Re: [QLab] qLab vs Isadora
Perimeter Productions
Robert C. Hammel
VP of Production
Perimeter Productions
1312 Tyrol Trail
Minneapolis, MN 55416
www.perimeterproductionsltd.com
Work: 763.374.9072 Cell: 612.877.2367
b...@perimeterproductionsltd.com
Christopher Ashworth
I'm not terribly familiar with Isadora, so it's hard for me to do a fair or complete comparison.
But in terms of what QLab can do:
On Aug 5, 2010, at 12:40 PM, Perimeter Productions wrote:
> Chris:
> I would like to run QLab for a project I'm doing. I have three projection areas that have different shapes and will be at different distances from the projector. Can I use one projector and map the images on different parts of the screen?
> I would project one image over the whole stage and change the images within that frame so they match the projection surfaces.
You can use the "Custom Geometry" setting to move the projected videos to different parts of the screen, as well as scale and rotate them. So yes, for that kind of situation you can have one projector that projects videos onto different parts of the stage.
If you need more advanced warping functionality, it's possible to do some of that using custom Quartz Composer patches that you'd drop into the rendering pipeline, but it's not as easy as having a built-in set of tools to warp the images onto a custom surface.
For example, if you're projecting on a sphere or column or some other "shaped" surface, and you need to warp to that surface, and if Isadora has tools baked in to make that easy, then that would be something Isadora probably does better than QLab.
> Can I control focus?
Do you mean control the focus of the projector from within QLab? It would depend on what controls your projector makes available for remote control, but you can, for example, send out serial commands using a combination of the Script Cue and a great little third-party utility called Scripting Bridge.
Best,
Chris
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Christopher Ashworth
> Thanks for the information -- that helps. As far as focus goes -- I meant, Can I use one projector and have different focal lengths for each of the images that I project from that projector. I'm projecting 3 images: one against the back wall, one in front of the proscenium, and one in the middle distance -- can software keep them all in focus or do I need different projectors?
Ah, gotcha. That's a job for different projectors. A lens can precisely focus at only one distance at any one time. (Well, technically, it can't *perfectly* focus at all, but it will have one distance at which the focus is as good as it can get.)
-C
Richard B. Ingraham
> -----Original Message-----
> From: qlab-b...@lists.figure53.com [mailto:qlab-
> bou...@lists.figure53.com] On Behalf Of Christopher Ashworth
> Sent: Thursday, August 05, 2010 7:48 PM
> To: Perimeter Productions
> Cc: Discussion and support for QLab users.
> Subject: Re: [QLab] qLab vs Isadora
>
> Ah, gotcha. That's a job for different projectors. A lens can
> precisely focus at only one distance at any one time. (Well,
> technically, it can't *perfectly* focus at all, but it will have one
> distance at which the focus is as good as it can get.)
>
Not necessarily. It depends on how nice of a projector or projectors you
have. :-)
There are some higher end projectors that can be refocused remotely.
Typically by RS232 commands or I suspect some of the newer ones are now just
using some sort of IP communications such as Telnet or the like.
Some of the Christies I've worked with on cruise ships have what they refer
to as "channels" which are really just presets for focus, input select,
resize, etc... And then with a RS232 command you can recall those settings
on the fly. Typically you would do this with the shutter closed, which is
also RS232 controllable.
So you could focus an image on a downstage scrim for one scene and then in
the next scene it's focused on the cyc all the way upstage. Just as an
example.
But obviously this is not the $1500 projector that a lot of places have just
kicking around. And of course the amount of focus has its limits as well.
Richard B. Ingraham
RBI Computers and Audio
http://www.rbicompaudio.20m.com
Christopher Ashworth
>>
>> Ah, gotcha. That's a job for different projectors. A lens can
>> precisely focus at only one distance at any one time. (Well,
>> technically, it can't *perfectly* focus at all, but it will have one
>> distance at which the focus is as good as it can get.)
>>
>
> Not necessarily. It depends on how nice of a projector or projectors you
> have. :-)
>
> There are some higher end projectors that can be refocused remotely.
> Typically by RS232 commands or I suspect some of the newer ones are now just
> using some sort of IP communications such as Telnet or the like.
Sure, as per:
On Aug 5, 2010, at 3:58 PM, Christopher Ashworth wrote:
>> Can I control focus?
>
> Do you mean control the focus of the projector from within QLab? It would depend on what controls your projector makes available for remote control, but you can, for example, send out serial commands using a combination of the Script Cue and a great little third-party utility called Scripting Bridge.
But I think Robert was asking if three different focal planes can be kept in focus simultaneously, without any refocusing of the projector. To which the answer is no, due to the physics of projection lenses.
-Chris "I shudder to count the unhealthy number of hours I spent in a windowless office calculating projection & camera matrices in grad school" Ashworth
Christopher Ashworth
>
> I think Robert was asking if three different focal planes can be kept in focus simultaneously, without any refocusing of the projector. To which the answer is no, due to the physics of projection lenses.
Luckydave has reminded me off list that this, while true, is also not the whole story. It's also worth mentioning for completeness:
In the same way that you can get depth of field in cameras you can also get depth of field in projection.
Which is to say, although there is only ever one "perfectly" focused plane (which isn't ever perfect anyway), if you have things set up right (length of throw, good lens, etc) you can get a range in which, as the surfaces deviate from the ideal distance, the projected image blurs gradually enough to still look sharp to the human eye. (Possibly depending as well on where those human eyes are located.) Luckydave informs me he's been able to achieve a depth of up to 5-8 feet under the right circumstances, in which everything projected in that range was close enough to look sharp.
So: under the right circumstances you might be able to fudge it. But it takes careful fudging.
Thanks LD for the nudge on discussing the fudge. :)
-C
Richard B. Ingraham
> kept in focus simultaneously, without any refocusing of the projector.
> To which the answer is no, due to the physics of projection lenses.
Gotcha. I missed that part of the initial question. Sorry.
Richard B. Ingraham
RBI Computers and Audio
http://www.rbicompaudio.20m.com
Mic Pool
> A lens can precisely focus at only one distance at any one time. (Well, technically, it can't *perfectly* focus at all, but it will have one distance at which the focus is as good as it can get.)
Although projectors do effectively have depth of field. Sometimes one projector will be well enough in focus for a range of projection distances.
Manufacturers assume that you are doing conventional projection on to a screen so there is very little published data. The best way is to set up the projector and try it.
Mic
Roland van Meel
2 Years ago i toured with a production in Europe and we used projection as a very important part of the stage setting.
We used 1x 5000 ansilumen Sanyo/Eiki beamer with a wideangle zoomlens,[± 13 m of throw] projecting on different planes on the set and we didn't refocus at all.
We used Keynotes as the mediaplayer, and there was 1 window ± 2x3 m in the back with a white projectionscreen ± 7 x 4 m fixed on a flybar behind it,
next plane was 8 different sized pictures hanging from a flybar ± 1,70 m before the Window.
Next plane was 2 old fashion standing houselamps [ from granny] ± 3 m before the window
and the last plane was a small fotoframe in a cubboard ± 4 m before the window.
all of the planes had different shaped video images projected exactly sized on the objects and we had many cues to change the content.
We noticed a little "unfocus" on the fotoframe but we didnt feel the need of using more than 1 projector.
It toke us more than 2 hours to set up and focus the beamer each time !!!!!
But than the lightdesigner carefully placed the lamps he used to not hit the projectionplanes.
Hope you find some courage in this set-up
Regards Roland
Christopher Ashworth
>
> 2 Years ago i toured with a production in Europe and we used projection as a very important part of the stage setting.
> We used 1x 5000 ansilumen Sanyo/Eiki beamer with a wideangle zoomlens,[± 13 m of throw] projecting on different planes on the set and we didn't refocus at all.
> We used Keynotes as the mediaplayer, and there was 1 window ± 2x3 m in the back with a white projectionscreen ± 7 x 4 m fixed on a flybar behind it,
> next plane was 8 different sized pictures hanging from a flybar ± 1,70 m before the Window.
> Next plane was 2 old fashion standing houselamps [ from granny] ± 3 m before the window
> and the last plane was a small fotoframe in a cubboard ± 4 m before the window.
> all of the planes had different shaped video images projected exactly sized on the objects and we had many cues to change the content.
>
> We noticed a little "unfocus" on the fotoframe but we didnt feel the need of using more than 1 projector.
> It toke us more than 2 hours to set up and focus the beamer each time !!!!!
> But than the lightdesigner carefully placed the lamps he used to not hit the projectionplanes.
LOL -- this is great!
See, this is why I love this list. Here I am, thinking "well, I know a little bit of the theory behind this, and I've futzed around with projectors, so this is one of those practical in-the-field questions I can actually feel confident about answering."
But here I am learning from multiple people that the fudge factor provided by the depth of field is a real, honest-to-goodness tool, and can be used as dramatically as the above. I love it.
In fact, I think this would not be an inappropriate moment to explicitly extend my sincere thanks to Richard, Mic, Roland, Luckydave, and all the other wise heads who bring such a broad base of experience to this list, and take the time to share it. I am so lucky to have folks like you to learn from. Truly.
Best,
And happy Saturday,
Chris
Charlie Richmond
> But I think Robert was asking if three different focal planes can be kept in
> focus simultaneously, without any refocusing of the projector. To which the
> answer is no, due to the physics of projection lenses.
Not to worry - there is a group working on this problem right now, per my
conversation with Richard yesterday ;-)
C-)