A few comments.
1. The 30% increase in brightness claim is easy to verify:
- Take a light meter measurement of the 2.35:1 image using an anamorphic lens, with the the projector at, say, 16 foot from the screen.
- Now, move the lens out of the way, but instead of zooming the projector lens in to fill the 2.35:1 screen, physically move the projector back in the room until the letter-boxed portion of the image fills the same 2.35:1 area as it did with the a-lens (the projector may now be about 18 - 20 foot from the screen). Take another light meter measurement.
You should get around a 30% increase in brightness using the anamorphic lens. This is also more of an apples to apples comparison, since opening up the projector lens using the zoom method may increase the overall brightness of the image but at the same time decrease the contrast. In other words, using the zoom method from the same throw distance may come closer to achieving equivalent brightness as the lens method, but the overall contrast will be decreased. Even so, even with Andrew's testing, the brightness was still higher using the lens.
2. As many here have pointed out, some projectors have a variable f-stop throughout the zoom range, so opening up the lens for zooming also increases light output (at the expense of contrast, as outlined above). Other projectors have essentially a fixed f-stop so that there will be no real increase in brightness using the zoom method. In the case of these projectors, you will again get closer to the 30% increase in brightness we are discussing.
3. If you read through the various posts I have made - and those of others who are involved with the manufacture of anamorphic lenses - you will see that we usually claim about a 20% increase in brightness over zoom, because we take into account the variables listed above. In our testing here at Panamorph, we have seen drastic increases in brightness (the 30% figure mentioned above) as well as minimal increases in brightness (about 5 - 10%) depending on projector model, throw distance, throw ratio, etc. However, I still stand behind the 30% increase in brightness as a true and verifiable marketing claim since it can be achieved with almost any projector model using the method I outlined in point #1. Real world results will vary, as they will with any product, since every possible combination of projector, lens, screen, and room cannot possibly be taken into account.
4. It is often pointed out that the light spill resulting from the black bars being projected onto the wall can be compensated for by putting light absorbing material onto the wall above and below the screen. To me, this is a "remedy" that applies to maybe 3 - 5% of the people likely to install a 2.35:1 / CIH system in their home. I have been promoting and selling front projection systems to end users from about 2002 right up until the present, literally dealing with hundreds of customers in that time frame. The number of people who would have even considered putting black velvet (or the equivalent) onto their living room / family room wall is extremely
small. Now I realize that the type of person who regularly posts on AVS Forum may very well be the type of person who would do this, the reality is the vast majority of people who just come here to read and learn would never even consider such a plan. Most "home theaters" are actually mixed use family / media rooms, not dedicated, blacked-out caves. On top of that, putting black velvet onto your screen wall top and bottom does nothing to help you when you go back to the disk menu and it is now projected onto black velvet and even harder to read.