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11-08-2018, 07:39 PM   #1
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67 to 645D and Z lens adapter

Recently, I purchased a 67 55-100 and a Pentax branded 67 to 645 adapter. Apparently, only AV and manual focus are supported. Is there an adapter that supports autofocus? Also, when I connect my 645Z to Image Transmitter 2 with that adapter on camera the software tell me that the camera is not connected. Is there an adapter that will allow the software to recognize the camera is connected?

11-08-2018, 08:44 PM   #2
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QuoteOriginally posted by nyghtfalcon Quote
Recently, I purchased a 67 55-100 and a Pentax branded 67 to 645 adapter. Apparently, only AV and manual focus are supported. Is there an adapter that supports autofocus? Also, when I connect my 645Z to Image Transmitter 2 with that adapter on camera the software tell me that the camera is not connected. Is there an adapter that will allow the software to recognize the camera is connected?


There is no mechanism in Pentax 67 lenses for autofocus. No offense, but this seems rather obvious, at least to those of us old enough to remember when autofocus didn’t exist.

The 645z will, however, provide focus confirmation at the selected focus point using the green indicator in the viewfinder (as do the 645N and NII with manual focus lenses), or you can use live view with focus peaking.

Rick “who’ll leave the Image Transmitter question to others” Denney
11-09-2018, 10:55 AM   #3
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As Rick pointed out, there's no way to adapt a 6x7 lens with autofocus - the 6x7 mount pre-dates the 645 and the 6x7 mount (and adapter) haven't changed since. If you want AF either the 645 FA45-85 or FA55-100 would be a better fit - the P6x7 55-100 is much larger/heavier, more restricted and takes huge 95mm filters. As much as I like mine on the P67, the 645 FA45-85 is a much more usable lens on the D/Z.

I've no knowledge of the Image Transmitter, but there's only one Pentax adapter, assuming it's working OK, there won't be a better option.
6 Days Ago   #4
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You could adapt the 67 lenses for autofocus, with something similar to this:

Pentax Rear Teleconverter F 1.7x Autofocus Adapter

Though perhaps the larger size & weight of the lenses could make it more difficult to do, compared to a 35mm version.

6 Days Ago   #5
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67 to 645D and Z lens adapter

QuoteOriginally posted by leekil Quote
You could adapt the 67 lenses for autofocus, with something similar to this:

Pentax Rear Teleconverter F 1.7x Autofocus Adapter

Though perhaps the larger size & weight of the lenses could make it more difficult to do, compared to a 35mm version.

There is no version of this for 645 or 67 lenses.

Rick “is focusing using a ring on the lens really that difficult?” Denney
5 Days Ago   #6
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Is manual focus that difficult? When you are visually impaired, yes. I am forced to wear specially designed sun glasses all the time - even inside - because my irises do not work. So, any help I can get, I will accept.

Additionally, when the lens arrived, I expected it to be manual focus only. However, at the base of the lens is a "switch" that says auto on one side, and manual on the other. Obviously, I don't have the user manual so I have no idea what that is for. I theorized auto diaphragm but thought I'd ask people who might have been doing photography long enough to know. I purchased my first camera in 2002 and that was digital. I have never worked with film.
5 Days Ago - 1 Like   #7
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Okay, let’s start again.

The A/M switch is indeed for the diaphragm. On A, the diaphragm stays open until the shutter is released, so that focusing can be done with full aperture. Pentax 6x7 and 67 cameras meter correctly because a lever within the lens mount tells the camera how far the lens is stopped down. On M, the aperture closes down with the setting ring, and the meter reads the light directly.

A 645z manages the auto diaphragm properly, at least when using the Pentax adapter.

Now, to focus.

As you turn the focus ring, the haxagonal green dot in the bottom center viewfinder display will light and the focus confirmation beep will beep when the subject at the focus point is in focus. The small red rectangle at the focus point will illuminate briefly. The only thing it doesn’t do is turn the focus ring.

You can also find a focus screen from a 645NII, which will fit perfectly in a 645z. Mine has a microprism donut around the center point. (The split-focus version is scarce as hen’s teeth.) I have not found any negative effect from using the microprism screen on the autofocus or metering. It does make focus snap more vividly.

So, if you can get it close, the technology of the camera will help you the rest of the way, even with manual-focus lenses.

Rick “who also depends on focus technology” Denney
5 Days Ago   #8
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QuoteOriginally posted by rdenney Quote
...
You can also find a focus screen from a 645NII, which will fit perfectly in a 645z. Mine has a microprism donut around the center point. (The split-focus version is scarce as hen’s teeth.) I have not found any negative effect from using the microprism screen on the autofocus or metering. It does make focus snap more vividly.
...

Rick “who also depends on focus technology” Denney
Rick: should I infer that a focusing screen from a 645N will also work on a 645Z, or will NOT also work on a 645Z? Defined focusing screens for the 645N are:
  • AS-80 (center spot matte - standard)
  • AB-82 (AF split-image matte)
  • AG-80 (AF cross-lined matte)
  • AA-82 (AF microprism matte)
The 645Z manual lists these focusing screens:
  • DF-80 (AF framed matte -- standard)
  • DG-80 (AF cross-lined matte)
  • DK-80 (AF golden section matte)
None of these Z screens appear to have either microprism or split image capabillity.

More to the question, while the drawings of these screens are presented at different orientations, they appear to have tabs in similar locations. Nothing can be inferred about equivalence in size from these illustrations.

P.S. The review at https://www.pentaxforums.com/accessoryreviews/pentax-ab-82-focusing-screen-for-645d-645z.html reports that the AB-82 N screen fits the Z. Hence the others should also fit. However, the reviewer did not find this split image screen to be helpful to him.


Last edited by kaseki; 5 Days Ago at 07:25 AM.
5 Days Ago   #9
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I’m using the AA-82 microprism screen in my 645z. The screens are physically identical, so they fit, but I was concerned they would affect metering or autofocus. I have found neither to be the case, though there may be an effect more subtle than I have noticed or care about.

I find the microprisms at least as precise as the focus confirmation when using manual lenses.

Rick “works for me” Denney
3 Days Ago   #10
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QuoteOriginally posted by rdenney Quote
There is no version of this for 645 or 67 lenses.
I know there isn't, but possibly someone could come out with one, especially with more medium format digital cameras coming onto the market.
3 Days Ago   #11
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QuoteOriginally posted by rdenney Quote
I’m using the AA-82 microprism screen in my 645z. The screens are physically identical, so they fit, but I was concerned they would affect metering or autofocus. I have found neither to be the case, though there may be an effect more subtle than I have noticed or care about.
I have an AA-82 I'm planning on putting into my 645D (haven't had enough time to work out how to do it yet - doing it on my LX seemed to be a fiddly, error-prone exercise). I too am concerned about metering - particularly spot metering (AF should be OK as it doesn't involve the focussing screen - the sensor looks out through the lens).

QuoteOriginally posted by leekil Quote
I know there isn't, but possibly someone could come out with one, especially with more medium format digital cameras coming onto the market.
It wasn't (isn't) a true AF adapter - you still have to get the focussing 'roughly right' and obviously it's a 1.7x teleconverter which changes focal length, effective aperture (and few 6x7 lenses are 'fast') and introduces aberrations. The 55-100/4.5 becomes something like a 95-170/8 ish lens (and something of a handful with an extra bit between it and the camera). Compared with turning the focussing ring until the green hexagon & AF sensor point LED light up* (and optionally the camera beeps), this seems like a big sacrifice.

* My 645D doesn't have Live View, I find manually focussing using the screen faster than waiting for the camera to confirm AF (hence the AA-82).

Last edited by johnha; 3 Days Ago at 08:51 PM. Reason: Another quote...
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