Fresnel Lamp Type Question...


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Ship (or anyone else) I have several Altman 65Q 6" fresnels on hand, and I have always used a BTN 750W/120V lamp for this fixture. But I know that I can also use a BTP (750W), BTM (500W), or BTL (500W)type lamp. What is the difference between these 4 lamps, which one is best, and what would you recommend?
Re: Ship - Lamp Type Question...

We just upgraded all our Colortran 6" Fresnels from BTL's to BTN's. The only differences between the two same wattage lamps is output, color temperature, and life. The 500W BTL puts out 11,000 lumens at 3000-3050K and lasts 500 hours. The 500W BTM puts out 13,000 lumens at 3200K and lasts 100-150 hours. Same deal with the 750W BTN/BTP. The 750W BTN puts out 17,600 lumens at 3050K and lasts 500 hours. The 750W BTP puts out 20,000-21,000 lumens at 3200K and lasts 200 hours. The shorter life ones burn hotter and brighter at the expense of life. Personally, I use the BTL and BTN because they last a long time, and I don't have to worry about them.
Re: Ship - Lamp Type Question...

Fosstech has it correct and I also recommend the BTL and BTN lamps over the others. There is other lamps available beyond these but those mentioned are the four main choices for this lamp.

BTN (dependant upon brand); 3,050°K to 3,200°K; 17,000 Lum to 17,600 Lumens; 500 hours in life. Some vary from Base Down ±30°, Base Down ±90° to any burning position. C-13D filament that should be bi-plane and about 10x11mm in size. This is the normal Halogen Medium Pre-focus (P-28s/24) based 750w/120v lamp with a LCL of 2.3/16" (lamp center length - from alignment fin to center of filament).

BTP (dependant upon brand meaning that the specifications of one brand to another are not always the same much less one catalog to another catalog within a brand are not always the same.) Halogen; 3,200°K uniformly between GE, Philips, Osram, Ushio and Wiko. 20,000 Lum to 21,000 Lumens in output, and 200 hours in life. (Same data on burn position or how much of an angle you are recommended to be using this lamp at. - don’t worry about the hang angle much - it can take it for show use just not for your work light use, just don’t hang them up side down or if possible at a over 90° angle.) C-13D filament that should be bi-plane meaning staggered in being thicker in two rows deep and consolidating some in width by way of this about 11x14mm in size. A little larger in square MM length but in a Fresnel it should not matter very much. This is the high output/shorter life version of the lamp. This would be useful for when you need a bit more punch out of your Fresnel such as say in a top hat based down light effect.

BTL (dependant upon brand): 2,950°K to 3,050°K; 11,000 Lumens; and 500 to 750 hours in life. Base Down ±90° to any burn position. C-13D that should be bi-plane and measure 8.5x10mm to 11x11mm in size. This is the normal Halogen Medium Pre-focus (P-28s/24) based 500w/120v lamp with a LCL of 2.3/16".

BTM (dependant upon brand) Halogen; 3,200°K; 13,000 Lumens in output; 100 to 150 hours in life. Burn Base Down ±90° in other words, Base Down to Horizontal. C-13D that can be a bi-plane 12x11.5mm Monoplane Grid Filament and probably also otherwise normally a bi-plane filament in a similar size. (The grid filament allows a more tightly packed filament without it being three dimensional. Not all brands give this data so it cold be either of the filament type, a number of filament support styles and should be considered approximate in filament size.) Again a larger filament but much more output in exchange for a shorter lamp life. Also a more uniform and higher color temperature that is standardized by need for a lamp that often will look good in a camera shoot.

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