NiSi Cine Lens Athena Prime 40mm T1.9 E-Mount (Without Drop-in Filter)

NiSi Athena Prime 40mm T1.9 E-Mount — Fast T1.9 Prime (Without Drop-In Filter)

The NiSi Athena Prime 40mm T1.9 in E-Mount delivers a fast T1.9 aperture in a cine-style prime designed for filmmakers who need consistent optics across a matched lens series. This listing is for the E‑Mount version without the Drop‑In filter system.

Key features and what they mean for your shoot

• Fast T1.9 maximum aperture for the 40mm lens, allowing for low-light shooting and shallow depth of field.
• Part of a matched prime series that spans 14mm to 135mm, ensuring consistent handling and visual character when you switch lenses.
• Designed to minimize focus breathing so changes in focus produce only a very small shift in field of view.
• Image circle of 46mm across the series, making these lenses suitable for full-frame and larger sensors.

Optical range and apertures in the Athena Prime series

The Athena Prime family covers a broad set of focal lengths to suit many shooting scenarios, from ultra-wide to portrait focal lengths. The series includes these focal lengths and maximum T-stops:

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

Compatibility and mounts

The Athena Prime series ships in multiple mount options to suit different camera systems. Available mounts include ARRI PL, Canon RF, Sony E, Panasonic/Leica L and Fuji G. Note that the E‑Mount option is offered in two variants: with or without the Drop‑In filter system. This specific product is the E‑Mount without the Drop‑In filter.

Drop‑in filter system and important usage notes

The series features a proprietary rear filtration system. Depending on mount selection:

• RF, L and G mounts have a Drop‑In filter option.
• PL mount uses a rear filter.
• E‑Mount lenses are available in versions with and without the Drop‑In filter. This listing is for the E‑Mount without Drop‑In filter.

Important notes from the manufacturer:

• Sony FX9 cameras cannot use the E‑Mount with Drop‑In filters.
• To achieve infinity focus and clear images, you must use the Drop‑In clear filter on RF, L, G and E mounts where applicable, and the rear filter on PL mount.
• NiSi provides weather sealing for the Drop‑In filter (where applicable to the mount/version).

Mechanical design and lens handling

The Athena Primes are designed for convenient use on professional rigs. All lenses in the series are similar in weight, which reduces the need to rebalance a gimbal when you swap lenses. Also, except for the 14mm lens, lenses in the series share a 77mm front filter thread.

Both aperture and focus rings are matched across the range for consistent tactile control. Each lens offers a 300° focus rotation and features fluorescent focus scales in both imperial and metric units for precise focus pulls. The focus and iris gears use the standard 0.8 mod, ensuring compatibility with a wide range of follow focus and matte box systems.

Image quality characteristics

The series emphasizes controlled aberrations and fine detail. NiSi specifies ultra‑low chromatic aberration and micro‑contrast control across the Athena Primes. These design choices aim to deliver finer image details while keeping optical artifacts to a minimum.

Accessories

NiSi offers a 77mm close‑up lens (sold separately) that reduces minimum focus distance to create macro effects. This close‑up accessory is compatible with Athena lenses that use the 77mm thread.

Usage tips

Because the Athena Primes are matched for weight, gear and handling, you can switch focal lengths quickly without major rebalancing on gimbals. Use the 300° focus throw and fluorescent scales for accurate manual focus pulls. If you need closer focusing for macro-style shots, add the NiSi 77mm close‑up lens.

FAQ

Question: Is this 40mm Athena Prime the E‑Mount version with the Drop‑In filter?
Answer: No. This specific listing is the Sony E‑Mount version without the Drop‑In filter. NiSi also offers an E‑Mount variant that includes the Drop‑In filter system.

Question: Will this lens work on full‑frame and larger sensors?
Answer: Yes. The Athena Prime series has an image circle of 46mm, which NiSi specifies as suitable for full‑frame and larger formats.

Question: Do I need to rebalance my gimbal when switching Athena lenses?
Answer: Generally no. All Athena Prime lenses are similar in weight, which reduces the need to rebalance when changing lenses—making them convenient for fast lens swaps on stabilizers.

Question: Can I use Drop‑In filters with a Sony FX9?
Answer: No. NiSi notes that the Sony FX9 cannot use the E‑Mount with Drop‑In filters. If Drop‑In filtration is required, check mount compatibility carefully.

Question: What should I use to ensure infinity focus with Athena Primes?
Answer: To reach accurate infinity focus and clear images, use the Drop‑In clear filter for RF, L, G and E mounts where those versions include it, and use the rear filter on PL‑mount lenses.

Question: Are follow focus systems compatible with this lens?
Answer: Yes. The lens uses standard 0.8 mod focus and iris gears, making it compatible with most follow focus and matte box systems used in professional cinema workflows.