Okay. I'm finding the LumenLab project pretty intruiging. What kind of throw ratios can one expect? How about lens offset? Is there any way to account for image skew?

My room is 17x15, with the image preferably being thrown the long way onto the 15' wall. The ceiling is only 7'3", but I can pull out the existing drop-tile if needed. I'd like to be sitting about 12' back (that'd give me enough room for a 2nd row of seating). I'd like to acheive a 16x9 image height of 45". Does the room look suitable?

Technical questions, I know, but when you spend WAY to much time reading about projos you can't afford at AVS, you start to ask questions.


Thanks all,
Dirk

The current version of the lumenlab projector creates a 1:1 image - so if the projector is 10 feet away it will produce a 10 foot diagonal image in 4:3 aspect ratio (tv). You will need an 8 foot by 6 foot screen to accomodate a 10 foot diagonal projection in 4:3 aspect ratio.

New lens are being produced exclusively for Lumenlab that will allow for a zoom lens. These are more expensive but will allow you to place your projector further back and they will be better quality. They will also allow for better resolutions - upto UXGA I believe.

Keystone adjustment has many solutions within the protected forums.

Cool. I can deal with the relatively short throw. Any idea about offset?

Offset...I think you mean keystone? Yes we can correct up to 15º or so.

But if you do mean offset as in projecting 'off center horizontally' - then a similar technique used to adjust for keystoning (vertical offset) should work too.

About the new zoom lens that is being developed, what will the range of magnification be?

I have a similar situation where my screen size (4:3) would be too large to fit the wall. This sure would help solve the problem and avoid sourcing a different field fresnel and objective lens. I could also avoid having to design in keystone correction.

Also, any idea on when the production zoom lenses will be ready for sale?

The range of focal length on the new lens is 450mm-500mm. You can use the focal calc to get projection size: http://lumenlab.com/focal_calc.php

Best answer I can give on the date is 'soon'.

Great that gives me some flexibility in my design. Really don't want to do keystone correction if it can be avoided.

I should be able to get 105" to 119" diagonal with the size of my room and placement of projector against the back wall.

Is the image quality affected in any way using the zoom? I know that zoom lenses can be difficult to design and sometimes have many elements.

The lens is a massive lens with a full 4" aperture. I expect the image quality to improve greatly.

Actually, I meant assuming the projector is perpendicular to the wall, does it throw more like the red or the blue?



I think "image throw" was the wrong choice of words. Lens offset might have been more appropriate.

RED

DAMN

But I guess it makes sense. From the pics I've seen, all the optics are aligned. Is there a calculator to judge how much keystone / tilt adjustment is required? I don't mind the shorter throw (or I'd have to ceiling mount), but I'd also like to place the projector low as possible to keep it out of any sight lines. If I get rough ideas of mounting height, I'll just go down to my basement, tape off a rough screen, use a cardboard-box to approximate the projector size.

Thanks guys. I want to do plenty of research and be sure I want to go the DIY route. If I purchase the guide, I'm going to purchase the whole bloody rig.