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

NiSi Cine Lens Athena Prime 25mm T1.9 E-Mount – Fast T1.9 aperture with optional Drop-In filter

The NiSi Athena Prime 25mm T1.9 in E-mount is a cine lens designed for filmmakers and videographers who need consistent T-stop performance and cinematic control. It is part of the Athena Prime series, which covers a broad range of focal lengths and offers options for Drop-In or rear filtration depending on the mount. This 25mm lens shares matched ergonomics and control with the rest of the Athena Prime lineup.

Key optical features

The Athena Prime series emphasizes consistent light transmission and image quality. Specifically:

• The series uses T-stop ratings to measure actual light transmission, providing consistent exposure across focal lengths.
• The 25mm model has a maximum aperture of T1.9, enabling shallower depth of field and softer bokeh for background separation when desired.
• The lenses deliver ultra-low chromatic aberration and micro-contrast control to preserve finer image details.
• The series produces an image circle of 46mm, making the lenses suitable for full-frame and large-format sensors.

Series aperture notes

The Athena Prime range includes several focal lengths with specific maximum apertures. These values ensure you can plan exposure consistently across the set:

• 25mm, 35mm, 40mm, 50mm and 85mm: maximum aperture T1.9.
• 18mm and 135mm: maximum aperture T2.2.
• 14mm: T-stop of T2.4.

Mounts, filters and Drop-In system

The Athena line offers multiple mount options and a flexible rear filtration system:

• The series is available in ARRI PL, Canon RF, Sony E, Panasonic/Leica L and Fuji G mounts.
• RF, L and G mounts include a Drop-In filter option.
• The E-mount is offered in two versions: with Drop-In filter and without Drop-In filter.
• PL-mount lenses utilize a rear filter.
• NiSi provides weather sealing for the Drop-In filter.

Important compatibility notes

Pay attention to mount-specific requirements and camera compatibility:

• The Sony FX9 camera cannot use the E-mount version with Drop-In filters.
• To achieve infinity focus and clear images, use the Drop-In clear filter for RF, L, G and E mounts (when equipped) and the rear filter on PL-mount lenses.

Handling, mechanics and consistency across the set

The Athena Primes are built for consistent handling and predictable operation during production:

• All Athena Prime lenses are similar in weight, so you do not need to rebalance a gimbal when switching between lenses in the series.
• Except for the 14mm, all lenses share the same 77mm front filter thread for traditional front filtration.
• Aperture and focus rings are matched across the range for consistent tactile response.
• Focus rotation is 300° on all Athena lenses, allowing precise focus pulls.
• Fluorescent focus scales appear in both imperial and metric units for accurate marks.
• The lenses use a standard 0.8 mod focus and iris gear, ensuring compatibility with common follow focus and matte box systems.

Accessories

• NiSi offers a 77mm close-up lens (sold separately) to reduce minimum focus distance and create macro effects when needed.
• Drop-In filters are weather sealed and designed to work with the specified mount versions.

FAQ

Question: Can I use the E-mount Drop-In version on all Sony cameras?
Answer: The E-mount Drop-In version comes with a Drop-In filter option, but it is not compatible with the Sony FX9 camera. Always check your camera’s compatibility before ordering.

Question: Do I need to fit a special filter to achieve infinity focus?
Answer: Yes. To achieve infinity focus and obtain clear images, you must use the Drop-In clear filter on RF, L, G and E mounts (when the Drop-In option is present), and use the rear filter on PL-mount lenses.

Question: Will switching between Athena lenses affect my gimbal balance?
Answer: No. All Athena Prime lenses are similar in weight, so you should not need to rebalance your gimbal when changing between lenses in the series.

Question: Are the focus and iris controls compatible with follow focus systems?
Answer: Yes. The lenses use standard 0.8 mod focus and iris gears and have matched aperture and focus rings across the range for seamless use with follow focus and matte box systems.

Question: Can I use front filters for all focal lengths?
Answer: Except for the 14mm lens, all Athena primes share a 77mm front filter thread. For PL-mount or where Drop-In filters are specified, follow the mount-specific filtration guidance to ensure correct focus and image clarity.

Question: Is there an option to reduce minimum focus distance for macro work?
Answer: Yes. NiSi offers a 77mm close-up lens (sold separately) that can reduce the minimum focus distance and enable macro-style effects when used with compatible Athena primes.