Zenzanon-RF 100mm f/4.5
Zenza Bronica · Bronica RF · 2001 · Gauss-type, 6 elements in 5 groups
single source, unconfirmedAlso known as: Zenzanon-RF 100mm f/4.5 · Zenzanon RF 100mm F4.5 · ZENZANON-RF 100mm F4.5 · Bronica RF 100mm f/4.5 · Bronica RF645 100mm f4.5 · Bronica Zenzanon-RF 100/4.5 · Zenza Bronica RF 100mm · ゼンザノンRF 100mm F4.5 · ゼンザノン RF 100mm F4.5 · ブロニカ RF645 100mm
Variants & identification
| Variant | Mount | Years | Serial ranges | Production |
|---|---|---|---|---|
| Zenzanon-RF 100mm f/4.5 (2001–2004) | Bronica RF | 2001–2004 | — | — |
- Construction (5群6枚), the 1.8 m closest focus with a 近接ゾーン of 1.8–1.2 m, and the 62 mm screw-in attachment are Japanese Wikipedia's; Tamron Japan's table gives F4.5–32, MOD 1.8 m, 62 mm, 83.5 × 76 (length × maximum diameter) and 450 g. camera-wiki quotes the minimum as 1.2 m, which is the bottom of the close zone, and carries Bronica's advice to use f/11 or smaller there.
- The seven blades, the 38° angle of view, the Gauss-type description and the $652 price are from Tamron USA's archived 2004 product page for the RF100.
- Dates: Japanese Wikipedia says the 100 was issued as the substitute for the planned 135; Tamron USA announced it as forthcoming in 2001 (Greenspun's review of that year names the 135 as the only telephoto); Tamron Japan's notice of September 2004 ended sales as stock ran out, at ¥75,000 (¥78,750 with tax). The 2001 start is the best reading of these and is not a dated release.
- Shutter speeds are the body's: the lens holds the #00 shutter and its cocking motor, the RF645 times it.
How to tell them apart
- The telephoto that was actually sold: a 60 mm equivalent on 35 mm film (Camera Legend), 38° across the frame; the body finder shows a 100 mm bright frame for it on serial-prefix-1 bodies and on early bodies whose masks were changed
- Longest barrel in the system at 83.5 mm, and the only RF lens with a 62 mm thread apart from the rare 135; a close-zone marking from 1.8 m to 1.2 m on the distance scale
- Not the Zenzanon-S 105mm, the Zenzanon-PE 100mm f/4 Macro for the ETR or the Zenzanon-PG 100mm f/3.5 for the GS-1: this one reads RF and f/4.5 and fits only the RF645
Zenzanon-RF 100mm f/4.5 (2001–2004):
- 'ZENZANON-RF 100mm F4.5' on the front ring; 62 mm filter thread; the long barrel of the system, 83.5 mm against 43.9 mm for the 45 and 65, 76 mm across
- Distance scale running to 1.8 m with a marked close zone from 1.8 m down to 1.2 m, where Bronica advises f/11 or smaller (camera-wiki)
- Aperture ring f/4.5 to f/32; RF645 bayonet with contacts and no cocking lever
- Zenzanon-RF 100mm f/4.5 (2001–2004): The only version, issued in 2001 in place of the withdrawn 135 and run out in Japan from September 2004, a year before the camera. $652 on Tamron USA's 2004 list; ¥75,000 (¥78,750 with tax) in Tamron Japan's end-of-sale notice.
Specifications
- Formula
- Gauss-type, 6 elements in 5 groups
- Construction
- 6 elements / 5 groups
- Aperture range
- f/4.5–f/32
- Diaphragm blades
- 7
- Shutter
- Bronica #00 electronically controlled leaf shutter in the lens, cocked by a motor in the lens; B, 1–1/500 manual, 8s–1/500 aperture-priority, 8s–1/750 program (timed by the body)
- Min. focus
- 1.8 m
- Dimensions
- 76 × 83.5 mm
- Weight
- 450 g
- Filter
- 62 mm
- Years manufactured
- 2001–2004
- Country
- Japan
- Original price
- ¥75,000 (¥78,750 with tax) in Tamron Japan's end-of-sale notice of September 2004; $652 on Tamron USA's 2004 list (today ¥85,000)
What reviewers say
- Mike Johnston, The Luminous Landscape (blog) — Issued in place of the 135 that the short rangefinder base could not focus: a useful portrait lens that works better in practice than its modest specification suggests on paper, within a line-up he still judged too slow to sell the camera.
History
The Zenzanon-RF 100mm f/4.5 is the telephoto the Bronica RF645 ended up with. The camera was announced in 2000 with a 135mm f/4.5, but that lens could not be focused reliably on the body’s 33 mm effective rangefinder base and was withdrawn almost at once; Japanese Wikipedia records the 100 as issued in its place, Tamron USA announced it as forthcoming in 2001, and bodies made from then on carry a 100 mm bright frame where the first ones had a 135. It is a Gauss-type of six elements in five groups covering 38°, about a 60 mm equivalent on 35 mm film, with seven diaphragm blades from f/4.5 to f/32, a 62 mm filter thread, a barrel 83.5 mm long and 76 mm across, nearly twice the length of the 45 and 65, and a weight of 450 g. The #00 electronic shutter and its cocking motor are inside, timed by the body.
Its focusing is the point to understand. The scale runs to 1.8 m, and below that a marked close zone continues to 1.2 m in which Bronica advised f/11 or smaller, because the rangefinder’s accuracy is marginal for a 100 mm lens at close range and the depth of field is shallow; camera-wiki quotes the 1.2 m figure as the minimum, Tamron’s own tables and Japanese Wikipedia give 1.8 m with the zone noted. Mike Johnston, who in 2009 called the 135’s calibration problem the main reason it had been dropped, found the 100 a useful portrait lens that worked better in practice than on paper.
It was the shortest-lived of the lenses that were sold: Tamron Japan announced in September 2004 that sales would end as stock ran out, at a list price of ¥75,000 (¥78,750 with tax), a year before the camera itself stopped in October 2005; Tamron USA listed it at $652 in 2004. There is one version. Camera Legend quoted $900–1,400 for a used copy in early 2022, more than for the 45 or 65 because fewer were made. A copy should be tried on a body at infinity and at the close-zone limit, since the lens cannot be fired or stopped down without one and a body whose rangefinder has drifted will show it first with this lens.
Left open: a production figure, any serial-number scheme, and a review of its optical performance beyond Johnston’s verdict.
This history is AI-written, from the sources listed at the foot of the page. Where the record is silent it says so rather than filling the gap — but no human wrote these sentences.
Example photos
Sample photo wanted — shot with a Zenzanon-RF 100mm f/4.5? We'd love to feature it (with credit).
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