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04-16-2016, 09:20 AM   #1
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how does the SPIIa:

Work with dedicated flash, and which flash....

Ancient minds wish to know

David

04-16-2016, 09:36 AM   #2
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Looking around the web, it seems there was a particular Honeywell flash called the Strobonar which had a particular hookup to this model of Spotmatic II. The effect was similar to that of a thyristor flash such as the AF200Sa, but with the sensor on the camera rather than the flash body.

The instruction manual is available here for a fee via paypal....

Die Cast Pro - Download Pentax Spotmatic IIa Operating Manual

...and here for free.

Pentax Manuals
04-16-2016, 09:44 AM   #3
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Does anyone know how rare a model the SP IIa is?

I'm only asking because of the dozens and dozens of Spotmatics that have passed through my hands over the years, not one has been an SP IIa.

It is possible they were only sold in the US, and weren't available up here in Canada anyway? That said, I do see the occasional "Honeywell" branded camera from time to time.
04-16-2016, 10:02 AM   #4
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In the Pentax Forums Pentax Spotmatic IIa review it states, "The Spotmatic IIa adds a flash sensor and dedicated coupling for a Honeywell flash. Having the flash sensor in the camera allowed for easy flash photography also with the flash hand held at a distance from the camera." However, it is not a form of TTL flash so it is a curious concept and I wonder how it works.

Looks like you need the awesome looking Honeywell strobe but likely any manual flash capable strobe would work.


04-16-2016, 10:23 AM   #5
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QuoteOriginally posted by LesDMess Quote
However, it is not a form of TTL flash so it is a curious concept and I wonder how it works.
As I stated above, it's like a thyristor flash but with the thyristor sensor on the camera body and (I suppose) with extra circuitry on what might loosely be called the X-sync bus, to enable the sensor to cut the flash off at the appropriate instant. This theoretically goes one better than having the thyristor sensor on the flash, because you can put the flash anywhere within its brightness and angle coverage and the exposure will still be correct at the camera.

If you try this with a normal flash-mounted regulating thyristor sensor (and I have), quite often you will NOT get a fully exposed picture because the flash is working on the assumption that it is mounted on the camera, roughly equidistant from the film/sensor plane, when all too often it is not.
04-16-2016, 11:29 AM   #6
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QuoteOriginally posted by pathdoc Quote
If you try this with a normal flash-mounted regulating thyristor sensor (and I have), quite often you will NOT get a fully exposed picture because the flash is working on the assumption that it is mounted on the camera, roughly equidistant from the film/sensor plane, when all too often it is not.
That makes perfect sense for an off the camera - particularly remotely located, flash. Personally I had been using flash meters and manual flash. Now I am using DIY high powered LEDs as continuous light source and it is has it's advantages - like no flash sync limitations.

Last edited by LesDMess; 04-16-2016 at 11:37 AM.
04-16-2016, 01:46 PM   #7
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It does seem like Honeywell wanted to leverage the partnership with Pentax and their own U.S-made flash equipment. I recall seeing the ads in back issues of old camera magazines (I would have been a young kid at the time and not playing with expensive cameras).

However, it really wasn't necessary to put the external sensor "eye" right into a dedicated camera body. Putting the sensor on a hot-shoe mounted module worked just as well for many other manufacturers of handle-mount flashes (Vivitar, Sunpak, Metz, etc.)

So, was it a really short-lived innovation, and the SP IIa disappeared quickly?
04-16-2016, 01:56 PM   #8
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IIRC there were and are (for still existing units) issues with light leaks around the sensor. In addition, a specialised body with its added manufacturing expenses probably proved not worth the costs.

04-16-2016, 08:05 PM   #9
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QuoteOriginally posted by Ontarian50 Quote
It does seem like Honeywell wanted to leverage the partnership with Pentax and their own U.S-made flash equipment
The other negative (besides defacing the camera body) was that Honeywell did not import any Pentax flash models from that period, so for example you could not get the Autorobo flash in the USA.

Phil.
04-17-2016, 01:43 AM   #10
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QuoteOriginally posted by gofour3 Quote
The other negative (besides defacing the camera body) was that Honeywell did not import any Pentax flash models from that period, so for example you could not get the Autorobo flash in the USA.

Phil.
So thats why the Autorobo flash seems so difficult to find?
04-17-2016, 10:27 AM   #11
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QuoteOriginally posted by Baard-Einar Quote
So thats why the Autorobo flash seems so difficult to find?
Yep could be, though I have seen a few here in Vancouver for sale. (I've got three now)

The Autorobo was included in the Canadian price lists from the period.

Phil.
04-17-2016, 10:55 PM   #12
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QuoteOriginally posted by gofour3 Quote
Yep could be, though I have seen a few here in Vancouver for sale. (I've got three now)

The Autorobo was included in the Canadian price lists from the period.

Phil.
You're lucky. Pentax did not have many flash models at all back in those days. I hope a Autorobo comes my way at some point.


Cheers, baard-einar
04-18-2016, 06:49 AM   #13
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QuoteOriginally posted by Baard-Einar Quote
I hope a Autorobo comes my way at some point.
I don't really need three of them, so if you are interested in buying one PM me.

Phil.
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