On Mar 23, 2014, at 6:25 PM, P.J. Alling <[email protected]> wrote:
> Well, actually it's the EV of the scene you're trying to focus on a bright > scene even with a slow lens will. I may have had a couple of cocktails today, but I have no idea what you’re trying to say here, and I doubt that total sobriety would help. > The maximum aperture of the primary lens is only a guideline. > > On 3/23/2014 5:47 PM, Alastair Robertson wrote: >> correct me if I am wrong, but it is the maximum aperture of the lens >> TC that matters on an automatic lens, not what you have stopped it >> down to, since the AF is done with the lens wide open just before the >> lens is stopped down and the shutter opens. So a setting of F22 on an >> F5.6 setup will make no difference to the AF capability compared with >> say F8. Putting a TC on a slow lens is a problem because even wide >> open, the light levels are already too low for accurate AF. I doubt >> whether Alan's F9-11 combination will allow AF because this is as open >> as the lens can go >> >> Alastair >> >> On 24 March 2014 09:25, Paul Stenquist <[email protected]> wrote: >>> I've tried autofocus at up to f22 with the 1.5X and the DA8 60-250, and it >>> worked fine, although that was with a high contrast scene. >>> >>> On Mar 23, 2014, at 2:32 PM, Alan C <[email protected]> wrote: >>> >>>> Very nice. What was the range, Paul? You've inspired me to dig out my old >>>> Vivitar MC 2x teleconverter which I used to use with a Vivitar (A) 75-200 >>>> f4.5. I'll try that combination & also with the FA100-300 f4.5-5.6 on a >>>> distant subject with the K7 & see what happens. MF, of course. It will be >>>> interesting to see if the AF confirm still works at f9 - f11. >>>> >>>> Alan C >>>> >>>> -----Original Message----- From: Paul Stenquist >>>> Sent: Sunday, March 23, 2014 7:54 PM >>>> To: Pentax-Discuss Mail List >>>> Subject: PESO Flying Rat, European Version >>>> >>>> Shot on a lake this afternoon. K-3 DA* 60-250/4 with the 1.4X converter, >>>> f5.6, 1/2500, 350mm, ISO 400 >>>> >>>> http://photo.net/photodb/photo?photo_id=17716268&size=lg >>>> -- >>>> PDML Pentax-Discuss Mail List >>>> [email protected] >>>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>>> follow the directions. >>>> >>>> --- >>>> This email is free from viruses and malware because avast! Antivirus >>>> protection is active. >>>> http://www.avast.com >>>> >>>> >>>> -- >>>> PDML Pentax-Discuss Mail List >>>> [email protected] >>>> 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 >>> [email protected] >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. > > > -- > A newspaper is a device for making the ignorant more ignorant, and the crazy, > crazier. > > - H.L.Mencken > > > -- > PDML Pentax-Discuss Mail List > [email protected] > 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 [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
