shoot one stop

overexposed in order to get a full histogram range. Now I'm discovering that the

problem seems to be even worse with the K10D and the flash - typically needing

+1.5 to +2.0

This is my first time working with a TTL flash.

The following three histograms are captured from the raw converter before making

any adjustments on the computer. The first histogram is at normal settings (+1.0

overexposure on the camera). For the second, I told the camera +1.0 flash power.

The third, I also told the flash to give me +1.0 flash power. All the histograms

are essentially identical.

What am I doing wrong?<div></div>

http://www.sigmaphoto.com/news/news.asp?nID=3286

I do not recall reading if Sigma has a problem with the K10D or just the K100D - this announcement was made before the K10D was released. You might check with Sigma.

I have the same flash you do, and I still have the *ist DS. Hope to upgrade to the K10D at some point, so I'll be interested to know what Sigma says, if you care to contact them.

The article you're pointing to suggests a problem with the K100D sync system. I'm not sure if it applies to my flash, as I bought it around December.

I know that the flash reads lens data from the camera, and will adjust zoom length as I adjust the lens. I'm supposing that indicates it is a different problem.