G7 noise?

J

Josh800

Member
Hey all,

I just purchased the G7 and have been testing it out the last couple days. I noticed in most of my shots a type of grainy noise in parts of the image, especially parts out of focus. I wondered if this was my just the look of my lenses or if the camera had bad gain or if this was just a low quality codec in the G7.

Am wondering if the camera is a keeper, and would appreciate any feedback.

Thanks!
- Josh


First shot:
* The noise I'm looking at can be seen well in the hair, particularly on the left side.
14-140 kit lenses
Picture Mode: Standard
iso: 800
autofocus: on
Mp4, 4K, 100Mbps


Second Shot:
This gives a good view of the noise, especially around the table and computer screen.
14-140 kit lenses
Picture Mode: Standard
iso: ?
autofocus: on
Mp4, 4K, 100Mbps


Both shots are cropped.

UPDATE: Here's the files on dropbox in higher resolution:

https://www.dropbox.com/s/4lcsjgczn6pgdp3/shot1a.png?dl=0
https://www.dropbox.com/s/fks0anoji32gb9j/shot 2.png?dl=0
 
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I see no noise, image tones in the areas you point to look quite normal to me. A common problem is that monitors often come out of the box with sharpening, contrast, and brightness set too high. Thats the way the manufacturers think we like them and the slightest bit of oversharpening can create the impression of noise where there is little or none.

The cure is to properly adjust/calibrate your monitor. This can be done by eye using monitor calibration images you can download from the web. Many have color scales as well as a grey scale.
 
Thanks Bruce for that info and suggestion. This seems like it may be more than a monitor issue, but I should check my calibration and make sure.

Also, I've edited the original post with the links to the images on Dropbox in higher resolution.
 
For the same generation of camera sensor, the image noise level is directly related to the sensor size. The "Rule of Thumb" for stills is that APS-C is 1 stop worse than Full Frame, and that M 4/3 is 1 stop worse yet again. "All else being equal." And, all else being equal, that also applies to video.

While everyone has different standards for the noise level they find acceptable, I find that is pretty much true with the cameras that I have used.

I shoot a lot of events, both stills and video, in low light. I also use multiple cameras per event- 2 DSLR's for stills, and 2-3 cameras for video.

For me, the limit for my Nikon D810 full frame (and my D750 last year), is about ISO 6400, for stills and video. I will shoot my APS-C cameras (Nikon D5300, Sony A6000, Canon 7DII) up to ISO 3200, and my limit for M 4/3 (Panasonic G7, GH4) is ISO 1600.

+++

Those ISO numbers are about 1 stop higher than the DxO "Sports" ISO rating for stills. I find those ISO's acceptable for stage events/ performances, but I wouldn't go that high for daylight events or portraits, where people "expect" a bit better quality.

And while there is more variance from camera to camera with video quality- color and resolution- in general the same relationship holds.

+++

Note that when you are at the margins, that 1 extra stop costs a lot of extra money! At events, I am at my minimum 1/100 second shutter speed for stills, and shooting wide open at 2.8 on my zooms.

So, for example, I bought a used Nikon D810 a few weeks ago for $2,100. I also paid $1,400 for a Nikon 24-70 2.8, for a total for the camera and lens of $3,500. If I was willing to "settle" for APS-C quality, my Nikon D5500 was $500, and I bought the Sigma 17-50 2.8 OS (24-70 2.8 equivalent), a really great lens, for $300 new, for a total of $800. So it cost me about 4x as much to get that 1 extra stop with full frame.

That higher quality is why people still "bother" to shoot a big, heavy DSLR like the D810, instead of a Panasonic G7 or similar, when you have to start to crank the ISO. Or even at base ISO at times, for that larger sensor "look." Depending on what kind of images you are making.

Now, you can do a few things to make the G7 more usable. First, ditch the slow kit zoom, and buy a Panasonic 12-35 2.8, or a Panasonic 25 mm 1.7 prime. If that isn't "enough", you could go to a Sigma 18-35 1.8 and a Speedbooster. Of course, you would need to be willing to shoot close to wide open for that to help. Then shoot in 4K and downsize to 1080 in post, to reduce the noise in the final image. And go to software reduction in post, like Neat Image or similar.

Or buy a Sony A7RII or A7SII. Then add an Atomos 4K external recorder if you still aren't happy, or get a Canopn 5D3 and shoot in Raw with Magic Lantern, etc. There is always a cost for the higher quality!

Good luck!
 
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I'm struggling to see much noise in the shot of the boy - perhaps its more evident when watching the video clip, but like Bruce I'm inclined to say look first on a different monitor.

My G7 has much improved noise over my previous GH2 and G6.
 
Thanks all for the quick replies. I went ahead and checked the video on two other screens and got the same noise, so I don't think the screen is the issue.

What I'm seeing is a sandy sort of noise, which looks to be gain noise. I'm thinking most viewers won't really notice it, especially if I downsize to HD.

- Josh
 
Josh800 said:
Thanks Bruce for that info and suggestion. This seems like it may be more than a monitor issue, but I should check my calibration and make sure.
Click to expand...

What you "do" to "check your calibration" is important. What I did on my setup (one computer showed tremendous noise and one showed none) was to first off back off on monitor sharpness (using the monitor adjustment controls) until I saw NO NOISE, then brought it back slowly until I started seeing a bit of noise. That noise was nothing but digital imaging artifacting and the sharpening was exaggerating it and turning it into noise. So I backed off until that was gone.

Then I brought contrast down a bit and brightness until I had an image that looked good but not overly bright or contrasty.

That did it. To check and be sure I still had a good image I used the following calibration images:

#1 http://www.stegmann.dk/mikkel/photo/calibration/calibration_b.jpg

Most important on #1 is to be able to see all gray scale steps on the top scale. Adjust monitor brightness and contrast to get there, USE THE MONITOR ADJUSTMENT CONTROLS, not computer adjustments. If you see noise on this image - back off sharpness, there is no noise.

#2 http://pasidor.com/Media/Calibration_Print_sRGB.jpg

On image #2 you have gray scales, too, and should be able to see all steps on them. But the image of the 3 musicians is very useful in judging how your monitor displays skin tones, clothing colors, etc. I look for clean whites in the headdress of the oriental lady and accurate representations of skin tones in all 3 of them. When I first started using this image I thought it too "bright" but my 33 years experience in studio portrait work tells me those tones are what they should be.


Josh800 said:
Also, I've edited the original post with the links to the images on Dropbox in higher resolution.
Click to expand...

I still see absolutely no noise. Now all digital imaging can have a bit of color artifacting especially in hair but I still see nothing problematic. OK, I talk about backing off sharpness, but in reality I am a sharpness "nut" and I still have more than enough sharp imaging in Photoshop and video editors. I shoot with both the GH4 and G7 in 4K.

Josh800 said:
Thanks all for the quick replies. I went ahead and checked the video on two other screens and got the same noise, so I don't think the screen is the issue.
Click to expand...

If you have the other two adjusted the same way (too much sharpening, a bit too contrasty, and a bit overly bright) you're going to see the same thing.

Josh800 said:
What I'm seeing is a sandy sort of noise, which looks to be gain noise. I'm thinking most viewers won't really notice it, especially if I downsize to HD.

- Josh
Click to expand...

The head in the first image is out of focus, the "sandy sort of noise" is likely out of focus color artifacting accentuated by oversharpening. But I don't even see anything there, there is no noise.

Back off sharpening as I outlined above, use the two calibration images to get brightness and contrast under control, then add back sharpening very gradually until you start to see what looks like noise and back off a tad.
 
G7 has been proven to have better low light ability than the gh4. Your lens has a lot to do with it. Get a fast lens and keep your ISO to a minimum. Over expose without clipping and bring it down in post. Get a speed booster and all your problems will go away. To keep your costs down I would recommend getting the MFT to Canon FD speed booster and buy some fast cheap Canon FD lenses on eBay or KEH and you'll be much more pleased than with that cheap kit lens.
 
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