NiSi Cine Lens Athena Prime 25mm T1.9 PL-Mount

NiSi Cine Lens Athena Prime 25mm T1.9 PL-Mount – T1.9 aperture and 46mm image circle

This NiSi Athena Prime 25mm T1.9 in PL mount is part of the Athena Cine Lens series designed for cinematographers and videographers who need consistent optics across a full prime set. It delivers the series’ stated image circle and optical behavior while offering the bright T1.9 maximum aperture for shallow depth of field and low-light work.

Key optical characteristics

The 25mm Athena Prime shares the series’ optical design goals. It offers a maximum aperture of T1.9, allowing for soft bokeh and clear subject separation when desired. In addition, the Athena series emphasizes low chromatic aberration and controlled micro-contrast, which contributes to finer image details in footage.

Furthermore, the Athena Primes produce an image circle of 46mm. This image circle makes the lenses suitable for use with full-frame sensors and larger-format sensors that fit within that 46mm coverage.

Aperture and focal length family details

The Athena Prime series covers a broad range of focal lengths from 14mm to 135mm, giving filmmakers options from ultra-wide to portrait focal lengths. Within the series, maximum aperture values vary:

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

These specified T-stops measure actual light transmission through each lens and help to maintain consistent exposure across matching apertures in the set.

Mount and filter system

The Athena Prime series is available in several mount options, and filter systems differ depending on the mount chosen. The available mounts include ARRI PL, Canon RF, Sony E, Panasonic/Leica L and Fuji G.

• PL mount: uses a rear filter. The 25mm PL version therefore uses the PL rear filter configuration.
• RF, L and G mounts: offer a Drop-In filter option in the rear of the lens.
• E mount: is available in two versions, one with a Drop-In filter and one without.

NiSi provides a weather-sealed Drop-In filter for compatible mounts. Note that for RF, L, G and E mount Drop-In configurations, and for PL rear-filtered lenses, NiSi states that the Drop-In clear filter (or the rear filter for PL) must be used with the lens to achieve infinity focus and clear images.

Handling, mechanics and compatibility across the set

The Athena Primes are matched across the range for handling and control. Aperture and focus rings are matched, which helps when swapping lenses during a shoot. Focus rotation on these lenses is 300°, and focus scales are fluorescent with both imperial and metric markings to aid precise focus pulls.

The lenses use standard 0.8 mod focus and iris gears, making them compatible with a wide variety of follow focus systems and matte boxes. Except for the 14mm lens, all Athena Primes share the same 77mm front filter thread.

NiSi notes that all Athena Prime lenses are similar in weight, which means you do not need to rebalance a gimbal when switching between Athena lenses in the set.

Minimized focus breathing and accessories

The Athena Prime design minimizes focus breathing. As a result, changes in field of view while pulling focus from minimum focus distance to infinity are extremely small compared with lenses that have larger breathing characteristics.

For close-up and macro-style work, NiSi offers a 77mm close-up lens (sold separately). This accessory reduces the minimum focus distance and helps create strong macro effects when used with Athena lenses that accept 77mm accessories.

Important compatibility notes

• 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, G and applicable E-mount versions, and use the rear filter on PL-mount lenses.

FAQ

Question: Will the 25mm Athena Prime work on full-frame and large-format sensors?
Answer: Yes. The Athena series provides a 46mm image circle, which covers full-frame and larger-format sensors that fit within that image circle.

Question: Do I need to rebalance my gimbal when switching to the 25mm from other Athena lenses?
Answer: No. NiSi states that Athena Prime lenses are similar in weight across the series, so you should not need to rebalance your gimbal when swapping lenses within the set.

Question: How should I use filters with the PL-mount 25mm lens?
Answer: The PL-mount Athena Primes use a rear filter. NiSi specifies that this rear filter must be in place to achieve infinity focus and clear images with the PL-mount lenses.

Question: Can I expect distracting focus breathing when pulling focus?
Answer: The Athena Primes are designed to minimize focus breathing. Therefore, the change in field of view when adjusting focus from minimum focus distance to infinity is very small, which aids in clean focus pulls.

Question: Are there Drop-In filters and are they weather sealed?
Answer: Yes. RF, L and G mounts have a Drop-In filter option and NiSi provides a weather-sealed Drop-In filter. The E-mount is offered in versions with and without Drop-In. PL-mount lenses use a rear filter instead of a Drop-In.