300w bulb in 650w arri fresnel?
 

Possibly stupid question. I see on bh that you can put 150 or 300 watt bulbs in altman fresnels...but is it possible to put less watt bulbs in arri fresnels?

Im specifically thinking a 300 in a 650...

I do it with my Lowell Rifas all the time as well as my Arri mini spots. You should be able to go lower without a hitch, but DO NOT GO HIGHER!! Now with that being said, it works for me, but that does not mean it's right or smart....

As with all lights, if it says 650w Arri, that means you can use anything up to 650watts.

Thanks, thats what i was assuming

Adam,
The biggest problem is will be if someone makes a 300W with the same pin size as the 650 bulb. On a 2K instrument I have they made 1K bulbs which were very fragile as the base was stronger than the connection to the smaller element.

Centered in the focal point?
 

Hmmm.... I wonder if the "bright spot" of the lamp would be centered at the focal point of the lighting unit. Maybe a given pin size/spacing guarantees correct height for the bright spot of the lamp.
Anybody know for sure?

Ken

If the light is designed around the bigger bulb then the question for the smaller bulb is does it end up in the correct position for the light and reflector. The spacing and size of the pins is more likely because of power requirements, heat dissipation and stability demands with the light reflector placement based on the bulb design unless the light manufacturer can make its own bulb design. (Many don't) The smaller bulb will probably fill the reflector well enough but not better or as good as the larger bulb as many instruments have different size bulbs recommended for them.