I’ll further explore that question tomorrow. stan
On Mar 26, 2014, at 2:59 PM, Ken Waller <kwal...@peoplepc.com> wrote: > I'm more interested in the smaller aperatures at which it fails to focus. It > would be nice to be able to use it on my 600. I have both the A-1.4X-L & > A2.0X-L but of course I lose AF with those. > > Kenneth Waller > http://www.pentaxphotogallery.com/kennethwaller > > ----- Original Message ----- From: "Rob Studdert" <distudio.p...@gmail.com> > Subject: Re: Because inquiring minds want to know (more on the 1.4x) > > >> Thanks for the report Stan, it does look useful, but I will have to >> sell a K5 body to afford it :( >> >> >> On 21 March 2014 02:38, Stanley Halpin <s...@stans-photography.info> wrote: >>> I just did a couple of focus "tests" with my two slowest lenses. I won't >>> post any results - I was just handholding on random twigs, turkeys, lawn >>> sculptures, trees, etc. The images would tell you nothing about sharpness. >>> All of the following using center-point focus, K-3. >>> >>> 1. Sigma DG 150-500mm f5-6.3 APO HSM + Pentax 1.4x TC >>> With the Sigma at 150mm zoom (presumably f/5.0) >>> - Sigma AF OFF: nothing happens - no AF. >>> - Sigma AF ON: snappy AF, no searching or other bad behaviors >>> >>> With the Sigma at 500mm zoom (presumably f/6.3) >>> - Sigma AF ON: Quite a bit of searching on low contrast >>> targets (e.g., tree trunks.) Fairly quick "snap" to focus on a weed seed >>> head 20 feet away against a backdrop of the river ice 150 feet away. Quick >>> "snap" to focus on tree trunks across the river. >>> - Probably usable at 500mm/6.3 when tripod mounted, looking >>> at a stationary target with reasonably high contrast. Not sure I would try >>> to handhold this combination to pick out flying birds above. If nothing >>> else, the motor noise as it searched would get on my nerves. >>> >>> 2. Pentax FA 28-105/4-5.6 PZ (the original model of this lens) >>> With the lens at 28mm (presumably f/4.0) >>> - Quick albeit noisy focus on pretty much everything I >>> looked at. >>> (I had forgotten how noisy the AF is on non-SDM >>> lenses! It has been awhile.) >>> With the lens at 105mm (presumably f/5.6) [AV, dialed to "wide >>> open", f/8.0 indicated on the display] >>> - Same results. Quick lock in on whatever targets. >>> >>> If anyone wants to try this on a different lens, let me know and I'll send >>> you my shipping address and return the results to you soonest. Or stop by >>> and play with it yourself. >>> >>> I will have this with me on an upcoming trip to Sweden/Norway/Denmark and >>> any Pentaxians I encounter along the way are welcome to do a try out of the >>> 1.4x. >>> >>> stan >>> -- >>> PDML Pentax-Discuss Mail List >>> PDML@pdml.net >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. >> >> >> >> -- >> Rob Studdert (Digital Image Studio) >> Tel: +61-418-166-870 UTC +10 Hours >> Gmail, eBay, Skype, Twitter, Facebook, Picasa: distudio > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
