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Home Theater Projector Buyer's Guide

What is Contrast?

Contrast is the difference in brightness between the brightest and darkest parts in an image. The greater the difference, the higher the contrast.

Why is Contrast so important?

With business projectors, lumen output is of primary importance, and contrast is a secondary concern. Home theater projectors are the exact opposite. Contrast is arguably the single most important measurable quality in a home theater projector. A high-contrast projector produces a picture with a deep black level and clearly defined shadow detail. Contrast, in essence, gives "depth" to video images. A projector with excellent contrast can make a two-dimensional image appear almost three-dimensional.

Contrast Ratios

The contrast ratios noted on a projector's spec sheet can be reported in one of two ways. If it just says "Contrast," it usually indicates On/Off contrast, which is the ratio of the whitest white and the darkest black that the projector is capable of producing. If it says "ANSI contrast," the ratio has been determined by displaying a checkerboard pattern of white and black squares and measuring the relative brightness of each. On/Off contrast is always a much larger number, and more typically listed on projector spec sheets, but ANSI contrast is a somewhat more accurate representation of what your projector is actually capable of displaying in any given scene. Note that neither of these measurements tells the whole story, and only taking both numbers into account gives even a moderate approximation of a projector's capabilities. To really know what a projector is capable of in relation to other models, either find a way to see it in person or read our Projector Reviews.

What about a dynamic iris?

A dynamic iris is a device built into some projectors that sits between the lamp and the lens. Many times per second, the projector evaluates the overall brightness of the image being projected and then opens or closes the iris to allow more or less light through.

A good dynamic iris will improve on/off contrast. Dark scenes will appear darker, while bright scenes will appear brighter. The on/off contrast rating will be based on the whitest white with the iris opened, and the blackest black when the iris is closed. Dynamic irises have no effect on ANSI contrast, though, so a projector with a lower contrast rating may appear higher in contrast in any given scene. As with ANSI lumen ratings, it is best to take official contrast specifications with a grain of salt. They can be highly misleading.

Dark Room Needed for Best Results

You've noticed that commercial movie theaters are dark, including dark-colored, non-reflective ceilings and walls. That is because any front projection system looks its best when there is no light in the room; this includes stray light from the screen that reflects off the walls or ceiling. Once you introduce light into the room, that light will make blacks look more like dark gray. This reduces the contrast of the image, making it appear flat or washed out. This will happen no matter what the contrast capability of your projector is.

Though the ideal viewing room is dark, most people don't want to darken the walls and ceiling of a living room or multipurpose room just to get ideal theater conditions. Today's high-contrast gray screens help to improve black level when there is some ambient or reflected light in the room. For the best possible image quality, though, take whatever steps you can to eliminate ambient light and reduce the reflectivity of the room's walls and ceiling.

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Contents: Overview Aspect Ratio Resolution Brightness
  Contrast Installation Cost
Comments (34) Post a Comment
bahha Posted Feb 28, 2011 4:17 PM PST
thank you, your guide is helpful . I'm going to buy a projector now, I want to use at school for teaching.
Vichu Posted Jul 19, 2011 6:59 AM PST
Thank you. The article is very informative
b.r.nath Posted Jul 25, 2011 12:43 AM PST
a nice handy guide for all the buyers
rman Posted Jul 26, 2011 11:19 PM PST
wonderful guide.. Thanks!
hussain Posted Sep 6, 2011 10:59 PM PST
sophie Posted Feb 24, 2012 2:29 AM PST
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bill Posted Apr 9, 2012 6:23 PM PST
thank you very much for making and sharing this guide (and the rest of the site's content, too). i've found it easy to follow and very informative. many thanks.
narco Posted Apr 18, 2012 2:46 AM PST
thanks for an informative and well written article.
Ash Posted Nov 12, 2012 8:14 AM PST
Thanks for a great article. The beginners like me can acutally now go out and search for the one we need. I am looking for one below $1200 with screen and ceiling mount. This article really is helping me narrow down on the selections and also helped understanding the importance of going for better screen. One suggestion...Please include a couple more sections, one for 3D compatibility and another for performance with gaming consoles.
home theater Posted Jan 15, 2014 9:09 PM PST
Great guide for everyone who is in planning to buy the home theater system. last year i am too confused in buying the best home theater system. After reading the products review and comparing home theater system in terms of technical specification, i find the best home theater system. [edited to remove link]
Anil Samuel Posted Feb 4, 2014 3:02 AM PST
Amazing article. I appreciate the effort. And thanking you all behind this site. I am from Germany And I want to buy one good projector for a charity association
steven prentice Posted Feb 7, 2014 12:35 AM PST
Fantastic breakdown for projectors thank you
TheWiredFox Posted Feb 21, 2015 1:50 PM PST
This guide is helpful, however it does not include any information regarding inputs, specifically '3D PC' vs. 'HD 3D' inputs. I currently have a 2D setup with HTPC and Blu-Ray switched through my receiver with HDMI. Upgrading to a 3D projector is the plan, and getting into specifics with '3D PC' vs. 'HD 3D' should be included in this Buyer's Guide. Thanks.
Steve Hiegel Posted Jul 26, 2017 2:47 PM PST
All the information needed to arm yourself with the information you need to buy a projector that fits your needs. Thank you for this resource.
amedius Posted Mar 9, 2018 8:38 AM PST
Awesome article if only I would have read earlier. I purchased a Epson tw6100 four years back and placed in the last corner way back 20 feet. Since its having keystone correction, I could adjust the image of 140 inch diagonal to get it perfectly aligned. Bluerays look sharp and very bright. I was happy with it. But after reading this article, I wonder if I would have placed the projector right in the center and just 12 feet from the screen, I could have got a better image, maybe still brighter and more sharper. Thanks for the article. My next projector placement will be a lot different.
larry Posted Dec 23, 2018 10:16 PM PST
I have the Epson 8500 projector using a 106 inch screen. I calibrated it with an Avia disc. I notice curtain scenes appear to be very dark compared to a panel TV. Any suggestions to brighten it up without throwing my calibration off?
Rob Sabin, Editor Posted Dec 24, 2018 8:07 AM PST
Larry, although setting black level (ie, the brightness control) with a disc theoretically puts you at the perfect setting to match how a control room or mastering studio monitor looked to the technician when the content was created, the reality is that it can sometimes be a little too dark and crush shadow detail. The ideal setting does vary somewhat based on the vagaries of content creation and or other characteristics of your display. Usually you can just click the brightness control up a notch or two if things look too dark; get it up just high enough to reveal detail in a swath of black hair or pull out the lapels on a dark suit or the texture in dark fabric. If that washes out the image too much, you can also play a bit with your display's gamma settings. You don't want to get too far off the default (probably 2.2 where most older content was mastered, or 2.4, or the newer BT.1886 profile). But adjusting gamma can alter the contrast on the mid-tones while leaving the deeper blacks less affected than adjusting brightness. Bottom line to all this: make the picture look good to you, and don't get hung up on what a disc tells you is the "perfect" setting.
Shanoof Posted Jul 1, 2019 12:07 PM PST
Hi I was planning to buy Benq TK800M 4K projector,but after reading this I am confused to have one as here its saying 1080 x 800 is good enough for a home theatre.Guys please help me on this,do I need to have spend for a 4K projector for a better view or I can get high quality views in a lesser resolution say 1920 x 1080 ,so I can save some money My room length is 5 Mtr. please help
Rob Sabin, Editor Posted Jul 1, 2019 2:24 PM PST
Shanoof, this article is somewhat dated and by today's standards, 1920x1080 full HD is about the minimum you'd want for home theater, and UHD/4K resolution is ideal because you get both additional detail and the ability to watch and benefit from HDR (high dynamic range) content. If you're interested in a compromise for purpose of saving money, a projector like the Optoma HD27HDR might be of interest. It's a 1080p projector that's compatible with 4K HDR content. It won't have the full performance with either detail or color as a 4K projector, but it offers some of the benefit. You didn't say how large a screen you intend to have, but the extra sharpness of a 4K projector does become more obvious at 100 inches and above.

shanoof Posted Jul 1, 2019 11:00 PM PST
Thanks Rob for the quick reply.My Screen size would be 100 Inches +.Please recommend me a best quality projector+screen .My budget is $1,200 Max
Rob Sabin, Editor Posted Jul 2, 2019 9:23 AM PST
Assuming you are doing dark-room viewing, I'd put aside approximately $200-$250 to get a budget screen and use our Find a Projector search feature to look at models at around $1,000 or less. We have reviewed many 1080p projectors in the $600-$1,000 range. You can also call any of our associated projector resellers and let them talk you through some options.
stella Posted Jul 17, 2019 3:15 AM PST
i am after a projector that will do a 43" perfect. I am not after any bigger. what is best for me? I like to have it portable and played from a coffee table. thanks
Bernie J Sullivan Posted Jul 25, 2019 9:26 AM PST
I'm trying to have a 172 inch screen on a 2.35 to 1 aspect ratio. I read that you could use a projector with a 1.3 to 1 zoom lens and a 2.35 to 1 screen to accomplish ....trying understand how that would be done...can you explain .??? Thanks, Bernie
Mike Posted Aug 15, 2019 11:24 AM PST
I have a brand new theater room, no windows with a very high vaulted ceiling. The room is 15' wide by 20' long. I don't want to mount the projector hanging from the high ceiling, so I need to mount it on the back wall which is 20' from the screen. I would like the screen size to be about 9-10' across. Any ideas of what the best projector would be for this? (I called BenQ and they steered me to their BenQ HT 5550.....but its $2,400. Any less expensive options??
Kari Posted Oct 1, 2019 9:02 PM PST
In a short and to the point answer... what would be the best projector for watching YouTube yoga videos and amazon prime shows and movies? I want to stream through my iPad or iPhone and take for travel if needed Thank you so much, Lost in the technology forest😉
Rob Sabin, Editor Posted Oct 6, 2019 11:45 AM PST
Kari, I apologize but there is no short and sweet answer for this with the information you've given. Based on your need for portability and your less-critical need for the very best image quality (versus a serious home theater enthusiast), I'd suggest you look at an affordable pico-style projector such as the Viewsonic M1 or M1+ for about $300. I also like the Optoma 750ST at somewhat higher cost. But these selections make assumptions about your budget, the size of the image you hope to achieve, the ambient light conditions you intend to view in, and the surface or screen you expect to project onto. I suggest you contact one of the projector resellers from our Where to Buy Projectors link on the home page and let a qualified sales consultant walk you through some options at your budget.
Abdul Azeez Posted Oct 21, 2019 5:49 AM PST
I am confused by the estimated image brightness on your calculator. I have a dark room with low ambient light. When I plugged in the projector model I need it shows me 40fl manufacturer spec for a 119 inch screen at a time 11.8 feet distance with a 0.7 gain. Do I interpret this number to mean the projector is not suitable for my room?
Rob Sabin, Editor Posted Oct 21, 2019 9:39 AM PST
Abdul, although you don't specifically mention the projector you are using for these calculations, the 40 ftL at the screen size and gain you mention is likely based on the projector's full rated brightness. That presumes you will use its brightest color mode setting, which in many projectors does not provide terribly accurate color and may even be too green to use for anything but very high ambient light viewing, if at all. For your dark room, you'll likely select a more color-accurate mode with less brightness. So if the concern is that this projector will be too bright, that's not likely to be an issue here once you select one of the preferred modes.

That said, even half of that light output should serve to give you a good picture in a dark room, as 16 to 20 ft-L or so is a common target these days for on-screen brightness with regular standard dynamic range content. For HDR content, the target may be 20-30 ft-L.

AJS Posted Oct 23, 2019 2:35 PM PST
How important is it to have lens shift in the projector. My projector would be ceiling mounted more of less center (horizontally) of the screen. The screen would be hung from ceiling as well (5 ft away). Do I need something which has shift ? Looking for projector under $750 (streaming on wifi). Any recommendations since this article seems to be recommending stuff from 2007 !
Rob Sabin, Editor Posted Oct 23, 2019 3:34 PM PST
This article is in need of updating as you've pointed out, but the central question of whether you need lens shift is timeless. The bottom line is that unless you can very specifically mount the projector at exactly the right height from the ceiling to drop the image to where your screen is using only the native vertical offset of the lens, you would want some degree of vertical lens shift to pull that image up or down slightly to match your desired screen position. If not, you'll be tilting the projector down, which creates keystone distortion which must then be corrected with a digital keystone control in the menu, which the projector would need to have available. We recommend avoiding the use of keystone correction because it can negatively affect the quality of the image.

There are a number of projectors in your price range that have some degree of zoom and at least a modest degree of vertical lens shift. I suggest you check our group roundup review of under-$700 models, and also go through our more recent reviews of models that fall into your price range since this mid-2018 feature was published. These are all 1080p projectors, but you'll find a couple of more recent units that accept 4K/HDR signals and can display them with HDR at 1080p.

Best Under-$700 Home Theater Projectors
AJS Posted Oct 24, 2019 6:30 AM PST
Thanks for the response Rob. So as I understand ideally the projector should be dead center of screen if it does not offer lens shift. Since in my case the projector is center horizontally I would ideally need a vertical shift at least to avoid the keystone. I have checked out the list and I will go through recent review as well ! Thanks again !
Rob Sabin, Editor Posted Oct 24, 2019 7:43 AM PST
Actually, every projector has a fixed vertical offset that in most cases will raise the image up by a fixed amount from the lens height if the projector is on a table or shelf or raise the image down by that same amount if the projector is ceiling mounted. So a projector without vertical lens shift that is ceiling mounted will usually be mounted with the lens at or near the height of the top edge of the screen -- otherwise, you can imagine that the projector would end up being so low it would get in the way of viewing the image. Having vertical lens shift allows you to make adjustments in the height in reference to this native vertical offset to avoid that keystone I mentioned. So if you don't have lens shift, you must find out what this fixed vertical offset is and apply it for a image size you're using to determine what distance from the top of the screen your projector must be mounted. The user manuals usually have this information along with charts that show the result with different screen sizes.

And yes, you do always want to mount your projector horizontally lined up with the center of with the screen.
AMEDIUS Posted Oct 31, 2019 8:50 PM PST
I own a eh tw9400 Epson with loads of shifts. My projector is off center by 5 inch. I have aligned the picture to the center by horizontal lens shift. Do you thing there will be a degration of picture quality. I did not find any. What are your views
Rob Sabin, Editor Posted Nov 1, 2019 7:10 AM PST
It's generally best to avoid using horizontal shift and properly centering the projector if possible, but you're honestly not likely to see any real detectable image degradation in a situation like yours with a modest amount of lens shift on a good projector. Pushing either horizontal or vertical lens shift to the very end limit of its range on either side can sometimes introduce some modest focus issues at the edges of the image on some projectors.

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