[cyberheater]

After being inspired by a thread on the US avsforum from a bloke that modded his X1 I decided to attempt a similar mod on my BenQ PB6100!

I had the machine apart for my monthly dust blob check and clean so had the ideal opportunity to attempt the mod.

Using black cardboard and gaffer tape. I constructed a small diamond shaped aperture that was around 75% smaller then the lens at the rear of the projector lens assembly and attached it to the rear of the assembly lens housing.

Quite simple really. Took a couple of goes to get the size right but no too difficult.

I then (with trepidation) sparked up the PJ.

The results.

Amazing.

Deep inky blacks. Much more contrast. More snap. Somehow a deeper image. It looks brilliant. It's like getting a new projector.
Now even dark bits in films look right. The LOTRs cave scene were transformed. It really is incredible.

Obviously there is a fair amount of lumens lost due to the diaphragm but as the BenQ is a bit of a light cannon and I project in a fully light controlled environment it's not a problem.

Well worth it in terms of time and effort.

Will post piccies later.

[Gary Lightfoot]

Great stuff Cyber.

The new Benq 8720 has two irises which give it an advertised figure of around 6200:1! Positioning is probably critical for performance though. Of course that figure will drop for video but anything over 4000:1 is pretty good for a digital. Have you got a light meter? I'd love to see what kind of readings you're getting now.

Gary.

[PJTX100]

Fascinating stuff. Is this simply a case of making the iris aperture smaller = darker blacks / better contrast but less lumens?

Or is there something more complex going on here?

...PJ

[Fordy]

is this a fire risk?

[cyberheater]

Piccies of the mod

[PJTX100]

Wish the TX was as easy to take apart as this!

Why diamond shaped as opposed to circular?

I do echo the concern about fire risk...PJ

PS is that your anamorphic lens?

[cyberheater]

No. The anamorphic lens looks like this. It's a bit of a beast.

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I used the diamond shape as it's the one the guy used in the US.

(I don't think it gets that hot at that point. Time will tell...)

[PJTX100]

Nice one!

...PJ

PS are you going to mod your sig to include "with DIY iris & anamorphic lens"

[cyberheater]

Originally Posted by PJTX100

Nice one!

...PJ

PS are you going to mod your sig to include "with DIY iris & anamorphic lens"

LOL. I might do that

[Gary Lightfoot]

Does the iris go inside the lens or before it? You could try one inside if you can get it apart and have two irises like the 8720.

You really must get a light meter and take some measurements because I really need to know how much you've improved the CR!!

Gary.

[PJTX100]

Just noticed your classified ad Cybes. Must admit if I was in the market for buying this I'd be slightly wary to see such experimentation going on while you are in the process of selling it!

...PJ

[cyberheater]

Originally Posted by PJTX100

Just noticed your classified ad Cybes. Must admit if I was in the market for buying this I'd be slightly wary to see such experimentation going on while you are in the process of selling it!

...PJ

I'm being very careful and everythings reversible. I'm starting to think about just keeping it now. I don't think i'm going to get a buyer anyway.

Does the iris go inside the lens or before it? You could try one inside if you can get it apart and have two irises like the 8720.

You really must get a light meter and take some measurements because I really need to know how much you've improved the CR!!

The iris goes before the lens. Actually, it's attached to the end of the lens.

I haven't got a light meter but I did go out today and get a couple of LDR's (light dependant resistors) which i'll attach to my meter.

I should be able to get a good reading from that.