# Fresnel Lens types



## ship (Feb 6, 2007)

Name three type of Fresnel Lens. There is four types of Fresnel lens that have been used in the industry over the years.

No, not step or PC... there is three different types of Fresnel lens, what are they in major differences?


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## Schniapereli (Feb 7, 2007)

Well, since you just said 3 types of "Fresnel Lenses", here are 7 types that they use for lighthouses.  They are in order of size biggest to smallest.

First Order
Second Order
Third Order
Third and 1/2 Order
Fourth Order
Fifth Order
Sixth Order
(I got this information from http://www.michiganlights.com/fresnel.htm)

and also, the Hyperradiant is larger than First Order (Wikipedia)

I also read they are making some inflatable types used for solar power. (thought that was interesting)

But, I have no idea what types they use for theatre, and I could not find the answers anywhere.


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## ship (Feb 7, 2007)

A few were hinted at in a post about Fresnel lenses out of the lighting part of the forum.


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## Schniapereli (Feb 11, 2007)

I think we give up now...


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## Schniapereli (Feb 18, 2007)

GAAAAAAAAAAAA! Ship, give us the answer.


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## ship (Feb 18, 2007)

Oh' come on now, nobody has really looked into the answer.

I'll give you one.

What's the difference between a Fresnel lens that is just a Fresnel lens and one that has parts of it's surface painted in - could that be an example of one that's while the same in general description going to be of a different use?

Three more types to go by my counts as specified in some long past book that gets into fixture theory design and construction really well = this long before DMX or computers were considered or thought of for theater.


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## Schniapereli (Feb 21, 2007)

I have searched everywhere on the internet, and could not find anything.

I give up.


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## ship (Feb 22, 2007)

Schniapereli said:


> I have searched everywhere on the internet, and could not find anything.
> I give up.



Keep searching or I believe I have mentioned a few really good older books one could Amazon or E-Bay and or hints on other parts of the forum. None the less, if not minded too much, let's say give it a month of other's attempting to figure it out. Imagine if in books, if just these lens types are not mentioned sufficiently in modern books, what else are you missing out on...

Really is that many Fresnel lenses that are engineered to do different things one might find on stage - especially if using older gear. I'll give a second, the oval Fresnel lens or what's possibly the same as what's called the "Ovalite." ("Possibly it's a different more PC lens instead in use on a Ovalite, but there is specific meniton of a Fresnel oval lens.) Never seen one myself but it's specified as a Fresnel lens type.

Also in such old books would be the concept of why the above painted glass to the inside angle Fresnel lens would be different enough to mention as different than a standard Fresnel lens.


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## Radman (Feb 22, 2007)

I'll give it a go, looks like a challenge!


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## LDtheLD (Feb 22, 2007)

This is so flustering, I've just got to try to figure this out...


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## gaffer240 (Feb 23, 2007)

Gee my first time here.
I have no idea what fresnel types are by name, but I currently work with two. One is a fresnel front with the lamp side of the lens flat and the other has the lamp side. in a con cave stlye--not refering to a steped lens, though that could be considered a third. I have the Fuchs book so maybe I can research it if I remember.

There is the possibility that the flat back sides either hava a pattern or are clear.


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## soundlight (Feb 23, 2007)

<hijack> Welcome aboard! Some of us have been trying to figure out this question for a while. (I haven't found what I think is the answer yet, but I'm gonna post if I do!)</hijack>

This is a real hard one ship!!


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## gaffer240 (Feb 23, 2007)

I did some quick research.

T. Fuchs book predates fresnel lenses in Theatre. The W. Bellman book (mid 70's) noted cheap lenses and expenseive lenses, cast lenses and ground lens with the step lens a variation of the fresnel. If there is something else then it is beyound simple research and will make us all feel stupi d


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## ship (Feb 23, 2007)

gaffer240 said:


> Gee my first time here.
> I have no idea what fresnel types are by name, but I currently work with two. One is a fresnel front with the lamp side of the lens flat and the other has the lamp side. in a con cave stlye--not refering to a steped lens, though that could be considered a third. I have the Fuchs book so maybe I can research it if I remember.
> There is the possibility that the flat back sides either hava a pattern or are clear.



Nice books to read...

Flat verses concave shape to it.... Hmm, why would one wish to do that?


Welcome to the forum, sounds like a great start you have already made.


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## ship (Feb 23, 2007)

gaffer240 said:


> I did some quick research.
> T. Fuchs book predates fresnel lenses in Theatre. The W. Bellman book (mid 70's) noted cheap lenses and expenseive lenees, cast lenses and ground lens with the step lens a variation of the fresnel. If there is something else then it is beyound simple research and will make us all feel stupi d



This is specifically about Fresnel lenses, no step lenses were intended to be a part of the question but it's an interesting observation on a possible type.


Feel free also to do your own question of the day's - as you can see, at times the most simiple things or odd concepts take off as interesting questions.


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## ship (Feb 23, 2007)

ship said:


> Name three type of Fresnel Lens. There is four types of Fresnel lens that have been used in the industry over the years.
> No, not step or PC... there is three different types of Fresnel lens, what are they in major differences?



By my counts, we have all four of them mentioned now. Anyone wish to sum up the four types and explain the differences between them?


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## gaffer240 (Feb 24, 2007)

Not quite sure of the optics on a con cave backed Fresnel Lens. However it does seem to capture more light and produce a wider and brighter output. Specifically refering to the ARRI line. Curious how the 5" lens in an ARRI Jr with a 1000w EGT lamp, produces alot more output and spread then an EGT in a Mole 407 with a plano back lens.

Gee am I on the right track? I seemed to have hit a nerve.

The only lens that I can recall seeing with black paint on the steps where Kliegl 1355 line, but they where step lenses. Not a correct answer.

( For the unitiated I work in a small TV studio, but do, and have done lots of live stage work.Studio rated equipment such as Mole and ARRI and B&M are pretty much required.)

Hey you can always read S. McCandless's books.


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## Radman (Feb 25, 2007)

Painted
Coated
Standard
Concave

Few more im pickin outta here

Cast
Ground
Inside angle?

This one WAS hard. Wish I coulda seen if the library had any books.


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## gaffer240 (Feb 25, 2007)

> By my counts, we have all four of them mentioned now. Anyone wish to sum up the four types and explain the differences between them?



```

```
[IMGR][/IMGR]

You asked for three types of Fresnel Lenses, but you said the above.
So far we have the plano lens (most with a pattern to defuse the light), then there is the Con-cave Fresnel Lens, the Oval Stlye, and the not correct for this question the step lens. That is four.

The other variations include cheap and expenseive, cast and ground. You also mentiond painted, that would be to control some scattering of the light.
Assuming that you are discounting the light house lens, what else is there, except enough money to buy what we need.

Oval tends to give a flattened but broader pattern, standerd plano is a good workhorse with a good balance of spread and brightness, con-cave is smoother and brighter and finally step lens does not count, but has been used instead of two plano convex.

Sums it up as best I can figure from the contents of this thread.


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## ship (Feb 26, 2007)

ship said:


> Name three type of Fresnel Lens. There is four types of Fresnel lens that have been used in the industry over the years.
> No, not step or PC... there is three different types of Fresnel lens, what are they in major differences?



I quote from the origional question.

Anyone else want to attempt to sum it up and explain the differences between the four types of lens? For instance, the Concave style Fresnel lens was gotten into a bit by gaffer240, anyone like to confirm or correct his observation? Also, Good definition or description on what the oval Fresnel lens is going to do. Possibly include it into info on the other three types including the Concave?

I wouldn't call cheap/expensive a type of lens - define how you can tell, otherwise if they are types, define the differences.




Light house Fresnel lenses I wouldn't classify as being used in the industry either.


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## ship (Feb 26, 2007)

gaffer240 said:


> The only lens that I can recall seeing with black paint on the steps where Kliegl 1355 line, but they where step lenses. Not a correct answer.



What was the purpose of the painting of the step lenses, perhaps it's the same purpose on Fresnel lenses?


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## gaffer240 (Feb 27, 2007)

Ship,

The answer to the question about painted steps is in my privious post.

I think W. Bellman in talking about cheap and expensive was refering to cheap cast lenses and exspensive ground lenses. Curiously enough most of us just use the things with no discoarse from the manufactures about the optical setup. Can't say I have ever seen any info on optics from a manufacturer. I do know they keep getting better, or at least the ones I use.

You have never done a nautical play that needed a lighthouse????? ;-)


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## gaffer240 (Feb 27, 2007)

Okay, research can be handy. Willard Bellman,_ Lighting the Stage Art and
Pratice _ second edition 1974(ISBN 0-8102-0040-6) pages 79-81
Discussion on Fresnel lenses "black enamel is used on oval beam cylindrical lense...these do not have the dappling pattern on the back and thereby produce a sharper edge beam" The oval beam is a pattern on the back of a Fresnel lens.

This oval pattern apparently provides slightly better optical properties, as I read the book there may be a lot more of this around then we might think.

Again, if I understand the priciple correctly the black enamel on the risers cuts down on stray light to help keep a sharper edge.

As I only currently use one instument with a concave lens I have noted all I can on that.


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## gaffer240 (Mar 5, 2007)

From the Kliegl.com website.

Turns out Kliegl had the patent for the oval beam lens.

www.klieglbros.com/patents/2853599/us002853599-002.pdf[/[/URL]URL]


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## avkid (Mar 5, 2007)

gaffer240 said:


> From the Kliegl.com website.
> Turns out Kliegl had the patent for the oval beam lens.
> ```
> http://www.klieglbros.com/patents/2853599/us002853599-002.pdf
> ```


A link would work much better!
http://www.klieglbros.com/patents/2853599/us002853599-002.pdf


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## gafftapegreenia (Mar 17, 2007)

Ok time to take a whack at it, first, the non-fresnel varieties, to clear things up.

1)Plano-Convex with clear plano side. Direct lighting with hard edge. 

2)Plano-Convex with stippled back. Lighting harder than Frensel but softer than a Leko. 

3)Step Lens without risers. Spill light resulted from the cutaway sections, gave rise to the...

4)Step Lens with risers. Baked black risers to eliminate spill light. Was developed for use in Lekos.

Ok Fresnel time.

1)"Standard" Fresnel. Cutaway portions on face with a plano back. Stippled to diffuse ring patterns, such as seen on Step Lens. Softest beam. I have also seen what amount to small plano-convex 'bubbles' or a hexagonal pattern instead of the stippling. There is also another version that has crosshatching for a wider spread, don't know if that saw stage use though. By my book a frost is a transluscent coating where as stippling is a textured "sand like" pattern molded in. 

2)Oval Fresnel. Has striping on the plano side to spread the light beam. 

3)Concave Fresnel. I actually saw this in the KOPP catologe. Has the fresnel cuts on the face and a concave back, not plano. I would assume it has a wide light spread. 

Guess time, could the fourth be:

Square Fresnels? The earliest Kliegl cateloge's to have Fresnels had them in square versions. I'd love to see one of those first hand, but then again I might already have, the old lights in the ceiling above the bleachers in the gym at school look like square Fresnels. 

Reverse Fresnels? Flat convex side with fresnel cuts on the concave side? The KOPP has a description of a "6" DIA. X 7-3/4" FOCUS CONVEX FRESNEL STEP LENS - 4 RISERS" Really I think this is just a version of the step lense with angled risers, similar to the very wide spread lenses used on those round semi-truck taillights

But what I think the fourth is is a Fresnel lense with black risers. I just found mention of one in a Kliegl architectural cateloge. Is is advertised as having low "ceiling spill". Essentially, its a built in tophat. 

I could probably sit here all night classifying every lens variation shown in the KOPP cateloge. 

And since I took the time to look through the KOPP cateloge, might as well mention the basic convex glass roundels:

1)Plain smooth.

2)Stippled roundel.

3)50 degree spread fluted roundel.

4)Cross hatched roundel

and one other I've come across

5)Plain roundel with small glass beads, such as used in highway lines, coated on the concave side. Found them on some old Major striplights.

Sometimes I think I obsess over variations.  KlieglBros.com is a great way to learn some history, if only there were similar sources for Major, Capitol and Century. I never find these old fixtures online and have NEVER seen catologes for them. The KOPP cateloge is useful too, I didn't even think they still existed till I found them a few months ago. 
Altman also has a "What's Old" page, good archive of old products. Its crazy how long the 360/360Q line has been made.The Source 4 is also 15 years old this year.


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