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Topic: Newbie questions on brightness and screen size
Joined: Jun 6, 2019
Posts: 1
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Hi guys,
I'm planning to buy a projector for my sister who's just bought an apartment. I've only started researching projectors a few days ago and so I'm a total newbie. My budget is around 600 USD. My sister's only wish is Full HD resolution.

My sister is planning to only use the projector in the evenings, with little ambient light in the room. The max screen size is 103 in (260 cm) diagonal, with 16:9 ratio. The throw distance would ideally be 14 ft 9 in, which is the distance from the wall to the windowsill on the opposite side of the room (assuming that the projector would fit on a 28 cm wide windowsill). It could also be placed closer to the wall, projecting a smaller image (anything in the range 80-103 in would be fine).

I've looked at the top recommended projectors in my price range on ProjectorCentral, but I'm very confused with brightness. No matter which model I choose in the Projector Throw Distance Calculator, when I limit the screen size to 103 in, the estimated image brightness rises to around 30 fL or higher, which is recommended for rooms with high ambient light. Are there any models suitable for such a screen size and ambient light conditions, in this price range?

Thanks in advance for help!
Joined: Mar 28, 2005
Posts: 12,687
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The brightness measurement on Projector Central is very deceiving.

Having more lumens is rarely a bad thing, but really, isn't a issue. Brightness calculations are based upon projectors having a 'fixed' number of lumens for output.

If you read the reviews of any projector.

The Optoma HD27HDR for example...

You can see that tested lumen output ranges from 2,800 lumens all the way down to 550 lumens.

That's a TON of brightness range, and is typical for most projectors. So, you don't have any world in which you really will have too much light output.

Don't worry about it.

What you DO need to consider:
1. Throw distance is measured LENS to screen, not wall to screen. If your wall to screen distance is 14'9", then your lens to screen distance is about 18" less than that, or right about 13 feet.

2. With a throw distance of 13 feet, there aren't any projectors which fit your limited budget which can produce an image as SMALL as 100" diagonal. That is, you MUST move the projector forward to get the image down to the size you are looking for. OR - You can spend more and get a projector which has more zoom range (or buy refurbished).

The Optoma HD27HDR I listed above, which is a good entry level choice, requires 10'9" to 11'9" to throw a 100" diagonal image. That's not an option. It's where the projector MUST go.

Spending a bit more, on a projector like the Epson 2150...

and you will have a projector with enough zoom range to hit a 100" diagonal from between 13' and 21'. So, a lot more zoom range and a lot more options there.

3. Projector height must be accurate. You can't just plop a projector wherever in a room and have it magically fit any size at any angle you want. It must be at the proper height to ensure the image is square, and it must be centered.

If it is not, you can use digital keystone correction to square the image up. But, this is an ARTIFICIAL correction to the image, and you lose resolution. Like chopping off the corner of the image, you won't be using the full 1920x1080 resolution anymore.

This video shows how keystone correction works, but doesn't really explain why you should never use it.

So, there is some information in the FAQs at the top of the different forum sections which may help you understand a bit more that may be worth reading.
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