Contax RTS

Overview

The Contax RTS (Real Time System) is the founding camera of the Yashica/Kyocera-era Contax 35mm SLR lineage — the 1975 product of Yashica's "Top Secret Project 130" collaboration with Carl Zeiss that revived the Contax brand 13 years after the original Zeiss Ikon Contax line ended in 1962.^[1][2] Premiered at Photokina 1974 and shipped 1975, the RTS established the Contax/Yashica (C/Y) bayonet mount and the partnership with Carl Zeiss that produced the T-coated lens lineup* — what became, over the next 30 years of C/Y system production, "the best 35mm SLR optics money could buy."

For 35mm SLR photographers building a C/Y mount kit on a budget today, the RTS is the cheapest entry point — used bodies trade in the $150–300 range, less than half the cost of comparable Contax RTS II or Contax 139 Quartz bodies. The RTS is also the most distinctive C/Y body cosmetically — the F. Alexander Porsche Group (a design consultancy unrelated to the auto company; founded by Porsche family member F. A. Porsche) conducted the body's industrial design study, establishing the rectilinear silhouette and leatherette grip surfaces that defined Contax visual identity through the entire C/Y era.

The trade-off vs later C/Y bodies: no quartz timing (the original RTS uses a non-quartz electronic shutter that drifts more over time), no AE lock, no TTL flash with later TLA flash units, no titanium-foil shutter curtain (RTS uses cloth). Photographers wanting refined daily-use features should consider the RTS II (1982); photographers wanting the original Contax revival aesthetic want this body.

Construction and build

• Body weight — 700 g.^[1]
• Body dimensions — 142 × 90 × 50 mm.
• Shutter — electronically-controlled horizontal cloth focal-plane shutter; speeds 1 s through 1/2000 s plus B. Mechanical fallback only at slow speeds without battery.
• X-flash sync — 1/60 s typical (specifics vary by source).
• Materials — die-cast metal body shell with leatherette covering; satin chrome trim. The F. A. Porsche styling study established the visual vocabulary.
• Battery dependency — yes; electronic shutter timing requires battery. Older silver-oxide cells; modern lithium replacements available.

Distinguishing features

The RTS's defining elements:^[1]

• Top Secret Project 130 origin — Yashica's internal name for the Contax-revival collaboration. The 1973 licensing agreement between Yashica and Carl Zeiss formalized the partnership; the Contax RTS was the agreement's first product.
• F. Alexander Porsche Group industrial design — established the rectilinear, deliberately-industrial body styling vocabulary that carried forward through the entire Yashica/Kyocera-era Contax SLR lineage. The RTS's body shape is the Contax visual identity at its source.
• Aperture-priority AE + metered manual — the two exposure modes available. No shutter-priority or program modes (added on later C/Y bodies).
• Interchangeable focusing screens — multiple ground-glass screen options for different shooting styles.
• Real Time System branding — refers to the camera's electronic real-time exposure metering and shutter control. The RTS designation continued through the RTS II (1982) and RTS III (1990) flagship line.

The Contax/Yashica (C/Y) mount and Carl Zeiss T* lens system

Same C/Y bayonet mount as every other Yashica/Kyocera-era Contax 35mm SLR (139 Quartz, RTS II, RTS III, Aria, plus 137 / 159MM / 167MT / RX / S2 / AX). Roughly 30+ Carl Zeiss T*-coated focal lengths from 15mm Distagon fisheye through 1000mm Tele-Apotessar. Canonical kit lenses:

• 50mm f/1.4 Carl Zeiss Planar T* — the standard "kit normal"
• 28mm f/2.8 Carl Zeiss Distagon T* — wide-angle
• 85mm f/1.4 Carl Zeiss Planar T* — portrait
• 135mm f/2.8 Carl Zeiss Sonnar T* — short telephoto

T* (T-star) is Carl Zeiss's multi-coating technology — the optical signature of the Yashica/Kyocera-era Contax. Yashica also produced ML-series budget lenses on the C/Y mount; these mount and function on the RTS but lack the T* coating prestige.

Working notes

• Battery dependency — the electronic shutter needs power. Without a battery, the RTS is non-functional except at flash-sync speed (no separate mechanical-fallback shutter speed).
• Cloth shutter requires care — pinholes in the cloth curtain develop over decades. Test with the back open against a bright light before purchase.
• Lens removal — push the lens-mount release button and rotate counterclockwise.
• The RTS is the largest-bodied C/Y body except the RTS III — at 700 g it's heavier than the 139 Quartz and meaningfully heavier than the later Aria (460 g).
• Common service items on a 50-year-old body: shutter timing drift (CLA fix), light seals (foam strips around the back), prism silvering (rare but expensive when present), focusing-screen condition. Contax specialist CLA: $200–400 typically.

Used market and reliability

• RTS body only — working condition: $150–300 (US 2026 pricing).
• RTS body + 50mm f/1.4 Planar T* — working condition: $300–500.
• RTS kit (body + 28mm + 50mm + 135mm Carl Zeiss T)* — working condition: $700–1,200. The lens premium dominates the kit price.

The RTS body itself is the cheapest C/Y entry; the value of any C/Y kit is in the Carl Zeiss T* lenses, which retain value far better than the bodies do.

Common buying-checklist items: shutter cloth integrity (pinholes), shutter speed accuracy (especially slow speeds), light seal condition, prism silvering, focusing-screen cleanliness.

Lineage and Tamron-er... I mean Kyocera-era discontinuation

The Yashica/Kyocera-era Contax 35mm SLR lineage:^[2]

• RTS (1975–1982) — this page; founding C/Y body
• 139 Quartz (1979–1987) — compact mid-range volume body
• 137 MD / MA (1980s) — motor-drive variants
• RTS II (1982–1990) — refined flagship; quartz timing + 97% viewfinder + titanium-foil shutter + AE lock
• 159MM (1985) — multi-mode mid-range
• 167MT (1987) — multi-mode + matrix metering
• RTS III (1990–~2005) — technological flagship; vacuum film flattening (RTV) + 1/8000 + 100% viewfinder
• S2 / S2b (1992–1994) — manual-only retro spot-metering bodies
• RX (1994) — focus-confirmation autofocus-assist
• Aria (1998–2005) — final manual-focus C/Y body; lightest at 460 g
• AX (1996) — autofocus C/Y via body-side helicoid

After 2001, Kyocera shifted Contax development to the Contax N system (autofocus, new N-mount). Kyocera ended all Contax production in 2005, terminating the Contax brand 73 years after its 1932 founding.

Related cameras

• Contax RTS II — the 1982 successor; quartz timing + titanium-foil shutter + AE lock
• Contax RTS III — the 1990 technological flagship
• Contax 139 Quartz — the contemporary mid-range C/Y body; ~200,000 produced
• Contax Aria — the 1998 final manual-focus C/Y body
• See [[contax-rts-aria-cluster-deepened]] for the broader Contax SLR comparison

External references

• Contax RTS (Camera-Wiki) — community-edited reference for body specifications and history
• Contax (Wikipedia) — brand history from 1932 Zeiss Ikon original through 2005 Kyocera discontinuation