HPX250: Noisy in wide angle shots?

M

mmaller

Well-known member
Just received my new HPX250. I've been testing out the camera using various modes as well as comparing AVCI-50 vs AVCI-100
I'm new to the Panasonic systems, but it seems that when my shots are at the wide end of the zoom, they are very noisy.
I would describe it as mosquito type noise. Closer shots at the telephoto end of the zoom don't show this noise in any setting.
Maybe it's a setting that I'm overlooking. I've tried out some of the built in scene files, F3 seems to be the noisiest. Could this be because the detail setting is at +4? in the F3 setting?

I'm shooting outdoors in bright sunlight and have engaged the neutral density filters to keep the f-stop at around 4.0
Any help or suggestions would be greatly appreciated

Also

I currently have only one 64gig P2 card
I'm about to shoot a long live performance that is in excess of 3 hours and I'm trying to decide if it would be ok to shoot in AVCI-50 vs AVCI-100
Should I just bite the bullet and buy another 64gig P2 card?
 
mmaller;1986117100I currently have only one 64gig P2 card I'm about to shoot a long live performance that is in excess of 3 hours and I'm trying to decide if it would be ok to shoot in AVCI-50 vs AVCI-100 Should I just bite the bullet and buy another 64gig P2 card?[/QUOTE said:
Well if I remember right (I am traveling and dont have my book) if you are going to shoot a solid 3 hours, then you will need another 64GB card and AVCI-50. Unless you are shooting SD, then you will be fine. I also do stage performances and my next one is coming up. you can get a used 64gb card for $525. You get much more bang for your buck getting a 64GB card than a 32 or 16 (its a math thing). Unless you get a ninja or samari around $800 (HDMI 8 bit) to $1500 (SDI 10 bit), but then you can get as long as your hard drive has space, might be a better to spend on a external device? Just a thjought.

As far as the other I havent seen this yet. Also I am guessing you have barreys book and have changed you defult scene settings. The stock settings are in my option really bad.
Click to expand...
 
I used to use up-coming long-form events as a reason to invest in more cards. If you're in this for the long haul and want to be able to take on long shoots with P2, then buy more cards as needed. Soon, you'll have enough for all day shooting.
You will not see much difference with the AVCi50 or 100, don't sweat it.
Get a lens controller like Varizoom too. You'll be so happy you did.
 
I shoot long events at AVC 50. It looks fine. But yes you will need another P2 card. With 2 64 Gb cards at 100 you get about 2 hours and 20 minutes and at AVC 50 a little over 4 hours.
 
Noise at the wide end of the lens - that is very strange indeed. Could you post some frame grabs? I see no technical reason at all for that to be occuring, other than some bizarre concoction of operator error. In any case, some frame grabs might provide some clue as to what kind of noise it is and where it might be coming from.
 
I know that many people have stated there is not much of a difference between AVCI-50 vs 100, but to me this doesn't seem to be the case.
I am wondering if those that are making this judgement are looking at the footage on an external monitor?
When viewing on an external monitor (not computer screen) you can clearly see compression artifacts in the AVCI-50 footage.
Of course these compression artifacts are dependent on the content of the footage, less detailed imagery doesn't cause much of a problem but in a complex
scenes they are more obvious.
Now maybe this is due partly to the downsampling to 720p of which I have based this assessment.
Or maybe I am doing something wrong, of which I would happily accept correction.


I am going to post 2 screen grabs of footage that was shot on the HPX250 using AVCI-50 at 720p 24pn.
It is difficult to see the noise without playing the actual footage but I have posted 2 adjacent frames and if you open in an image editing app you
can toggle between the two to see the noise.

Any opinions or criticisms are completely welcome. I would love to be told I am doing something wrong.
 
Here is a dropbox link to the frame grabs that were shot at AVCI-50 720-24pn
They are pngs with no added compression.
The archive is about 4megs in size

The frames were exported from a FCP7 timeline. The footage was imported natively and placed into an Apple ProRes 422 timeline.
The footage has some minor Color Correction to account for a bad white balance.

http://dl.dropbox.com/u/29910403/HPX250 frames.zip
 
That looks like some pretty awful compression... like low quality jpeg almost. I'm going to shoot a quick test off my balcony and see what my hpx250 does.
 
Ok so these are hugely unscientific and done in a bit of a rush, but here are some samples from my hpx250. Was too lazy to drag the tripod out (it was in another building...) so the last couple of seconds of each clip are what you're looking at. Certainly doesn't seem to be the same level of noise as in your example.

My settings: Auto focus/iris. WB Preset 5.6k. Scene File F1. Basically set the camera to factory settings. ND 1/64

MXF files straight out of camera, just renamed for quick identification.

https://www.wetransfer.com/dl/3g68h...bf9c0547d9c6010e60a89686fcd193e660cd2d2f79006

Let me know if that link doesn't work. It will probably go dead in a few days.
 
Thanks for taking the time to do that quick test brynsank. The settings you had were the same in my case.
You're right, certainly not the same level of noise as my clips.
But, after watching your footage on an external monitor I can clearly see many compression artifacts around the top area of the telephone pole
It is most prevalent in the AVCI-50 720 24pn footage, less so in the ACI-50 -1080 footage, but still there.
I can also see it in the AVCI-100 720 24pn clip. Obviously the AVCI-100 1080 clip is the cleanest.

It seems to me that the downsampling to 720 by the camera is magnifying this issue.
Like you said not scientific, but certainly visible even by casual viewing.

Do you think this is a problem and shouldn't be happening, or is this just the nature of the HPX250?
I question this because my HMC40 never made me question the quality of AVCHD.
In some cases the footage from the HMC40 (not low light) is cleaner than the HPX250
 
male_man...
Just bring the files into compressor and convert to ProRes.
You need to install the AVC-Intra codec for Compressor available on Panasonic's website
 
Yes, definitely still some visible artifacting and more prevalent in the AVC-I 50 for sure. I'm really curious to know what could have been causing the compression artifacts in your case, the example you uploaded was really quite awful.
 
male_man said:
FCP doesn't recognize the MXF files. You need to transcode to a quicktime file.
Click to expand...

Male_man - no offense, but the test was done for mmaller, not you. So if you want it some other way you're going to have to ask a little nicer than that. There are many ways to read the MXF files without needing it to be transcoded for you.
 
LOL@Brynsank. Come on man! I thought this was an open forum, for the benefit of all members?

@mmaller Thanks for the info.
 
Oh, my bad! (Something got lost n the translation) I wasn't trying to issue a directive. I thought you made a mistake, but it's obvious I did. I totally forgot about compressor and the reader from panasonic(Thanks to mmaller)
 
Guys, lets try and keep this on topic and not get into any flames here.
Everyone on this forum is incredibly helpful and it's great to have this exchange available.

Thank you agin brynsank for taking the trouble to post your test,
and you're welcome male_man for the info.

I don't know why my sample was so bad, maybe someone else can offer an explanation as to why.
My main concern at this point is if there is a specific problem with my (HPX250) camera that is causing this or if it's operator error to some extent.

I will continue to test when I get the chance and post any more findings to this thread
 
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