Program Plus, stepless shutter speeds?

murrelet · 06-14-2020, 07:25 PM

I can't seem to find if the Program Plus has stepless shutter speeds in auto mode in the manual or any marketing materials. This feature seems common for similar mid-80s cameras in the same class. And I find it odd it's not document if it was a feature on the Program Plus, which makes me think it wasn't. But that's equally odd. Maybe it was so ubiquitous it didn't need to be said?

BTW, I'm loving the Program Plus, more so that the Super Program and ME Super.

stevebrot · 06-14-2020, 10:33 PM

Originally posted by murrelet

Program Plus, stepless shutter speeds?

That is a very good question. My guess would be no for P mode and maybe for Av mode. The K2 along with the Spotmatic ES/ESII were promoted as having stepless shutters and I would assume the trend continued for the non-program Av mode bodies. Whether that was also true for the A-series program models is hard to say.. I do know that the shutter speed display on my Super Program is in full stop increments in Av mode even through half-steps of aperture.

Edit: On further thought, it is hard to say for P mode as well. I did take a peak at the service manual for the Super Program and stepless speeds are inferred from the program line diagram.

Steve

**From1980** · 06-14-2020, 10:36 PM

The Program Plus and all other M and A series automatic cameras had an electronically timed vertical run shutter with stepless speeds in Auto mode. The Pentax Forums camera review section can be consulted for further info.

stevebrot · 06-15-2020, 09:06 AM

Originally posted by From1980

The Program Plus and all other M and A series automatic cameras had an electronically timed vertical run shutter with stepless speeds in Auto mode. The Pentax Forums camera review section can be consulted for further info.

It is the stepless part that is in question and I am pretty sure that neither the member reviews nor promotional brochures from the time nor the camera manuals shed light on this. The problem is that just because the shutter is electronically timed does not mean that the camera utilizes it in a stepless manner. A good example would be my K-3 on the counter behind me. The shutter times in 1/3 or 1/2 stop increments (depending on how I set it) regardless of mode. Edit: On further consideration and despite recorded settings in the EXIF, I suspect that the shutter speeds are actually stepless on the K-3.

That said, you are likely correct with shutter being stepless in both P and Av modes. After all, it is straightforward and most likely; though short of putting a camera on a shutter tester, it would be hard to confirm.

Steve

Last edited by stevebrot; 06-15-2020 at 03:56 PM. Reason: accuracy

gebco · 06-15-2020, 11:22 AM

I found this mention by Popular Photography that says yes:
(December 1984 page 56)

Popular Photography - Google Books

stevebrot · 06-15-2020, 03:25 PM - **1 Like**

Originally posted by gebco

I found this mention by Popular Photography that says yes:
(December 1984 page 56)

Popular Photography - Google Books

Cool!

I did some more Google sleuthing and VERY careful combing through of available brochures and such and found a section of the Super Program brochure where both stepless shutter and stepless aperture (!) are claimed with notation that the display shows the nearest value to the one used. The official specifications in the same brochure are silent on this, but what the hay.

Well, we learn something new every day...I think. The same brochure has a photo of the aperture control block with an explanation of how optical detection of movement of the notched dial signals how far to move the aperture actuator. Those are discrete steps, not stepless...

I take the shutter speed statement at face value.

Steve

leekil · 06-15-2020, 09:55 PM

Originally posted by stevebrot

Well, we learn something new every day...I think. The same brochure has a photo of the aperture control block with an explanation of how optical detection of movement of the notched dial signals how far to move the aperture actuator. Those are discrete steps, not stepless...

Which brochure? Do you have a link?

---------- Post added 06-15-20 at 10:12 PM ----------

I found it in both the Super Program and Super A marketing brochures. But they kind of bury that information far into the brochure, not mentioning it up front when they talk about the exposure modes.

stevebrot · 06-15-2020, 10:24 PM

Originally posted by leekil

Which brochure? Do you have a link?

On the Pentax Manuals site...Super A brochure in table to the right on page 17 and Super Program brochure on pages 20 and 21.

Pentax Manuals| Literature

The description of the aperture control is in the Super Program brochure on page 19.

Steve

**Papa_Joe** · 06-16-2020, 06:43 AM

I would assume every SLR with auto mode on the shutter speed has stepless shutter speeds. First of all that was one of the main marketing arguments for auto mode cameras. Every one had it if you read the magazines (1985). Second I think building steps into an electronical controled shutter automatic would have been an additional efford no one would have done. What for? Rember analogue control means stepless.
That the cameras do only show half or 1/3 steps of time is a thing of practical usage. What would you make of 1/1283 in the camera display ?

06-14-2020, 07:25 PM	#1
murrelet Pentaxian Join Date: Dec 2007 Location: Portland, OR, USA Photos: Gallery \| Albums Posts: 506	Program Plus, stepless shutter speeds? I can't seem to find if the Program Plus has stepless shutter speeds in auto mode in the manual or any marketing materials. This feature seems common for similar mid-80s cameras in the same class. And I find it odd it's not document if it was a feature on the Program Plus, which makes me think it wasn't. But that's equally odd. Maybe it was so ubiquitous it didn't need to be said? BTW, I'm loving the Program Plus, more so that the Super Program and ME Super.

06-14-2020, 10:33 PM	#2
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by murrelet Program Plus, stepless shutter speeds? That is a very good question. My guess would be no for P mode and maybe for Av mode. The K2 along with the Spotmatic ES/ESII were promoted as having stepless shutters and I would assume the trend continued for the non-program Av mode bodies. Whether that was also true for the A-series program models is hard to say.. I do know that the shutter speed display on my Super Program is in full stop increments in Av mode even through half-steps of aperture. Edit: On further thought, it is hard to say for P mode as well. I did take a peak at the service manual for the Super Program and stepless speeds are inferred from the program line diagram. Steve Last edited by stevebrot; 06-14-2020 at 10:57 PM.

06-15-2020, 10:24 PM	#8
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by leekil Which brochure? Do you have a link? On the Pentax Manuals site...Super A brochure in table to the right on page 17 and Super Program brochure on pages 20 and 21. Pentax Manuals\| Literature The description of the aperture control is in the Super Program brochure on page 19. Steve

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Pentax Program A/Program Plus/Program A Plus	Finntax	Film SLRs and Compact Film Cameras	12	06-11-2020 03:36 PM
True Shutter Speeds compared to Nominal Shutter Speeds - Actual Measurements	AstroDave	General Photography	14	02-08-2018 02:07 PM
Does the electronic shutter provide anything other than ultrafast shutter speeds?	jake14mw	Pentax KP	19	06-21-2017 04:34 AM
Is the Shutter in the Pentax ME Stepless?	zx-m	Film SLRs and Compact Film Cameras	5	05-23-2010 02:30 PM
ME Super Stepless Shutter Speed?	KungPOW	Film SLRs and Compact Film Cameras	4	05-06-2008 08:45 PM

06-14-2020, 10:36 PM	#3
From1980 Site Supporter Join Date: Dec 2012 Location: Essex, Ontario Posts: 682	The Program Plus and all other M and A series automatic cameras had an electronically timed vertical run shutter with stepless speeds in Auto mode. The Pentax Forums camera review section can be consulted for further info.

06-15-2020, 09:06 AM	#4
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by From1980 The Program Plus and all other M and A series automatic cameras had an electronically timed vertical run shutter with stepless speeds in Auto mode. The Pentax Forums camera review section can be consulted for further info. It is the stepless part that is in question and I am pretty sure that neither the member reviews nor promotional brochures from the time nor the camera manuals shed light on this. The problem is that just because the shutter is electronically timed does not mean that the camera utilizes it in a stepless manner. A good example would be my K-3 on the counter behind me. The shutter times in 1/3 or 1/2 stop increments (depending on how I set it) regardless of mode. Edit: On further consideration and despite recorded settings in the EXIF, I suspect that the shutter speeds are actually stepless on the K-3. That said, you are likely correct with shutter being stepless in both P and Av modes. After all, it is straightforward and most likely; though short of putting a camera on a shutter tester, it would be hard to confirm. Steve Last edited by stevebrot; 06-15-2020 at 03:56 PM. Reason: accuracy

06-15-2020, 11:22 AM	#5
gebco Veteran Member Join Date: Mar 2010 Location: Winnipeg Photos: Gallery \| Albums Posts: 329	I found this mention by Popular Photography that says yes: (December 1984 page 56) Popular Photography - Google Books

06-15-2020, 03:25 PM - 1 Like	#6
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by gebco I found this mention by Popular Photography that says yes: (December 1984 page 56) Popular Photography - Google Books Cool! I did some more Google sleuthing and VERY careful combing through of available brochures and such and found a section of the Super Program brochure where both stepless shutter and stepless aperture (!) are claimed with notation that the display shows the nearest value to the one used. The official specifications in the same brochure are silent on this, but what the hay. Well, we learn something new every day...I think. The same brochure has a photo of the aperture control block with an explanation of how optical detection of movement of the notched dial signals how far to move the aperture actuator. Those are discrete steps, not stepless... I take the shutter speed statement at face value. Steve

06-15-2020, 09:55 PM	#7
leekil Pentaxian Join Date: May 2016 Photos: Albums Posts: 2,003	Originally posted by stevebrot Well, we learn something new every day...I think. The same brochure has a photo of the aperture control block with an explanation of how optical detection of movement of the notched dial signals how far to move the aperture actuator. Those are discrete steps, not stepless... Which brochure? Do you have a link? ---------- Post added 06-15-20 at 10:12 PM ---------- I found it in both the Super Program and Super A marketing brochures. But they kind of bury that information far into the brochure, not mentioning it up front when they talk about the exposure modes.

06-16-2020, 06:43 AM	#9
Papa_Joe Site Supporter Join Date: Sep 2018 Location: SW Bavaria Posts: 562	I would assume every SLR with auto mode on the shutter speed has stepless shutter speeds. First of all that was one of the main marketing arguments for auto mode cameras. Every one had it if you read the magazines (1985). Second I think building steps into an electronical controled shutter automatic would have been an additional efford no one would have done. What for? Rember analogue control means stepless. That the cameras do only show half or 1/3 steps of time is a thing of practical usage. What would you make of 1/1283 in the camera display ?