Strange behavior of A 50mm 1.2 during Av mode?

stevebrot · 11-07-2020, 10:47 PM

Originally posted by gofour3

The MZ-S supports matrix metering with all A/F/FA lenses and only supports centre weighted with K/M lenses.

Am I remembering correctly that the MZ-S is also rather unique in that it will display the aperture even when the aperture ring is off the "A" setting?

Steve

pschlute · 11-07-2020, 10:54 PM

Originally posted by kayakfari

On a related aperture ring note .. Pentax killed off the old rheostat aperture detector and forced us to use stop down metering years ago on DSLRs.
Well remember those aperture readout windows on the prisms like the KX, MX and others?
So how about a modern version with OCR so that the body can know exactly what aperture K and M series lenses (and 3rd party) are set at!?
The info is always in that same spot on those lenses, should be a relatively simple optical and software implement, no mechanics needed.
I would welcome such a feature!

My understanding is that when the "crippled" K-mount was introduced it lacked the physical coupling that enabled the camera to read the aperture position set on "K" and M series lenses (and A series when not using the A position)

I think they would need to redesign the K mount and re-instate the coupler to get full functioning with K and M lenses.

someasiancameraguy · 11-07-2020, 11:07 PM

Originally posted by stevebrot

Am I remembering correctly that the MZ-S is also rather unique in that it will display the aperture even when the aperture ring is off the "A" setting?

Steve

It correctly shows apertures for F or FA lenses AFAIK

Not a Number · 11-07-2020, 11:46 PM

It's easy to check if the mount is "crippled" or not. Take the lens off and see if there is a coupler lever at around the 1:30 - 2:00 o'clock position inside the mouth of the camera mount.

Mosphoto's compatibility chart shows that bodies prior to the MZ/ZX-30 (which include the MZ-M and MZ-S) have the coupler (e.g. not "crippled"). Even if the cameras have the coupler though it may not use it in under different conditions.

womble · 11-08-2020, 03:03 AM

The K mount pages give this info too.

MZ/ZX-Series Film Bodies | The K-Mount Page

**gofour3** · 11-08-2020, 09:46 AM

Originally posted by stevebrot

Am I remembering correctly that the MZ-S is also rather unique in that it will display the aperture even when the aperture ring is off the "A" setting?

Steve

Correct for F/FA lenses, but only if the meter is active. (K/M/A show F--)

Phil.

stevebrot · 11-08-2020, 12:06 PM

Originally posted by gofour3

Correct for F/FA lenses, but only if the meter is active. (K/M/A show F--)

Phil.

I was surprised to find that the MZ-3 manual indicates the same for the MZ-3. The AF lenses provide the max/min information through the data contact.

Steve

kayakfari · 11-08-2020, 12:18 PM

Originally posted by pschlute

My understanding is that when the "crippled" K-mount was introduced it lacked the physical coupling that enabled the camera to read the aperture position set on "K" and M series lenses (and A series when not using the A position)

I think they would need to redesign the K mount and re-instate the coupler to get full functioning with K and M lenses.

Idk that you understood what I was saying.
Using OCR and the same type of optic path as those old models mentioned, Pentax could now visually read the actual aperture set without the need for any mechanical coupling(s). No need to make any mount changes, all simple optics and software.

stevebrot · 11-08-2020, 01:02 PM

Originally posted by kayakfari

Using OCR and the same type of optic path as those old models mentioned, Pentax could now visually read the actual aperture set without the need for any mechanical coupling(s). No need to make any mount changes, all simple optics and software.

It might actually be easier to simply restore the non-crippled mount, no OCR required. The mechanism is simple and compact, no rheostat required.

Steve

pschlute · 11-08-2020, 01:45 PM

Originally posted by stevebrot

It might actually be easier to simply restore the non-crippled mount, no OCR required. The mechanism is simple and compact, no rheostat required.

Exactly. Reinstate the k-mount coupler. Creating a Judas window with the camera having to read the number is a very inelegant solution . Low light use ?

11-08-2020, 09:46 AM	#21
gofour3 Site Supporter Join Date: Oct 2008 Location: Vancouver, Canada Posts: 8,092	Originally posted by stevebrot Am I remembering correctly that the MZ-S is also rather unique in that it will display the aperture even when the aperture ring is off the "A" setting? Steve Correct for F/FA lenses, but only if the meter is active. (K/M/A show F--) Phil. Last edited by gofour3; 11-08-2020 at 09:57 AM. Reason: Added more info.

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11-07-2020, 10:47 PM	#16
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by gofour3 The MZ-S supports matrix metering with all A/F/FA lenses and only supports centre weighted with K/M lenses. Am I remembering correctly that the MZ-S is also rather unique in that it will display the aperture even when the aperture ring is off the "A" setting? Steve

11-07-2020, 10:54 PM	#17
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,211	Originally posted by kayakfari On a related aperture ring note .. Pentax killed off the old rheostat aperture detector and forced us to use stop down metering years ago on DSLRs. Well remember those aperture readout windows on the prisms like the KX, MX and others? So how about a modern version with OCR so that the body can know exactly what aperture K and M series lenses (and 3rd party) are set at!? The info is always in that same spot on those lenses, should be a relatively simple optical and software implement, no mechanics needed. I would welcome such a feature! My understanding is that when the "crippled" K-mount was introduced it lacked the physical coupling that enabled the camera to read the aperture position set on "K" and M series lenses (and A series when not using the A position) I think they would need to redesign the K mount and re-instate the coupler to get full functioning with K and M lenses.

11-07-2020, 11:07 PM	#18
someasiancameraguy Veteran Member Join Date: Jul 2017 Location: Hong Kong Posts: 419 Original Poster	Originally posted by stevebrot Am I remembering correctly that the MZ-S is also rather unique in that it will display the aperture even when the aperture ring is off the "A" setting? Steve It correctly shows apertures for F or FA lenses AFAIK

11-07-2020, 11:46 PM	#19
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	It's easy to check if the mount is "crippled" or not. Take the lens off and see if there is a coupler lever at around the 1:30 - 2:00 o'clock position inside the mouth of the camera mount. Mosphoto's compatibility chart shows that bodies prior to the MZ/ZX-30 (which include the MZ-M and MZ-S) have the coupler (e.g. not "crippled"). Even if the cameras have the coupler though it may not use it in under different conditions.

11-08-2020, 03:03 AM	#20
womble Pentaxian Join Date: Apr 2010 Location: Hertfordshire Photos: Gallery Posts: 4,324	The K mount pages give this info too. MZ/ZX-Series Film Bodies \| The K-Mount Page

11-08-2020, 12:06 PM	#22
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by gofour3 Correct for F/FA lenses, but only if the meter is active. (K/M/A show F--) Phil. I was surprised to find that the MZ-3 manual indicates the same for the MZ-3. The AF lenses provide the max/min information through the data contact. Steve

11-08-2020, 12:18 PM	#23
kayakfari Senior Member Join Date: Oct 2016 Location: South Florida Posts: 173	Originally posted by pschlute My understanding is that when the "crippled" K-mount was introduced it lacked the physical coupling that enabled the camera to read the aperture position set on "K" and M series lenses (and A series when not using the A position) I think they would need to redesign the K mount and re-instate the coupler to get full functioning with K and M lenses. Idk that you understood what I was saying. Using OCR and the same type of optic path as those old models mentioned, Pentax could now visually read the actual aperture set without the need for any mechanical coupling(s). No need to make any mount changes, all simple optics and software.

11-08-2020, 01:02 PM	#24
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by kayakfari Using OCR and the same type of optic path as those old models mentioned, Pentax could now visually read the actual aperture set without the need for any mechanical coupling(s). No need to make any mount changes, all simple optics and software. It might actually be easier to simply restore the non-crippled mount, no OCR required. The mechanism is simple and compact, no rheostat required. Steve

11-08-2020, 01:45 PM	#25
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,211	Originally posted by stevebrot It might actually be easier to simply restore the non-crippled mount, no OCR required. The mechanism is simple and compact, no rheostat required. Exactly. Reinstate the k-mount coupler. Creating a Judas window with the camera having to read the number is a very inelegant solution . Low light use ?