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Shoot Review: Panasonic AG-HPX170

Oct 1, 2008 12:00 PM, Reviewer: Jan Ozer

Mulitple-market P2 camcorder sets the usability bar.

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.

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.

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.

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.

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 1920x1080 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 960x540 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.

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.

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bottomline

Company: Panasonic
www.panasonic.com/broadcast

Product: AG-HPX170

Assets: Excellent color, relatively noise-free video, includes a waveform monitor and vectorscope as well as focus assist with two focus guides.

Caveats: Limited to P2 storage, less detail than the Canon XH A1.

Demographic: ENG and similar fast-switch shooters as well as independent filmmakers.

PRICE: $5,695

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