Focus lights LED vs Halogen

Today I plunked down some coin on a new focus light - a Hartenburger. It is a halogen bulb which seems to be the preference (over an LED) for those shooting a dSLR. Being a P&S shooter I was informed that either Halogen or LED would be fine. I chose the halogen as it also seems to be preferred for video as well as it preserves the reds better.

This was all new to me and I had not seen a discussion so I thought I would throw it out to the group.

As long as there's 'enough' of whatever colors are necessary for focus, but not so much to cause a hot-spot during the actual shot....why would it matter what color the focus assist lamp is?

I clearly see the video advantage - and for newer DSLRs with video capability, by extension. But I'd argue that the focus light discrimination for DSLR stills is simply do you have enough light to provide the necessary focus assist yet not goof up the actual image lighting. So in that vein, a halogen may still be preferrable, as LEDs might not be bright enough or might be so blue as to create a hotspot in that channel (assuming you have one that doesn't click off when it senses a strobe flash). OTOH, I'd trust that 'auto-off' function on an LED a bit better than on a halogen, and bet that the LED "bulbs" survive the stresses of off-and-on cycling better than a halogen bulbs might.

This is all 'uneducated' opinion off the top of my head, so I reserve the right to totally change my mind when told I'm a fool in the posts to follow.

(Partly)

Can someone explain to me why a focus light should be anything other than small, light, inexpensive and only just bright enough to permit AF?

Is there confusion between a modelling light, a focus light and the underwater equivalent of a studio light?

Tim

(maybe)

Can someone explain to me why a focus light should be anything other than small, light, inexpensive and only just bright enough to permit AF?

No, that's what it should be. There's some disagreement on what is bright enough (varies with lens) and then there are different ways to mount / aim that determine how wide the beam needs to be. Still, a light doesn't need to be bigger or brighter than what's necessary to assist focus.

I'd say that halogen is less efficient and more fragile than LED. It has good CRI and strong red output. Halogen is easier to see than LED and I think that makes people think it's more effective. Hartenberger offers an LED light that has increased output in red intended for focusing. Not sure how well a normal LED light works when combined with a red filter.

I have used a Fisheye LED48DX light with a red filter for Mandarin fish and had no problem obtaining quick and sharp focus with the red light. Also did not need to have the light on its brightest setting. I find the red light is particularly helpful with night dives and does not seem to bother the fish as much as a white light.

Elmer

Here is the article by Hartenberger on the red LED:

http://www.hartenberger.de/english/e_harte...minant/001.html