PentaxForums.com - View Single Post - New *istD--Pentax noobie thoughts

Lowell Goudge · 10-11-2007, 09:09 AM

Originally Posted by RiceHigh

P-TTL need focusing distance information for the calculation of flash exposure. So, P-TTL is never possible with K and A lenses which lacks this essential info.

I disagree, P-TTL does not need focusing distance. Note that my Tamron Adaptall2, KA mount on the *istD works as KAF and later mounts with the AF540, P-TTL nbut no TTL.

However, with F lens or later, Pentax should let the *ist D or DS users to choose which mode they wish to use as the 360 and 540 are actually TTL capable.

No disagreement on selection option.

10-11-2007, 09:09 AM	#14
Lowell Goudge Pentaxian Join Date: Jan 2007 Location: Toronto Gallery Photos: 2 Posts: 3,580	Originally Posted by RiceHigh P-TTL need focusing distance information for the calculation of flash exposure. So, P-TTL is never possible with K and A lenses which lacks this essential info. I disagree, P-TTL does not need focusing distance. Note that my Tamron Adaptall2, KA mount on the istD works as KAF and later mounts with the AF540, P-TTL nbut no TTL. However, with F lens or later, Pentax should let the ist D or DS users to choose which mode they wish to use as the 360 and 540 are actually TTL capable. No disagreement on selection option.