necron

There is an easer way. You can just push lens release button and rotate the lens a bit but not detach it. You need to focus on 10mm first, zoom to 24mm and do the above. Then zoom back to 10mm. Unfortunately focus will not be in the same position and focus ring won't work. So move camera further or close to find proper focus distance. Of course, make sure you turn on Preview Exp in manual option, and set aperture to actual 4.0. UPD, also enable Shoot without lens option. Note, you may damage your camera or lens as it's not recommended to detach the lens while camera is switched on.

HI guys, Did you ever wonder why 10-24 doesn't have fixed aperture values on it's aperture ring like other lenses with constant aperture? The answer is that 10-24 have actually variable aperture! But it slows it down by 4/3 f-stop on wide end. You can see that by looking through the front element of the lens while shooting wide open on 10mm. I found a way to shoot on f2.5 but it's not too reliable and may broke lens or camera. I believe it's possible to do the same by firmware update. So how does it perform on f2.5? Lens becomes slightly soft and there is some vignetting. I'm not sure if that is why Fuji decided to restrict it to f4 only. It also can be because on 14mm it becomes f2.8 - the exact the same as XF 14 2.8 prime lens. So it can be marketing restrictions. I did a quick test just to see how different can be DOF on 2.5 vs 4. Test conditions and scene are not too accurate, I'm going to do a proper test when I have enough time.