9.03.2017

The GH5. What does it really look like at ISO 3200. One quick example shot in murky conditions.


Leslie as the evil queen in a Zach Theatre production of 
"The Lion, the Witch and the Wardrobe" for kids.

My friend, James, and I have views about camera noise performance that seem to sit on opposite sides of some spectrum of visual aesthetics. You have to beat me over the head with noise in a photograph before I protest. If I can't see noise in a file at the resolution at which I'll be using the file it just doesn't exist for me. In early days of digital the noise always consisted of color splotches and random color crap but now everyone's camera seems to deliver a nicer (to me) monochrome, film grain-like noise that effectively mimics film grain from black and white films overlaying a color file. James, on the other hand, seems to have a severe allergy nearly as strong as a deadly peanut allergy to the presence of moving noise in the shadow areas of video files; and by extension, still image files. He's usually on the search for a video camera (or still camera) that's more or less devoid of noise. 

I'm pretty happy with the general control of noise I get out of one inch sensor cameras and most micro four thirds cameras; as long as the detail and color are there. 

We've lately been having coffee and sharing resources about the GH5 camera since we are both interested in it. My interest bleeds over from video and into the photo realm. He would use the camera strictly for video production. I think the high ISO noise presented by my Sony RX10iii or Panasonic FZ2500 is quite acceptable for most productions. James considers cameras like the Sony FS-7 or A7Rii to be the more appropriate tools with which to create un-noisy video files. 

I wanted to see if I was in the self-delusion mode (happens from time to time) about the amount of noise in GH5 files at various settings so I did what I usually write about here at VSL. I took the camera out on an assignment and tested it in the kind of situation I find myself in from time to time.

I was at the Zach Theatre campus to shoot a children's play in their small, theater-in-the-round stage. It's a theater that seats about 140 people. The walls are painted black as is the high, high ceiling. Since all the productions in this auditorium are presented in the round there is no effective front fill for the lighting. It all comes from catwalks high above the stage. This means that every face has bright highlights and unfilled shadows. There is very little fill from any direction. This small auditorium will also be the last one updated to use new LED lights. The lights currently hanging from the rafters are ancient tungsten spots and floods. This means that when they are filtered heavily you can only get so much power down onto my subjects. 

While the lighting looks dramatic and fun for audiences it's not often optimal for camera work. In the film years we routinely dragged in huge amounts of flash and set up the scenes we wanted to capture and lit for them. We tried to match the "feel" of the theatrical lighting but with all the proper ratios, and an ample amount, to make slow film emulsions happy. We don't do that now. There's no time or budget to get too fancy now. 

With all this in mind I dragged a Panasonic GH5 and an Olympus 12-100mm f4.0 to shoot a dress rehearsal of the play ( without an audience; thankfully). When we got rolling I realized that my base exposure/working exposure was going to settle in at 1/125th of a second (needed to have even a chance of freezing motion) at f4.0 (my widest available f-stop) at ISO 3200. Several of the parameters are fixed. I couldn't drop below 1/125th without having too many images blurred by subject movement. I couldn't shooter at a faster aperture than f4.0 because the lens I brought doesn't have a wider aperture setting. I couldn't change the lighting. That left ISO. I started out at 1600, which I consider to be safe for the GH5 sensor. I migrated to 3200 to keep the shutter speed up.

I shot for an hour and tried a number of strategies but in the end it all boils down to the fact that sensors of various sizes and generations have various noise limits. The noise generated is also dependent on the subject matter and lighting. Even, well filled light situations seem to yield less noise while low key, unfilled lighting situations tend to pump up noise. Nailing exposure is a big help. If you have to push up the exposure in post you invariably push up the parts of the image that are most subject to noise generation. Over use of the shadow slider in Lightroom or PhotoShop will affect the noise in shadow pretty profoundly.

Here are my personal takeaways from my shoot/test yesterday: I am okay with most of the noise I saw in the files; given how the files will be used. I would not want to go above 3200 ISO in low key situations with the m4:3 sensors, even the latest 20 megapixel versions, if I could prevent it. The noise reduction controls in both programs can be very effective but take experience and trial and error to get right. The camera's implementation of noise reduction is better for generating large numbers of nicely less noisy files than trying to batch a "one size fits all" setting in post. There is a caveat to letting the Jpeg engine do your de-noising; the default NR setting in the standard profile at ISO 3200 is too aggressive and blurs too much fine detail. I back off one or two notches in the parameter settings now. 

Even in situations with ample light you can run into noise issues if you are basically underexposed. Camera meters tend to compulsively protect highlights and they do so by pulling overall exposures down by anywhere from 2/3rds stop to a full stop. Sometimes even more. Recovery costs noise. 

Finally, if you read the information about the GH5's "improvements" over previous models you'll find that the new types of noise reduction use formulas to decide whether an area in a frame is detailed or flat and the camera applies different kinds and amounts in each area. There isn't such a thing, in camera, as uniform noise reduction. Which means that sometimes the camera gets it just right and sometimes it leaves you with the question: "Dear God Camera! What were you thinking???"

My noise abatement solution for the next dark show in the all black theater? Bring fast primes! I probably could have done a good job covering the show with two lenses: the Panasonic 15mm f1.7 and the Panasonic 42.5 mm f1.2. Maybe I'd toss a 25mm f1.7 in as well. I think all of them could be used wide open which would get me either two stops more of shutter speed or the ability to shoot at ISO 800. 

It's all part of my continuing experiment with photography...


13 comments:

runbei said...

I'm delighted that you've thought deeply about this. I shoot stage events with generally good lighting. I gave up on my old Nikon V1 for this - it was nice with adequate lighting on faces, but a disaster otherwise. I'm shooting with a Canon full-frame 6D now, and I'm seeing effectively the same thing, but at much higher ISOs, I reckon due to sensor technology: how some faces look wonderful at ISO 10,000 or 12,800 while others may look shabby at 3200 to 6400, depending on the lighting.

Related to using prime lenses, I'm currently shooting virtually all stage stuff with the Canon 135mm F2 lens because I became enamored of its wonderful sharpness, and I was hoping it would do some special magic. It certainly is living up to its reputation for being sharp, but I'm finding that it's also quite contrasty for stage work, especially when I go back and compare photos shot with a 70-300 stabilized zoom. I wonder if this would be a problem with other primes? I kind of somehow (how's that for tech-smart?) get more eye-sweetness in the photos I take with the (much less sharp) zoom, go figure.

Mike Rosiak said...

What noise?

Yoram Nevo said...

Kirk, can you please mark the noise areas in these shots with red circles.
I failed to see noise, even after stretching the images full on a 24 inch screen.
BTW - the queen does not look evil at all :-)

Best regards,
Yoram

Anonymous said...

I think you might like the work of this portuguese vet.

Best regards

Artur Cola├žo

http://jorgebacelar.fineart-portugal.com/photos#topo

Anonymous said...

Kirk

As you know I'm a sucker for pictures from Zach. With that caveat in mind, I see the noise in both pictures when I blow up the pictures and look at her neck. Doesn't bother me at all. In the areas that have direct lighting, I see great color, no noise, and surprisingly good detail.

Does the GH5 have a new noise reduction algorithm? In the past, when I've seen `modern' noise in the shadows, I've been able to convince myself that I saw some small amount in lighted areas. Eyebrows, smooth areas of skin, etc. Not this time.

Makes me wonder how the G85 would do with its older 16mb sensor. For that matter, I wonder how the fz2500 would perform.

Jay

Kirk Tuck said...

Hi Jay, You should be able to find many FZ2500/Zach Theatre shots from the recent show: "In the Heights" in recent VSL blogs. The quick answer? It works pretty darn well. Also, look for stage shots done with the G85 in the tech rehearsal photos from: "Million Dollar Quartet." I used that camera a lot. Also quite good. Gee, wouldn't it be cool if some of the major camera review sites actually shot real jobs with the cameras they review? Might be novel.

ODL Designs said...

Looking pretty darn good for shooting at F4... Imagine how good it would look at f2.8 or using a 75mm f1.8 at ISO 640. Of course you could pick up a slew of those types of lenses if you sold off your Sony system.

On this subject when I shot at the houses of parliament I knew there would be some heavy hitting Nikons around, indeed there were a coupld of D4 bodies with the standard 2.8 zooms. I had my EM5.2 bodies with a 45mm and a 17mm lens, I exchanged the flexibility of a zoom for aperture size. However I also ended up far more discreet in the event not waving about a giant body and lens.

I have thought about getting a 14-35 and 35-100 f2 now that I have my EM1.2 for these types of event... but then I realize the moment I do I know Olympus or panasonic will release an up to date version :) so I stick to my primes in low light.

Just teasing, these look pretty good to me, some grain in the shadows but lots of detail in the clothing, skin and hair. I would personally do a bit of my own selective NR if I were to print a poster from this, but for normal print sizes this would look near perfect.

All the best Kirk!

FasterThanEver said...

My wife and I take wildflower and insect closeups with Panasonic G7 and G6 cameras with Olympus 60mm macro lenses. These 16 Mpixel m43 cameras offer features and effective magnification that can't be matched with larger sensor cameras. Mostly we can stay at iso 200-800 and use 1600 when it is needed. Sometimes at the beginning of the day or at the end of the day, we see subjects we want to capture. Then we use whatever iso speed we have to get get a decent shutter speed.

This gallery has photos taken in dim light in a redwood forest. We used iso 3200 and 6400 when needed to get two digit shutter speeds. Click on the small "i" under each photo to see the iso and shutter speed.

FasterThanEver said...

Sorry, here the link.

https://naturelover.smugmug.com/Nature/Fetid-adders-toungue-Forest-of

I didn't find that noise made the photos less enjoyable.

John Krumm said...

I've shot m43 and 43 for a long time, and in my experience more than noise you have to watch out for blotchy tonal transitions on skin in shots like this, between shadow and light. I don't see that here, so that's good!

Rufus said...

Interesting experience and thanks for writing on this. To my eyes, the GH5 images look great.

Mind you, had you had the "correct" body for your Olympus 12-100 lens ( namely the EM1-II that was practically the camera the lens was designed built for ) you would probably have had another stop ( maybe two ) to play with because of the EM1-II and 12-100 freaky good combination image stabilisation.

Panasonic and Olympus lenses play really well together. But I have learned that with some Oly lenses you get the maximum benefit from an Olympus body. I think this is the case with the 12-100.

Kirk Tuck said...

Ah Rufus, would that it was all so simple. The bottom line for the shutter speed was not the I.S. of the camera and lens combination but SUBJECT MOVEMENT. No use being able to handhold something at 1/10th second if the subject you are photographing is moving around, gesticulating and speaking. 1/125th is about as low as we can go and freeze the motion. At that point al the extra oomph from the IS is meaningless. I'm happy enough with the GH5+12-100 combo. It's really great.

Rufus said...

Subject movement - of course. Good point well made.

In other situations, the other-worldly IS combo is great fun. You can hand hold for long periods and get movement from cars or people juxtaposed with the stillness of your subject. I've tried it for portraits where one person stands very still while another moves - you get cool effects which until now were not even possible.