2other Minolta cameras in my collection:

 

JapanMinolta Hi-Matic 7s [1966 - 1977*]

 

Background

The Hi-Matic was a long running series of automatic exposure, rangefinder focusing cameras first introduced in 1962.

The Hi-Matic 7 came in 1963. It had a faster f/1.8 lens and used a CdS cell instead of a selenium meter. Additionally, it gave photographers the option of setting the exposure manually.

The Hi-Matic 7s and Hi-Matic 9, both released in 1966, were slightly improved versions of the 7. The 7s added a hot shoe and Safe Load System (SLS) indicator to show that film was being transported properly. The rangefinder windows changed from a contrasting pink/green tint to yellow/blue. The carrying strap lugs were moved up to the side and given a more rounded shape. The end of the lens barrel is black rather than the brushed aluminium of the 7. The 9 was the same as the 7s with the addition of a slightly faster f/1.7 lens, and an easy flash system, where the flash guide number was dialled into the lens, and the aperture was set automatically, according to the focus distance.

The 11 of 1969 was a version of the 9 with no manual aperture controls.

From 1969, Minolta produced a range of smaller and simpler models until 1977 when the Hi-Matic 7sII almost reproduced the 7s in a compact package (which I believe was made by Cosina for Minolta).

I don't know when production of the Hi-Matic 7s ceased, but it may well have continued until 1977, when the 7sII was introduced. It was certainly still being made in 1975, according to an article in Camera User magazine.

 

Overview

Minolta adThe Hi-Matic 7s is a large and heavy coupled rangefinder camera with automatic viewfinder parallax correction, a built-in CdS exposure meter providing automatic exposure adjustment, and a viewfinder display of EV numbers rather than shutter speeds or f stops.

Many Minolta cameras of this period featured a Contrast Light Compensator (CLC), and most Internet resources on the Hi-Matics (7s, 9, and 11), including Wikipedia, state that the CLC comprised two CdS cells connected in series .... But ... Hi-Matics have only ONE cell !

Among psychologists this is an example of what is known as the illusion of truth effect: say something often enough and it becomes true.

What is the CLC?

I have explained the CLC as found in the two-celled Minolta SR-T 101 on that camera's page, but what the CLC does in the Hi-Matics is a mystery, since contrast is a difference in luminescence, and two readings have to be compared to identify a difference. One cell cannot simultaneously have two different viewpoints.

The ever helpful Camera-Wiki folk have uncovered a Minolta patent of the period that describes a lens housed light-cell with a viewpoint that's off-the-axis of the camera lens, and which favours exposure based on the foreground. It would appear to be a possible alternative CLC (if that's how one choses to describe it). My understanding of the patent is the angle of view of the cell is altered by a lens cover, and the field of view by a form of slot blind.

Light receiving device for electrical exposure meter for cameras - patent US 3286609 A

I have read that Hi-Matics meter differently upside-down. I tried it, with a carefully framed, high contrast sun set ... but my Hi-Matic gave the same EV reading in any orientation. I can therefore present no anecdotal evidence in support of this hypothesis. I've noticed that a lot of Minolta advertising plays down the CLC feature; indeed, the magazine cutting above does not mention it, and talks about a in-the-lens CdS cell. Some advertisements qualify the CLC term with an explanation that exposure is automatically adjusted when filters are fitted (as with any other lens housing a CdS cell).

Maybe what CLC facility Hi-Matics have will remain a mystery, but I am inclined to conclude that it's a badge stuck on any 1960s Minolta light metering system - like Agfa's sensor point shutter release system

 

 

The camera can be set to automatic shutter speed and aperture selection (see information panel right). The slowest speed the camera sets in automatic mode is 1/15th of a second. If there is insufficient light, the indicator needle will rise to the top of the scale and go into the red zone, but the shutter does not lock. Speeds 1/8th, 1/4th, 1/500th, plus B can only be used in manual mode.

The light meter EV reading can be used to manually set exposure. This is done by selecting any shutter speed you wish to use, reading the EV number indicated by the needle in the viewfinder, and setting that number in the lens EV window by adjusting the aperture ring. Equally, the aperture can be set first, and then the shutter speed adjusted to produce the correct EV number.

The Hi-Matic 7s also features a Safe Load System (SLS). It comprises two elements, the first being a four slot take-up spool, which makes insertion of the leader easier since the spool does not need to be rotated to a favourable threading alignment (as with a single slot spool). The second is a film load indicator window (on the back-plate above the spool) which shows red to indicated film advancement.

US magazine Modern Photography evaluated the 45mm f/1.8 Rokkor-PF lens in 1967 - as fitted to the Hi-Matic 7. Their subsequent assessment of the Hi-Matic 7s concluded that the CLC exposure system metered accuracy in a variety of light and contrast conditions (so they obviously believed it has some sort of contrast compensation device - but so does everyone except me apparently). They liked that the meter could be switched off, and approved of the SLS indicator.

 

Modern Photography Magazine's evaluation of the Minolta 45mm f/1.8 Rokkor-PF lens
Aperture f/1.8 f/2.8 f/4 f/5.6 f/8 f/11 f/16 f/22
Centre Sharpness Good Acceptable
Edge Sharpness Acceptable Good Very Good
Why sharpness decreases with the smallest apertures. While closing down the diaphragm to create a smaller aperture increases the depth of field, it also increases the impact of diffraction, i.e. the bending of light rays as they pass over the edge of the aperture blades. These diffracted rays donít converge on the film surface, and consequently they produce a softer image. The smaller the aperture, the fewer the number of light rays pass through it, while a greater proportion of rays are bent.

 

A 1968 edition of Amateur Photographer advertised the Minolta Hi-Matic 7s for £57 - 19s - 6d. At that time the average UK weekly wage was the equivalent of £28.63, making the camera worth a little over two weeks wages.

 

Specifications

viewfinderViewfinder: Viewfinder combined with rangefinder. Bright frame with parallax correction. EV scale with exposure indicator needle, and under/over exposure red warning marks.

Focus: Coupled rangefinder with manual ring on lens barrel. Diamond shape rangefinder spot in centre of frame.

Lens: Rokkor PF 45 mm f1.8 to f22. There are 6 lens elements in 5 groups. Focus distance marked in both feet and metres.

Close Focus: 3' (0.9m).

Diaphragm: Five blade f/1.8 stopping down to f/22.

Shutter: SEIKO-LA. Speeds range from 1/4th, 1/8th, 1/15th, 1/30th, 1/60th, 1/125th, 1/250th and 1/500th of a second plus B on manual (1/15th to 1/250th on auto). 10 second self-timer.

Cable Release: Standard socket in shutter release button.

Meter: CdS cell in the lens barrel coupled to programmed shutter. There is also an off switch at the end of the ASA scale.

Exposure: Automatic or manual.

Exposure range: EV 5.7 to EV 17.

Film Speed: ASA 25 to 800.

Filter Size: Filter size 55mm screw-in, 57mm slip-on.

Flash: Accessory shoe with direct contact and cable contact. Electronic flash works at all speeds.

Film Advance: Single stroke approx. 220°.

Frame Counter: Counts up. Resets automatically when camera back is opened.

Rewind: Collapsible crank, and rewind selector switch.

Back Opening: Sliding catch.

Size: 140 (w) x 82 (h) x 47 (d) mm.

Weight: 720g.

Battery: PX625 1.35v mercury cell (use the equivalent WeinCELL MRB625 zinc air cell).

 

My Camera

I paid £11.49 for this camera in July 2014 (£10.49 after re-sale of the unwanted case). My camera is in good condition, full working order, and I've replaced the light seals.

This is a cool camera. Its looks are inoffensive rather than stylish. The wholly mechanical automatic exposure facility is marvellous, especially given that it is an operating option. I always research cameras before buying, and the buzz on this Minolta is that it has a really sharp lens, and accurate metering in most circumstances.

There are things I don't like about it. The travel distance of the wind-on lever is extreme at 220 degrees, the camera is a bit of a giant, and I find the idea of turning off the meter by altering the ASA setting inconvenient.

This is a camera of mystery. There are two key areas in which the way it works is not as implied by literature or the every-day-collector's description. I look forward to loading it with film one day, and finding-out for myself just how good it is.

 

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Minolta Hi-matic 7s

Minolta Hi-matic 7s

Minolta Hi-matic 7s

Intermediate settings on Automatic Exposure?

Page 34 of the instruction manual (36 for the 9, and absent for the 11) includes a graph of the automatic exposure aperture and shutter speed selection profile. This suggests that some intermediate apertures and shutter speed values are invoked on auto.

There are only four EVs at which the profile intersects standard stop combinations:
• f/2 @ 1/30th for EV 8,
• f/5.6 @ 1/60th for EV 11,
• f/11 @ 1/125th for EV 14, and
• f/22 @ 1/250 for EV 17.

Those very nice people over at Camera-Wiki have researched Minolta patents of the period, and found one that talks about an improvement to the trapped needle method of auto-exposure via a rubberized gripper rather than a toothed mechanism. This would facilitate less-stepped exposure settings, so it appears Minolta's graph may indeed be accurate, and the Hi-Matic might set intermediate apertures and shutter speeds?

There has to be some feature that accounts for the cameras reputation for exposure accuracy ... and it isn't the CLC for sure!

Exposure control mechanism - patent US 3309974 A

Minolta Hi-matic 7s

Minolta Hi-matic 7s

Above: The Hi-matic 7s is about the same size as a typical SLR of the period. Apologies for the photo being a little blurry, but the winter light is poor, and the picture was taken at 1/9th of a second - hand held!