SLR

In the latter half of the 1960's, Mamiya sold a series of SLR cameras using the popular 42mm threaded lens mount:

- Mamiya/Sekor 500 TL
- Mamiya/Sekor 1000 TL
- Mamiya/Sekor 500 DTL
- Mamiya/Sekor 1000 DTL
- Mamiya/Sekor 2000 DTL

The TL models were introduced in 1966, the 500 and 1000 DTL in January 1968, and the 2000 DTL was introduced at Photokina 1968.

These models may be grouped together, as they all share the same basic body; their differences are clearly reflected in their model designations. The numeral represents the highest shutter speed (1/500, 1/1000 or 1/2000 of a second); the letters TL or DTL signified Through the Lens or Dual Through the Lens light metering. The "500" models typically lack a self-timer.

The later DTL dual-metering models introduced a switch beside the lens mount which allowed the photographer to select between an averaging meter pattern and a "spot" meter (actually a square area marked at the bottom of the viewfinder), with a viewfinder indication of the mode selected. This was a unique innovation for its day which was protected by U.S. Patent No. 3,612,703, filed February 29, 1968. Interestingly, the single metering mode offered by the TL models was the "spot" mode, not the averaging mode one might expect. Thus it was the Mamiya TL and not Pentax who implemented the original meaning of Pentax's Spotmatic brand.

As with other SLRs of the era, these cameras had no linkage between the light meter circuit and the f/stop selected; thus the lens needed to be stopped down to shooting aperture in order to take an accurate exposure reading. But it may be less than obvious at first glance how one is intended to activate the meter on a TL/DTL body. Mamiya made an interesting choice to have the film-wind lever also double as the stop-down lever and meter switch. The user pulls the lever away from the body until it clicks; after which, pressing the lever inwards against spring pressure stops down the lens and activates the meter circuit. To put the camera away without risking accidentally draining the single 1.5v silver-oxide meter battery, one stows the wind lever in its "off" position by clicking the round cap atop its axis. The switching mechanism is also unusual, instead of typical contacts the metal band around the battery is a loose fit until the wind lever is pushed inwards, at that point the band tightens around the battery to complete the circuit.

Even by the SLR standards of their day, the TL and DTL models were at the large and heavy end of the spectrum. A 1000 DTL with its original 50mm f/1.4 lens weighs 1,077g (2 lb. 6 oz.) and measures 150 x 94 x 100 mm (W x H x D).

The 500TL has match-needle exposure metering. It's normally powered by a 1.5v MS76 button battery (aka LR44/SR44 easily bought at any drugstore or camera store). You turn the meter on by pulling the wind-lever forward until it's in its 30° "ready" position. You release the meter by pushing the button on the top of the winding lever.

The Minolta SR-T 101 is a 35mm manual focus SLR camera with Through-The-Lens exposure metering – TTL for short - that was launched in 1966 by Minolta Camera Co.

It was aimed at demanding amateur and semi-professional photographers. The SR-T 101 stayed in production for ten years with only minor changes.  

The design is based on the Minolta SR-7 model V camera of 1962, but the principal design is inherited from the original 1958 Minolta SR-2. The SR-T 101 however, has several significant features apart from the TTL meter. The most significant one is perhaps the full aperture metering facility, allowing the exposure to be set accurately without stopping down. Full aperture TTL metering was commercially first realised in the 1963 Tokyo Kogaku Topcon RE Super.

Another unique feature of the SR-T 101 besides the open aperture metering at the time of its release to the public at Photokina in 1966 was the so called "CLC"-metering characteristic. "CLC" stands for "contrast-light-compensation" and was a kind of an early Matrix metering: Two CdS-cells, placed at the front and rear end of the viewfinder prism, provide an overlapping coverage of the center-weighted light-detection area and are electronically coupled together. Therefor the metering system always detects an average of the light travelling through the lens, determined by the contrast division of the metered motive. Landscape photographs with a large area of bright sky and a smaller area of dark ground, for example, are automatically corrected by the contrast-matching "CLC"-metering system. This system works for almost every landscape-format image regardless of the metered contrast range, but requires a much more skilled usage when it comes to portrait-format images. Because of this, Minolta recommended SR-T 101-users to first meter the photographed area and then to swing up the camera for taking the picture to enable the "CLC" an accurate metering.

Due to a large pentaprism and double-hinged reflex mirror, the SR-T 101 has an extremely bright viewfinder with a central micro prism focusing aid that in most cases proves to be appropriate, requiring no apparent lines in the motive, since all out of focus objects appear to shimmer. Shutter speed and match needle exposure is visible in the viewfinder, including a battery check index mark showing the required meter needle deflection for a healthy battery when the ON/OFF meter switch on the camera base is set to BC. The SR-T 101 was also available in black. The top cover and the base plate are finished in black enamel while most metal parts are black chromed, but the wind lever is black anodised. The parts still chromed, to name the most obvious ones, include the shutter-release button, the mirror lock-up knob, the depth-of-field preview button and the lens-release button.

Equipped with its Pentax Meter II as here, the Pentax SV was a remarkably powerful device for the time: a semi-automatic with priority speed before the hour, in a way, since the cell, fixed on the prism by clamps enclosing the eyecup , was coupled to the speed barrel. It was enough to read the proposed diaphragm and put it on the lens ring. On the other hand, the cell making the measurement outside the objective, it was necessary to make the necessary corrections when using filters, ring-extensions, etc ...

The canvas curtain shutter offered a choice of speeds between 1s to 1/ 1000 th, plus poses B and T, the latter being however neutralized once the Pentax Meter in place.

The viewfinder included a large ring of microprisms to facilitate focusing.

The most common basic lens (42 screw), was the Super Takumar 1: 1.8 / 55, which included a ring with two positions: A and M, in fact work at full aperture with preselection of the diaphragm or aperture real.

The self-timer (which gives its name to the case, "V" for Vorlaufwerk, retarder in German) is curiously placed: it is necessary to turn the large crown which surrounds the rewind crank to arm the mechanism; then push a tiny button placed between this crown and the prism to start the self-timer, provided you have previously armed the shutter. What a pleasure to still hear this clockwork mechanism today!

Two front sockets ( FP and X) allow you to connect a flash, either electronic or magnetic . The sync speed of the Pentax SV is 1 / 50th .

The Pentax SV cost 1,367 francs in 1966 at Grenier-Natkin , and thePentax Meter 188 francs.

The SV was released in 1962, primarily as an upgrade from the H1/S1 to H3/S3 camera lines. A budget model of the SV, the S1a, was also released in 1962, although it lacked the timer found on the SV, was 'marketed' as being limited to 1/500s (but can be set to 1/1000s). The SV came equipped with a Super Takumar 55/1.8 lens while the S1a came with a slower 55/2 lens.

The SV (Also marketed as Honeywell Pentax H3v) was released in 1962, primarily as an upgrade from the H1/S1 to H3/S3 camera lines.

A budget model of the SV, the S1a, was also released in 1962, although it lacked the timer found on the SV, was 'marketed' as being limited to 1/500s (but can be set to 1/1000s).

The SV came equipped with a Super Takumar 55/1.8 lens while the S1a came with a slower 55/2 lens.

The SV came in an early and a late type. The latter has an orange 'R' on the rewind knob which tells that the camera can use the 50mm f/1.4 lens (which protudes farther into the camera than all other 50mm lenses)