The Schlumbergeras are tropical cacti which flower during the shorter days. The ones which flower in the autumn & early winter are sold as "Christmas Cacti". Those which flower in the spring are sold as "Easter Cacti". I have a number of named varieties and this is the first of the former group.
If they are not kept at above 15C as the flower buds develop, the colours will be darker than expected. Last year I was a bit late in moving mine into the warmer conditions and the colours were a bit dark, as in the last image. This year I seem to have done it in time.
These used to be divided into Zygocactus and Schlumbergera but they are all now the latter.
A 30mm lens was used for the new images but a 50mm for the last image.
The stereos are crosseye.
Olympus EM-1, (aperture priority), Olympus m4/3 30mm f3.5 ED macro, 1/125 at f11 ISO 250, hand-held.