Be sure to let them warm up before you start shooting, especially if you're taking hand measurements during setup. From the moment you turn it on to 15 minutes, the difference in light output can be 4-5 levels. I plan to only turn mine on for 10-15 minutes before I start doing anything. They are bright enough but not as bright as I thought. Should be suitable for shooting with any DSLR that can handle high ISO well enough. Longevity is a problem I can't solve yet, I haven't had it long enough.