NiSi Cine Lens Athena Prime 50mm T1.9 Fuji G-Mount

NiSi Cine Lens Athena Prime 50mm T1.9 — Fuji G-Mount with Drop-In Rear Filter

The NiSi Athena Prime 50mm T1.9 in Fuji G-Mount is part of the Athena Cine Lens series made for cinematographers and videographers who need reliable, cinema-style prime optics. It shares the design and operational features of the Athena family while offering a fast T1.9 aperture for shallow depth of field and low-light shooting.

Key features at a glance

• 50mm focal length with a maximum aperture of T1.9 for soft bokeh and background separation.
• Fuji G-Mount version includes a Drop-In filter option for flexible rear filtration.
• Image circle of 46mm, suitable for full-frame and even large-format sensors.
• Matched aperture and focus rings across the Athena range for consistent operation.
• Designed to minimize focus breathing for stable framing during focus pulls.

Apertures and available focal lengths in the Athena series

The Athena prime series covers a broad focal length range to suit many shooting styles. The available focal lengths and their maximum T-stop ratings are:

• 14mm — T2.4
• 18mm — T2.2
• 25mm — T1.9
• 35mm — T1.9
• 40mm — T1.9
• 50mm — T1.9
• 85mm — T1.9
• 135mm — T2.2

These T-stop values reflect the lens series’ actual light transmission, which supports consistent exposure across different focal lengths.

Optical performance and image characteristics

The Athena primes aim to deliver refined image rendering. They offer ultra-low chromatic aberration and controlled micro-contrast to preserve finer image details. In addition, the series has been designed to reduce focus breathing so that changes in field of view during focus pulls remain minimal.

Mounts, filter options and important notes

The Athena primes come in multiple mount options and provide flexible rear filtration solutions. The series is available in:

• ARRI PL
• Canon RF
• Sony E
• Panasonic / Leica L
• Fuji G

Filter options by mount:

• RF, L and G mounts: Drop-In filter option available.
• E-Mount: Offered in two versions — one with Drop-In filter and one without.
• PL mount: Utilizes a rear filter.

Note: Some cameras have restrictions. For example, the Sony FX9 cannot use an E-Mount version that includes Drop-In filters. Also, to achieve infinity focus and obtain clear images, you must use the Drop-In clear filter on RF, L, G and E mounts (where applicable) or the rear filter on PL-mount lenses.

NiSi also provides weather sealing for the Drop-In filter to maintain reliability in varied shooting conditions.

Handling, compatibility and mechanical features

NiSi designed the Athena primes for practical use on professional rigs and in multi-lens workflows. Key handling and mechanical details include:

• All Athena prime lenses are similar in weight, so you do not need to rebalance your gimbal when switching between Athena lenses.
• All lenses, except the 14mm, share a 77mm front filter thread.
• Aperture and focus rings are matched across the range for consistent feel and operation.
• Focus rotation of 300° enables precise focus pulls.
• Fluorescent focus scales are provided in both imperial and metric units for clear marks during pulls.
• Standard 0.8 mod focus and iris gears ensure broad compatibility with follow focus and matte box systems.

Accessories

A 77mm NiSi close-up lens is available separately. You can use it to reduce the minimum focus distance and create macro effects when needed.

Who should consider the Athena 50mm T1.9 (Fuji G)

Choose this lens if you need a cinematic 50mm prime in Fuji G-Mount that integrates with a matched family of primes, offers fast T1.9 performance, and supports rear Drop-In filtration. It is well suited for filmmakers using full-frame or larger sensors, shooters who require consistent handling across a lens set, and anyone who needs precise focus control for narrative or commercial work.

FAQ

Question: Is the Drop-In filter required to achieve infinity focus?
Answer: Yes. For RF, L, G and E-mount (Drop-In version) lenses you must use the Drop-In clear filter, and for PL-mount lenses you must use the rear filter, to obtain infinity focus and clear images.

Question: Can I use the E-Mount Drop-In version on a Sony FX9 camera?
Answer: No. The Sony FX9 cannot use the E-Mount version that includes Drop-In filters, so choose the appropriate mount/version for that camera.

Question: Do I need to rebalance my gimbal when switching Athena primes?
Answer: No. All Athena primes are similar in weight, so you do not need to rebalance your gimbal when switching between lenses in the series.

Question: Are the focus and aperture rings consistent across the range?
Answer: Yes. Aperture and focus rings are matched across the Athena series for consistent operation, and the 300° focus rotation plus fluorescent scales support accurate pulls.

Question: What filter size do these lenses use?
Answer: All Athena primes except the 14mm use a 77mm front filter thread. Additionally, RF, L and G versions support Drop-In filters as noted.

Question: Can I use close-up or macro accessories with the 50mm Athena?
Answer: Yes. NiSi offers a 77mm close-up lens (sold separately) that reduces minimum focus distance to create macro effects when needed.