The release button reacts fast and works fine. For Fujifilm GFX 50S, X-Pro2, X-T4, X-T3, X-T2, X-T1, X-T30, X-T20, X-T10, X-E3, X-E2S, X-E2, X-A5, X-A10, X70, X30, X100T, X100F, XF10. Shutter release lock (for long exposures).
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