iShoot Improved CNC 84mm Tripod Mount Ring Collar for Sigma 100-400mm

In this review the iShoot Improved CNC 84mm Tripod Mount Ring Collar is evaluated as a purpose-built support accessory for owners of the Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary lens. The bottom line: this collar is for photographers who need a lightweight, precise tripod mounting solution with built-in Arca-Swiss compatibility and hard anodized aluminum construction. It stands out because it is tailor-made to fit the EF and F mount versions of the lens, adding a secure quick release plate while keeping overall weight low.

Key Features

• Dedicated compatibility: The ring is specifically shaped for the Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary lens, ensuring a snug fit and accurate alignment when mounted.
• CNC machined aviation aluminum: Precision CNC machining and anodized finish deliver a durable, lightweight collar that resists wear in the field.
• Hollow-out weight reduction: The design pares down mass without compromising rigidity, making the assembly easier to carry on long shoots.
• Built-in Arca-Swiss quick release plate: The integrated plate (approx 70mm length, AS 39mm standard) provides immediate compatibility with a wide range of Arca-style ball heads.
• Multiple screw options: The base includes 1/4 and 3/8 screw holes and a stainless steel anti-slip screw for secure attachment to tripods or clamps.
• Soft 3M internal film: The interior padding protects the lens finish while maintaining a tight, non-rotating connection to the collar.

Who It's For

This collar is aimed at photographers who own the Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary lens in EF or F mount and who want a compact, Arca-compatible solution for tripod use. Wildlife, sports, and travel shooters who switch quickly between monopod, tripod, and ball head setups will appreciate the integrated quick release plate and the light net weight of about 160g.

It is not for owners of the Sigma 100-400mm f/5-6.3 DG DN OS for E-mount or L-mount, nor is it a universal collar for other lenses. Users who need a rotating collar or who require compatibility with non-Arca quick release systems should look for alternatives.

Pros & Cons

Pros

• Tailor-made fit provides secure, repeatable alignment for the specified Sigma lens.
• Lightweight CNC aluminum construction balances durability and portability.
• Integrated AS 39mm quick release plate increases compatibility with many Arca-style heads.
• Includes 1/4 and 3/8 mounting holes and stainless steel hardware for flexible attachment options.

Cons

• Cannot rotate on the lens and is only compatible with the EF/F mount Sigma 100-400mm; not universal.
• The plate is fixed length and may not suit every clamp style despite broad Arca compatibility.

Specifications

Compatible Lens	Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary (EF and F mount)
Inner Diameter	About 84mm
Width	About 23mm
Material	Aviation aluminum, CNC machined, anodized
Quick Release Plate	AS 39mm standard, approx 70mm length
Mounting Holes	1/4 and 3/8 screw holes with stainless steel anti-slip screw
Net Weight	About 160g

Our Verdict

The iShoot Improved CNC 84mm Tripod Mount Ring Collar is a solid, purpose-built accessory for photographers using the Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary lens in EF or F mount. Its CNC aluminum construction, integrated Arca-style plate, and lightweight design make it a practical, good-value choice for field use, provided you need a fixed collar and confirmed compatibility.

Frequently Asked Questions

Is this collar compatible with Sigma 100-400mm DG DN OS?
This collar is not compatible with the Sigma 100-400mm f/5-6.3 DG DN OS (E-mount or L-mount); it is designed only for the EF and F mount Contemporary version.

Will the plate fit standard Arca-Swiss clamps?
Yes, the quick release plate follows AS 39mm standard and is compatible with many Arca-style clamps and popular clamp brands.

Can the collar rotate on the lens for portrait/landscape switching?
No, the collar is tailored and cannot be rotated; it provides a fixed mounting point with internal 3M film to protect the lens.