ERNR wrote: --------- Bought an AF 1.7x converter some months ago -- used, without an instruction manual. I notice that sometimes it just won't AF. (I generally use it with a fast 50, so it's not the speed). Is this a known weakness of this device? or is there something in the instructions that I should know about, to stop this from happening? (I checked and didn't find instructions for this on the Pentax website.) ERNR ---------------------
Hi, the Af-adapter will only be able to focus the adapter-lens unit to infinity, if the lens is set to infinity. This is because the adapter focuses by moving it's own lens group and not that by moving that of the lens; so at 'infinity', both the adapter and the lens must be set to infinity. OTOH when, in the AF mode, the adapter is not able to focus close enough, preset the lens to a closer distance. Then the AF adapter will be able to auto-focus on nearer subjects, however it will not focus to infinity. The distance indicated at the scale of lens the does not correpond to the actual film to subject distance. When the Af-adapter is locked to infinity it works like any other teleconverter. In this case you can manually focus the lens and the distance indicated at the distance scale of the lens correponds to the actual film to subject distance. Hope this helps, Alexander Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
