Does Fujifilm X-T5 work with Sigma 18-50mm f/2.8 DC DN via E-mount to X-mount Adapter?

What works & limitations

• Physical attachment via a passive dumb E-to-X adapter is mechanically possible — the E-mount flange seats into the adapter, which then mounts to the X-T5's X-mount bayonet
• Manual focus is fully functional — the X-T5's focus peaking (configurable to High/Mid/Low sensitivity and Red/White/Blue color) clearly highlights in-focus edges at f/2.8
• Image quality of the Sigma 18-50mm f/2.8 DC DN optics is preserved — the optical formula performs normally once focus is manually set; wide-open sharpness at f/2.8 is retained
• Aperture is locked at f/2.8 wide open with a passive adapter — this is actually useful for consistent low-light exposure if you only need f/2.8 and never need to stop down
• No autofocus of any kind — phase-detect and contrast-detect AF both require electronic mount communication; a passive adapter provides no electronic path between lens and camera
• Aperture cannot be adjusted from the camera body — the lens is permanently wide open at f/2.8; depth of field control and exposure adjustment via aperture are impossible
• No EXIF focal length, aperture, or lens identity data — metadata fields are blank or placeholder values; Lightroom lens profile corrections cannot auto-apply
• No OIS communication — the X-T5's IBIS cannot receive focal length data from the lens, forcing the user to manually enter the focal length in the IBIS menu for accurate stabilization; even with manual focal length entry, IS effectiveness is reduced without OIS data
• No exposure confirmation from the lens — depth-of-field preview using the aperture lever is not available; only the wide-open f/2.8 view is shown in the EVF
• No electronic E-to-X adapter exists that would restore autofocus — Sony E-mount uses a proprietary digital communication protocol and Fujifilm X-mount uses a different proprietary protocol; the two are electronically incompatible and no third-party has produced a functional AF-capable E-to-X adapter as of 2026
• Sigma manufactures the 18-50mm f/2.8 DC DN Contemporary directly in Fujifilm X-mount (model number 583963, released October 2022) — purchasing the X-mount version directly solves all compatibility issues: full AF, aperture control, OIS, and EXIF data at f/2.8 maximum aperture; the X-mount version retails for approximately $549 and weighs 290g
• If you own the Sigma 18-50mm f/2.8 DC DN in Sony E-mount and want to use it across both a Sony body and a Fujifilm X-T5, Sigma does not offer a mount conversion service for this lens model; the practical solution is to purchase the X-mount version separately and keep both — the lens is compact enough that carrying both adds minimal weight
• The correct native Fujifilm X-mount fast zoom alternative with AF: Fujinon XF 18-55mm f/2.8-4 R LM OIS (variable aperture, 310g, approximately $500 used) or the Sigma 18-50mm f/2.8 DC DN in X-mount (constant f/2.8, 290g) — the Sigma X-mount version is the closer equivalent to what you intend with this combination