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Forum: Pentax SLR Lens Discussion
08-28-2014, 04:52 AM
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Forum: Pentax Camera and Field Accessories
02-27-2014, 04:38 PM
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If you have a true CS-105 cable release, it has a DIN-type plug and will not fit the *istD.
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Forum: Pentax SLR Lens Discussion
12-12-2011, 07:33 PM
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Tamron Adaptall and Adaptall-2 lenses and mounts are interchangeable. Introduction of Adaptall-2 brought PK/A functions to Adaptall and Adaptall-2 lenses, if there was either f32/A or an AE position on the aperture ring of the lens. All Adaptall-2 lenses has f32/A position, some Adaptall lenses had AE position, these lenses when coupled with an Adaptall-2 PK/A adapter will give you equivalent automation as a Pentax A series lenses. The Adaptall lenses without either of those markings on the aperture ring would be limited to PK/M automation.
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Forum: Pentax SLR Lens Discussion
12-13-2011, 03:38 PM
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Forum: Film SLRs and Compact Film Cameras
10-31-2011, 05:51 PM
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I have two SF10's which I bought for the lenses. Since the camera body has no re-sale value, I dissemble one just to see how it operates. The camera has two magnesium alloy frames as shown in the photo; the one on the left is film transport and shutter block; on the right is mirror box. There is no mirror motor. The camera uses two solenoids to operate the mirror and the aperture (on top and bottom of gear box). One could call the bottom one (green color) a linear motor because it push/pulls a center steel rod in and out. It has relatively large focusing motor (bottom left corner). On top of the prism, there is a tiny lens which concentrates light on a photo cell for metering. This is a first generation auto camera, I think its design is rudimentary. The eye-piece of viewfinder is single element thick plastic lens. The construction of MZ-5N is much more advanced. People criticize Sony for using fixed mirror, in fact, all the mirrors in auto focus cameras are half silvered to allow some light to transmit through and then reflects to the CCD sensor for focusing. This is the reason that viewfinders in manual focusing cameras are brighter owing to fully silvered mirrors. The construction of the shutter is rather simple. Two coil springs and two solenoids operate a few thin metal blades. The blade traveling time must be much shorter than the shortest shutter time, otherwise the exposure would not be uniform across the frame. In cameras such as PZ-1 which have 1/8,000 sec., the springs would be very strong to flip the metal blades even faster, but probably would create unwanted vibration in the camera. The uncrippled lens mount has a lever which goes inside the lens to couple with the aperture ring. This lever has 9 contact points corresponding to the common 9 settings on the aperture ring.
Vranx, I would guess that in your case the top solenoid (gray color) is not working, resulting in aperture control lever slides all the way to the end and thus the smallest aperture under A setting.
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Forum: Photographic Industry and Professionals
10-23-2011, 10:28 PM
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One needn't be a fetishist to admire toes and ankles and nicely-articulated metatarsals, eh?
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Forum: Pentax SLR Lens Discussion
08-04-2011, 05:03 AM
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I have used the 1.7X Autofocus Adapter with all sort of lenses and I can confirm it will convert any lens (even an office magnifier) into an autofocus lens. I have used old barrel lenses dating back from the 19th Century and they magically turn into autofocus lenses.
As you stated, you will need to shotcut the contacts in order for the Autofocus Adapter to work with older lenses which are not equipped with the proper contacts. You can indeed use a piece of aluminium foil for this purpose, either between body and adapter, or between adapter and lens. I find it more convenient tu put it between adapter and lens, because I can leave the piece of aluminium in place when unmounting the adapter + lens assembly. You could even imagine having two telephoto lenses in you bag, each one having its own AFA semi-permanently mounted with a piece of aluminium foil, allowing you to switch between lenses more rapidly while shooting.
When using a mount adapter on top of the Autofocus Adapter, just make sure the whole contraption is rigid enough, especially with long and heavy lenses. The P67 adapter shouldn't be a problem, but I have had some trouble with flimsy M42 adapters.
The Autofocus Adapter is really a great contraption: it turns any old telephoto into a powerful AF supertele lens, with a built-in focus limiter insuring lightning fast AF operation. This is certainly the cheapest way to get a 500mm+ AF lens for birding!
The only caveat is the max aperture of the lens. If you want to get a fast and reliable AF lock, you'll preferably need a lens faster than F/5.6. AF performance depends somewhat on the lens formula: it might be nearly impossible to get a focus lock with some F/5.6 lenses, while it can be feasible with others. You shouldn't have any problem with an F/4.0 or F/4.5 lens.
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
08-03-2011, 08:32 AM
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Uh, I think you are confused what the 1.7x afa adapter does. It has internal elements that can be moved to autofocus any lens, including manual focus lenses.
I've used it on my 1000mm reflex and my 2000mm reflex without issue. Those lenses have no contacts of any kind. I expect your 6x7 will work the same. You prefocus close and then use the afa to snap the focus into place.
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Forum: Pentax SLR Lens Discussion
08-03-2011, 03:29 PM
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Littledrawe, you are in luck. I mounted a generic P67 to PK adapter to P67 SMC Takumar 300/4.0 and the AFA 1.7x to my K20D (I have no doubt the genuine Pentax P67 to P645 + p645 to PK adapter would work just as well, but they are buried deep in my Medium format bag). Set the camera to AF.s, manually focus the camera and half press the shutter and AF works quite well. Any subject within the same vicinity (+,- 50 feet) the AF works. Mind you it's very bright outside, in less than ideal conditions AFA 1.7x and an f4.0 lens do not work so well. I haven't checked the IQ but I've had good results with AFA 1.7x and other 300mm lenses.
I can also confirm that an m42 lens with an infinity type adapter will not AF with the AFA 1.7x, however with a non-infinity type adapter (chrome plated) the AF functions as well as the P67 lens. I haven't tried it with the black anodized non-infinity adapter - will try to do so later on.
Hope this helps,
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Forum: Pentax SLR Lens Discussion
10-11-2010, 05:13 AM
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I did this a couple years ago with a K100D. The foil under the mounting ring lasted more than a year ( I took it out to try conductive paint which I never got around to.)
I used the foil-under trick last night on my K-x; I plan to leave it in place.
I used no adhesive or ball, just a piece of foil larger than the pin diameter; the mount ring clamps it in place. There is no risk of its falling out.
Here's a photo summary of the procedure on a K-x:
Dave
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