Joshua G.

Arri T2

But as one can see going by the photometrics, the open-face does not put out more light, so how is it more efficient?

I have always found open face lights are great for bounces as they will always put out more light than a comparable size fresnel.

 

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It doesn't mean a fresnel won't work. It's just an open face will be more efficient.

What's the comparable in size, fresnel counterpart to the Arrilite 2000 Plus?

Thanks for these, Chris!

Exactly what numbers are you referring to when you make that determination?

The lux results using Arri's photometric calculator posted previously.

The Arri T2 is a newer design, so it's possible that the reflector is more efficient than the old fresnels we are used to. [...]

 

But if you're buying, then the fresnel would be the better all-rounder.

Not meaning to sound difficult here, but the Arrilites are also an improved unit: for example, Arri claims the 750 Plus is comparable to or exceeds their now-defunct 1000w open-face model.

 

If the aim is purchasing or say picking up a single unit between two 2K fixtures -- one a fresnel, the other open-face -- to deliver the higher output light or meter reading off a bounce or diffusion material, the choice is clear based on the charts, right?

 

This choice being the fresnel strikes me as contradictory to the prevailing wisdom I've gleaned from the DoP community. The rationale was, as I understood it, if one wants the punching power or higher light output alone with which to utilise a diffusion or bounce material, the open-face was the fixture of choice (over an equivalent tungsten fresnel). The numbers, though, do not or no longer bear this out.

Completely unscientific, but if you're bouncing, use an open face lamp. If you're diffusing, use a fresnel. If you only have one lamp, then use what you've got.

And if a situation arises wherein -- and this is if the photometric data or calculations hold -- you have both fixtures or is tasked to bring only one fixture, the one that gives the higher light output given a set distance or area, be it to bounce against or diffuse through, that fixture would have to be the fresnel, isn't that right?

If using an online calculator, set the distance and the beam spread the same for both types of light.

Which is what I did, the results of which I posted. And the fresnel came out on top an which I thought didn't add up.

 

I am an absolute beginner and have no access to a rental house.

Full spot for that fresnel fixture is not the same beam angle (and diameter) as full spot on open face, so to fill the same surface with a fresnel as with an open face you'll have to increase the angle on T2, and so you will get less light.

Yes, but if the aim is to extract the maximum light output to punch through or bounce against a given area, it still stands that a fresnel would be the unit to give you the better results, does it not? This seems to me to go against conventional wisdom of favouring the open-face on such jobs. I suspect I'm misunderstanding an element to this principle.

Using Arri's own photometric calculator one comes up with the following

 

Arri T2 with the CP/41 2000w lamp at full flood:

- 5.0m beam diameter = 4.7m distance = 1609lx illuminance

- 5.0m distance = 5.3m beam diameter = 1423lx

 

Arrilite 2000 Plus with an FEX 2000w lamp at full flood:

- 5.0m beam diameter = 4.2m distance = 1357lx

- 5.0m distance = 6.0m beam diameter = 940lx

 

Arri T2 at full spot:

- 5.0m beam diameter = 20m distance = 418lx

- 5.0m distance = 1.1m beam diameter = 6693lx

 

Arrilite 2000 Plus at full spot:

- 5.0m beam diameter = 11.8m distance = 795lx

- 5.0m distance = 2.1m distance = 4400lx

 

And,

 

Ianiro Blonde at 5.0m distance:

- full flood = 948lx

- full spot = 3984lx

 

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- http://calc.arri.de/calculator

- http://www.ianirouk.com/product.php?ProductID=260

I was after sourcing a light fixture whose main job was to punch through or bounce against diffusion (and possibly, periodically in a chimera), and so naturally, I had my eyes set on open-faced units. Upon closer look however, I see that the fresnel equivalents output a higher lumens than its open-face counterparts, judging from their photometric data (Arrilite 2000 plus v. Arri T2 v. Ianiro blondes). How is this so -- I thought the sense in preferring open-face units on diffusion is their luminance advantage? Have I misunderstood the rationale and/or misread the charts? I'd very much appreciate some clarification.

[...] Is this a Blackmagic camera? Has the camera's factory mount FFD been checked?

 

It's the Pocket version, to be exact. As to the last question, I don't exactly know what that means. Who is to do this check?

Got one. I paid more than I originally budgeted, but I guess it's a seller's market out there for these lenses. While lens is on its way to me, could anyone tell me what is the general practice or precautions with second-hand cine lenses? Is it a good idea to have it serviced? It is also my understanding that since I'd be using a PL adapter for my camera, that it'll most likely need to shimmed. Could anyone recommend a place or technician in the UK where I can get all these done?

That's very helpful, Gregg. I had always thought that lens mismatches were only a concern with stills lenses and that with cine the variance only pertained to indiviual pieces, owing perhaps to varying degrees of wear and/or maintenance.

With cinema lenses, are individual ones harder to come by than sets in the second-hand market? Am I better off buying a whole set rather than building one piece by piece (if/when funs allow)?

Thanks for the tip, Jeff. However, I'm only after the 16mm and not a whole set (and which your seller doesn't have).

 

Regards,

Josh

Preferably in PL mount, and from sellers in the UK/EU (as I'm based in the UK), though open to offers from further afield.

 

Kind Regards,

Josh

My apologies for putting this in the wrong sub-forum. I had the Marketplace tab open, but obviously missed it.

Preferably in PL mount, and from sellers in the UK/EU (as I'm based in the UK), though open to offers from further afield.

 

Kind Regards,

Josh

For ease of use and flexibility, any advice on the most optimal way of terminating lighting cable? Keeping in mind that I am based in the UK and would be initially using the lights at home — though, as mentioned, looking in the long-term and on-location use — what type of plug should I be using? On the Arri 650w I bought was an in-line power switch; is that also mandatory? Would appreciate some help!

Regards,
J