TLS Prometheus 55mm T1.5 Test on Sony VENICE 6K Full Frame

The test was shot on a Sony VENICE using the camera’s largest sensor mode, 6K 3:2. The lens covers the full-frame image area without difficulty, but its behavior changes significantly between wide open and stopped down to T2.8. That is entirely normal for a still-photography lens from the late 1960s or early 1970s.

Wide open at T1.5, the vintage character of the lens is immediately visible. The image is very soft, with controlled spherical aberration that creates a slightly milky, veiled quality. There is also noticeable chromatic aberration, clearly visible around the lights behind the subject. The overall tone is warm. The flares are orange and highly visible, similar in character to those produced by lenses such as the Canon FL 55mm f/1.2, the Mamiya 55mm f/1.4, or the Kowa R full-frame still-photography lenses. When pushed hard enough, a rainbow-like reflection can also appear, not unlike the kind of effect sometimes seen with Bausch & Lomb Super Baltar lenses. Wide open, the bokeh has an irregular distribution, with the well-known “cat’s eye” effect appearing toward the edges of the frame.

Stopped down to T2.8, the image changes significantly, as often happens with still-photography lenses of this period. The image becomes sharper, the spherical aberration disappears, and the previously low contrast recovers to a noticeable degree. Some chromatic aberration remains, but it is less visible. The image is still warm, although apparently less so than at full aperture. Vignetting also disappears. As is often the case, closing the iris by roughly two stops from maximum aperture makes the flares more clearly defined and precise; personally, I often find them more interesting this way. The bokeh becomes more circular and regular not only in the center of the frame, but also toward the edges, and the “cat’s eye” effect disappears.

Whatever the original source lens may be, the rehoused TLS Prometheus produces a distinctive, soft and highly expressive image. The fact that it is a single focal length limits its use to specific creative purposes rather than as a complete taking-lens set, but its unusually close minimum focus of just 43 centimeters makes it especially attractive for portraits, details or isolated moments within a project photographed primarily with another set of lenses. It is not a neutral lens, and that is precisely its value: it can shift the emotional tone of a scene without requiring filtration or digital manipulation. Mechanically, the lens has a 95 mm front diameter, a relatively compact weight, geared focus and iris rings, and the robust, precise mechanical construction typically associated with TLS rehousings.

• Mount: PL
• T-Stop: T1.5
• Minimum focus: 0.43 m / 17 in
• Front diameter: 95 mm
• Weight: 0.82 kg