EB-1 wrote:
What is the point if there is not some mysterious advantage over the Sony TCs?
EBH
Pure speculation:
Possibly around half the price of Sony’s own teleconverters (or close).
Potentially compatible with more third-party lenses.
And perhaps even sharper than Sony’s, which are fairly dated.
I was expecting maybe a non-protruding TC that works with most all lenses, but that one protrudes. I suppose it could work with some 3rd party teles with rear holes that Sony TCs don't. But what lenses are those?
Hasn't Sony only made E series lenses for 10 years or so?
Maybe Sigma lenses that are TC compatible for L Mount. Might imply there is space for a TC in the E mount version. Along the same lines as you noted.
EB-1 wrote:
I was expecting maybe a non-protruding TC that works with most all lenses, but that one protrudes. I suppose it could work with some 3rd party teles with rear holes that Sony TCs don't. But what lenses are those?
Hasn't Sony only made E series lenses for 10 years or so?
Official Support List：
328GM
428GM
640GM
70-200GMii
70-200GM
100-400GM
70-200Gii
200-600G
400-800G
Viltrox 135/1.8 Lab ( maximum aperture F5.6 )
=================================================
Some wild information：
It can work with Sigma 70-200/2.8 DGDN and Sigma 500/5.6, but the aperture remains the same as the main lens, you will need to manually adjust exposure compensation 2EV.
( note：the above informations cannot be confirmed, no information on other lenses )
Official Support List：
328GM
428GM
640GM
70-200GMii
70-200GM
100-400GM
70-200Gii
200-600G
400-800G
Viltrox 135/1.8 Lab ( maximum aperture F5.6 )
=================================================
Some wild information：
It can work with Sigma 70-200/2.8 DGDN and Sigma 500/5.6, but the aperture remains the same as the main lens, you will need to manually adjust exposure compensation 2EV.
( note：the above informations cannot be confirmed, no information on other lenses )
Thanks. Shame that the 50-150 GM doesn't have room at the rear for any teleconverter.
Per GroK:
Viltrox Teleconverters for Sony Cameras
Viltrox, a third-party lens manufacturer known for affordable autofocus lenses and adapters, has recently expanded into teleconverters specifically compatible with Sony's E-mount system. As of November 24, 2025, they've just announced their first native rear-mounted teleconverter for Sony E-mount cameras, marking a significant development since Sony has previously limited third-party access to full E-mount communication protocols. This new product is positioned as a budget alternative to Sony's own FE 2x Teleconverter (which retails for around $500). Below, I'll break down the key offerings, focusing on Sony compatibility.
Newly Announced: Viltrox 2x E-Mount Teleconverter (Rear-Mounted)
This is a true teleconverter that mounts between a compatible Sony E-mount lens and the camera body, doubling the focal length (e.g., turning a 100mm lens into 200mm) while losing about 2 stops of light (e.g., f/2.8 becomes f/5.6). It's the world's first third-party E-mount teleconverter with full electronic integration.
Key Specifications:
Magnification: 2x
Optical Design: 9 elements in 5 groups
Weight: 229g (lightweight and portable)
Features:
Full electronic contacts for EXIF data transmission and lens-based image stabilization (IBIS) support.
Autofocus compatibility with high-speed shooting, including full 120fps burst rate on the Sony A9 II (a major win over most third-party lenses, which cap at 15fps).
Dust- and splash-resistant construction.
Price: Approximately $160 (1,129 Yuan), making it far more affordable than Sony's equivalent.
Availability: Announced today (November 24, 2025); preorders not yet open, but expected soon via Viltrox's official store, B&H Photo, Amazon, and Adorama.
Compatibility: Designed for Sony full-frame (FE) and APS-C E-mount lenses with sufficient rear clearance (e.g., not ultra-compact primes like the 135mm GM). It works with Viltrox's own E-mount lenses and should pair well with telephoto zooms like the Sony 70-200mm f/2.8 GM II.
Performance Notes: Early claims suggest minimal impact on autofocus speed and image quality compared to Sony's TCs, but real-world tests are pending. It bypasses typical third-party limitations by intercepting lens-body communication.
Fboss wrote: olalafoto wroteIt seems that combined stabilization ( oss + ibis ) is not supported.Quite a major drawback if confirmed. What is the source of this information ?
The information comes from an online conversation between a chinese user and the customer service of Viltrox's official china online store.