Film-Tech Forum ARCHIVE: DCI Projector lens

This is topic DCI Projector lens in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Nastia Motovilova (Member # 7184) on 05-07-2013, 01:38 PM:

Hello,

I have been looking at various DCI projectors and the available lens options in the manufacturers' page. Lenses usually begin from 1.25 going upwards. Is there a particular reason for this? For example why there are no lens options with 1.0 or lower? I've checked the DCI specification document but it doesn't provide any guidelines regarding lens specifications (or maybe there is one but I haven't found it). If anyone could provide any info it would be great.

Thanks!

Posted by Carsten Kurz (Member # 5396) on 05-07-2013, 02:36 PM:

The reason is probably that there are few screens/auditoriums with a need for such short lenses. Some are available aside from the standard lists, but wide angle lenses usually have their issues as well.

- carsten

Posted by Gavin Lewarne (Member # 5397) on 05-07-2013, 05:19 PM:

We have a 12m throw to a 6m wide (common height) screen.

Using a 1.95-3.2 lens on our barco and the ratios are perfect and actually within a couple centimeters off the masking for our 35mm

Posted by Nastia Motovilova (Member # 7184) on 05-08-2013, 08:09 AM:

I see. I initially thought that there may be a DCI limitation i.e. you cannot use a lens below for example 1.0. As I understand this is not the case.

Thanks for the replies!

Posted by Gordon McLeod (Member # 33) on 05-08-2013, 08:40 AM:

And TI charges lens manufactures a big licenseing fee as well

Posted by Nastia Motovilova (Member # 7184) on 05-09-2013, 04:12 AM:

Thanks for the tip Gordon.

Out of curiosity, is there a DCI requirement that a projector needs to be installed in a specified projection booth? i.e. can the projector be installed in an open space, if this of course is practical while having the server in a room?

Thanks!

Posted by Carsten Kurz (Member # 5396) on 05-09-2013, 06:45 AM:

DCI has no objectives there. As long as the projection guidelines regarding brightness, image distortion, etc. are met, it doesn't matter where or how the projector is operated.

Projector and server usually create quite some noise, so 'open space' is usually prohibited. Boothless usually means mounting the projector or server in a large, ventilated hushbox.

- Carsten

Posted by Ken Lackner (Member # 1002) on 05-09-2013, 07:54 AM:

quote: Nastia Motovilova
various DCI projectors

Isn't that kind of like calling yogurt that has been approved by the FDA "FDA yogurt?" DCI neither manufactures nor puts their name on equipment.