Bronica ETRSi

Overview

The Bronica ETRSi is the last and most refined body in Bronica's 6×4.5 ETR series — a 1988/89 successor to the ETR-S that adds TTL/OTF flash metering, mirror lockup, locking dark slides, an improved film-advance mechanism, and a flip-out crank winder while preserving the modular system architecture and in-lens leaf-shutter design that defined the ETR line from its 1976 introduction.^[1] Production ran through 2004 under Tamron ownership, ending alongside the broader Bronica SLR lineup as Tamron wound down medium-format film camera manufacturing in the 2002–2004 timeframe.^[2]

For photographers buying into medium-format film today, the ETRSi is the cheapest legitimate professional 6×4.5 SLR on the used market — body+lens+back kits trade in the $500–900 range, less than half the cost of comparable Mamiya 645 Pro TL or Pentax 645N gear. The trade-off: no autofocus (the ETRSi is fully manual focus), no integrated motor drive (separate Speed Grip accessory), and a smaller used-market accessory ecosystem than the Mamiya or Pentax alternatives.

The ETRSi's defining advantage is flash sync at all shutter speeds via the in-lens leaf shutter — a Bronica with a high-power flash works at 1/500 s where a Mamiya 645 or Pentax 645N is limited to 1/60 s X-sync without dedicated leaf-shutter lenses.

Construction and build

• Body dimensions — 105 × 86 × 66 mm (W × H × D).
• Body weight — 480 g body only (~1.5 kg fully loaded with lens + back + waist-level finder + Speed Grip).
• Auxiliary focal-plane shutter in the body (mirror-up function only; does not time the exposure).
• Electronic Seiko leaf shutter in lens — speeds 8 s through 1/500 s plus B.^[1] B mode is new to the ETRSi (earlier ETR / ETR-S used T mode).
• X-flash sync at all shutter speeds — the great advantage of leaf-shutter design.
• Materials — engineering-plastic body shell over a die-cast aluminum chassis; rubber-textured grip surfaces; metal lens mount, back interface, and finder interface. Aesthetic is "1980s-1990s pro-grade Japanese MF" — workmanlike, not jewelry-like.

The body is fully battery-dependent — a dead battery prevents shutter operation entirely (the in-lens shutter requires power for timing). Battery: 6V silver-oxide / lithium (PX28 / 4LR44).

Distinguishing features (vs. ETR-S)

The ETRSi's "i" suffix marks the iteration that made the ETR series fully professional-grade:^[1]

• TTL/OTF flash metering — through-the-lens, off-the-film flash exposure measurement. Requires a flash with a Bronica-compatible SCA connector on the lens shutter side (the connector lives on the lens, not the body). Compatible flashes meter the flash exposure during the actual shutter cycle and cut off when the integrated flash energy is sufficient.
• Mirror lockup switch — located near the film winding crank. Pre-fires the mirror so it can settle before the shutter opens; useful for tripod work below ~1/30 s where mirror vibration can soften images.
• Multiple-exposure red indicator — viewfinder LED warns when ME mode is enabled. Earlier ETRs offered ME mode without explicit visual confirmation; the ETRSi addresses the "I forgot ME was on" failure mode.
• Improved film advance gearing — smoother and more reliable than the ETR-S mechanism; also produces more consistent frame spacing on 220 film.
• Locking dark slide with grey-handle marking — the dark slide locks into the back when removed, preventing accidental loss; the grey handle is a visual marker that this is an ETRSi-era back vs. earlier ETR-era backs.
• Flip-out crank winder — replaces the earlier ETR's lever winder; faster and more comfortable for high-shoot-count work.
• Improved grip areas on the lower body half — small but meaningful ergonomic refinement.
• Lens release returns to the front of the camera — the ETR-S had moved this control; the ETRSi puts it back.
• Traditional B (bulb) shutter setting — replaces the earlier ETR / ETR-S T mode.

Modular system

The ETRSi accepts the full Bronica ETR system of interchangeable accessories.

Interchangeable film backs

• 120 roll film back — 15 frames at 6×4.5.
• 220 roll film back — 30 frames at 6×4.5.
• Polaroid back — instant-film proofing.
• 70mm long-roll back — bulk-film professional applications (rare).

Backs lock to the body via a dark-slide-required interlock. Pull the slide → unlock back → swap → reinsert slide → fire shutter. The ETRSi's locking dark-slide refinement reduces the failure mode where the slide could shift in transport.

Interchangeable finders

• Waist-Level Finder — folding hood, no metering, ground-glass viewing. Lightest option.
• Standard Pentaprism Finder — eye-level prism, no metering.
• AE Prism Finder E — eye-level prism with center-weighted TTL meter and aperture-priority autoexposure. Exposure compensation ±2 EV. Most-recommended finder for working photographers.
• Pentaprism Finder C — earlier non-AE prism (from ETR-S era; carries forward).
• Speed Grip — accessory grip for portrait-orientation handling (does not include metering; pairs with any finder).

Lenses

The Bronica ETR mount accepts roughly 15 focal lengths in the Zenzanon-PE / Zenzanon-MC lens lineups:

• 40mm fisheye (PE)
• 40mm f/4 wide-angle (PE)
• 50mm f/2.8 (PE — wide-normal)
• 60mm f/2.8 Macro (PE)
• 75mm f/2.8 (PE — the standard "kit" normal)
• 80mm f/2.8 (PE — alternative normal)
• 100mm f/4 Macro (PE)
• 105mm f/3.5 (PE)
• 120mm f/4 Macro (PE)
• 150mm f/3.5 (PE — short telephoto / portrait)
• 180mm f/4.5 (PE — alternative portrait tele)
• 200mm f/4.5 (PE — telephoto)
• 250mm f/5.6 (PE — long telephoto)
• 45–90mm f/4–5.6 zoom (PE)
• 125–250mm f/5.6 zoom (PE)

All ETR-mount lenses have integrated Seiko electronic leaf shutters. PE = "Plus E" (newer optics with multi-coating); MC = earlier multicoated lineage.

Working notes

• Battery dependency is total. Both the body's electronics and the lens's leaf shutter need power. Carry spares.
• Mirror lockup essential for tripod work below 1/30 s. Same mirror-vibration considerations as any 6×4.5 SLR.
• Lens release on the front of the body — left of the lens mount. Push the release while rotating the lens counterclockwise to remove.
• Speed Grip is highly recommended for handheld use. The bare body's grip area is workable but not comfortable for extended shooting; the Speed Grip transforms ergonomics.
• The leaf-shutter advantage is most visible with flash. Studio strobes at 1/500 s with the ETRSi freeze action that 1/60 s on a focal-plane MF body cannot.
• Self-timer — electronic, ~10-second delay.
• Common service items on a 25+-year-old body: foam light seals (in the back, the body, and the prism interface), shutter timing drift (per-lens, since the shutter is in the lens), AE Prism Finder battery contacts oxidation, mirror dampers. Bronica specialist CLA: $200–350 typically; per-lens CLA $150–250.

Used market and reliability

• ETRSi body only (no finder, no back) — working condition: $200–400 (US 2026 pricing). The cheapest entry point.
• ETRSi body + 120 back + Waist-Level Finder + 75mm f/2.8 PE — working condition: $500–700. Common kit for landscape / casual work.
• ETRSi body + 120 back + AE Prism Finder E + 75mm f/2.8 PE — working condition: $650–900. The most-recommended kit configuration.
• ETRSi body + 120 back + AE Prism Finder E + Speed Grip + 75mm f/2.8 PE + 150mm f/3.5 PE — working condition: $900–1,300. Wedding-photographer kit configuration.

The ETRSi system has the largest used-lens supply of any Bronica system because the ETR series ran for 28 years (1976–2004) and produced over 100,000 bodies; lens prices reflect that supply.

Common buying-checklist items: leaf shutter timing on the lens (each speed), AE Prism Finder battery contacts, light seals on the back, mirror dampers, dark-slide lock function. For multi-lens kits, test each lens's shutter independently — leaf-shutter problems are per-lens, not body-side.

Lineage and Tamron-era discontinuation

The Bronica ETR series:^[1]

• ETR (1976) — the original 6×4.5 SLR; non-leaf-shutter body design (pre-leaf-shutter electronics)
• ETRC (1976) — variant with mechanical Compur shutter option
• ETR-S (1979) — added internal modifications and improved electronics
• ETRC-S (1979) — ETRC with the ETR-S refinements
• ETRSi (1988/89–2004) — this page; the final, most-refined ETR

Production end:^[2] Tamron acquired Zenza Bronica in 1998 (75% capital 1995, full merger July 1998) and continued ETRSi production through 2004 alongside the SQ-Ai, SQ-B, and GS-1 (ended June 2002). The decision to discontinue medium-format film SLRs was driven by digital-SLR market displacement and the absence of a Bronica digital back equivalent (Hasselblad's H-system pivoted to digital; Bronica did not). The Bronica brand was terminated entirely in October 2005 with the discontinuation of the RF645 rangefinder.

Related cameras

• Mamiya 645 Pro TL — the Mamiya 6×4.5 competitor; modular like the ETRSi but with a different mount system, focal-plane shutter (1/60 max sync without leaf-shutter lenses), and TTL flash via Metz/SCA-3952
• Pentax 645N — Pentax's autofocus 6×4.5 SLR; fixed-back architecture vs. the ETRSi's interchangeable backs; integrated motor drive; world's-first MF AF
• Bronica SQ-A — Bronica's 6×6 sibling; 6×6 format vs ETRSi's 6×4.5
• Bronica GS-1 — Bronica's 6×7 sibling; 6×7 format with TTL flash from launch (1983)

External references

• Bronica ETR (Camera-Wiki) — community-edited reference covering the entire ETR series including ETRSi
• Bronica (Wikipedia) — company history, Tamron acquisition, brand-end timeline