Shoot Review: Panasonic AG-HPX170

Panasonic’s AG-HPX170 delivers groundbreaking new usability features in several key areas, along with excellent color and relatively noise-free video. While the lack of a tape drive makes the camcorder about 20 percent lighter than the popular AG-HVX200 that precedes it, the HPX170 thereby limits you to P2 storage. This is fine for ENG, indie films, and other similar productions, but solid-state media can get pricey and/or inconvenient for event or long-form production shooters. For the record, the camera will retail for $5,695 with a 16GB P2 card, Barry Green’s new HPX book, and a very generous five-year warranty.

In terms of hardware specs, the AG-HPX170 is smaller and about 1.4lbs. lighter than the HVX200, while using the same 1/3in. progressive 16:9 3CCDs as the HVX200A. The form factor is familiar, with a .44in. color viewfinder with 235,000 pixels in the back and a 3.5in., 235,000-pixel color LCD on the left. Most controls are on the left, with manual zoom ring and switchable focus/iris ring on the front. The lens is a Leica Dicomar 13X relatively wide-angle lens with a focal length of 3.9mm to 51mm, for a 28mm-to-364mm zoom, which is a 35mm equivalent.

The HPX170 offers an onboard stereo mic and two XLR inputs — mic or line compatible — with phantom power and a headphone jack for monitoring. You can record in 21 modes in DVCPRO HD at 1080/60i, 1080/30p over 60i, 1080/24p over 60i, 1080/24pA over 60i, 720/60p, 720p/30p over 60p, 720p/24p over 60p, 720p/30pN, and 720p/24pN. In DVCPRO 50, DVCPRO, and DV, you can record at 480i/60i, 480i/30p over 60i, 480i/24p over 60i, and 480i/24pA over 60i. In these descriptions, the “N” designation means native recording, recording only the frames required — be it 24, 30, or any of the variable frame rates. The “pA” stands for advance pulldown (2:3:3:2), which allows for an easier extraction for a 24p timeline of the progressive-segmented frames that are recorded in the interlaced standards of 1080 and 480. In 720p, the camera supports variable frame rates of 12/15/18/20/21/22/24/25/26/27/28/30/32/34/36/40/44/48/54/60fps.

In terms of storage, the HPX170 can accept 4GB to 32GB P2 cards, and it will work with 64GB cards when available. The maximum size for individual files on the cards is 4GB, and the camera automatically splits any scenes larger than 4GB. As a rule of thumb, full-bandwidth DVCPRO HD consumes about 1GB per minute, while DV25 consumes 1GB every 4 minutes.

Video output includes SDI, component, and composite with FireWire and USB output for those who don’t have a handy PC card slot. On the back are camera remote connectors for remote iris/focus and record start/stop controls. All menu and playback controls are on the top left above the LCD panel. You drive the menu and control playback with an accessible and easy-to-control four-way joystick.

With this as background, let’s have a look at the camera’s major new features.

hm170-1.jpgFigure 1. It’s simple to attain correct exposure and white balance with the HPX170. The camera’s 3.5in., 235,000-pixel LCD panel includes a waveform monitor (pictured), a vectorscope, and two levels of zebra stripes.

Waveform monitor/vectorscope

Let’s face it: Getting exposure and white balance correct is more than half the battle. The HPX170 makes it simple by including a waveform monitor and vectorscope, as well as two levels of zebra stripes. Better yet, the two scopes show up only on the LCD panel, not on the viewfinder, and they remain visible while you’re recording. This lets you simultaneously monitor exposure and focus, frame, and shoot with ease.

You access the scopes via a button on the lower-left body panel, clicking once for waveform, twice for vectorscope, and three times to close them both. If you’re not a big fan of one scope or the other, you can configure it to your preference, and the switch will simply enable and disable the remaining scope.

There’s also a zebra button that lets you toggle between the two configurable settings (I used 80 and 100), so you can check skin exposure and whites, and then clear the screen.

When markers are enabled, the camera also displays the luminance value in the center of the shot. This was particularly useful during white-balancing, because if the value wasn’t at or near 99+ (the maximum), I knew lighting was probably inadequate. Overall, if you blow exposure with this camera, it’s not because you don’t have the tools. It’s because you weren’t paying attention.

Focus assist

One of the curses of shooting in HD is that often you have to focus on the same relatively low-resolution LCD panel (or tiny viewfinder) that you used for SD. Many HD camcorders offer a zoom focus assist, which helps, but even that is usually unavailable while you’re actually recording — as if your subjects never move while the red light’s on. In contrast, HPX170 offers a zoom focus assist with two focus guides that all remain in view while you’re recording, as shown in Figure 2.

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Figure 2. The AG-HPX170 offers a zoom focus assist with two focus guides—a focus bar and a histogram—that remain on while you’re a recording.

You enable the focus assist via a button located just above the auto/manual focus toggle. In this mode, the camera displays a zoomed view in the center of the LCD and EVF panels, along with a focus bar on the bottom and histogram to the upper right. Working with the bar is simple; as you improve your focus, the bar extends to the right, shortening if you move beyond optimal focus. The histogram is more confusing and less useful to me; fortunately, you can disable it in the camcorder’s menu system and just display the zoomed region and bar.

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Figure 3. This image has too much contrast in the face, but you have to love the narrow depth of field the HPX170 provides.

The HPX170 also features Panasonic’s Manual Focus Assist feature. Essentially, with this mode enabled, you manually focus with the focus ring. Once you get close enough for the camera to identify your focus target, it takes over and makes the final adjustments, which you can track via tiny motions in the focus bar.

You can disable Manual Focus Assist if it interferes with your true focus target or artistic goals, but for most day-to-day shooting, it’s a godsend, even if only to relieve that last bit of focus angst that seems inherent to shooting in HD. Other focus aids include a peaking display and an Push Auto button that engages the autofocus mechanism while pressed and then releases back to manual focus.

Figure 3 shows the final result. I considered not showing this image because the face is too dark in the shadows, but I wanted to show the HPX170’s depth of field with the aperture opened to the max and the 1/16 ND filter engaged. (There are two other ND settings: 1/4 and 1/64.) To set up the shot, the subject was about 20ft. away from the background flowers and the camera was about 20ft. from her. While HPX170’s depth of field won’t challenge that of the Red Digital Cinema Red One camera anytime soon, it felt shallower than most of the 1/3in. CCD camcorders I’ve used in the past. Those chasing a narrower depth of field via a 35mm lens adapter will be happy to know that the HPX170 has an image-flip function, so you won’t need a fancy contraption or other hack to preview right side up.

Roni, Patsi and Donna Stoneman perform at the Blue Ridge Music Center

Figure 4. Roni, Patsi and Donna Stoneman, the first family of country music, perform at the Blue Ridge Music Center.

Real-world testing

Beyond tests in my yard and lab (discussed later), I also took the HPX170 on a local concert shoot. Leveraging the HPX170’s P2 card hot-swapping feature, I shot two 1-hour sets in DVCPRO HD with two 16GB P2 cards. DVCPRO HD consumes about 1GB per minute, so I had to offload each card to my HP Compaq 8710w notebook while recording to the other, which took about 12 minutes. Reformatting the drive was faster than deleting the data, so I used Panasonic’s P2 viewer to format, then I popped the P2 card back into the camera with 2 to 3 minutes to spare.

This approach only works if you have power for the notebook and an assistant to copy and format the card. Otherwise, you have to buy sufficient cards for the entire show, which gets pricey at about $800 for 16GB cards and $1,500 for 32GB cards. Obviously these requirements change with the format you’re shooting. DV requires about a fourth the bit rate of DVCPRO HD, so you can get more than 70 minutes of DV on a 16GB card.

Beyond the P2 shuffle, the HPX170 performed well paired with my Canon XH A1. However, Canon’s 20X optical zoom made it better suited for close-up work than the HPX170’s 13X zoom. On the other hand, when shots contained the same general content, Panasonic’s video had better contrast, more accurate color, and less noise; although, the Canon video seemed slightly more detailed. This made me really curious to see the results of comparative resolution-chart testing.

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Figure 5. Comparing the image quality of the HPX170 and Canon XH A1.

Lab testing

Next, it was to the labs, where I compared the HPX170 to the XH A1 using DSC Labs’ CamAlign ChromaDuMonde chart. My primary focus was on the resolution of video produced by each camcorder. The XH A1 test footage presented superior detail in both the horizontal and vertical axis.

What would account for this? There are three factors that impact image detail, as shown in Table 1. I discussed the latter two in detail in the Sept. 22 issue of Affordable HD, where I found that HDV had a very slight advantage in detail retention and sharpness over DVCPRO HD, but nothing that viewers could possibly notice in real-world videos. Briefly, in these tests, I shot the resolution chart shown in Figure 5 with an 8-megapixel digital SLR camera and converted that to a pristine, uncompressed 1920×1080 video file.

Then, using Rhozet’s Carbon Coder, I rendered the test file into DVCPRO HD and HDV formats, which subsampled the video down to the storage resolution shown in Table 1, and applied the noted compression techniques. When I decompressed and compared the output of the two formats, they were virtually identical, leading to the conclusion that to the extent that there were any substantive quality difference between the HPX170 and XH A1, they were likely CCD-related, not format-related.

In this regard, in terms of pixel count, the HPX170 uses three 1/3in. CCDs with 960×540 native pixels, scaled to the storage resolution via a technology called pixel shifting. In contrast, Canon uses three 1/3in. CCDs that capture at the native resolution of the storage format, no interpolation necessary.

Much has been written about the effectiveness (or lack thereof) of pixel shifting and similar techniques to improve the resolution of relatively low-pixel count CCDs, and I have no comment on that one way or the other. I will say that the XH A1 is the only camcorder I’ve tested with sufficient CCD pixels to capture at the native resolution of its storage format, and that no other camcorder that I’ve tested has equaled its output resolution. Obviously, this is why I use it for comparison purposes.

That said, I’ll note that very few shooters get paid to shoot and produce resolution charts, and that when it comes to overall video quality, resolution is only one factor. In all comparisons, the HPX170 exhibited less noise than the XH A1 and produced a brighter image with noticeably better contrast and more vivid colors. Viewed from typical television or movie distances, the HPX170 image was clearly more impressive.

I tested with the HPX170 set in Video Camera mode (as opposed to Film Camera mode) with Gamma set to HD Normal and all other scene settings set to zero. I did retest with Detail boosted, but I found no significant difference in resolution. I also tested with increasing levels of Dynamic Range Stretch (DRS), which helped improve the contrast in the image, but not the resolution.

These options highlight the sheer configurability of the HPX170, with multiple useful presets that you can modify and save. As with the HVX200A, Panasonic will produce different scene files with different looks that you can download from its website. If you’re shooting a project that needs a consistent look and feel, you’ll find these presets and the simple ability to customize and save your own invaluable.

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Table 1: Comparing the primary quality-related features of the HPX170 and Canon XH A1.

Overall, the HPX170 is ideal for multiple markets, with the exception of the budget event shooter. ENG and similar fast-twitch shooters will adore the waveform and focus aids. Independent filmmakers and others who painstakingly craft their images will love the unit’s comprehensive configurability. Everyone will love the video’s vibrant colors and sharp contrast, as well as the speed and convenience of P2 cards.

The HPX170 sets a usability bar that you’ll use to judge all future camcorders. If you test drive this baby, you’ll never buy another camcorder without a waveform, and if your current camcorder disables its HD focus assist (such as it is) during recording, you’ll be grumbling under your breath every time you shoot.

About Jan Ozer

I help companies train new technical hires in streaming media-related positions; I also help companies optimize their codec selections and encoding stacks, and evaluate new encoders and codecs.

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