8mm Forum: Why is a 1.1 lens so good?

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Posted by Maurice Leakey (Member # 916) on January 12, 2008, 04:15 AM:

When I buy projectors they come with a lens. It's something I never really think about. A lens is a lens. Or is it?

I recently bought an Elmo GS800 which came with a 1.1 lens. I was completely astounded to see my usual test film running. Yes, I suppose it was brighter, but it was the clarity and colour of the picture which so impressed me.

So I must thank Claus for recently drawing my attention to the German eBay listing for a Xenovaron 1.1. This I have purchased to fit on my Bauer T510. After reading comments on the Forum I am now expecting even better results from this super projector.

Is this a point of "you gets what yer pays for"? I always assumed that a faster lens would just give more light on the screen but I was obviously wrong. What have I been missing all this time.

Can anyone explain why these lens are so good? Is it their optics or higher quality construction?

Maurice

Posted by Kevin Faulkner (Member # 6) on January 12, 2008, 05:06 AM:

I think that a lot of it is down to the precision they are made with.
An f1.3 lens doesnt have to be made with the same precision that an f1.1 or 1.0 lens does.
The f1.0 and 1.1 has to be made to give better flatness of field over the small image area as the depth of field is very much smaller than with say an f1.3

As the 1.3 is more of a mass produced lens coating and tolerances dont have to be so spot on because a lot of it is lost due to the large depth of focus they have. Notice that a lot of 1.3 lenses such as the Elmo's are in fact plastic bodied but then when you move up to the 1.1 and 1.0's they are metal bodied as more care is taken with the manufacture of them.

Kev.

Posted by Lee Mannering (Member # 728) on January 12, 2008, 06:09 AM:

Hi Maurice
Whoever you purchased that machine from must have loved and taken very good care of it I expect.

I also have the 1-1 in all my Elmo machines and they do a nice job in projection.

Happy projecting day!

Posted by Maurice Leakey (Member # 916) on January 12, 2008, 06:28 AM:

Hello Lee

I always think that if a projector still has its original box and all packing, plus accessories and of course, the instruction book, then it must have had a very careful owner.

Maurice

Posted by Claus Harding (Member # 702) on January 12, 2008, 08:59 AM:

Maurice,

You are very welcome; I am happy to see that my post had the intended effect: to get this fine lens into the hands of 'one of us' who can appreciate it, as opposed to going someplace where it might not be used to its advantage.

Give us an update when you receive it and let us know how it works for you.

Best,
Claus.

Posted by Graham Ritchie (Member # 559) on January 13, 2008, 01:48 PM:

Maurice, using a 15/150 watt lamp the centre brightness is

ST1200D.....1.3 lens...On Low...18 foot candles
On High...24 foot candles

ST1200HD....1.1 lens..On Low...25 foot candles
On High...31 foot candles

GS1200 24/200watt lamp....1.1 lens..On Low..27 foot candles
On High..39 foot candles

I started using a 1.1 lens on my old ST1200 over 20years ago, a big improvement brightness and sharpness wise over the 1.3, the 1.1 is a bit more critical on focusing, for myself, using a good quality lens would be the most important item on a projector.

Graham.

Posted by Maurice Leakey (Member # 916) on January 13, 2008, 03:04 PM:

Graham

Thanks for your information. In the case of the GS1200, was this using the "proper" ESC lamp?

Maurice

Posted by Andy Oliver (Member # 604) on January 13, 2008, 03:12 PM:

Say, you should try the 11-30 on a noris special-D, standard 8 looks stunning, especially filmed thru a bolex. Have also found that a noris machine gives better edge to edge sharpness when compared to my bauers coupled with the 11-30

Posted by Graham Ritchie (Member # 559) on January 13, 2008, 03:34 PM:

Hi Maurice
Years ago [Roll Eyes]

I wrote all this information down in a book, I think it came from an old "Movie Maker" and I guess at the time the proper "ESC" lamp would have been used, it was claimed that you got 25% more light on the screen with the 1.1. I remember when I first used the lens I was so impressed with it on the ST1200 that I have never used anything else since.

Graham.

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