I hope this is the type of answer your looking for.
I use domed fixtures such as these, because they are made to withstand the wattage, the heat, plus they direct the heat or light downward to a spot I wish for it to go to. Do not trust the clamp most of these come with, they have been known to fail, dropping the light or CHE into an enclosure or on a tortoise with horrible results (fires and death). Your normal light fixture can not do that. (I am not stating anything about the company that is selling these, I just happened to come across them first to use as an example.)
Thank you for the response. I currently use a zoomed brooder lamp and was curious if folks use a fixture or just the bulb.
I never use the clamps. They're an accident waiting to happen!
I use fixtures with domes for mine. In a closed chamber you could use one without the dome. ALWAYS use a ceramic fixture, never the cheaper plastic type.