RE: Pentax 1.7X AF Adapter
On Mon, 9 Aug 2004, Jan van Wijk wrote: > On Mon, 9 Aug 2004 14:33:51 +0100 (BST), Kostas Kavoussanakis wrote: > > >85/2.8, it does not go under that, says the manual. > > You got that mixed up a bit :-) > > The manual states that you can not (reliably) use the 1.7x AF adapter > with a lens slower than f/2.8. So the 50/1.4 is fine. > > The resulting largest f-stop for the combo is simply the lens one > multiplied by the converter magnification (1.7 here), so the > 1.4 will be 1.4 * 1.7 = 2.38 No, I have got it right, here is the quote from the manual: "In the case of a lens faster than f/1.7, the compound maximum f-stop becomes f/2.8." I don't have a 1.4 lens to try it, unfortunately. Kostas
RE: Pentax 1.7X AF Adapter
On Mon, 9 Aug 2004 14:33:51 +0100 (BST), Kostas Kavoussanakis wrote: >> My favorite use for it was to turn a 50/1.4 into a sort of 85/2.4 macro. > >85/2.8, it does not go under that, says the manual. You got that mixed up a bit :-) The manual states that you can not (reliably) use the 1.7x AF adapter with a lens slower than f/2.8. So the 50/1.4 is fine. The resulting largest f-stop for the combo is simply the lens one multiplied by the converter magnification (1.7 here), so the 1.4 will be 1.4 * 1.7 = 2.38 This is a fixed relationship, and equates to one and a half stops light loss. Regards, JvW -- Jan van Wijk; http://www.dfsee.com/gallery
RE: Pentax 1.7X AF Adapter
On Sat, 7 Aug 2004, Don Sanderson wrote: > My favorite use for it was to turn a 50/1.4 into a sort of 85/2.4 macro. 85/2.8, it does not go under that, says the manual. > The ZX-L (MZ-6) has recieved good reviews but I've never tried one. The thread -5n vs -6 has been done a few times :-) I really like the adapter. Kostas
Re: Pentax 1.7X AF Adapter
I'll bet this becomes a chorus. Yes. Jens Bladt wrote: The maunal doesn't mention K-lenses. Wouln't it be possible to use let's say a K 2.8/105mm and a K 2.5/135mm? Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -Oprindelig meddelelse- Fra: Jens Bladt [mailto:[EMAIL PROTECTED] Sendt: 8. august 2004 19:55 Til: [EMAIL PROTECTED] Emne: RE: Pentax 1.7X AF Adapter Thanks, Jim. Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -Oprindelig meddelelse- Fra: Jim Colwell [mailto:[EMAIL PROTECTED] Sendt: 8. august 2004 15:54 Til: pdml Emne: RE: Pentax 1.7X AF Adapter You can download the 1.7x AF teleconverter manual from http://www.pentaxusa.com/docstore/index.cfm?show=6 the manual file is named: SMC Pentax-F AF Adapter 1.7X Jim www.jcolwell.ca
RE: Pentax 1.7X AF Adapter
The maunal doesn't mention K-lenses. Wouln't it be possible to use let's say a K 2.8/105mm and a K 2.5/135mm? Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -Oprindelig meddelelse- Fra: Jens Bladt [mailto:[EMAIL PROTECTED] Sendt: 8. august 2004 19:55 Til: [EMAIL PROTECTED] Emne: RE: Pentax 1.7X AF Adapter Thanks, Jim. Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -Oprindelig meddelelse- Fra: Jim Colwell [mailto:[EMAIL PROTECTED] Sendt: 8. august 2004 15:54 Til: pdml Emne: RE: Pentax 1.7X AF Adapter You can download the 1.7x AF teleconverter manual from http://www.pentaxusa.com/docstore/index.cfm?show=6 the manual file is named: SMC Pentax-F AF Adapter 1.7X Jim www.jcolwell.ca
RE: Pentax 1.7X AF Adapter
Thanks, Jim. Jens Jens Bladt mailto:[EMAIL PROTECTED] http://hjem.get2net.dk/bladt -Oprindelig meddelelse- Fra: Jim Colwell [mailto:[EMAIL PROTECTED] Sendt: 8. august 2004 15:54 Til: pdml Emne: RE: Pentax 1.7X AF Adapter You can download the 1.7x AF teleconverter manual from http://www.pentaxusa.com/docstore/index.cfm?show=6 the manual file is named: SMC Pentax-F AF Adapter 1.7X Jim www.jcolwell.ca
RE: Pentax 1.7X AF Adapter
You can download the 1.7x AF teleconverter manual from http://www.pentaxusa.com/docstore/index.cfm?show=6 the manual file is named: SMC Pentax-F AF Adapter 1.7X Jim www.jcolwell.ca
Re: Pentax 1.7X AF Adapter
the only lens worth using it on is the 35-105/3.5, but it is marginal even in bright light because of the loss of light in the adapter. i think anything slower than a 2.8 isn't worth it. also, an extender magnifies the center portion of the lens circle and so if you are using it on a less than superb lens, you'll get nothing but magnified softness and distortion. Herb... - Original Message - From: "Robert Woerner" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, August 07, 2004 10:08 AM Subject: Pentax 1.7X AF Adapter > Hello, > > I have a friend who is considering moving into AF Pentax film SLR from MF > Super Program. She has the excellent A 35-105 f3.5, A 50 f2.0 in addition to > a Gemini 28 f2.8. I have recommended the ZX-L due to budget constraints > (otherwise I'd recommend the MZ-S). My question is:
RE: Pentax 1.7X AF Adapter
Hi Robert. It will turn the 50 into an 85 F3.4, and the 28 into a 47 F4.8, both should work fine. The 35-105 becomes an F6 and may not autofocus very well, anything over 5.6 seems "iffy". I just tried the converter on a 70-210/3.5 and wasn't pleased, sometimes it focused OK, sometimes not. This was on a ZX-5n, the ZX-L mileage may vary. It's a great converter but you do need to "pre-focus" to get in the ballpark, it will take over from there. My favorite use for it was to turn a 50/1.4 into a sort of 85/2.4 macro. The ZX-L (MZ-6) has recieved good reviews but I've never tried one. Keep in mind the 1.7x is usually rather hard to find and pricey. Don > -Original Message- > From: Robert Woerner [mailto:[EMAIL PROTECTED] > Sent: Saturday, August 07, 2004 9:08 AM > To: [EMAIL PROTECTED] > Subject: Pentax 1.7X AF Adapter > > > Hello, > > I have a friend who is considering moving into AF Pentax film SLR from MF > Super Program. She has the excellent A 35-105 f3.5, A 50 f2.0 in > addition to > a Gemini 28 f2.8. I have recommended the ZX-L due to budget constraints > (otherwise I'd recommend the MZ-S). My question is: > > How well will the Pentax 1.7X AF adapter work with these lenses? She is > considering purchasing this instead of buying AF lenses at this time. > > I assume there will be a light loss making an f2.0 into an f4.0, etc. > > What are opinions good/bad about the ZX-L? From my reading it has > impressive > specs. > > Thanks in advance, > > Robert > >
Re: Pentax 1.7x AF Adapter
On 18 Oct 2002 at 18:43, Doug Franklin wrote: > Works with any K mount lens as far as I can tell. AF shaft does not go > through the teleconverter (only the lenses inside the t/c move during > AF operations). It will even work with screw mount lenses on a K-adaptor if you poke some aluminium foil in the gap between the back of the screw lens and the AF TC aperture contacts. The TC is surprisingly high performance, in fact I'd say it may even be on par with the optical performance of the 2X-L when used on long fast lenses. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
RE: Pentax 1.7x AF Adapter
It will work the same way: as a tele-extender with a limited AF distance range. (I don't think that the AF drive shaft passes through the adapter. BR > -Original Message- > From: Michael Cross [mailto:mcross@;ncen.org] > > > Does it work with F/FA lenses or only with manual focus lenses? > >
Re: Pentax 1.7x AF Adapter
Does it work with F/FA lenses or only with manual focus lenses? Rubenstein, Bruce M (Bruce) wrote: I think that it is a pretty good tele-extender, although I never compared it to an expensive 7 element one. It one of the better ways to get an 85mm AF portrait lens (with a 50mm). The elements move to provide the AF capability, so it only works over a particular distance range that varies with the particular lens being used. BR -Original Message- From: Michael Cross [mailto:mcross@;ncen.org] I am particularly interested in the image quaility loss and autofocus performance. Thanks! Michael Cross
RE: Pentax 1.7x AF Adapter
I think that it is a pretty good tele-extender, although I never compared it to an expensive 7 element one. It one of the better ways to get an 85mm AF portrait lens (with a 50mm). The elements move to provide the AF capability, so it only works over a particular distance range that varies with the particular lens being used. BR > -Original Message- > From: Michael Cross [mailto:mcross@;ncen.org] > I am particularly interested in the image quaility loss and autofocus > performance. > > Thanks! > > Michael Cross >
