Posted on March 28, 2018 By Art Feierman
Viewsonic PX727-4K – An Affordable 4K UHD Projector Review – Hardware: Overview, Inputs and Connectors, The Lens
We’ll start with the nickel tour of the PX727-4K, then we’ll get into some more detail. From the front, you’ll notice that the manual 1.2:1 zoom lens is recessed and is offset to the side (to the right, if facing the projector). The IR sensor is in the center, at the top. Venting of hot air is found on the left side of the front.
This is a relatively small projector, so if you have it on a table, you probably won’t want to be sitting a foot or two forward of the projector and just to the right of it, or you will get very slowly cooked with warm air shooting from the vent. Down below the front is a screw thread height adjustable foot. That takes care of the front.
Looking at the top, right behind where the lens is, you’ll find two lens controls – focus and zoom – to adjust. These controls are also recessed. When you go to adjust the zoom, the focus goes way out of focus. It’s a minor nuisance. Just takes you a little extra time, if you are setting up frequently (surprise, the BenQ HT2550 exhibits the same issue.) The control panel is also on the top, as is the door to replace a lamp. All the inputs and connectors are to be found on the back of the PX727-4K.
The PX727-4K is is well equipped with inputs and other connectors for a lower cost projector. It is true, though, like most home projectors today, that there are no more “legacy” composite video or S-Video connectors. What there is, from left to right:
A pair of stereo audio jacks – one in, one out. A PC VGA input (standard DB15 connector) comes next. It can handle an analog computer, or component video.
A pair of HDMIs is next. They are different! The left one is HDMI 1, and is HDMI 2.0 with HDCP 2.2 – which meets the requirements of Blu-ray UHD and other copy-protected content.
The second one is the good old HDMI 1.4, which has been around for a number of years. In theory, the first one should handle anything HDMI, but most manufacturers include an HDMI 1.4 – just in case there’s a problem, perhaps with a 10-year-old player.
As always, I must complain: a third HDMI input would be very helpful for those not doing switching through an AV receiver. I tell all the manufacturers, but few have done so. Most recently, a Vivitek had three. Other than high-end commercial projectors, two is all you will normally find.
Next comes a USB Type B, for servicing, followed by an old-school, RS-232 serial port, for command and control of the projector. Then comes the USB Type A port which is there to provide a 5V 1.5amp output (it can be used for recharging most 3D glasses). Finally, there’s a 12-volt screen trigger. That’s something not often found on lower cost home projectors, but, if you need it, great. It’s used for raising and lowering a motorized screen which has a 12-volt trigger. More and more these days, however, companies are moving to wireless control rather than 12-volt triggers.
The PX727-4K’s 1.2:1 zoom lens provides about the minimum in placement flexibility. Fortunately, if ceiling mounting, the couple of feet of range offered will usually be enough for you to be able to mount it. Other projectors in the $1,000 to $2,000 price range may have as little as 1.1:1, or as much as 2.1:1. No lens shift on the PX727-4K, (just like the BenQs of course). It’s best described as having little placement flexibility.
Without lens shift, however, you really want to have the projector mounted, or on a table at the correct height, so as not to have to use keystone correction, which degrades the image sharpness slightly. Think this way, why spend for 4K UHD, if you use a feature that probably reduces sharpness down to that of a 1080p projector that is not using keystone correction.
If you focus the projector looking at the dead center, edge sharpness is pretty good, no – let’s call that very good for a projector in this price range, especially one where a chunk of the price is dedicated to having 4K UHD resolution. Well, one advantage to a lens with very little zoom is that it’s a lot harder to find “very sharp” in a zoom lens that has a lot of zoom range.
Other than the Kensington lock slot near the bottom right (for security), there’s only the power receptacle. That’s all folks!
Here’s a lens throw chart for using the PX727-4K projector with a 100” 16:9 screen. And also the lens offset, which tells you how far above or below the screen surface the projector lens should be. If you are getting a larger screen, or smaller one, you can calculate the numbers you need, in a few seconds. Example:
Lens Throw Chart for 100,” 16:9 Screen
If you are going with a 125” diagonal screen and want the closest placement of the projector to the screen, then multiply the 10 feet 8 inches (128”) by 1.25, since your larger screen is 25% larger. That’s 160 inches, which is 13.8 feet, for the closest placement.
Lens offset is almost 5 inches (125mm). Translated, if you put the PX on a table top pointing at a 100” screen, the center of the lens should be 5” below the bottom of the screen surface (or, if ceiling mounted, 5” above the top of the screen surface).
That’s a very reasonable amount of lens offset.
And, if you went with a larger screen, say a 120″ diagonal (20% larger), then the offset would be 20% more than the 5 inches, which works out to six inches.
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