Here’s a complete list of all 68 improvements the X100S has over the X100. Most of these changes were as a result of the fantastic feedback provided by X100 users.
1. 16-megapixel sensor, up from 12-megapixel
2. X-Trans CMOS II sensor eliminates need for Optical Low Pass Filter
2. The resolution has improved to match Full Frame domain sensors
3. The Signal to Noise ratio improved to be on a par with Full Frame domain sensors
4. Phase detection pixels allow 0.07 sec Auto focus
6. 1080p 60fps full HD movie
7. Improved start-up time. From 2.0sec to 0.9sec
8. Continuous Shooting from 5fps up to 6fps
9. Number of consecutive frames while using Continuous Shooting from 10 frames to 31 frames
10. Improved Shooting Interval from 0.9 seconds down to 0.5 seconds.
11. EXR Processor II Lens Modulation Optimiser reduces diffraction
phenomenon and peripheral aberrations.
12. EXR Processor II features X-Trans processing & new noise reduction.
13. Outputs 14bit RAW files
14. EVF has a 2.35 mil dot LCD
15. A new protective coating on the surface of the view-finder window prevents fingerprints and smudging.
16. The handling and response on focus ring has been improved.
17. The shooting range of the OVF has been expanded from 80cm-∞ to 50cm-∞
18. The world’s first MF system ‘Digital Split Image’. It uses the phase detection to show accurate focus peaking.
See demo: http://youtu.be/_fJDX1hzUIg
19. ‘Focus Peak Highlight’ function helps you to check the focal plane.
See demo: http://youtu.be/PMdQpgOzd4o
20. In Movie Shooting, it is possible to choose 3 kinds of focusing modes
MF/ AF-C and AF-S.
21. Expanded AF shooting range from 40cm – infinity (X100) to 21cm – infinity (X100S). *not on Macro mode
22. Quick (Q) Button for speed and instant access to shooting menus.
23. Multi Tab Menu easy and fast navigation
24. Two new Film simulation functions added: Pro Neg.Std and Pro Neg. Hi
25. ‘F-simulation bracketing’ function – one shot can produce 3 different Film Simulation images which can be pre-set.
26. ‘Advanced filter’ mode
27. ‘Multi Exposure’ function. While viewing your first shot on EVF or LCD as overlay, you can shoot a second shot.
28. ‘Shutter Counter’ counts every 100 shots.
29. The shape of viewfinder window changed to help prevent dust build-up
30. The strap attachment rings are double coated with stainless-steel layer
31. Improved the shape of ‘Viewfinder lever’
32. Improved the layout of ‘Focus lever’ (goes MF > AF-C > AF-S now)
33. Improved the operability of the ‘MENU/OK button’
34. Improved shape of the ‘Q button’ (was previously the RAW button)
35. Improved the shape of ‘Front Ring’
36. Improved the torque of ‘Exposure dial’
37. Improved layout of ‘Shutter speed dial’
38. Improved the design of Battery-chamber
39. Improved the shape of Hot shoe
40. Max ISO from 3200 to 6400 *ISO AUTO Mode
41. WB shift available in any mode
42. Variation of aspect ratio 3:2, 16:9, and 1:1
43. Improved functionality in MF mode
44. Able to reset the setting separately
45. No formatting on the setting when updating FW
46. Change the default LCD information setting -> standard
47. Reset function added for every custom mode
48. Information of all F-simulation modes
49. Add ‘MARK FOR UPLOAD TO’ MyFinePix.com
50. Support ‘Eyefi Connected’
51. Holding Q-button is short-cut function
52. Remove ‘ISO AUTO’ to Shooting Menu
53. Change the location of ‘AF area select button’
54. Change the sub-function of ‘AF area select button’
55. Change the sub-function of ‘AE button’
56. Add the sub-function of ‘Fn button’
57. In Playback mode, add the ‘Information function’
58. In low light scene, LCD display becomes smooth.
59. After release the shutter button, immediately switch to playback mode.
60. After release the shutter button, could immediately use some key.
61. After bracket shooting,immediately switch to palyback mode.
62. When holding shutter button, LCD doesn’t freeze.
63. Support the SD-card used Macintosh.
64. In low EV scene, the exposure of LCD will adapt.
65. In Manual Exposure, the histogram will adapt.
66. In Post-viewing, eye sensor function can work
67. Support external microphone and electric release.
68. Change the information of setting external Flash
69. The ND filter is now available in panorama mode.
Also see Fuji X100s vs Fuji X100 Major Specification Comparison Review