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.
