Re: flash for *ist D

[Joseph Tainter]

Michael, TTL flashes do not seem to work consistently well with digital 
SLRs. Some people get good results some of the time, at some ISO 
settings but not others, with some exposure compensation, etc. The 
reason is that TTL measures light off the film plane. Of course, a dslr 
does not have a film plane, so light has to be measured off the sensor. 
The sensor does not have the same reflectivity as film, so exposures are 
often inaccurate.

P-TTL fires two flashes. The first measures the light bouncing off the 
shutter to determine the exposure. The second flash illuminates the 
subject for the photograph. The AF 360 and the Sigma models with P-TTL 
are both good. The Sigma is more powerful and the head swivels. The 
Pentax covers a wider angle (24 mm. film/16 mm. dslr) without having to 
add a diffuser.

As for the exposure problems that you noted in another post, try 
center-weighted metering rather than program metering and see if the 
results are better.

Joe