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06-14-2020, 07:25 PM   #1
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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
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QuoteOriginally posted by murrelet Quote
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.
06-14-2020, 10:36 PM   #3
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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
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QuoteOriginally posted by From1980 Quote
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
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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
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QuoteOriginally posted by gebco Quote
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.


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06-15-2020, 09:55 PM   #7
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QuoteOriginally posted by stevebrot Quote
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.
06-15-2020, 10:24 PM   #8
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QuoteOriginally posted by leekil Quote
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.


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06-16-2020, 06:43 AM   #9
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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 ?
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