Is color accuracy off with HMC40?

J

J.C. O'Neill

Member
I recently shot some test footage with the HMC40. The video was of a black cow with green grass. Listed below is the link to the video hosted on You Tube. I was testing the Dynamic range stretch. The color of the green grass was very reddish. I was using a white balance preset of 5600K because I was not able to manually custom white balance. I kept trying to do a manual white balance with a white card and kept getting an error message. I noticed when I closed down the Iris past open, the reddish color started to diminish. I realize the iris was not really closing, but rather the neutral density filter was engaging.

I also shot some test footage with the Dynamic Range Stretch set to off. Same reddish color in the grass. Earlier I shot some video with this same camcorder, and it gave the brown tones a reddish cast, but did not turn the green grass reddish.

For the scene file settings I used for the video - gamma curve was set to low, and all other setting were the factory default settings. The video was shot in 1080 30P.

http://www.youtube.com/watch?v=gfhYOb2T-u0

I have read all the great comments about the HMC40 on this user forum and all the great reviews about this camcorder off the B&H website. I have not had good luck with camcorder. I tested the TM700 and had good luck. I am wondering if this camcorder is not functioning properly.
 
JC,

You didn't mention how you were viewing the footage which can make a huge difference.

You didn't white balance which can make a huge difference and is probably your issue.

Your scene file was, well idunno what, but some saturation either through increasing chroma or gamma is good.

Generally DRS is something to use only if you have to, since it limits other camera shooting controls. In most circumstances, you won't need it.

From what you have said, you have no basis to blame this on the cam or bad luck. If you want to let the cam do the work, switch it to auto, and it will likely turn out fine. What you have so far is a manual cam without operator control. I suggest you start from the beginning and set up your cam; each shooting parameter will have effect. If you can't manually white balance, do an auto setup and then lock it in place.

If you got the Barry Green HMC book with your cam, read it twice. If you didn't, buy it once, then read it twice.

Welcome to DVXuser. You'll get lots of help here.

Grant
 
(1) How I was viewing the footage was just on my computer screen and then I uploaded to You Tube without any corrections

(2) I did try to white balance, but kept getting an error so I used the preset 5600K

(3) The scene file I was using was a gamma curve set to low and all other settings at the factory default levels

Please note, I got the same reddish color in the grass when I turned the DRS off. I have used the Panasonic TM700, which has the same image sensors and did not have this problem. I can see getting the wrong color if a person changed the chroma settings, but I left them at the factory default settings. I have Barry's book and have been reading it.

What's interesting is I shot some footage with this camcorder a day earlier and I did not seem to have a reddish color in the green grass, and the only difference was the white balace was on auto.
 
It looks very likely that white balance was the issue. What error message were you getting when you tried to set WB manually? Are you using the Auto mode on the camera?

Also, are you using either the waveform, marker, or zebra displays to determine exposure? This sample clip looks over exposed to me.
 
I was also in manual mode. There were zebra stripes at times . I had the zebra set to 105%. Typically I find I have to overexpose the highlights slightly to be able to get enough detail on the black animal. A video of a black animal is different than a regular picture because in most pictures a black object is not the subject -- there are just black portions of the picture.

I agree that an incorrect white balance caused the green grass to be reddish. The preset was set to 5600K because I not able to manually white balance. I kept following the directions in the manual using a white card and I kept getting the message that appears on the screen. I have used the Panasonic TM700 with the 5600k preset and colors were slightly off, but easy to fix in the Vegas Pro 10 or Edius software.

I could not do anything with this footage to fix it. The reddish color of the grass went away when I changed the Iris (the neutral density filter was engaging), but the scene was then too dark.

I have also found that this camera does not autofocus as well as the TM700 did; however, I have read comments on this forum that state otherwise.
 
If your zebras are set to 105 and you are seeing them, then that is too hot and would probably explain some of your color issues. 105 is the maximum exposure before white out. And as previously mentioned , you need to white balance. I suggest you think in terms of changing the gamma curve to adjust how the blacks appear without blowing out the rest of the scene, and then reduce exposue.

Set knee to low to reduce blow out, this will let you iris up, but may effect the lighter colors
Raise the master pedestal as high as you can tolerate. At some point, the blacks will become milky but you will see more detail in the blacks
Work with the preset gamma settings to find a compromise. (this will change the pedestal also)

The scene as done, wanting detail on a black cow in bright overhead sunlight is a pretty difficult chore for any cam.

Also, judging color on a computer screen or YouTube is pretty iffy, though if the grass is green, you should get a sense of that no matter how you view it.

Grant
 
There were times when there were no zebra stripes when the zebra level was set to 105%, and the green grass was still reddish. I agree it is a white balance problem. I did try to white balance, but I was unable to manually white balance. I have read nothing but great reviews on this forum about the HMC40, but what is interesting is just about the entire sales staff in the pro-video department at B&H does not like the HMC40. They all tried to talk me out of buying it.

Even though I was unable to correctly white balance, I have used other camcorders as well as the Panasonic TM700 with a preset of 5600k and while the color was a little off, it was not off as much as it was in this video.

I am in the process of returning this HMC40.
 
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