Will this full-frame EF mount lens sufficiently cover the medium format sensor of Fujifilm GFX cameras? With Metabones® EF-GFX Smart Expander™, the answer is always "yes".

Multiplying the focal length by 1.26x and the F-number by the same amount, Metabones EF-GFX Smart Expander perfectly matches the image circle of full-frame EF mount lenses to the medium-format sensor of the GFX series cameras, with the diagonal field-of-view (FoV) remaining exactly the same.

The optical design consists of 5 elements in 3 groups, incorporating ultra-high index Lanthanum-based optical glass as well as one element made of fused silica, resulting in extremely good performances with professional-grade zoom lenses. For example, a 24-70mm f/2.8 lens becomes a 30-88mm f/3.5 zoom, and a 70-200mm f/2.8 lens becomes an 88-252mm f/3.5 zoom.  And perhaps most exciting of all, the 11-24mm f/4 Canon becomes an extremely sharp 13.8-30.2mm f/5 without any disturbing vignetting or corner aberrations. Due to the nature of focal extenders, the aperture values decrease by 2/3 of a stop; f/2.8 becomes f/3.5 and f/2 becomes f/2.5. High-speed fixed focal length lenses such as the 50mm f/1.4 will be transformed into a very fast 63mm f/1.8 standard lens for the GFX system.

Electronic Features

The EF GFX mount Smart Expander features Metabones' electronic integration, including phase-detection autofocus (PDAF) and in-body image stabilization (IBIS) on GFX 100, optical image stabilization (called IS/OS/VC by various lens manufacturers), and smooth iris.

To the best of our knowledge, Metabones makes the only Fujifilm adapters, which support IBIS with every EF mount lens, including long telephotos and zoom lenses. There is no need to wait or hope for other adapter vendors to add IBIS support for your lenses at their next firmware update. With Metabones, IBIS support is general and across-the-board.

When a recent lens that supports smooth iris is used, Metabones makes aperture changes quiet and creates smooth transitions by slowing down the electronically-controlled aperture diaphragm. The button on the Smart Expander toggles between auto aperture (programmed exposure or shutter priority) and manual aperture (aperture priority or manual exposure). If a manual lens with no electronics is attached, the button brings up the manual lens selection on the camera body so that focal length can be chosen for correct IBIS operation and EXIF.

EF-GFX Smart Adapter

Without Caldwell Photographic's optics but otherwise, with the same electronic integration, EF-GFX Smart Adapter™ is an alternative for the adventurous. In many cases, there will be vignetting and degradation in corner performance. However, tilt-shift lenses will work perfectly fine from corner to corner, and most zoom lenses will nicely cover the large sensor in the middle and long end of the zoom range. A nifty feature is added where the user may configure the Smart Adapter and it will remember which lenses need to be in 35mm crop mode and which ones cover medium format. This saves time by not having to navigate the camera's menus for a 35mm crop after a lens change.

Limitations and Issues

Disclosure of known limitations and issues with the initial release:

1. In some rare cases, lens hoods designed for 3:2 may need to be removed for 4:3 use with Smart Expander.
2. Each lens needs to go through a calibration procedure when first used. Refer to the online user manual on Metabones' web site for instructions.
3. Autofocus may have unsatisfactory performance and may not work at all with some lenses
4. For video autofocus, increasing FOCUS SENSITIVITY and decreasing AF SPEED are required under the AF-C CUSTOM SETTING (MOVIE) menu.
5. AF+MF and lens aberration correction are not supported.
6. Some film-era lenses may not be able to achieve the sufficient AF accuracy required for digital cameras. Worn lenses with faulty sensors may lead to AF problems on a mirrorless camera even though the lens may appear to function normally on a DSLR.
7. Aperture diaphragm makes frequent noises with older lenses. Use aperture priority and manual exposure modes, or use a lens that supports smooth iris.
8. With IS/OS/VC lenses the IS MODE setting is ignored and both SHOOTING ONLY and CONTINUOUS modes behave in the same way which is similar to a Canon camera but different from what Fujifilm OIS lenses do. This is done to maximize IS effectiveness. A negative consequence of this is that there may be no OIS during focus check.
9. MF Distance Display does not work (although AF Distance Display does if the lens transmits distance information).

Since Metabones has a track record of releasing new firmware updates that significantly improve the features, performance, compatibility, and reliability of existing products, these limitations are subject to change in the future. Please refer to the product pages on Metabones' web site for the most up-to-date disclosure. To update firmware, download Metabones App™ from Metabones' web site on a Mac or a Windows PC and connect the Metabones product to the computer with a micro-USB cable. The same Metabones App upgrades firmware for all Metabones products.

Availability

Metabones® Canon EF-GFX Smart Expander 1.26x is available right now from the Metabones website and its worldwide dealer network for US$729, plus shipping, applicable taxes and duties.

The optic-free version, EF-GFX Smart Adapter will be available shortly afterward for US$439, plus applicable taxes, duties and shipping.

Specifications:

• Product name: Canon EF-mount Lens to Fujifilm GFX (G-mount) Smart Expander 1.26x
• Model Code: MB_EPEF-FG-BT1
• Color: Black Satin exterior; Black Matte interior
• Magnification:  1.26x
• Crop Factor with Fuji GFX camera:  1.0x
• Maximum Output Aperture:  f/1.8 (with f/1.4 lens attached)
• Rectilinear Distortion:  < 0.5%
• Lens Elements/Groups:  5/3
• Camera Mount:  Fujifilm G Mount
• Lens Mounts:  Canon EF
• Tripod Mount:  Robust removable type with Arca Swiss compatibility
• Dimensions: 91.6mm x 80.1mm x 38.5mm (incl. tripod mount)
• Weight: 346 grams
• Retail Price: USD 729.00
• Product Page: http://www.metabones.com/products/details/MB_EPEF-FG-BT1