most efficient way to string CIFilters together?

FROM : Josh Burnett
DATE : Sat May 03 20:06:01 2008

In a photography app, I'm chaining a series of CIFilters together to 
process the image.  I'm able to do the chain just fine, but I'm only 
using a few filters at the moment.  As I increase the length of this 
chain, am I going to run into performance issues?  Here's my code:

exposureFilter  = [CIFilter filterWithName: @"CIExposureAdjust"
   keysAndValues:
       @"inputImage", inputImage,
       @"inputEV", [NSNumber numberWithFloat: exposureValue],
       nil];
outputImage = [exposureFilter valueForKey: @"outputImage"];
[exposureFilter retain];

zoomFilter  = [CIFilter filterWithName: @"CILanczosScaleTransform"
   keysAndValues:
       @"inputImage", outputImage,
       @"inputScale", [NSNumber numberWithFloat: mappedZoom],
       @"inputAspectRatio", [NSNumber numberWithFloat: 1.0],
       nil];
outputImage = [zoomFilter valueForKey: @"outputImage"];
[zoomFilter retain];


Obviously, it's easy to continue to add to this chain.  Is this the 
most efficient way to string multiple filters together?  I can 
probably use Quartz Composer to create a single image unit that does 
all of the processing.  Would that be any more efficient, or would it 
be essentially the same result?

Thanks,

Josh