Yeah, there seems to be this mistaken belief that the AF500FTZ is the most powerful Pentax flash, but the GN is based on the flash zoomed out to cover an 85mm lens. At 24mm it has a GN of 30, at 85mm the GN is 50. The AF400T has a GN of 40 at 28mm. I believe that it is the Pentax flash with the most output.
-- Best regards, Bruce Saturday, January 31, 2004, 5:31:51 PM, you wrote: GL> How does the AF-500FTZ's power compare to the AF-280T? GL> I had thought that the AF-500FTZ was much more powerful since it has a GL> guide number of 164'/50m compared to 91'/27.4m for the AF-280T. But I see GL> on B&H's web site that the AF-500FTZ's 164'/50m guide number applies to GL> its 85mm telephoto coverage, while at 50mm coverage its guide number is GL> 138'/42m. GL> Since the AF-280T is not a zoom and has a fixed angle of coverage of 28mm, GL> I would guess its guide number of 91'/27.4m applies to 28mm, even though GL> wide angle and telephoto adapters are available separately for it. GL> Correct? GL> Any idea what the AF-500FTZ's guide number is at 28mm? GL> I usually use a Stofen filter on my AF-280T, and I'm not really interested GL> in how powerful the AF-500FTZ is at 85mm coverage. Instead, I'm interested GL> in how much more total light it would put into the Stofen than the AF-280T GL> does -- I'd like to be able to bounce more often and use smaller GL> aperatures. GL> Thanks, GL> Greg
