The problem with a torch light is the bright circle causes various degrees of brightness that the camera can't balance. You want a flood light. There are torch lights with a diffuser head.
I am a big fan of the Sola lights. I sometimes mount 2 of them on my camera since I do a lot of night diving. I'll use a video model as my main light, in flood mode so I can use it as a camera focus light. It can toggle to spot mode if I want to see further away. Sometimes I'll increase the brightness, which drains the battery faster, so a backup is necessary. My "backup" camera light is the Sola photo model which has a red light as well. I can toggle between white and red, flood mode only.
Brighter is *not* always better. If you do not have a strobe, then you might want a brighter light. Personally, I recommend a strobe if you are mostly taking pictures.
Many critters do not like the bright white light and will turn away from it. On a night dive, I will use the red light to take pictures of critters which don't like the white light. Many seahorses and nudibranchs will do this.
Sola photo light (supports red)
Sola Photo 1200
Sola video light (supports spot and flood)
Sola Video 2500 Flood
Inon strobes:
INON Strobe [Lineup]
You should really consider a strobe. A focus light is great for night dives or lighting up dark areas under ledges where you need light for camera focus.
