Originally posted by Ozclick It`s the K.
It`s a manual lens so I`m a bit confused as to how the AF converter can work with it??
I have the SMC 300 F4.0 lens. Strictly K mount, no automatic apature.
Although the manuals all say the 1.7x AF adaptor can only work on F2.8 and faster it works just fine on F4.0 lenses. I bought the adaptor when I bought my PZ-1 in 1991, and tested it on my 100mm F4 macro and my 70-210 f3.5 vivitar before buying it.
When I bought the 300mmF4.0 I again checked to make sure the AF worked on my PZ-1.
I have since used this combination on both my *istD and my K10D and it works fine in manual exposure mode. For flash, since there is no apature info, it can only work on my K10D with the AF540FGZ in the "auto" mode using the sensor in the flash. On the *istD it works with the TTL flash metering using either the AF540 FGZ or the AF500 FTZ flash.
The only thing the lens cannot do with the autofocus adaptor is work in auto exposure modes due to lack of apature information.
With the AF adaptor it works out to something like an F6.7 500 mm autofocus lens.