C100: 1st Major Event Shoot...The Good...The Ugly

M

mhood

Veteran
I used it from the back of a ballroom and the new 70-200mm EF L IS f/4 was wonderful. The camera recorded for hours without a break (as in 4.5 hours before lunch and 4 hours after lunch solid) and there were no hiccups at all. Got an audio feed from the house sound and it worked gr8. I even shot a green screen (my portable setup) in a breakout room one afternoon and the keys were fine (I checked while on location with my CS6 Win7 laptop machine). Yea, I'm a happy camper...BUT:

The Ugly.

The camera is as susceptible to moire as my 7D ever thought about being. Several cases of fabric moire on the green screen shoot and some moire on the back wall (it was fabric coated) of the main tent. After I noticed it on the first day, it was suggested that I close the iris down a bit. I did that the second day (the lighting was pretty low) by jumping the ISO up to 8000 and closing the f/4 70-200 down to 5.6. I also widened my shot up a bit back to 80mm and often out to 120mm. That seemed to beat the moire on the back wall.

The moire from the shirts on two of my 15 green screen segments was enough to make you cry and I didn't see it on the LCD while shooting. For some stoopid reason, I had thought the C100 was impervious to moire. Hopefully there are some tips this vidiot missed about beating moire...any advice is welcomed.

The 8000 stuff looked really nice but the moire I got looked really bad...Barry Green was right again. It ain't perfect and if you run and gun at large events, bring your moire repellant for sure.
 
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Just an FYI, there is no such thing as a Moire free digital camera. Every single cam with an array of pixels on its sensor can moire.

You should have done the opposite with the aperture. If u narrow the dof slightly so your talent is in focus but the green isn't the moire on the green will go
 
The moire was on the talent's shirt. I shot at f/2.8 ISO 850 on the green screen stuff with the Tamron 17-50mm non-IS lens. AFter watching so much beautiful footage from the C100 and never noticing any moire, I was stoopidly confident that moire wouldn't be a big problem for me. I learned my lesson the hard way.
 
sorry man I was reading and typing on phone. Moire on the dslr's is due to downsampling as you know but moire on the the c100, c300, red, alexa and any digital sensor can happen like you are describing. You need to understand the cause and then you can be better armed to combat it. As Noel says, sharpening makes it worse so kill that setting in camera.

the material has a fine weave which forms a grid, the sensor has an array of pixels which forms a grid, moire is caused by the interpretation of one grid by the other when the ratio of one grid to the other goes beyond the nyquist limit. changing the distance between the subject and the camera (*) forces a change in the ratio but this may not be an option if you are not allowed to reframe. Another trick is to shoot just slightly off focus, just enough for the moire to disappear, then sharpen in post. On set, 1:1 monitoring is key as you have discovered.

I know some post production tricks that will get rid of moire on your footage, you can read them here
http://jdmax.com/how-to-fix-chroma-moire-and-chromatic-aberration-in-post-for-canon-dslr/

* or zoom.
 
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Another shoot yesterday (on portable green screen again) and there was bad moire again. I did back of the sharpness (down to -7 as suggested) in WideDR but fabric got me again. At least I was able to ask the talent to take off the coat and take two this time. But again, moire is quite prevalent with my C100. I don't understand why I haven't seen *any* moire to speak of in the demo footage I've looked at. I hope I'm doing something wrong here.

Shooting WideDR, 30FP, 850 ISO, 2.8, Tamron 17-50 at about 37mm. In a typical ballroom with two small LEDs for talent and overhead lighting for the screen.
 
Are you seeing the moire on the camera monitor or only when you bring the footage into your NLE? If the latter the NLE may be interpreting the footage as interlaced.
 
hey man change the focal length on your tamron by 1-2mm, take the shot again and check the difference. play around with moving the cam 12 inches closer or further, then refocus and check the difference. You'll soon see that moire is a direct product of the ratio of your sensor pixel grid to the grid in the material. Changing that relationship is the key to getting rid of moire. BTW - ignore the camera lcd as you need to be checking 1:1
 
OK, thanks JD. I am in a rut with my portable green screen set...I nearly always do it the same. Next time I'll change things up a bit. I have a problem though...I have no monitor in my portable rig (it has to fit in the Pelican carry on case and there's just no room for a monitor). I did spot the moire on my LCD this time though.
 
mtnski said:
Are you seeing the moire on the camera monitor or only when you bring the footage into your NLE? If the latter the NLE may be interpreting the footage as interlaced.
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This time I spotted it on my LCD. I was looking closely for it though, but it was there on capture.
 
Can you post a frame grab of the Moire? I've never experienced it on my c300. The only time I have "seen" it is when I'm playing footage back on my computer and not viewing it at full rez. When it down samples to play on a smaller screen or or viewing window moire can be seen
 
NDA on everything that I shoot but I'll try a grab at 200% l8er. Trust me, it's moire, it's bad and it's in the stock and makes it all the way to my master. I haven't tried JD's mask fix yet (it's a bit beyond me and I'll need to tackle the learning curve) but the last moire off talent's tightly checkered jacket was very visible on the LCD.

It's always possible that I'm doing something stoopid like not interpreting the footage right. But I think it's right and I don't see any interlaced artifacts.
 
Well, isn't this embarrassing. Apparently, I am an idiot. I forgot to interpret all footage as progressive when I imported with Media Browser. There's still some very slight moire in a few places but nothing at all like I was getting. Would it be easier just to give up and shoot everything at 24p? Nothing I do ever gets broadcast and is nearly always delivered on the intra/internet. Sorry for the fire drill. To quote Roseanne Roseannadanna: "Nevermind."

This camera rocks...even in the hands of an old vidiot.
 
If you are shooting for web only, shoot 29.97. NEVER shoot 24 unless you are intercutting with film shot at 24.
 
drummondb said:
Why do you say that? Plenty of people who shoot primarily for the web also choose 24p over 30.
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I just liked the thought of the footage absolutely being progressive...none of the 60i wrapper nonsense to worry about. But now that I'm finally interpreting my 30FP correctly, all is good.
 
Jeff@8k said:
If you are shooting for web only, shoot 29.97. NEVER shoot 24 unless you are intercutting with film shot at 24.
Click to expand...

This makes no sense. I rarely ever shoot 30p, wrapped or not. The C100 can shoot native 24p in AVCHD, but 30p is always with 2:2 pulldown in 60i.
 
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