Panasonic GH5S Field Test Part I

Is the GH5S the new low-light king?

by Jaron Schneider | Posted 01/08/2018


With the GH5S, Panasonic makes vast improvements to an already excellent camera

The Panasonic GH5 is already one of the best video cameras you can purchase, especially once you consider its size and low cost. Its ability to produce extremely high quality video in multiple formats, the inclusion of ultra-high definition 4Kp60 capture, the improved ISO performance and the continued excellence of its battery life (which has been a hallmark of the GH series of late) made for a truly excellent video camera.

But what if I told you it could be improved. And not just a little, but a lot?

But first, the minor changes

Before we get into the major things that make the GH5S different from the GH5, I wanted to first mention a few small things. On the new GH5S, Panasonic added some red embellishments to the camera that 1) look awesome (red is my favorite color, so I may be biased) and 2) quickly and effectively differentiate it from the GH5. The record button was also lightly modified, and now actually has the "€œREC" letters printed on the giant red button.

Panasonic also slightly modified a couple of the quick menus to show the vast number of recording modes a bit more effectively. I like the new layout, which shows different options in a paginated format and organized by likeness.

Finally, and this is actually more than a minor change, the GH5S actually has a different crop factor than the GH5. The GH5S is actually noticeably wider than the GH5 with the same lens, same camera settings, and same positioning. I'm not sure what the actual crop factor is at this time, but just know that it is indeed wider.

Making excellent into extraordinary

The idea of improving on excellent is the angle that Panasonic took when they showed us the newly announced GH5S. They seem to have done the impossible, and created a camera with a Micro Four Thirds sensor that can out-perform full-frame sensors in ISO performance. Panasonic has turned much of the logic of opting for a full-frame video camera like a Sony A7S II or a Canon 1DX Mark II on its head, and created a product that can give both a serious run for their money.

In order to achieve vastly improved sensitivity, Panasonic dropped the resolution down to just 10.2 megapixels with what they call their Digital MOS Sensor with Dual Native ISO Technology, paired to a Venus Engine 10 image processor. The result is a digital imager that can "faithfully reproduce even the dark parts of the image," with a new ISO range of 80 through 204,800. This is dramatically larger than the original GH5, which saw its ISO range stop at 12,800.

And the thing is, the GH5 wasn't even bad at 12,800. The footage produced at its max ISO was and continues to be completely acceptable and usable. The GH5S just takes what was good, and makes it even better.

Side by side at ISO 12,800, the GH5 and GH5S both produce excellent video. You can see above that at 4Kp60, both clips are very clean and look quite good. But the GH5S just looks...better. Lines are cleaner and more defined, and the blurriness that tends to start to show at high ISOs on any sensor doesn't really exist at all on the GH5S like it does on the GH5. It's one thing to improve on an under-realized feature (like the ISO performance on the GH4 compared to the GH5). It's entirely another thing, and one worthy of significant praise, to choose to improve on something already excellent. That is what Panasonic did here with the GH5S.

What's even more impressive is how the GH5S compares to a full-frame camera like the 1DX Mark II. Now, the 1DX II isn't known as a low light camera by any means, but one of the major selling points of a full-frame sensor is better low-light performance than smaller sensors. I don't think anyone would have thought we would be comparing a Micro Four Thirds sensor to a full frame and really debating which did better, but here we are.

Honestly, video from the GH5 actually looks better than the 1DX II, but the GH5S is on a whole other level. You can see some noise appear on the GH5 and quite a bit is evident on the 1DX II, but there is none (really, none visible at all) on the GH5S. It looks as clean as a shot I would expect at something like 400 or 800 ISO; it's that good. 12,800 is the max video ISO for the 1DX II, and same for the GH5. But the GH5S doesn't stop there. Clean performance at 12,800 is already extremely impressive, but what about at even higher ISOs?

The GH5S introduces four new higher-end ISO settings (and adds ISO 80 on the low end), but how many of those new ISO settings are usable? With the addition of ISO 25,600, 51,200, and two expanded ISOs of High 102,400 and High 204,800, you're going to find that three of the four are actually usable, and two of the four are in the "€œexcellent" category.

As high as ISO 25,600, there is very little noise and the end result is extremely clean. I'm very impressed with the performance at 25,600 considering it's two stops more than I can achieve with either the 1DX II or the GH5. ISO 51,200 is starting to look like the noise level we saw from the Canon 1DX II at ISO 12,800, so it's acceptable but not "€œclean." The two "€œHigh" ISO settings of 102,400 and 204,800 are pretty noisy, muddy and overall not great. I would not recommend using the ISO that high unless all you care about is capturing a scene, not capturing a scene well. And you know what? Sometimes it's better to have some footage than no footage, and in those cases you can rely on the GH5S to pretty much see in the dark.

Shockingly good ISO performance for such a small sensor

Editor's note: This section has been updated to reflect new footage captured with the A7S II. Originally we claimed the GH5S performed better at high ISOs than did the A7S II, but that was based on incorrectly comparing resampled still images from the A7S II with 4K video frame grabs from the GH5S. Comparing apples to apples with video grabs from both cameras, the GH5S still does surprisingly well up to about ISO 6400, but beyond that the Sony's larger sensor and dynamic noise reduction catapults their camera's capabilities far beyond what we expected, and changed our opinion in the comparison. Likewise, the A7S II's full-frame sensor leads it to do much better shooting high-ISO still images as well, although the GH5S does deliver surprisingly good images for a Micro Four Thirds camera.

But neither the GH5 nor the 1DX II are considered "low light cameras." The GH5S appears to want to be considered as such, so it is only fair to compare to the only camera that has been hailed as king of that segment since its inception: the Sony A7S II.

For the best idea of how they performed against one another, I recommend watching the video above. Otherwise, below are some comparisons between the two cameras (Click images to see them at full resolution).

Though the GH5S performs extremely well and even hangs with the A7S II up until ISO 6400, the Sony begins to pull away after that. At ISO 12800, the GH5S starts to show muddy colors and the noise grain is larger than that on the A7S II. This trend continues up until neither camera is useful. I found that the GH5S is no longer performing at a "usable" level at ISO 51200, and the A7S II is no longer good enough at 102400. So, not only is the A7S II able to be used at one more stop of ISO, it also looks better than the GH5 at every level past 6400.

When examining the two cameras, the A7S II appears to be a bit less saturated than the GH5S, and that is much more noticeable the higher the ISO we go. Low saturation is a good way to hide ISO noise, but I'm not prepared to say that's the reason the A7S II looks so much better. Sure, it's less saturated, but the size of the noise grain is much smaller than that of the GH5S, and overall the sharpness is better on the A7S II. So while it is less saturated, that's not the whole reason why the A7S II look better here.

That's not to say the GH5S is bad. It's actually outstanding, and looks much better than just about any other video camera it could be compared to in its class other than the A7S II. It can absolutely compete with other video cameras and is usable at a much higher ISO than many shooters are going to be used to, provided they don't already own the A7S II.

But that's not all

The big story surrounding the GH5S is going to be the ISO performance, but there have been other changes to the camera as well. The camera can record at an internal 400 MBPS All-Intra format out of the box, which the GH5 was able to do only after a firmware update last fall. Additionally, V-Log, which is normally an additional fee, has been included in the GH5S as part of the package.

The GH5S can now also record up to 10x slow motion video in 1080p. It can also shoot anamorphic and desqueeze that footage on a monitor all through the camera's firmware.

The GH5S is the first camera in its class capable of recording Cinema 4K (4096x2160) in 60p. While the GH5 can already do so in UHD, the GH5S adds the additional pixels in Cinema 4K. Additionally, Panasonic also added C4Kp30 in both 8 and 10 bit, which are new when compared to the GH5.

Making sacrifices for ISO superiority

In order to achieve the new recording options like Cinema 4K at 60 frames per second and the new low-light performance, Panasonic had to make some sacrifices. For example, they reduced the total photo megapixel output of the sensor to 10.2MP. This reduction also means that the GH5S cannot perform Panasonic's normally highly-touted 6K Photo. Additionally, Panasonic removed in-body image stabilization in the GH5S, meaning if you want stabilization you'll have to rely on the lens.

That last bit about the removal of IBIS puts this camera in a funny place for me. Though from a pure image-making perspective it's superior to the GH5, losing IBIS removes part of what makes the GH5 such an excellent camera.

You won't find many GH5 owners who will be upset to find that the camera only takes 10-megapixel images, since those who love the GH5 don't love it for its photos. This is a video-centric camera, and the fact it takes photos really is secondary. In that same vein, losing 6K photos is also something many GH5 owners will be ok with if it means getting two more clean stops of ISO performance and greater flexibility with recording options.

But where you will see current GH5 owners draw the line is losing the in-body stabilization. For documentary shooters or run-and-gun videographers, IBIS is a huge deal. It makes shooting hand held so much easier and the IBIS in the GH5 is excellent.

So who is this for?

Looking at the GH5S, it's hard to say exactly who this camera is for. Side by side with the GH5, it's better in nearly every way. But then when you realize that with the GH5S you lose IBIS, suddenly the conversation shifts. Is it more important to have good ISO and IBIS, or excellent ISO and no IBIS?

When it comes down to it, the folks who will be more inclined to purchase the GH5S are those who already own the GH5. It's the camera to get out when you really need to push the limits of current sensor tech. It's not a replacement for the GH5, but an enhancement. And part of me thinks that's a good thing, and the other part of me thinks that's a missed opportunity.

Because it's one thing to upset the people who just bought the GH5 less than a year ago by introducing one that's better, but it's another to force those same people to buy two cameras instead of one. I'm not sure which is worse.

Final takeaways

I'm still trying to wrap my head around the technology that Panasonic packed into the GH5S, especially with its incredible low light, high ISO performance. I've been pretty much resigned to the fact that my smaller sensor cameras would always be far behind in performance when compared to full-frame cameras, but the GH5S has completely turned my reality on its head. This is one of the best video cameras you can buy today, and basically the best video camera at or under $2,500 (the closest competitor camera is the original GH5, and again it depends on what you value more: ISO or IBIS). The $500 price bump for the "S" is absolutely worth it, and the camera is a total steal at US$2,500. I can't think of any other video camera that can do as much as the GH5S that has that kind of value. It's straight up cheap.

This is an excellent camera, and if you already were a fan of Panasonic, you'll find a lot to love in the GH5S.


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