Mechanical + electronic hybrid shutter

benjiboy · May 22, 2023

Les Sarile said:
Oddly, the exhausted battery must be removed from the chamber in order for the camera to work. Not sure why this is the case.

Yes I know Les. I'm not sure either why this is, but I do know it requires in order to remove the battery the Power Winder FN has to also be removed first which is awkward, but with the Motor Drive FN fitted it's impossible without exposing the film in daylight .

Chan Tran · May 22, 2023

benjiboy said:
Yes I know Les. I'm not sure either why this is, but I do know it requires in order to remove the battery the Power Winder FN has to also be removed first which is awkward, but with the Motor Drive FN fitted it's impossible without exposing the film in daylight .

I think

Les Sarile said:
Oddly, the exhausted battery must be removed from the chamber in order for the camera to work. Not sure why this is the case.

If the battery is low it can give wrong autoexposure so Canon designed it to shutdown the camera when the battery is low. You have to remove the battery so that there is no battery power at all to do this shutdown.

Les Sarile · May 22, 2023

Chan Tran said:
I think

If the battery is low it can give wrong autoexposure so Canon designed it to shutdown the camera when the battery is low. You have to remove the battery so that there is no battery power at all to do this shutdown.

If you're just guessing, that would also be my guess as I don't h as ve schematics. However, a cutoff circuit is the most trivial to design so that steered me to think there must be a different reason.

Chan Tran · May 22, 2023

I am partly guessing but there is for certain a shut off circuit when the battery voltage is low.
I attach the test report from Pop Photo by Norman Goldberg and Michelle A. Frank.

Les Sarile · May 22, 2023

Chan Tran said:
I am partly guessing but there is for certain a shut off circuit when the battery voltage is low.
I attach the test report from Pop Photo by Norman Goldberg and Michelle A. Frank.

I don't see an attachment but I've seen many of their great in-depth mechanical and electrical breakdowns but never down to the components on a schematic.
I'm with you that a cutoff circuit must be in place. I am thinking all the shutter speeds are electronically controlled unless the battery is removed as opposed to the electronics only control the low speeds and B, sync and above are completely mechanical.

benjiboy · May 23, 2023

Chan Tran said:
I am partly guessing but there is for certain a shut off circuit when the battery voltage is low.
I attach the test report from Pop Photo by Norman Goldberg and Michelle A. Frank.

I think the the circuit is called a "Wheatstone Bridge", that ensures that if the battery power drops too low it cuts out.

Chan Tran · May 23, 2023

benjiboy said:
I think the the circuit is called a "Wheatstone Bridge", that ensures that if the battery power drops too low it cuts out.

It's not the wheatstone bridge. The wheatstone bridge doesn't cut out if the battery drops too low. The wheatstone bridge isn't affected by battery voltage if used at the null point.
The Nikon F3 turn itself off too if the battery voltage drops below 2.4V. It doesn't have a wheatstone bridge. Also I don't think the new F1 has Cds cell as wheatstone bridge only used with Cds cell and not silicon cell. When the New F1 was introduced technology has advanced passs that.

benjiboy · May 26, 2023

I know you are probably right Chan, I admit I know little to nothing about electronics , I bow to your superior knowledge.
The New F1 indeed has a silicone blue metering cell, the original F1, and the F 1n have CdS cells.

Autonerd · May 29, 2023

pkr1979 said:
Go for it

OK, since I was asked...

I think mechanical shutters are highly overrated, and electronic shutters unfairly maligned. Yes, clockwork shutters have a charm all their own, and they sound great. But they are also complex and more likely to lose their timing due to wear and gummed-up lube. In my experience, if an electronic shutter works at all, it probably works correctly. And the older I get, the nicer it is to have the option of an automatic mode. (Though I've also hosed myself and my photos by forgetting my Pentax K2 *wasn't* in automatic mode...)

I've bought several electronic-shutter cameras and find they do a great job. Plus they're cheaper. I've repeatedly had the happy experience of buying a $20-or-less camera and finding it produces perfect negatives without the need for a CLA. Most of the mechanical cameras I've bought have needed attention -- and it's hard to justify a $100 CLA when I have $15 cameras that are working just fine thankyouverymuch.

So that's my rant!

Aaron

Bill Burk · May 30, 2023

If you start repairing cameras you’ll appreciate the mechanical cameras of better craftsmanship.

You may also appreciate the really simple cameras because you can make them work. It’s easy to get a Kodak 35 working.

Electronic cameras are really hard to repair. When they don’t work you might have a difficult problem.

As a camera starts getting old, mechanical cameras degrade more gracefully than electronic ones.

I’ve had electronic cameras become doorstops when their weird, hard to find batteries die (Canon A-1). I’ve had them not even open the shutter in self-timer mode (OM-4).

Meanwhile a Contax-II won’t stop working. I hated it enough to leave at the cabin for a year just so I could have some kind of camera when I go there. It never worked above 1/250 and sometimes not lower than 1/15 but it always worked.

It’s hard to work on a Contax-II so I wouldn’t recommend it as a first repair attempt.

ic-racer · May 30, 2023

Most 35mm focal plane shutters of which I am familiar are mechanical with electronic trigger. I don't know of any that are fully electronic (anyone??).

For example, the Rolleiflex SLX/6000 SLR shutters are fully electronic.

benjiboy · May 30, 2023

ic-racer said:
Most 35mm focal plane shutters of which I am familiar are mechanical with electronic trigger. I don't know of any that are fully electronic (anyone??).

For example, the Rolleiflex SLX/6000 SLR shutters are fully electronic.

The Canon A and T series cameras
are all electronic.

ic-racer · May 30, 2023

AE-1 along with the T series use fully mechanical shutters with electronic release.

Les Sarile · May 30, 2023

ic-racer said:
AE-1 along with the T series use fully mechanical shutters with electronic release.

View attachment 340195

So the Rolleiflex SLX/6000 does not have a mechanical shutter with electronic release? I was under the impression all are although configured differently - horizontal, vertical and leaf. In my mind only the mirrorless are fully electronic.

Autonerd · May 31, 2023

When I refer to an electronic (film) shutter, I'm referring to electronic timing, ie needs a battery (as opposed to a fully mechanical or "clockwork" shutter mechanism) -- so a Nikon FE has an electronic shutter but a NIkon FM does not. I believe that's the proper terminology, but if I'm mistaken, please tell me!

ic-racer · May 31, 2023

Les Sarile said:
So the Rolleiflex SLX/6000 does not have a mechanical shutter with electronic release? I was under the impression all are although configured differently - horizontal, vertical and leaf. In my mind only the mirrorless are fully electronic.

Exactly, the Rolllei shutter has no mainspring and does not need to be cocked. The leaves of both the shutter and diaphragm move via electric motors.

ic-racer · May 31, 2023

The archetype 35mm electronic shutter mechanically releases the first curtain via the mirror movement upward, and releases the second curtain via electromagnet.

However, what is described in this thread, is the continued inclusion of the mechanical escapement. Not unreasonable since the electromagnet can be made smaller than a mechanical escapement. So you can have both without making the camera much bigger.

Chan Tran · May 31, 2023

ic-racer said:
Exactly, the Rolllei shutter has no mainspring and does not need to be cocked. The leaves of both the shutter and diaphragm move via electric motors.

I think the Canon EOS-1V has the same type of shutter as well as their DSLR's.

Les Sarile · Jun 1, 2023

ic-racer said:
Exactly, the Rolllei shutter has no mainspring and does not need to be cocked. The leaves of both the shutter and diaphragm move via electric motors.

Did not know that a motorized shutter can achieve relatively quick speeds!

ic-racer · Jun 1, 2023

Les Sarile said:
Did not know that a motorized shutter can achieve relatively quick speeds!

They came out with that in 1975! Top speed was 1/500, but upped to 1/1000 in the late 1990s.

Even back in 1975 this is how it performed:

Electric switch shutter button pressed
Diaphragm closes until correct exposure is achieved with TTL meter
Shutter closes
Mirror goes up
Shutter opens/closes based on set speed
Mirror goes down
Shutter and aperture open
Motor winds the film to next frame

Les Sarile · Jun 1, 2023

ic-racer said:
They came out with that in 1975! Top speed was 1/500, but upped to 1/1000 in the late 1990s.

Even back in 1975 this is how it performed:

Electric switch shutter button pressed
Diaphragm closes until correct exposure is achieved with TTL meter
Shutter closes
Mirror goes up
Shutter opens/closes based on set speed
Mirror goes down
Shutter and aperture open
Motor winds the film to next frame

View attachment 340346

In my mind, mirror and aperture movements done by motors seems simple enough but I have no idea how a motor can close the shutter that quickly with precision! I wonder how they spin up the motor that quickly as well as decelerate it? Working on electronic pinball machines, I can almost conceptualize using a solenoid but not motors!

ic-racer · Jun 1, 2023

Les Sarile said:
In my mind, mirror and aperture movements done by motors seems simple enough but I have no idea how a motor can close the shutter that quickly with precision! I wonder how they spin up the motor that quickly as well as decelerate it? Working on electronic pinball machines, I can almost conceptualize using a solenoid but not motors!

I think they are more like a solenoid but they call them "linear motors" in the literature. I have a treasure trove of Rollei repair documents, but nothing on those lenses.

Bill Burk · Jun 2, 2023

Is this the sequence? Does the camera have two different shutters?

Or is the mirror a capping shutter?

(Front) Shutter closes
Mirror goes up (rear shutter opens)
(Front) Shutter opens/closes based on set speed

ic-racer · Jun 2, 2023

Bill Burk said:
Is this the sequence? Does the camera have two different shutters?

Or is the mirror a capping shutter?

(Front) Shutter closes
Mirror goes up (rear shutter opens)
(Front) Shutter opens/closes based on set speed

The mirror forms a light tight seal.

Mechanical + electronic hybrid shutter

Privacy & Transparency

Privacy & Transparency