Re: contacts. was AF lenses on AF 1.7X adapter

On Wed, 07 May 2008 11:51:47 -0400, P. J. Alling wrote: >James wrote: >> Very well put. >> But please explain why every AF sigma lens I have doesn't show the correct >> apature range on my super A. despite haveing some A contacts. >> >It's Sigma. cannot argue there. I have an older sigma A

Re: AF lenses on AF 1.7X adapter

Of courses it would. There is a digital pin on the AF, adapter, it does the same thing that the F, FA, DA variable aperture do. The AF adapter passes the A pin information to the body the Digital pin supplies the offset. That would be the simplest way to make it work. If you're manually ch

Re: contacts. was AF lenses on AF 1.7X adapter

James wrote: > Very well put. > But please explain why every AF sigma lens I have doesn't show the correct > apature range on my super A. despite haveing some A contacts. > It's Sigma. > Also why does the MZ60 have only 2 contacts missing when it was never > designed to use A lenses at all.

Re: AF lenses on AF 1.7X adapter

Thank-you Mark, and thanks to all those answering my questions about the AF1,7x converter. Dario - Original Message - From: "Mark Roberts" <[EMAIL PROTECTED]> To: "Pentax-Discuss Mail List" Sent: Wednesday, May 07, 2008 4:52 PM Subject: Re: AF lenses on AF 1.

Re: AF lenses on AF 1.7X adapter

I just tried the 1.7x AF adapter with my K10D and 16-50/2.8 and found it works just as you'd expect from a non-SDM lens. Doesn't know the lens' focal length but focuses very quickly. Gets the working aperture correct. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listin

Re: AF lenses on AF 1.7X adapter

The proof should be in the results you get. I regularly shoot wide open with the A*300 f4 and the AF 1.7x on an *ist=D[s] and there is minimal visual degradation of the image. Admittedly the K20 has 50% higher liner resolution, but that shouldn't make that big a difference. I would expect th

Re: contacts. was AF lenses on AF 1.7X adapter

James wrote: > Why does the sigma lens when I pulled it apart have all contacts except for > the * go > via a flexiable circuit trace to a board in the lens when all that is > required of A > contacts is to be shorted or open? Of all your questions, that's the easiest to answer: They do it th

Re: AF lenses on AF 1.7X adapter

The odd thing is that it pickes f:7,1 with 50-135 x 1,7. So it seem the camera does know how fast the mounted lens is. Another odditiy. Manually changing programline to Normal, gives different values. In MTF it is locked, but in Normal it bumps up and down with the light. So I don't know what to t

Re: contacts. was AF lenses on AF 1.7X adapter

Very well put. But please explain why every AF sigma lens I have doesn't show the correct apature range on my super A. despite haveing some A contacts. Also why does the MZ60 have only 2 contacts missing when it was never designed to use A lenses at all. Why does the sigma lens when I pulled i

Re: AF lenses on AF 1.7X adapter

Mmm not sure MTF works. It should not work IMO since there's no communication between lens and body except A-type informations. Your MTF program line probably fall back to standard program in this case. A lenses do not provie any MTF informations. -- Thibault Massart aka Thibouille -

Re: AF lenses on AF 1.7X adapter

I have and use this combo. Works fine. But your friend will probbly need to step down to f:11 or something in that area to get good results. The K20D suggests f:10 using the MTF programline. MaritimTim 2008/5/5 Dario Bonazza <[EMAIL PROTECTED]>: > Mark Roberts wrote: > > >> Dario Bonazza wrote: >

Re: contacts. was AF lenses on AF 1.7X adapter

It's not conjecture that lenses without the pin are identified by Pentax DSLRs as A lenses ,and if the pin is blocked the camera shows the same behavior. The other connections are simply conductive on non conductive spots on the lens mount.on A lenses Even if digital pin simply powers the chi

Re: AF lenses on AF 1.7X adapter

Just a follow up on my earlier serious answer. The 1.7x AF Adapter lacks the digital data pin, (seen here at Boz's K mount technical page), on it's female mount. Without that pin there can be no communication between the lens and camer

Re: contacts. was AF lenses on AF 1.7X adapter

On Mon, 05 May 2008 14:27:04 -0400, P. J. Alling wrote: In my mind, there is a lot of conjecture about the "digital" pin. I believe that it is power for the lens chip. Noone knows what is really going on with all the contacts except pentax. Sigma have reversed enginered the contacts and maybe tamr

Re: AF lenses on AF 1.7X adapter

The AF 1.7x doesn't support pass through digital information for any AF lens, nor would it supply power for the SDM motor so the answer is no the lens and the adapter won't both try to autofocus. The camera will think and treat the SDM lens for all intents and purposes as an A lens if it's mou

Re: AF lenses on AF 1.7X adapter

It does so have to, it just doesn't want to... Mark Roberts wrote: > Dario Bonazza wrote: > >> Hi all, >> >> I've been asked this question, but couldn't answer it. What happens by >> matching a DA* 300mm AF lens (or any other SDM lens) with the AF 1.7X >> converter? Do both AF devices (the SD

Re: AF lenses on AF 1.7X adapter

Yes Mark, you're right. However, the question was more general: is there any "no, don't do that, because..." about that combo? Dario - Original Message - From: "Mark Roberts" <[EMAIL PROTECTED]> To: "Pentax-Discuss Mail List" Sent: Monday,

Re: AF lenses on AF 1.7X adapter

Dario Bonazza wrote: > Hi all, > > I've been asked this question, but couldn't answer it. What happens by > matching a DA* 300mm AF lens (or any other SDM lens) with the AF 1.7X > converter? Do both AF devices (the SDM one in the lens and the screwdriver > type in the adapter) start & try to au

Re: AF lenses on AF 1.7X adapter

Dario Bonazza wrote: > Yes Mark, you're right. However, the question was more general: is there any > "no, don't do that, because..." about that combo? Can't imagine anything. I'll give it a try when I get home! -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdm

Re: AF lenses on AF 1.7X adapter

Mark Roberts wrote: > Dario Bonazza wrote: >> Yes Mark, you're right. However, the question was more general: is there >> any >> "no, don't do that, because..." about that combo? > > Can't imagine anything. I'll give it a try when I get home! Thanks! I've been asked that question by a guy who o

AF lenses on AF 1.7X adapter

Hi all, I've been asked this question, but couldn't answer it. What happens by matching a DA* 300mm AF lens (or any other SDM lens) with the AF 1.7X converter? Do both AF devices (the SDM one in the lens and the screwdriver type in the adapter) start & try to autofocus? Thanks. Dario -- P