It doubles the focal length of a compatible Canon EF lens (2x magnification), effectively turning e.g. a 200mm into 400mm. It reduces effective depth of field (about half) and requires approximately 2 stops more exposure (about 4× exposure factor).
It is intended for Canon EF-mount lenses of 100mm focal length and above (ideal for 200–500mm). Lenses under 60mm are not recommended. Performance is best with high-quality prime or telephoto lenses.
Yes — the C-AF 2XII supports autofocus, but AF performance depends on the lens and camera body. Because the teleconverter reduces the effective aperture by 2 stops, some lens/camera combinations (especially those that become effectively f/8 or smaller) may lose AF capability or be slower.
Yes. The unit preserves EXIF information and supports electronic communication with the lens/camera, so TTL metering and most EXIF fields remain intact.
A 2X teleconverter reduces the effective light by approximately 2 stops (e.g., an f/2.8 lens becomes about f/5.6). Plan for longer exposures or higher ISO accordingly.
Yes. Image stabilization that is built into the lens or camera should continue to operate because the teleconverter is an optical extender and does not disable IS systems.
Using a 2X teleconverter typically introduces some loss of sharpness and contrast compared with the naked lens. Viltrox uses 7 optical elements in 4 groups with multi-coating to minimize degradation, but the final result depends heavily on the quality of the base lens.
The teleconverter is designed for Canon EF-mount lenses. While Canon EF lenses work on both full-frame and APS-C bodies, EF-S lenses are generally not recommended and may not physically or optically be compatible. Check lens physical design before attempting to mount.
Yes. Manual focus remains possible when the teleconverter is mounted. AF is supported as well, but manual focus can be useful in low-light or marginal AF conditions.
TTL flash metering should work because electronic communication and EXIF are preserved, but remember the teleconverter reduces effective exposure by about 2 stops, so flash power or exposure settings may need adjustment.
The C-AF 2XII includes a USB firmware interface. For firmware files and update instructions, visit Viltrox's official support/download page and follow their provided procedure. Check the user manual for any specifics.
Because the teleconverter magnifies the image, camera shake and focusing errors are more pronounced—use a tripod or faster shutter speeds when possible. Also use it primarily with fast, high-quality telephoto lenses for best results.
The package includes the teleconverter body with front and rear covers and a user manual in English and Chinese. Camera and lens are not included.
The teleconverter measures about 6.7 × 6.7 × 6.7 cm (with covers) and weighs approximately 159.5 g. It uses 7 optical elements in 4 groups and has 7 diaphragm blades.
Yes. Do not expect the same AF speed or optical quality as without a teleconverter. Avoid using with short focal-length lenses (under 60mm) and be aware AF compatibility varies by camera body (many bodies struggle to autofocus at effective apertures of f/8 or smaller). Always confirm physical compatibility before mounting EF-S lenses.
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