Closed Light Monkey 20W variable LED sidemount light

[Texasguy]

Square LED lights are the ones that have variable zoom for controlling tightness of the beam. If you zoom to the most tight beam possible, it starts projecting the LED lamp itself without taking into the account the light breaking in the reflector cone.

 

[halocline]

Light is sold.

Interestingly, I recently went diving with someone that has a halcyon focus, and it has a square hot spot when foused, just like you mentioned. Not a great light IMO.

 

[Curious_George]

Square pattern is unique to the two versions of the Halcyon focus. As far as "great light", I would suggest it depends on how many reflective particles there are in the water. LM has a very loose beam with lots of aura or whatever it’s called that will blind you with reflection in cloudy water and actually reduce its effectiveness. Better suited for clearer water. Just look at the wide halo around the bright center beam when you shine it on a wall. Halcyon on the other hand has a very tightly controlled beam whether wide or narrow focus and almost zero halo although likely less lumens at the wider focus settings.

 

[halocline]

Square pattern is unique to the two versions of the Halcyon focus. As far as "great light", I would suggest it depends on how many reflective particles there are in the water. LM has a very loose beam with lots of aura or whatever it’s called that will blind you with reflection in cloudy water and actually reduce its effectiveness. Better suited for clearer water. Just look at the wide halo around the bright center beam when you shine it on a wall. Halcyon on the other hand has a very tightly controlled beam whether wide or narrow focus and almost zero halo although likely less lumens at the wider focus settings.

It's true that the LM light has a wider beam than the focus does. But there were other things about the focus I wasn't crazy about; pretty yellowish on the color spectrum and overall just not very powerful for a canister light. I personally wouldn't buy one. I do generally dive in very clear water. Then again, I just sold my LM, so obviously I wasn't nuts about that one either. I'm going cheap and cordless for a while and wait for something to come out that really looks like my old HID in the water. I miss that light, although it was bulky and fragile and had unreliable electronics. But it was very beautiful and useful light in a cave.