you guys are making assumptions about the lense which just aren't known yet.
Nope, I can only speak for myself but I am not making assumptions. I am making an educated statement based on experimentation over the last five years or so using a variety of wet mount lenses. I think I can say that for certain very few people have owned as many wet mount lenses as me and tested them to the extent I have on a variety of cameras. More than enough to fully understand what they need in terms of a camera to function correctly optically without my making excessive assumptions.
It may be that the wide end is at the extended end of the lense, similar to the S90/S95. If so, it's a non issue.
Just too early to tell.
No, it is an issue, the rack distance of the 5X lens ratio on the S100 will be greater than the approximate 3.8X of the S90/95. As well, the now 24mm lens will require further zooming and the longer 5X lens will require a longer port thus placing the wet mount lens too far from the camera lens.
It may be that the new Inon H100 lens or that the Oly lens used on the XZ-1 might work due to their very large rear optical element but the Inon WAL100, Inon WAL100-28AD, Inon UFL165AD, Ikelite W20, Fisheye UWL-04 and similar will not work without excessive zooming and vignetting.
So, OK, it is 24mm, does it need a wide angle lens and the answer is a big yes. A 24mm lens behind a flat port is hardly wide at all and will have distortion and diffraction in the corners. If corrected with a dome it would have a 90 degree DFOV. But, the Inon UFL165AD or the Fisheye UWL-04 on the S90 with the original FIX housing or S95 with the Recsea housing have over 130 degrees and closer to 150 degree DFOV. This neither is an assumption since I have measured it.
BTW, the S series lens, as is common on many compact cameras from Canon and others, actually gets shorter (retracts) as you initially zoom and then about half way through the range it begins to extend and finally extends further than the minimum focal length starting position. Since the S100 has the same size sensor, basically the same size optical elements and a greater zoom range, it will need to rack further in and out to accommodate the focal range than the S90/S95. It is not an assumption, it is optical physics.
The S100 is going to be a real challenge for wet mount wide angle and ultra wide lenses. I suspect it will do OK with the UCL165 macro and perhaps that new Inon macro dome lens, UFL-M150. Like I said, I would not yet rule out the Inon UWL-H100. Since I do not own either of these, I have not been able to measure their optical requirements as I have for many of the other common lenses.
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