Panasonic GX7 Notes: Big Noise about Noise

Reviewed by Carl Weese

[This is Part II of Carl's notes about the Panasonic GX7.
Part I is here.]

For the pictures I make with digital capture, my concerns about sensor performance, on a scale of 1–10, have put exposure range at 9 or 10 and high ISO performance down about 5. Give me a choice of an extra 1.0 EV of exposure range or an extra 1.0 EV of acceptable high ISO, and I’ll take the exposure range without hesitation. This is mainly because exposure range still lags behind negative film, while high speed results surpassed film ages ago ("ages" digitally speaking). But I didn't know how much farther they had come recently.

When I'd caught up with comments on the first GX7 post after a weekend away in NYC with dicey Internet service, I found that commenter Steve Goldenberg had asked, "Have you tried a 6400 print from this yet? They're simply astoundingly good." I had not. So I made a series of snaps in the kitchen at night, 800, 1600, 3200, 6400. Of course they're noisy at 100% view, but the increase is quite moderate as the speed goes up, and even at 6400 the noise remains random, without the repeating patterns that scream "digital noise!" After adjusting the 6400 file in ACR and reducing it for letter-size paper in Photoshop CC, I applied a modest amount of Smart Sharpen and sent it to my Epson 3880. The print is surprising. There's noise, but you really have to look for it in the highlights and mid-tones, and even in smooth darker areas it doesn't hit you over the head. If you look close enough, there is some chroma noise in shadow areas that would detract from some pictures.

Rather than comparing the GX7 to other current cameras (to which I have no access anyway) what I can compare to is B&W film used at high speed (I never used color film faster than Kodachrome 200). I went back to the RAW file, converted it to monochrome in ACR, tweaked some of the adjustments, then prepared it for letter-size printing. The noise in that print is even less noticeable.

Here's an example of what I think of as "good grain." This is Tri-X from long ago, push-developed in Acufine for exposure at E.I. 1200 (to be fair, more recent Tri-X and other films would be less grainy even when pushed to this speed, and of course you can't evaluate anything based on the web JPEG—these illustrations are just to let you get an idea of the pictures/prints I'll describe).

Isfahan, Iran, 1969

The grain is obvious in a print, but, typical of Tri-X, it's really beautiful and I think makes a positive contribution to the moody, gritty sense of the picture.

Would real world pictures made at very high ISO with the GX7 do something similar? What I found was a complete surprise. Wednesday was a dark, stormy day. I decided to go out and look for subjects that would give me an excuse to use ISO 6400.

Ansonia, CT #1, 2013

This is a really, really, dark passageway, through an old industrial complex, in a light rain under a heavy sky. I wanted a crisp picture of all this detail and texture, with lots of depth of field. Getting 200th @ ƒ/8 justified high ISO. I intended it for monochrome conversion.

Ansonia, CT #2, 2013

This is in an even darker area beneath the elevated walkway near the stairs you see in the first shot. I thought this would make a good color test, and the 6400 exposure has fallen to 100th @ ƒ/5. At this fairly close distance, keeping the railing and the bricks in focus wouldn't happen at a wide aperture like ƒ/2.

After working up the two files in ACR, then slightly downsizing to about 11x14 and applying a fairly small amount of Smart Sharpen in Photoshop CC, I printed the pair with my HP Z3200. The prints are, to quote Steve, "astounding." The noise in the mono print seems to me only the slightest bit more noticeable than the grain in a print this size from normally exposed and developed 35mm Tri-X. The color print doesn't show obvious noise unless I bury my nose in the smooth-toned bricks on the left. It's much less obvious than the grain in a Kodachrome 200 35mm transparency printed or reproduced at this size. While typing up these notes on my MacBook at the kitchen table, I've gotten up half a dozen times to walk back to the printer room and look at the pair of test prints again, to make sure I'm not imagining things. I've been aware of people's rave reviews of high ISO performance on "full frame" sensors but I had no idea things were moving to this level with smaller sensor cameras. I'm suddenly much more interested in high ISO capture than I was last week.

Now, there's a bit of a cheat going on here because these pictures have tight texture and detail everywhere, which does a good job of hiding grain or noise. Pictures with lots of smooth non-detailed areas of tone wouldn't fare so well. But I'm going to raise the upper limit on the camera's auto-ISO control.

Next time, we will get to features and camera-handling.

Carl
Website / Working Pictures blog

©2013 by Carl Weese, all rights reserved

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Comments

[Dave P]

Looking to this class of camera, has anyone seen the comparison? Fujifilm ex-2, Panasonic GX7 and Olympus EP-5? I don't think there's much to choose between them?

[psu]

The performance of smaller CCD sensors really is pretty astounding.

My E-M5 will sometimes smudge out small details at ISO 3200 to try and hide some of the grain, but it really doesn't need to.

What's even more striking to me is that I can get pictures in the dark with my phone that are probably as good or better from a "technical" standpoint (color, noise, detail) as my old D200 DSLR which was admittedly weak in the noise handling department.

You use of a Tri-X frame also reminds me that the recent Peter Turnley book mixes seemingly perfect and grainless digital black and white pictures with what looks to me like pretty classic Tri-X black and white ... and it makes me miss the look of that grain.

Not enough to go back to spilling D76 all over myself, but enough to sigh a bit.

[Mike Fewster]

It is also worth having a look at what the Sony sensors are now doing. A few years ago, I thought IBIS or OIS were "must haves" on digital cameras. Today these features have their moments but I no longer see them as essential. Just raise that ISO a little. in fact. I think a built in ND filter is arguably at least as useful now as IBIS.

[Tom Nelson]

Keep in mind that an inkjet print will have finer apparent grain than a digital photo print. I did ISO tests and printed full-size inkjets at 300ppi. Grain was almost invisible below ISO 6400. Then I made 4x6" crops and had digital prints made. While still impressive, grain was more apparent in "real" prints than inkjet prints.

[Henry Richardson]

"But I'm going to raise the upper limit on the camera's auto-ISO control."

Yes, on my m4/3 Olympus E-M5 I have the auto-ISO upper limit set to 6400.

[Stan B.]

They're making amazing little cameras these days (even though no one has yet to make a Micro 4/3 20mm(e) prime).

But I can wait... Come 2015, organic sensors are gonna launch digital invasion Part II, and today's latest and greatest will get mighty old, mighty quick. I can see the comparison photos already...

[ronin]

No doubt, mono tonal gradation of digital capture still leaves something to be desired. Something about it looks... just... somehow... artificial compared to film.

On the other hand for those who thought 160 ASA was about as fast as you wanted to go on print film... and maybe GAF 500 for the transparency daring on rare occasions... and even pushing Tri-X to 800 E.I... the possibilities of digital are amazing. Even the more modest of today's digital compacts yield amazing results compared to film when it comes to high ISO.

[Oskar Ojala]

I keep being astonished at the dynamic range my Nikon D800 can pull from raw files and believe it completely obsoletes smaller film formats on technical grounds, but smaller sensors are indeed no slouches either. Yesterday I shot in a club at ISO 1600 with my Olympus E-M5 and the color shots look really good, can't wait to make a large print.

In addition to sensor development lenses have also got much better at large apertures. I'm starting to think that this is affecting the way we make photographs.

[YS]

Yet, so many people "claim" that Four Thirds sensors cannot be used above ISO 1600 because it's too noisy.

[Cmans]

I see the "good grain" on the Mill, but I question the IQ of the camel ;-)

[NL]

I find the problem with high ISO is not noise but colors. The colors go bad quickly, as soon as ISO400 on an APS-C sensor.

[NL]

I find the problem of high ISO is color. Colors become washed out as low as ISO400 on a DX sensor. My Canon S90 has bad colors at all ISOs, including base ISO80, which I attribute to the high pixel density. I shoot my Nikon D3200 (24mp) at base ISO of 100 whenever possible, and consider all higher ISOs as a compromise similar to pushing color film. If you convert to black and white, these problems obviously go away, and digital noise actually looks a lot like film grain. For a grainy look in BW, I can shoot at max ISO12,600 on my Canon S90, and virtually any ISO on a larger-sensor camera, with acceptable artistic results.