Is LED/Laser finally ready for prime time?
IntroductionWhen the concept of an LED/Laser light source was first announced, we immediately sat up and took notice. The major weakness of any normal projector is the bulb, which will dim over time resulting in an inconsistent performance. The effective life of a bulb is also fairly limited; 1,000-2,000 hours typically and you need extensive cooling which results in fan noise. You also can't just turn a bulb-based projector on and off, there has to be a warming up and cooling down period to protect the integrity of the bulb itself. Theoretically, at least, an LED/Laser hybrid eliminates all of these problems, making it an ideal light source for a home cinema projector.
However, to date, the only projectors we have seen that use this technology are the Acer K750 and Panasonic's PT-RZ470, both of which are aimed at the more professional end of the market. As we discovered with the Acer 750 the reason for this might well lie with colour accuracy because whilst the use of a laser increases the brightness of the projector compared to a standard LED light source, the colours were wildly over saturated. At a cost of around £3,600 the RZ470 certainly hits a sweet spot in terms of projector pricing and with the inclusion of 3D, it makes a more attractive home cinema prospect than Acer's K750. It has taken nearly a year for us to get a sample, so let's see if Panasonic's RZ470 was worth the wait.
Design and ConnectionsThe RZ470 is aimed at the professional market and this is certainly reflected in its design which favours a utilitarian approach. The chassis is made of hardened matte dark grey plastic, with rounded edges making the projector durable and easy to handle. The lens is centrally mounted and appears to be of reasonable quality. To the right of the lens is a lockable joystick that is used for lens shift, whilst the zoom and focus are also performed manually. There's a decent amount of lens shift for a DLP projector, which obviously makes it easier to install the RZ470 into professional installations. However, the lack of motorised lens controls precludes any kind of lens memory feature. The RZ470 measures 455 x 137 x 415mm and weighs 11kgs. There are exhaust vents for the internal heat sink at the sides and rear, with some basic controls situated on the right hand side.
All the connections are situated on the left hand side of the projector and again reflect the RZ470's intended purpose. There are single inputs for HDMI, DVI, composite video and VGA, along with a LAN/Digital Link and a RS-232 port for serial connection. There are also 3.5mm audio in and out jacks, a 3D sync connector and a three-pin power socket, along with a main power switch. The remote control is a simple silver plastic affair that is small and comfortable to hold. It doesn't have many buttons and those that are there largely reflect the projector's professional usage. However, you can turn the RZ470 on and off, select the input and access the menu, which is all you're ever likely to need from a projector remote.
MenusThe menu system is fairly basic, with a simple layout and colour coding. There are a lot of options related to possible installations within the professional market. For example, the projector can be installed in portrait mode for use in digital signage, and there are features such as 'Daylight View' which uses a sensor to measure the ambient light and adjust the contrast for use in brightly lit rooms.
However there are also some menu options aimed at the home cinema market and the majority of these can be found in the Picture submenu. Here you can select the Picture Mode and adjust the Contrast, Brightness, Colour and Tint. You can also select the Colour Temperature, turn the Daylight View feature on or off (leave it off), adjust the Sharpness control and turn the Noise Reduction on or off. The System Selector is best left on auto, which will allow the RZ470 to automatically detect the incoming signal and adjust accordingly.
The majority of the other submenus relate to positioning the projector correctly - ceiling, stand or portrait and in front of or behind the screen. There are also multi-screen and multi-brightness controls for blending and colour matching the image from one projector with those from other projectors when used in unison. There are also submenus for setting up the various inputs, along with remote monitoring, system control, 3D settings and eco setup.
LED/Laser Light SourceThe major selling point of the RZ470 is that it uses what Panasonic refer to as Solid Shinelamp-free technology. What this actually refers to is the LED/Laser hybrid light source which uses a combination of LEDs and a laser to deliver the benefits of a LED light source but with superior brightness. The RZ470 uses a red LED and a blue LED combined with a blue laser. This blue laser is bounced off a phosphor wheel which creates the green element of the picture and increases the brightness. As a result Panasonic claim that the RZ470 can deliver approximately 20,000 hours of operation, thus eliminating the need to change any bulbs. The RZ470 also has a claimed lumens of 3,500 which is three times that of any of the LED projectors we've reviewed. The use of a LED/Laser hybrid light source also means that there is no major dimming and you can achieve a consistent performance over the life of the projector. Finally, since there is no warming up or cooling down period required, the RZ470 can be turned on and off immediately and as many times as you like.
These features obviously appeal to professional installations in places such as museums for example, where the projector can be left on all day and not require any maintenance - handy if it's in a difficult to access location. However these advantages would also work within a home cinema installation and the use of a LED/Laser light source provides other benefits. The RZ470 uses a proprietary power circuit with an ultra-fast drive that switches the LED/laser on and off, eliminating the need for a colour-wheel and reducing the rainbow effect often seen on single-chip DLP projectors. There is also a heat pipe cooling system that dissipates the heat to cooling fins, thus reducing the noise level to 29dB. In addition the use of a single-chip DLP means an extremely sharp image and a sealed optical block that eliminates any issues with dust or other particles in the air. Whilst Panasonic's professional division use DLP chips in their projectors, the consumer division uses LCD panels and these can be subject to 'dust blobs' due to the fact that the optical path can't be air-tight.
Test ResultsThe RZ470 comes with a number of preset picture modes, with Cinema and Rec709 the most likely options to deliver an image that approaches industry standards. Of the two the Rec709 mode was the closest, although as the graphs below show, that term is very relative. Using a combination of the Rec709 picture mode and the Warm colour temperature option, we discovered that the greyscale was reasonably accurate,with a slight deficit in red that resulted in errors that were on the edge of visible perception. The gamma was also very accurate and was hitting our 2.2 target. When it came to the colour gamut things weren't quite as good, with an excess of green pulling yellow and cyan away from their ordinates. Interestingly, the measurements are very similar to those we took on the Acer K750, which suggests this is a characteristic of the LED/Laser light source.
The RZ470 includes a two-point white balance control which allowed us to accurately calibrate the greyscale, delivering errors that were below one in most cases. There was still a minor excess of green at 10IRE but the gamma was spot on and overall this is a reference performance from the RZ470.
Unfortunately we were unable to correct the colour gamut as easily, despite trying the Colour Matching feature as a form of alternative colour management system. This control is designed to match one projector with another but we found activation resulted in a much wider colour gamut that was impossible to bring back to Rec.709. It also caused the greyscale to change and once again we were unable to correct it. So overall we felt that the combination of the Rec709 Picture Mode and the calibrated greyscale and gamma, provided the best compromise. It wasn't ideal and we suspect that the high luminance for green and the large hue error might represent limitations in the current technology. In actual viewing there was a slight green caste to images and the greens and blues appeared quite saturated but overall the colours were still very watchable.
If there is one area where DLP projectors tend to have a weakness, it is in terms of native black levels, and so it proved with the RZ470. The better the blacks on a projector, the better the dynamic range and the more solid and film-like the image appears. The blacks on the RZ470 were mediocre, appearing more like a very dark grey and this detracted from the impact of the image, robbing it of some of its dynamic range. Panasonic claim an on/off contrast ratio of 20,000:1 but we actually measured it nearer to 1,740:1 after calibration. The projector's inherent brightness was obviously offsetting the weak native blacks, so at least in bright scenes it retained some impact. DLP projectors often perform better when it comes to ANSI contrast ratio measurements and here the K750 measured 800:1, so in terms of even intra-frame dynamic range it wasn't as bad. Shadow detail was also limited, although we were able to improve this by setting the Brightness control higher because in its default setting it was crushing the blacks.
The video processing on the RZ470 was very good and using the SMPTE 133 test pattern it was able to correctly scale the standard definition images without any loss of detail or unwanted ringing. With the video deinterlacing test the results were also very impressive, with very little jaggies on the rotating line. In the motion adaptive deinterlacing test the performance was also good, with jaggies only appearing on the bottom line. In the cadence tests the RZ470 correctly detected both the 2:3 (NTSC - USA/Japan) format and the 2:2 (PAL - European) format. It also had no problems displaying mixed film material with scrolling video text and was able to reproduce the text without any shredding or blurring. The RZ470 also performed well with high definition content and with the player set to 1080i the projector correctly deinterlaced and displayed both the video and film resolution tests and showed excellent scaling and filtering performance, as well as good resolution enhancement. With 1080i material the projector had no difficulties in showing video text overlaid on film based material and also handled 24p content without any problems. In fact the only test that RZ470 had problems with was the peaks for the luma channels of the three primary colours, where all the colours were clipping.
Picture Quality - 2DDespite the fact that the RZ470 is primarily aimed at the professional projector market, we actually found that it was capable of producing a very watchable picture in a home environment. Whilst not perfect, it is likely that most people won't even notice some of the errors in colour and will probably like the saturated image. The superb greyscale and gamma performance, certainly help to provide a solid base on which the rest of the image can be built. The excellent video processing also helped and upscaled standard definition content looked good with no obvious artefacts, whilst high definition content looked very impressive.
Since the RZ470 is a single chip DLP projector, it inherits all the benefits of that technology and some of the disadvantages. The use of a single chip means perfect convergence, so thanks to the decent quality lens images looked very detailed. This was especially true of high definition content, where the projector could take advantage of the increased resolution. The downside was that the sharp image could expose any weaknesses in source material. As we would expect from a DLP projector it also handled motion superbly, with 24p material in particular showing movement that was smooth and judder free. This is one of the major strengths of DLP and the RZ470 performed admirably, reproducing movement and camera pans with clarity and detail. There was none of the smearing or loss of detail that you will often get with LCD based projectors.
The big selling point of the RZ470 is the LED/Laser hybrid light source and Panasonic's claims of 3,500 lumens certainly weren't exaggerated. We could easily get over 1,000 lumens, even in the low power mode, which is more than enough for our screen and pitch black home cinema. The RZ470 and plenty of horsepower left for 3D or larger screens and less ideal environments. It's also worth remembering that the LED/Laser hybrid light source won't dim like a regular bulb, so the RZ470 should be able to maintain these levels of brightness during its lifetime. The other advantage of using a LED/Laser hybrid light source with a DLP projector is that is should eliminate rainbows and whilst this is mostly true, people that are very susceptible might still see them occasionally.
Aside from the colour accuracy, the only other weakness was in terms of the black levels and shadow detail, both of which were quite poor. This meant that despite the brightness of the RZ470, the weak blacks robbed the projected image of some of its dynamic range and thus its impact. With darker scenes this was especially true and shadow detail was often obscured but then, the RZ470 has primarily been designed for use in brightly lit environments. We watched a number of new arrivals on the RZ470 such as Star Trek Into Darkness, Iron Man 3 and Fast & the Furious 6. Overall the images produced by the Panasonic were excellent, although there was a slight green caste to the colours and as mentioned the blacks let the side down at times.
Picture Quality - 3DThe RZ470 is a 3D capable projector but unfortunately in the time that we had the sample for review we were unable to test this feature. The HDMI input supports 3D and the RZ470 also supports DLP Link with a built-in transmitter, although you can also use an external one if necessary. Panasonic use third party glasses, which is why they were unable to provide any for review and we were unable to source some ourselves in the review time allotted to us. However given the inherent brightness of the RZ470 and given how well DLP projectors generally perform with 3D because of their faster response times, we would expect the RZ470 to deliver an excellent 3D performance.
- LED/Laser light source
- Instant on/off
- Consistent performance
- 20,000 hours lifespan
- Reference greyscale after calibration
- Very bright
- Excellent video processing
- Great motion handling
- Detailed image
- Attractive price
- Poor black levels
- Over-saturated colour gamut
- Aimed at professional market
Panasonic Professional PT-RZ470EAK 3D LED/Laser Hybrid Projector ReviewThe RZ470's design clearly reflects its intended purpose, with a fairly utilitarian and robust chassis. The centrally mounted lens aids installation, as does the joystick-based lens shift but that, plus the manual zoom and focus, precludes any for a lens memory feature. There is a fairly basic remote control and on the left hand side are a set of connections, with one each for all the main input types. The RZ470 is a 3D projector but Panasonic don't make the glasses, so those will need to be bought from a third party. The setup was quite straightforward and the menu system is clear and concise, with extensive features designed for use in the professional market.
The RZ470 is certainly bright, putting out enough light to fill our review screen, even in the low power mode. As a result it can handle some very large screen sizes and would be ideal for mitigating the dimming nature of 3D glasses. Despite this brightness, the absence of a bulb means that the RZ470 is quite quiet, which is useful in an average home cinema environment. The best out-of-the-box setting delivered a reasonably accurate greyscale and gamma, although this could be calibrated to a reference performance with the two-point white balance. Despite the picture mode being called 'Rec709', the colour gamut was rather inaccurate, with an excess of green in particular. We were unable to correct this with any of the picture controls available and suspect this may be a limitation of the technology.
As a result of the over saturated colour gamut, images did have a slight green caste to them, although overall the performance was actually quite good. As we would expect from a DLP projector, the precision and detail was excellent, as was the motion handling and the video processing. The reference greyscale and gamma also helped, although the RZ470 suffered from some very weak blacks and limited shadow detail. The flip side was that the projector's brightness gave images plenty of impact and although we couldn't test the 3D, the combination of light output and DLP's inherent strength in this area should result in an impressive performance.
The Panasonic PT-RZ470 is certainly a great projector for the professional market in which it will mainly be used and the LED/Laser light source provides a possible glimpse of the future. However the technology will need to be improved in terms of colour accuracy and black levels before it becomes a serious contender for home cinema implementation.
Contrast/Dynamic Range/Black levels5
2D Picture Quality8
3D Picture Quality9
Ease Of Use7
Value For Money7
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