Hey again all!
I am going to get back on my OHP project after not doing anything for a few weekends now! I have a 250W HQI I am going to use to build a setup for. I just have a ?. The light source should be at the bottom fresnel's focal length away from the fresnel correct? I believe my fresnel FL is about 14", cause thats the distance from the fresnel - to mirror- to bulb. I was just thinking, in the OHP such as ELMO A305 SD, where the light source is directly under the fresnel (not reflecting off a mirror), that the FL of the ELMO's fresnel is much shorter than mine correct? So if i get a fresnel off a OHP with a shorter FL i can move my light closer right? Cause I want bright as possible. THanks!
I am going to get back on my OHP project after not doing anything for a few weekends now! I have a 250W HQI I am going to use to build a setup for. I just have a ?. The light source should be at the bottom fresnel's focal length away from the fresnel correct? I believe my fresnel FL is about 14", cause thats the distance from the fresnel - to mirror- to bulb. I was just thinking, in the OHP such as ELMO A305 SD, where the light source is directly under the fresnel (not reflecting off a mirror), that the FL of the ELMO's fresnel is much shorter than mine correct? So if i get a fresnel off a OHP with a shorter FL i can move my light closer right? Cause I want bright as possible. THanks!
I would think that you are on the right track about the light being at the proper focal length for the lower fresnel. The only thing I can think about how to get more light into the fresnel (regardless of FL) would be to install a reflector below the lamp, reflecting otherwise unused light into the fresnel. I've found some inexpensive concave mirrors here:
http://www.microscope.org/l-optics/sl240.htm
Hope this helps you out some! 🙂
http://www.microscope.org/l-optics/sl240.htm
Hope this helps you out some! 🙂
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