X70 Concerns: Please tell me I'm doing something wrong

[Tim Akin]

I've been comparing the X70 with an XA20 and I'm hoping I don't have something setup right on the X70. Compared to the XA the noise at low light levels is really bad. Anything above 12dB is not good. The XA20 can go 21dB before it get's that bad.

I ahve tried the factory profiles and set one myself that looked the best and it helped but not enough.

Will the XAVC recording mode be better with handling the noise I'm seeing? It doesn't seem to matter when viewing via HDMI to a 42" Samsung LCD.

I don't have any SDXC cards yet so I can't record XAVC. I have brought the AVCHD into Vegas and I'm getting the same bad results as I'm seeing on the TV.

I'm setting both cameras up side by side and setting both to the same brightness, the way I would if I were shooting the scene, using the zebras. Both cameras look the same when comparing the exposure and brightness of the shot. X70 reds are a little more saturated, black levels look the same. The XA20 is at F2.4 / 18dB gain / shutter 60. The X70 is F4.0 / 18dB gain / shutter 60

I know the XA is doing some in camera noise reduction because the 70 does seem to show more small detail but the small detail is full of noise.

[Tim Akin]

Here's a short video test of these two cameras. I might have been to hard on the X70. I was just expecting more from that 1" sensor but when it starts at 2.8 and ramps to 3.7 when zoomed in, I guess that really puts it at a disadvantage. But I wanted to test it that way because that's how I will be using it, I don't care how they compare at the same F stop.

I played around with the settings in picture profiles but went back to profile off for the test.

AVCHD 1080 60p

Take a look and I would really like to here some opinions on this. How do you think they compare?

X70 vs XA20 Low Light Test - YouTube

[Mark Watson]

X70 has same sensor and lens as AX100 right, so I am not surprised at what you are seeing.

I haven't tried AVCHD so I recommend you get the faster cards and shoot in the higher bit rate modes.

The AX100 is better than my XF305, especially when NeatVideo noise removal is applied. I shot some very low light clips with both XF305 and AX100 at same shutter, iris, frame rate and the XF305 was okay, but the AX100 was better, not by a huge amount, but it was better and with NeatVideo, it really cleaned up much better than the XF305 clips. I also applied some Sony White Balance adjustments to both camera's clips and the Sony camera responded better there as well. I shot with 4K, 60Mbps on the Sony.
So bottom line is that in my opinion, the low light is better than what I have, but the response to post correction is much better.


Mark

[Noa Put]

As far as I know XAVC will only be better theh AVCHD on higher motion scenes with lot's of fine detail, the lower bitrate AVCHD codec will fall apart sooner showing artifacts like macroblocking but it should not have less noise.

When I shoot 4K and downscale to 1080p with my ax100 it does have an impact on the noise as that gets smaller as well so the resulting image will look more detailed and cleaner then when I would shoot at 1080p. I have compared the ax100 to my cx730 and the cx730 was also cleaner at very high iso, low light performance was about the same, only my ax100 retained much more detail at those very high iso's so like Mark also found out that if you would apply neatvideo to such an image (if it's shot in 4k and downsized) you get a remarkably sharp and clean looking shot, something I couldn't achieve with my cx730.

At the same f-stop your xa20 should perform about the same as your ax100 but since the x70 starts to ramp sooner then I think what you see in your test is what you get, if that was shot in 4K it would only be less noisy and more detailed.

[Tim Akin]

Thanks Mark and Noa. I would like to try the higher bit rate but until Sony figures out a way to upload the footage I wouldn't shoot a wedding with XAVC. I'm going to test some more today with no gain and see how clean it is compared the the XA20.

I stopped having to use Neatvideo when I sold the FX1000's and went with AC90 and XA20 and have enjoyed not having to use it so I'm not crazy about going back to it.

[Tim Akin]

Very little noise at no gain or very low gain, so that's good. High gain is only noticeable as you get closer to the monitor. I think that's what got me worried, I was standing 2' from the 42" screen when I was checking it and man it was bad. After viewing on an 60" plasma at normal distance the noise is not to noticeable, just a little worse than the XA20 though.

[Tim Akin]

One thing I'm not sure about or don't understand I guess, is in the test video, the last test where both cameras are at 0dB with lights in the room low, the noise is bad in both cameras, really bad in the X70. As the gain increases the noise actually gets better, even at 24dB.

[Ron Evans]

Maybe there is no noise reduction applied at 0 db and more is applied as the gain is increased . I know that in automatic exposure using AE shift my XR500, CX700 and NX30U will increase gain before the iris is full open. I expect this keeps the camera at its best image. Most all the time I use automatic exposure and AE shift or spot controls with these cameras and this approach may give the best performance with the X70 too. The engineers know where it performs the best and using AE shift or spot controls leaves them in control but with the user saying how dark or bright they want the image.

Using this approach you don't need any rings on the lens !!!

Ron Evans

[Tim Akin]

Gotcha, makes since. the camera would never be used that way anyway I don't think.

Looks like X70 AE shift needs to be 4 or 5 clicks from neutral, not sure what the reading is, maybe -0.7. Does that sound about right?

Yeah I really like spot meter! That's going to come in real handy.

[Ron Evans]

Yes . Settings are usually about -0.25 to -0.7 on my little Sony's most of the time. Use spot focus all the time and Lanc controllers for zoom. Don't really use the spot meter as these cameras are used mainly unattended so are set up with spot focus and left. My wife uses the NX30U for closeups and she uses spot focus all the time when re framing a shot as well as AE shift.

Ron Evans