Projector Lens throw question

CAvolleyballguy · February 2008

On projector central you can do a calculation based on lens throw.

I'm looking at this sanyo a lot of people seem to like (based on price and quiet)...
but seems limitations is not to go over a certain screen size of 100 inches.
My question is, if my throw is 17 feet, the calculator says it will be 130 inches, and the image is outside the recommended brightness.

I realize this is a basic question, but I am clueless
Are there adjustments that allow you to shrink the image thus focusing more light and making it brighter...

If so, How do I figure out how bright the image will be with a fixed throw distance (since the calculator wont let me change screen size without changing throw distance)
thanks

mutelight · February 2008

Mine is at about 18 feet firing at a 100" screen. There is a zoom ring to adjust image size. Making the image smaller will raise the lumens rating. There should be a slider on the calculator to adjust for zoom.

Dennis Gardner · February 2008

You can shrink the image, but brightness is affected alot by distance. You should move it to within design limits for best results or look for another PJ with more lumens if the distance isn't negotiable. Too many nice PJs on the market for the $$$ today to suffer with less than a great picture.

CAvolleyballguy · February 2008

got it thanks.

seeclear · February 2008

Does Sanyo have a calculator on it's website that may allow you more flexibility in the calculations? Just a thought, i know infocus has that on their website (but not for sanyo projectors, obviously).

kuntasensei · February 2008

CAvolleyballguy wrote: »

On projector central you can do a calculation based on lens throw.

I'm looking at this sanyo a lot of people seem to like (based on price and quiet)...
but seems limitations is not to go over a certain screen size of 100 inches.
My question is, if my throw is 17 feet, the calculator says it will be 130 inches, and the image is outside the recommended brightness.

I realize this is a basic question, but I am clueless
Are there adjustments that allow you to shrink the image thus focusing more light and making it brighter...

If so, How do I figure out how bright the image will be with a fixed throw distance (since the calculator wont let me change screen size without changing throw distance)
thanks

The calculator at Projectorcentral lets you check available screen sizes for the projector's zoom range. Set throw distance to 17', then click the radio button for DIAGONAL RANGE. From that throw distance, this gives you a possible range of screen sizes from 84" to 170". A 100" screen at that throw distance would give you about 14 ft.l. of brightness on a 1.1 gain screen (which is what I'm using with my Z2000, though my throw distance is 13'). You'd still be in the recommended brightness for low ambient light, so if your room has good light control, it'd work for you. If that's not bright enough for you, you could always invest the money in a higher gain screen. Personally, I'm using a cheap Elite manual 100" screen that I got for $103 shipped from NewEgg... and it works like a charm!

Serendipity · February 2008

kuntasensei wrote: »

The calculator at Projectorcentral lets you check available screen sizes for the projector's zoom range. Set throw distance to 17', then click the radio button for DIAGONAL RANGE. From that throw distance, this gives you a possible range of screen sizes from 84" to 170". A 100" screen at that throw distance would give you about 14 ft.l. of brightness on a 1.1 gain screen (which is what I'm using with my Z2000, though my throw distance is 13'). You'd still be in the recommended brightness for low ambient light, so if your room has good light control, it'd work for you. If that's not bright enough for you, you could always invest the money in a higher gain screen. Personally, I'm using a cheap Elite manual 100" screen that I got for $103 shipped from NewEgg... and it works like a charm!

I have just one question...does the brightness of the image matter on where you put the projector? Like very close with max. zoom or far away with minimum zoom? I'm used to CRT projectors in which you can only put the unit at ONE throw distance, since there is no way to zoom the image in/out.

kuntasensei · February 2008

Yes, the brightness changes both with distance you put it away from the screen and with the amount of zoom you use (i.e. zooming to a larger picture size = less brightness). That afore-linked calculator shows you areas in the distance/screen size sliders in red, yellow and green to indicate the sweet spots for brightness depending on room condition (i.e. control of ambient light) and screen size vs. throw distance.

LCD and DLP projectors are definitely more flexible than CRTs, especially for units with lens shift. You don't even have to center the projector with the screen like you do a CRT, since you can move the lens in the optical path to shift the image thrown. For instance, my Z2000 can be put damn near to either side of the screen and still be shifted to hit it squarely (though shifting to the extremes of its potential shift can cause focus issues at the edges).

Serendipity · February 2008

Thanks, looks like digitals are very flexible! You guys also have keystone adjustment on your projectors!

mutelight · February 2008

appadv wrote: »

Thanks, looks like digitals are very flexible! You guys also have keystone adjustment on your projectors!

There is also a lens shift on the Sanyo and other digital projectors so keystone is not necessary which eats up your resolution.

Serendipity · February 2008

mutelight wrote: »

There is also a lens shift on the Sanyo and other digital projectors so keystone is not necessary which eats up your resolution.

Now why didn't I discover digital projectors earlier ?

mutelight · February 2008

Haha, well CRT projectors do reproduce those great inky blacks. :cool:

Serendipity · February 2008

mutelight wrote: »

Haha, well CRT projectors do reproduce those great inky blacks. :cool:

Not just CRT projectors. Direct-view CRT TV's and CRT-based RPTV's can also produce some wonderful blacks and amazing contrast.

But I agree that digitals are brighter.

mutelight · February 2008

Very true, I was referring to the CRT tech in general.

kuntasensei · February 2008

Believe it or not, the Sanyo Z2000 doesn't have keystone adjustments. My old Z3 did though. Honestly, it isn't necessary. You level the projector, make sure it's parallel to the screen, then use the lens shift and zoom to line it up. When I got my Z2000, it literally took me 10 minutes to get it out of the box, on its shelf, lined up to the screen and running.

I have an ISF-calibrated CRT-based RPTV sitting behind my drop-down screen. With my previous Z3 projector, the CRT was definitely brighter and with obviously better contrast. Honestly... the Z2000 comes damn close. I could take a picture of the same test pattern on both the RPTV and the screen ('cause I'm using a matrix switcher to run a component feed to both), and you'd be surprised at how well the Z2000 holds up by comparison.

Projector Lens throw question

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