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

NiSi Cine Lens Athena Prime 50mm T1.9 E-Mount – T1.9 aperture with optional Drop-In filter

This is the NiSi Athena Prime 50mm in Sony E-mount, offering a maximum aperture of T1.9 and available in two E-mount versions: with or without a Drop-In filter. It is part of the NiSi Athena Cine Lens series that covers a broad focal-length range and is built for cinematography and video production.

Series coverage and optical design

The Athena Prime series spans focal lengths from 14mm to 135mm. That range covers ultra-wide angles through portrait focal lengths, which gives you versatility for many shooting scenarios. NiSi designed the series with ultra-low chromatic aberration and micro-contrast control to help preserve finer image details across the range.

Apertures and light transmission

The series uses T-stop ratings to indicate actual light transmission. Most mid-range primes in the series—25mm, 35mm, 40mm, 50mm and 85mm—have a maximum aperture of T1.9, enabling shallower depth of field and softer background separation. The 18mm and 135mm lenses have a maximum aperture of T2.2, while the 14mm reaches T2.4.

Image circle and sensor coverage

The lenses produce an image circle of 46mm. Therefore, they are suitable for use with full-frame sensors and also accommodate larger-format sensors that fit within that image circle.

Mount options and rear filtration

The Athena Prime series comes in multiple mounts: ARRI PL, Canon RF, Sony E, Panasonic/Leica L and Fuji G. The series offers a proprietary rear filtration system with Drop-In filter capability on several mounts.

• RF, L and G mounts include a Drop-In filter option.
• The E-mount is available in two versions: one with a Drop-In filter and one without.
• The PL-mount uses a rear filter system rather than a Drop-In module.

Note the following important compatibility points: Sony FX9 cameras cannot use the E-mount version that includes Drop-In filters. Also, to achieve true infinity focus and clear images you must use the Drop-In clear filter on RF, L, G and E versions that support Drop-In, and the rear filter on PL versions.

NiSi additionally provides a weather-sealed option for the Drop-In filter to help protect the rear filtration system in challenging conditions.

Mechanical consistency and handling

NiSi matched mechanical characteristics across the Athena range to simplify lens changes and on-set workflow. All Athena Prime lenses are similar in weight, which means you do not need to rebalance a gimbal when you swap between Athena lenses. Aperture and focus ring positions are consistent across the series, which speeds lens changes and repeatable setups.

Except for the 14mm lens, all Athena Primes share a 77mm front filter thread. Both the focus and aperture gears use a standard 0.8 mod, making them compatible with most follow focus and matte box systems. The lenses also feature a focus rotation of 300° and fluorescent focus scales marked in both imperial and metric units to support precise focus pulls.

NiSi offers a 77mm close-up lens as an optional accessory to reduce minimum focus distance and create macro effects; this close-up lens is sold separately.

Technical specifications

Practical notes for shooters

When you choose the 50mm E-mount Athena Prime, decide whether you need the Drop-In filter version. If your workflow requires rear filtration, the E-mount model with Drop-In gives that option; otherwise select the non-Drop-In E-mount. Remember that some camera bodies, such as the Sony FX9, cannot use the E-mount Drop-In variant.

Because the lenses share weight, balance, ring positions and gear standards, you can change focal lengths quickly with minimal rigging adjustments. Use the fluorescent scales and 300° focus throw for accurate, repeatable focus pulls during takes.

FAQ

Question: Can I use the E-mount Drop-In filter on a Sony FX9?

Answer: No. The Sony FX9 camera cannot use the E-mount version that includes Drop-In filters.

Question: Do I need to use the Drop-In or rear clear filter to reach infinity focus?

Answer: Yes. To achieve infinity focus and clear images you must use the Drop-In clear filter on RF, L, G and E-mounts that support Drop-In, and the rear filter on PL-mount lenses.

Question: Will I need to rebalance my gimbal when switching Athena lenses?

Answer: No. All Athena Prime lenses are similar in weight, so you do not need to rebalance the gimbal when swapping between Athena lenses.

Question: Which focal lengths in the Athena series offer T1.9?

Answer: The 25mm, 35mm, 40mm, 50mm and 85mm lenses have a maximum aperture of T1.9.

Question: Are the focus and aperture gears standardized for accessories?

Answer: Yes. Both focus and iris use a standard 0.8 mod gear, and the lenses feature a 300° focus rotation with fluorescent scales in imperial and metric units for precise pulls.