Fresnel vs. Par (again)

[M Joel W]

I think I've asked this very same question before, but... This time it's more specific. Basically, what is the (practical) difference between a par and a fresnel?

 

I may be DP'ing my first feature this summer (yay?) on an hvx200, and I am trying to get a 1.2k HMI because most of the film takes place at night, frequently outside...but the producer wants to use a kit that maxes out at 1k (tungsten) and I'd want to put CTB over that and that isn't enough light for the 250ISO hvx, especially when slow motion will be involved! (Apparently, the producer doesn't really want any lighting, which upsets me...so this would be the best I could do!)

 

So I have a chance to buy (and I'd use it for "personal" reasons later) a par or a fresnel for myself for pretty cheap, but the frensel is much cheaper than the par. My "personal" use would be as a key light for night scenes, as a soft fill for day interiors, and (in particular) as a backlight/keylight for day exteriors (CTO 1/4 because I love warmth, and a muslin butterfly over the talent...this would be for close ups only!)

 

To summarize:

 

I need a light (1.2k max due to edison...) for night exterior key (motivation: moon), bouncing for soft fill (although chances are I'll use kinoflos for this), and to shape light during the day (but only in close up, of course). Would the fresnel be good for me, or would the more versatile and efficient lenses that a par can offer be much better? The spotlight par would probably rock during the day for fill...my inkies are no more powerful than 75w par I bought at home depot...

 

Anyhow, thanks as always for the help. This is a tough call since I think I need this light (and rental is not an option; too expensive for these long shoots) badly, but when I told my dad I was going to spend 1/3 of my savings on a light he flipped out. :-<

Edited June 26, 2007 by Matthew Wauhkonen

[David Mullen ASC]

1.2K HMI Fresnels tend to be old lights -- almost all 1.2K HMI's made these days are PAR's.

 

Fresnels put out a more even sharp light, whereas a PAR don't create as "clean" a shadow pattern. However, they can be brighter for their wattage than a fresnel. New 1.2K HMI's often have a fresnel lens as part of their lens kit. It's not quite the same thing as a true fresnel light, but it helps create a more even beam edge to edge.

 

It's hard to get a good venetian blind pattern using a PAR unless it is backed far away. Otherwise, it doesn't make as much of a difference, especially with modern soft-light techniques.

[M Joel W]

1.2K HMI Fresnels tend to be old lights -- almost all 1.2K HMI's made these days are PAR's.

 

Fresnels put out a more even sharp light, whereas a PAR don't create as "clean" a shadow pattern. However, they can be brighter for their wattage than a fresnel. New 1.2K HMI's often have a fresnel lens as part of their lens kit. It's not quite the same thing as a true fresnel light, but it helps create a more even beam edge to edge.

 

It's hard to get a good venetian blind pattern using a PAR unless it is backed far away. Otherwise, it doesn't make as much of a difference, especially with modern soft-light techniques.

 

Thanks for the advice. I doubt I will be using cookies with either, thankfully. I looked at Arri's site and noticed that their 1.2kw fresnel offered (at ten meters) 9125 lux at full spot, whereas the Arrisun 12 offered 16450 with a spot lens (and 33250 with no lens!). And the PAR actually had a wider beam, so that's nearly four times the efficiency as a spot light.

 

At full flood, however, both were neck and neck in terms of efficiency, but the par's oval lenses allow for a tiny edge.

 

But, the PAR with the frosted fresnel (like you mentioned) is about 15% less efficient than the fresnel, and far less versatile in terms of focusing range. Hmm... I need to think this one through before I blow all my cash...

[Chris Keth]

Thanks for the advice. I doubt I will be using cookies with either, thankfully. I looked at Arri's site and noticed that their 1.2kw fresnel offered (at ten meters) 9125 lux at full spot, whereas the Arrisun 12 offered 16450 with a spot lens (and 33250 with no lens!). And the PAR actually had a wider beam, so that's nearly four times the efficiency as a spot light.

 

At full flood, however, both were neck and neck in terms of efficiency, but the par's oval lenses allow for a tiny edge.

 

But, the PAR with the frosted fresnel (like you mentioned) is about 15% less efficient than the fresnel, and far less versatile in terms of focusing range. Hmm... I need to think this one through before I blow all my cash...

 

Make sure you double check what the beam angle for those spotted lux readings. They might spot to different angles, giving you another thing to think about (and changing the meaning of those spotted lux readings)

[M Joel W]

Make sure you double check what the beam angle for those spotted lux readings. They might spot to different angles, giving you another thing to think about (and changing the meaning of those spotted lux readings)

 

The beam angle is similar; I think it's actually wider with the fresnel at full spot than with the par with no lens, so score one more for the par. Of course, spending my own money on a light for a shoot where the producer doesn't even want lights makes me hesitant to buy anything, but I need an HMI in my arsenal one way or the other...