By the way the flowers are held (individually) and the scale of flowers (big) compared to leaf (small), I'd say this was an azalea rather than a rhododendron. But there are many red forms and it would take someone far more skilled than I to narrow it down to a specific cultivar!!

Tell us where you live. Some varieties are more common in some regions and climates. Also, with reds there are lots of subtle colors or shades of red in the many varieties. And digital cameras don't always capture them faithfully.

How true is your photo is to the actual color?