Sony T99 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Bionz processor. On the other hand, Panasonic ZS40 has a
18.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Venus Engine processor.
Below you can see the T99 and ZS40 sensor size comparison.
Sony T99 and Panasonic ZS40 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Sony T99 has 28% larger pixel area compared to Panasonic ZS40, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.