NiSi Cine Lens Athena Prime 40mm T1.9 L-Mount

NiSi Cine Lens Athena Prime 40mm T1.9 L‑Mount — T1.9 aperture for soft bokeh and full‑frame coverage

The NiSi Athena Prime 40mm T1.9 in L‑Mount is part of the Athena Cine lens family designed for cinematography and videography. It provides a T1.9 maximum aperture that enables soft bokeh and reliable light transmission. In addition, the Athena optics produce an image circle of 46mm, making this lens suitable for full‑frame and even large‑format sensors.

Key features

• Maximum aperture: T1.9 — offers shallow depth of field and soft background separation.
• Image circle: 46mm — supports full‑frame and larger sensors.
• L‑Mount version — the series is available in multiple mount options, and this model is the L‑Mount variant.
• Minimized focus breathing — maintains a consistent field of view when pulling focus.
• Matched ergonomics across the series — aperture and focus rings are matched for consistent use.

Mount and rear filtration system

The Athena Prime series comes in several mount options across the lineup: ARRI PL, Canon RF, Sony E, Panasonic/Leica L and Fuji G. Specifically for the L‑Mount 40mm, NiSi provides a Drop‑In filter option. The Drop‑In system gives filmmakers flexibility for creative filtering and consistent optical performance when used as instructed.

Note the following important points about filters and compatibility:

• Sony FX9 cameras cannot use the E‑Mount version with Drop‑In filters.
• To achieve infinity focus and clear images, use the Drop‑In clear filter on RF‑, L‑ and G‑mount lenses and the rear filter on PL‑mount lenses.
• NiSi provides weather sealing for the Drop‑In filter to protect the filter mount against the elements.

Handling, focus and control

The Athena Prime series is built for practical use on set. The 40mm shares common mechanical characteristics with the rest of the range, which simplifies lens swaps and rigging:

• All Athena primes (except the 14mm) use a 77mm front filter thread — simplifies filtration across the set.
• All lenses in the series are similar in weight, so you typically do not need to rebalance your gimbal when switching between Athena lenses.
• Focus rotation: 300° — allows precise, repeatable focus pulls.
• Fluorescent focus scales in both imperial and metric units — help with accurate focus marks under varied lighting.
• Standard 0.8 mod focus and iris gears — compatible with common follow focus and matte box systems.

Optical characteristics

NiSi specifies T‑stop ratings across the series to ensure consistent exposure and accurate light transmission. The 40mm lens shares the T1.9 peak aperture that several other primes in the set have, which makes it easier to match exposure and depth of field across focal lengths when needed.

Additionally, the Athena optical design emphasizes reduced chromatic aberration and controlled micro‑contrast to preserve fine image detail. The minimized focus breathing supports smoother focus transitions during shots.

Accessories and close‑up options

NiSi offers a 77mm close‑up lens (sold separately) that can reduce the minimum focus distance for macro‑style effects. This accessory uses the shared 77mm filter thread found on the Athena primes (except 14mm) to expand creative options without changing core optics.

FAQ

Question: Is the 40mm L‑Mount compatible with full‑frame cameras?
Answer: Yes. The Athena 40mm produces a 46mm image circle, which covers full‑frame sensors and can support even larger sensor formats.

Question: Do I need to use a specific filter to reach infinity focus?
Answer: Yes. For RF, L and G mounts you must use the Drop‑In clear filter, and for PL mount you must use the rear filter. These filters ensure infinity focus and clear images when using the lenses.

Question: Can I swap Athena lenses on a gimbal without rebalancing every time?
Answer: In most cases, yes. All Athena primes are similar in weight, so switching between lenses normally does not require gimbal rebalancing.

Question: Does the 40mm share the same mechanical layout as other Athena primes?
Answer: Yes. The series shares matched aperture and focus rings, a 300° focus rotation, fluorescent focus scales in imperial and metric, and standard 0.8 mod gears for follow focus compatibility.

Question: Is there a macro or close‑up option for this lens?
Answer: NiSi offers a 77mm close‑up lens (sold separately) that reduces minimum focus distance and enables macro‑style effects while using the shared 77mm front thread.

Question: Are there any mount limitations I should be aware of?
Answer: Yes. The Sony FX9 cannot use the E‑Mount version with Drop‑In filters. Always verify mount and filter compatibility for your camera body before purchase.