when to use HMI

I

ianmo

New member
Hi guys, I am relatively new at this and have my 1st project coming up that actually has a budget ( even if a small one)

Wondering if someone can tell me when one would use an HMI Par as opposed to an HMI Fresnel?

I am looking to blast it through some windows to achieve the look of daylite coming in. Will slightly smoke the set as well.
Just not sure if I should rent a par or fresnel type hmi.
Thanks very much
Ian
 
Given the same wattage, the par will generally put out more light thanks to its usually bigger lens, parabolic reflector and bulb placement. Getting a wide or narrow beam with a par though is a question of which interchangeable (hopefully they have a set with the par) lens you use. On the other hand, with a fresnel, even though it doesn't blast out as much light, you can put it into a wide or narrow beam based on the focus knob setting. You'd probably want a wide beam shining though there to make light rays coming through the entire window and not just a part of it. All the more noticeable with a bit of smoke on the set.
 
I don't think it really matters what you use, its usually a personal preference.
Let me ask you this... If you get par's are they coming with lenses so you can control the beam, or is it just an open faced par?
I think you're good to go w/ either but if you want more control over the beam pattern get the fresnel or make sure you get the different leses for the par if you go that route.
 
i don't use HMI fresnal until i step above 6k .. i just find the pars have much more light output over fresnel units - especially putting them thru windows .. you can use different glass on par for spread/diffusion ... in general i find 2.5k pars have good punch thur windows during day light - it would take at least a 4k fresnel to give me the same punch ... for plug in to house wall socket you can't beat 1.2k HMI pars - 1.2k fresnel will not do much outside a window during the day ... if you have more amps available then i say 2.5HMI pars out winodws ... if $$ & power not a issue then 6k pars !!! ...
 
Thanks everyone! I am told we cant afford anything larger than 3 4K's.
I am pretty sure we can get interchangable lens with the pars.
My other question is what kind of genie would I need to power these? WIll a basic honda do the trick?
 
Basic honda for 3 4Ks? Probably not. Remember, there is an emormous startup spike on an HMI that will blow the breaker on a generator that's not picked for the best capacity. So, its a startup problem that has to be planned for, not a runnng problem. In an ideal world, a 4.1K generator would run a 4K HMI. The startup voltage pulse means you need something more like a 5.5K generator to be safe for each 4K hmi.

On the lens, make sure you have the widest beam lens possible.
 
You must log in or register to reply here.
Back
Top