SR-3


(1960)  The SR-2 was a very advanced camera for the time, but it had two major drawbacks.  First, it was expensive and second, it lacked a built-in meter -- a feature that was introduced years earlier with cameras such as the Contaflex II of 1954.  These were enormous drawbacks and kept Minolta SLR sales down.  The year before, 1959, Canon had introduced its Canonflex SLR camera which had a clip-on selenium meter that was coupled to the shutter speed dial, and in 1960, Nikon unveiled the Nikkorex 35 SLR with a selenium meter that was built into the camera body!  Minolta addressed the first issue (i.e., cost) by producing the budget SR-1, and it addressed the second (i.e., metering) with the high-end SR-3.  

A separate, hand-held meter was necessary in order to use Minolta's first SLR, the meterless SR-2.  This made the SR-2 a less desirable camera, especially when compared to other, contemporary SLR cameras that had a built-in meter, such as the Contaflex Super and the Voigtlander Bessamatic.  Minolta had to scramble so as not to lose the competitive edge that it had gained in the market with the introduction of the SR-2 in 1958.  The SR-3 was an improved model of the SR-2 in that it added a provision for a clip-on, selenium meter -- the SR Meter (it could also accept the later SR Meter II).  Without the meter attached, the camera operated just like the SR-2.  But with the meter connected (it sat right on top of the shutter speed dial), the camera provided what Minolta called "semi-automatic" exposure control.  It was only automatic in the sense that as the needles on the top of the meter were matched-up, the shutter speed was changed -- "automatically".  Yet, this approach was very advanced in 1960 and made exposure much more convenient.  Today, most of us would refer to this feature as "metered-manual" exposure control.  But it 1960, it was "automated" -- when compared to the use of a separate, hand-held meter.

With the SR-3, you had the advantage of being able to buy a camera and get a meter later.  Still, the SR-3 meter lacked the compact, built-in nature of other camera-meter combinations, like the Contaflex Super and the Voigtlander Bessamatic.  With these cameras, the meter was integrated into the camera -- something that Minolta would accomplish two years later with the SR-7

The SR-3 was designed to be used with a special, clip-on, SR meter.  The shutter speed dial has a small tab that connects to the bottom of the meter.  First, dial in the film speed on the meter, and then select a shutter speed.  As you select a shutter speed on the meter, the same speed is set on the camera.  Next, point the meter toward the scene and read the correct f-stop on the top of the meter.   Set that f-stop on the lens, and take the picture.   (Alternately, the f-stop could be selected first and then the shutter speed dial turned until the needle in the meter readout points to the same f-stop.)  This process was so convenient that they actually called it "semi-automatic" exposure control back in those days!  It was a process that Minolta had developed on the Super A camera of 1957 -- the first Japanese camera to offer this feature. Minolta should have used this feature on the SR-2 of 1958, but instead, Canon stole the idea and used it on the Canonflex of 1959 -- grabbing the thunder that rightfully belonged to Minolta.

But the SR-3 had other improvements over the SR-2, besides the clip-on meter option.  The shutter on the SR-3 was more quiet, although it's still loud by present-day standards.  Also, the viewing screen in the SR-3 added a split-image rangefinder in the middle of the microprism circle -- a big deal at the time.  From now on, all of Minolta's top-of-the-line cameras would have this type of screen.  In addition, the SR-3 had equidistant shutter speeds on the shutter dial.  On the SR-2, the faster the speed, the closer it was the the next speed on the dial.  This gets pretty awkward at the higher speeds, and can cause errors, especially in dim light.

Last, but not least, Minolta modified their viewfinder mount on the SR-3.  On their previous cameras, viewfinder accessories were screwed into place on the round viewfinder.  On the SR-3, the viewfinder is still round, but the accessories are attached with a new bayonet fitting.  The new accessories will not fit onto the older cameras, just as the old accessories will not fit onto the newer cameras.  The names of the accessories were changed as well.  For example, the screw-in Angle Finder SR which fit the SR-2 became the bayonet Angle Finder SR-2 which fit the SR-3.  This, of course, leads to some confusion.  The Angle Finder SR-2 has nothing to do with the SR-2 camera;  it was just the second style of anglefinders.  

There were actually two versions of the SR-3 although the bodies of the camera look identical and these model numbers are not marked on the bodies:

SR-3 (model a) -- (1960)

On the original model of the SR-3, the lens diaphragm action was "semi-automatic".  Just like with the earlier SR-2, with automatic diaphragm lenses, while the lens stayed at full aperture until the moment of exposure, it did not automatically return to full aperture after the exposure. In order to regain the full aperture setting, it was necessary to advance the film, which cocked the shutter and reset the diaphragm to the open position.

SR-3 (model b) -- (1961)

On this version of the SR-3, the diaphragm retained the open position even after the shutter is released.  Minolta made a similar change to it's SR-1 camera at the same time. This automatic diaphragm was an advanced, convenience feature, but it had one drawback.  When someone wanted to check the depth-of-field, they could no longer do this in the viewfinder since the lens never "stopped-down".  Minolta solved this problem by adding a DOF (depth-of-field) lever to their lenses.  This was, in fact, a major change.  The problem for Minolta was that their lenses already had enough levers.  First, there is the f-stop ring and the focusing ring.  In addition, all their lenses had an f-stop lock tab to help prevent accidental movement of the f-stop ring.  With the addition of a DOF lever, the lenses would become unnecessarily complicated.  To resolve the issue, Minolta opted -- wisely -- to remove the f-stop lock tab and replace it with the DOF lever.  This required no change in the cameras, but confused some consumers since it's difficult to tell the difference between an f-stop lock button and a DOF button. On some lenses, they looked nearly identical.  Oh well, it was a step in the right direction.  It was only a change made on the Rokkor lenses of the time and Minolta added stop-down "clicks" to each setting on the f-stop rings on these new lenses to indicate change in the diaphragm and prevent accidental movement.  So you will see the same Rokkor lens in two different styles (see the MINMAN SLR lens list for complete details -- the most complete Minolta lens list in the world!). But in order for this to happen a change had to be made to the Auto-Rokkor lenses.

Initially, the Auto-Rokkors were designed for the SR-2 and early SR-1 cameras that had semi-automatic aperture function.  With this feature, the aperture on the lens was cocked when the film was advanced.  A pin in the camera kept the lens at full aperture.  When the shutter was released, the pin in the camera released the pin in the lens, and the lens was stopped down.  Resetting the lens required the slow pressure of the film advance.

But this changed when Minolta introduced the SR-3 and SR-1 (model c) which were designed for fully-automatic aperture operation.  These camera automatically reset the lens to full aperture immediately after each exposure -- without advancing the film -- and the old mechanisms proved inadequate to the task.  An important change had to be made to the Auto-Rokkor lenses at this time.  To allow the new cameras to instantly re-open the aperture in the lens after the exposure, it was necessary for Minolta to modify the aperture linkage in the original Auto-Rokkor lenses. (The Rokkor lenses didn't require any change since they lacked the aperture linkage.)  Specifically, the original Auto-Rokkor lenses have their aperture linkage on a rotating, external plate on the back of the lens.  This approach proved inadequate to handle the speed of a fully-automatic aperture, and Minolta modified the mechanism to an internal, lateral-operating pin.  This approach had additional advantages other than just a fully-automatic aperture.  

On the original Auto-Rokkor lenses (those with the rotating external plate), the aperture linkage moved up and down as it rotated.  This required a fairly tall lever inside the camera body, to make sure that the two would always engage -- as the pin in the lens moved up and down, and the pin in the camera moved left and right.  It also required a fair amount of pressure from the lever in the camera to open the lens up.  With the new, lateral-moving aperture pin in the lens, the lever in the camera could be shorter and, as a result, the mirror in the camera could be made bigger.  This helped eliminate the image cut-off that was seen with long telephoto lenses.  (Minolta called it an over-sized mirror and it was used in all of their subsequent 35mm SLR cameras.)  The drawback is that the original Auto-Rokkor lenses will not operate at all f-stops on later cameras.  You'll be able to select any f-stop on the lens, but when the older lens stops down, the aperture will stop at around f8.  For example, let's say you dial in f16 on the aperture ring.  When the exposure is taken, the lens will only stop down to f8 and the picture will be over-exposed by two f-stops.  These older lenses were designed for cameras with tall aperture pins and when used on newer cameras, at higher apertures, the tab in the lens is not fully released.  While this will not cause damage to the lens or camera, it prevents the smallest f-stops settings from being used.  

The SR-3 was a stop-gap camera.  It was an attempt by Minolta to keep up with other manufacturers that were offering cameras with built-in metering.  Minolta was caught with its pants down.  To deal with the issue, in the next year, 1961, Minolta would market the ER SLR.  It was an SLR with a built in meter.  And although it lacked interchangeable lenses, the ER featured automatic exposure -- a remarkable achievement in SLR cameras.  And in the next year, 1962,  Minolta marketed the amazing SR-7, the first Minolta SLR with interchangeable lenses AND and built-in meter -- a CDS meter to boot!  It was the first Japanese SLR to accomplish this feat.  Minolta was back in business, and the SR-3 was lovingly placed into the history books.

For a comparative look at the major features of the SR-3 models, check out MINMAN's SLR table -- the world's most complete!

CAMERA SPECIFICATIONS
Camera SR-3 SR-3
Model a b
Years made 1960-1961 1961-1962
Type Mechanical 35mm SLR Mechanical 35mm SLR
Shutter Fully mechanical, horizontal, cloth focal plane shutter Fully mechanical, horizontal, cloth focal plane shutter
Metering None None
Meter sensitivity -- --
Exposure modes Manual Manual
Automatic exposure
adjustment
-- --
Viewfinder Fixed eye-level pentaprism Fixed eye-level pentaprism
Focusing screen Fresnel-field screen with a micro-prism center Fresnel-field screen with a micro-prism center
Lens mount Minolta SLR bayonet Minolta SLR bayonet
Lenses Optimum: early Auto Rokkor
Usable: later Auto Rokkor, Rokkor, MC Rokkor, MC Rokkor-X, MC Celtic, MD Rokkor, MD Celtic, MD Minolta
Optimum: later Auto Rokkor
Usable: early Auto Rokkor, Rokkor, MC Rokkor, MC Rokkor-X, MC Celtic, MD Rokkor, MD Celtic, MD Minolta
Mirror Instant return mirror Instant return mirror
Film speeds -- --
Shutter speeds Mechanical: 1 - 1,000; B
Manual: 1 - 1,000; B
Mechanical: 1 - 1,000; B
Manual: 1 - 1,000; B
Flash synch X: B; 1 - 1/45
FP: B; 1 - 1/15
M: B; 1 - 1/15
MF: B; 1 - 1/15
X: B; 1 - 1/45
FP: B; 1 - 1/15
M: B; 1 - 1/15
MF: B; 1 - 1/15
Flash connection Clip-on, cold shoe
X and FP PC contacts
Clip-on, cold shoe
X and FP PC contacts
Film counter Automatically resetting type counting upward Automatically resetting type counting upward
Battery -- --
DOF/Stop-down button No No
Film Back Non-interchangeable Non-interchangeable
Multiple exposures No No
Film advance Lever type Lever type
Self-timer Mechanical, overrideable, non-cancellable, adjustable from 4 to 10 seconds Mechanical, overrideable, non-cancellable, adjustable from 4 to 10 seconds
Film reminder No No
Other Cable release connection, tripod socket Cable release connection, tripod socket
Body size 2 x 3 1/2 x 5 3/4 inches 2 x 3 1/2 x 5 3/4 inches
Body weight One pound two ounces One pound two ounces

RETURN TO THE MANUAL MINOLTA HOME PAGE

We didin't want to do this, but since other websites have been stealing our stuff, we have no alternative but to state:
COPYRIGHT@1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006 by Joe McGloin.

All Rights Reserved. The material on this website is protected by US Federal copyright laws. It cannot be copied or used in any manner without specific approval from the owner.

The material on this website is protected by US Federal copyright laws. It cannot be copied or used in any manner without specific approval from the owner.