Pentax-F 1.7X AF Adapter
craig rieger
new? Does anyone have any experience with this AF adapter?
Stan Halpin
>
> Does anyone know whether the Pentax-F 1.7X AF adapter is still available
> new? Does anyone have any experience with this AF adapter?
It was discontinued about 4 months ago. I found one new in a small
camera store about two months later, there may still be others out
there.
It is a truely marvelous gadget! Transforms SMC-M or SMC-A lenses into
autofocus lenses. My SMC-M 50 1.4 becomes an autofocus 85mm f2.0 with no
detectable loss in sharpness, etc. (Well, I am sure if you go to a huge
blow-up you could probably find some loss from the adapater, but it sure
isn't anything obvious!) If you can find one, grab it.
Stan Halpin
Mark McMaster
Since you can fit a screw mount to K-mount adapter ring to the AF
adapter, you can even get autofocus operation from 35 year old screw
mount lenses!
Mark McMaster
MMc...@ix.netcom.com
GLewis4457
writes:
>> It is a truely marvelous gadget! Transforms SMC-M or SMC-A lenses into
>> autofocus lenses. My SMC-M 50 1.4 becomes an autofocus 85mm f2.0 with no
>> detectable loss in sharpness, etc. (Well, I am sure if you go to a huge
>> blow-up you could probably find some loss from the adapater, but it sure
>> isn't anything obvious!) If you can find one, grab it.
>
I found mine on the clearance table at a local camera shop...for $16, brand new
still in the box. I use mine mostly on my Vivitar 100/3.5 macro lens. Makes
it AF at 170mm. Really nice piece of eqpt. Unfortunately they must be getting
scarce. I have seen a couple of them on ebay, but you will have to watch
closely.
Jerry in Houston
Jerry Lewis
League City, TX., USA
EJ
extension behind the lens???
Mark McMaster wrote:
> Stan Halpin wrote:
> >
> > craig rieger wrote:
> > >
> > > Does anyone know whether the Pentax-F 1.7X AF adapter is still available
> > > new? Does anyone have any experience with this AF adapter?
> >
> > It was discontinued about 4 months ago. I found one new in a small
> > camera store about two months later, there may still be others out
> > there.
> >
> > It is a truely marvelous gadget! Transforms SMC-M or SMC-A lenses into
> > autofocus lenses. My SMC-M 50 1.4 becomes an autofocus 85mm f2.0 with no
> > detectable loss in sharpness, etc. (Well, I am sure if you go to a huge
> > blow-up you could probably find some loss from the adapater, but it sure
> > isn't anything obvious!) If you can find one, grab it.
>
Bozhidar Dimitrov
: OK, I'll buy that explanation. But what happens to infinity focus with all that
: extension behind the lens???
Remember that this is a teleconverter, so it works like one, and not like
an extension tube where you lose infinity focus.
Cheers,
Boz Dimitrov
EJ
Yeah, I'm up to speed with the 1.7x by itself, I was just questioning the use someone
mentioned with the scew to K mount converter on top of it all. ????
Eric
Mark McMaster
>
> Boz
>
> Yeah, I'm up to speed with the 1.7x by itself, I was just questioning the use someone
> mentioned with the scew to K mount converter on top of it all. ????
Works fine, just like when you use a screwmount to K-mount directly on
the camera.
Mark McMaster
MMc...@ix.netcom.com
Rui L. Mendes
Are you sure about this?
I own this AF adapter, and Pentax cautions (in the instruction manual)
against the use of the screw mount adapter, saying that the lens will
not provide autofocus function.
Pentax lists all the Pentax lens compatible with this AF adapter.
Regards.
Rui L. Mendes rlme...@mail.teleweb.pt
Mark McMaster
Well, optically and mechanically there is no inherent reason why the
screw mount adapter shouldn't work. The camera itself is programmed not
to try to autofocus if it detects an aperture of f/8 or smaller, so my
KA-mount lenses of f/4 or larger work fine with the AF adapter but those
of f/4.5 or smaller do not. K-mount lenses (without electical contacts)
also work with the AF adapter, even though the camera has no idea of the
max. aperture of the lens. Since the screw mount adapter simulates a
K-mount lens at widest aperture by moving the aperture coupling lever to
the max. aperture position, a screw mount lens should work - the AF
adapter shouldn't know the difference between the screw mount adapter
and an actual K-mount lens. The posible incompatibility may be certain
screw mount lenses whose rear element projects backward behind the
mount, which could hit the optics of the AF adapter. There are some
screw mount lenses which should not be used with the K-mount adapter
directly on the camera body for this same reason, since they could
interfere with the mirror.
Mark McMaster
MMc...@ix.netcom.com
vitta...@gmail.com
> Does anyone know whether the Pentax-F 1.7X AF adapter is still available
> new? Does anyone have any experience with this AF adapter?
I recently bought one used for USD 43 equivalent in Thailand. The ebay price has roses as high as USD 460.
If you own one, cherish it.
Sincerely,
Vittaya from Thailand (1990 kid)