|Nikon D750, AF-S NIKKOR 28-300mm f/3.5-5.6G ED VR, ISO 100, ƒ/9, 1/200|
|Fujifilm X-E2, FUJINON XF 55-200mm, ISO 800, ƒ/8, 1/4000|
|Nikon D750, ISO 4000, ƒ/5.6, 1/4000|
Until recently virtually all digital cameras had an anti-aliasing or low-pass filter over the sensor. This filter had the effect of softening the image very slightly to reduce the likelihood of moiré patterning happening in parts of the image with a very fine repeating pattern that is close to the resolution limit of the sensor.
There is no filter on the Fuji and there is one on the Nikon D750.
The benefit of leaving off the filter is that the camera is able to record a little more detail and produce slightly sharper images, with less need for post-capture sharpening.
Nikon just introduced at the Consumer Electronics Show this week there new Nikon D5500 which tt's high-resolution sensor has no optical low-pass filter. It joins the Nikon D810 which also doesn't have the anti-aliasing or low-pass filter over the sensor.
I think we may be experiencing the change in the industry. Since the introduction of the Nikon D800E we have started to see more cameras being introduced without an anti-aliasing, or low-pass, filter over the sensor. This is because the pixel density of sensors has become so high that there are fewer and fewer patterns that we are likely to photograph that have a high enough frequency to cause moiré patterning.