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High ISO NR se odnosi samo na JPEG, i to od ISO 1600 pa na više, barem je tako kod mene.

Long ex. NR...upravo čitam Gary Friedmanovu knjigu za svoj aparat, pa je napisao detaljno o tome

This setting applies to Long Exposures, defined as those lasting more than one second (when your camera is on a tripod and Steady Shot is ideally turned OFF). In such situations, digital image sensors tend to produce a lot of “noise” even though your ISO may be set to its lowest value. All DSLRs (okay, DSLTs too) from all manufacturers address the problem in pretty much the same way: They employ, in-camera, a technique called “Dark Frame Subtraction”.

When Long exp. NR is set to “On” (which is recommended), the camera will take TWO pictures every time a shutter speed of one second or more is used. The first picture is of your subject – as you would expect. The second picture is taken with the shutter closed, removing all light from the sensor, resulting in a black picture which contains only the natural noise from the sensor at the same temperature, ISO setting, and duration as the first picture.

With this second “dark frame” picture, the camera has a clear idea of the kind of noise that is permeating the first picture. And then it can remove (to a certain degree) this characteristic noise from the image you just took. This technique is very worthwhile, BUT you are forced to wait twice as long until you can take your next picture. This means if you had set the camera on a tripod at night and took an exposure of a meadow on a moonlit night, the camera would be unresponsive for twice as long as your set exposure as it captures the sensor’s noise for subtraction.

Preporučuje izbjegavati kod fotkanja vatrometa jer, naravno, traje dugo pa prođe baba s kolačima. NR ne radi kad je bracketing u funkciji ili neka druga vrsta continuous okidanja.