I have a canon 700D, and I'm contemplating buying a second hand Fuji X-T1. But I have invested in a Sigma 18-35 F/1.8 and am very happy with it. Is there an adapter for the EF-S mount lens that will allow me to use it with the Fuji camera with full functionality?
There are now several "smart adapters" for EF-FX that allow AF and OIS to work: Fringer, Kipon, Steelsring, and Viltrox. Viltrox is the cheapest. Kipon Baveyes is the most expensive.
If you already own multiple compatible lenses, getting an adapter may be worthwhile. Otherwise, for both price and performance, you are better off with native lenses.
Compatible lenses should work reasonably well, but not as well as native lenses. Firmware updates have been known to introduce problems with previously compatible lenses. Incompatible lenses can be expected to be plagued with problems.
OIS and AF aren't as good with adapted lenses as with native lenses.
The Kipon Baveyes has a 0.7x focal reducer built in. It's the most expensive, and there is no lens compatibility list. It is also made of a hard brushed metal that will abrade metal from your lens and camera mounts.
You can search YouTube for demo videos.
Some lenses to illustrate variable compatibility among adapters:
Sigma 18-35/1.8 Art – I have not used this lens.
- Is on the Fringer compatibility list.
- Not on the Viltrox compatibility list.
Canon EF 40/2.8 STM – Works well with Fringer and Steelsring adapters. Reports incorrect aperture with Viltrox adapter, despite being listed as compatible.
Canon EF-S 24/2.8 STM – Works very well with Fringer, Steelsring, and Viltrox adapters. Fast and responsive, but loud (kind of like the XF 35/1.4).
Canon EF-S 18-135/3.5-5.6 IS USM
- Works best with Fringer adapter.
- Works reasonably well with Steelsring adapter.
- AF does not work with Viltrox adapter. Not sure about IS.
Tamron 28-300/3.5-6.3 ??? VC – Autofocus does not work with any adapter I've tried. Can be used as an image-stabilized manual-focus lens with the Fringer adapter.
I have tried other adapter-lens combinations, but do not recall results. Generally, as noted above, if it's on the compatibility list, it usually works well. Otherwise, it's pretty miss or miss, especially with third-party lenses.
This article at Fuji Rumors might be interesting for you.
But, I'm not sure how 'smart' that adapter is: nothing guarantees that the lens can understand the signals from the camera, or that the camera understands the replies, even if the pins on lens and camera are properly connected. And indeed that adapter mentioned above includes some firmware.