Movie problem, can anybody please help me? (screenshot included)

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#1
Hi, I just got my 60D.
I did some tests outside and I'm extremely pleased with the result.
Today I wanted to film a music video indoor and I'm getting a distorted image.
I tried lots of different settings but I can't correct the problem.
I have a brand new transcend class 10 card so the card is not the problem I guess.
I'm shooting in the 720p60fps mode.
Here is the screenshot:
http://i219.photobucket.com/albums/cc105/nocaster_2007/problem.jpg
Look at the metal stands and the top of the bass drum...
I really don't understand why the result is so bad. :-\
Thank you very much in advance.
 
#2
Joecaster, can you be more specific about what bothers you in this frame? I see moderate barrel distortion, but I can't say that it's too out of the ordinary - barrel distortion is a fact of life for all wide angle lenses (expensive ones control it better) but if you want truly straight lines, step way back and use a longer lens.

However, I don't even know if barrel distortion is your complaint, or if you are referring to the aliasing (jaggedness) on the edges of the base drum and on the thin bars on the stands. Unfortunately, SLRs are notorious for aliasing problems in video. Long story short, it boils down to this: your camera sensor has say 18MP, and HD video is only 2MP, so the camera discards rows of pixels, to achieve the lower resolution of HD video. The resulting image will suffer from aliasing most evident on thinner straight lines in your frame.

You can help the problem a little bit by lowering the "sharpness" setting on your camera when you're shooting with "everything in focus", but this problem never really goes away completely.

I hope this somewhat helps.
 
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#3
Thanks for replying bro!
I looked for barrel distortion but it's not what I'm talking about here.
I did a bigger screenshot to better show the problem.
Look at the higher edge of the bass drum, the edges of the cymbals, the bottom of the cymbal stands on the left side. It's all distorted and the overall quality is pretty disgusting.
http://i219.photobucket.com/albums/cc105/nocaster_2007/60D.jpg

Now the same drums filmed with a Sony HDRCX505 cam with a raynox wide angle:
http://i219.photobucket.com/albums/cc105/nocaster_2007/sony.jpg
It looks much better doesn't it?

It's hard for me to beleive that my 60D cannot do what that Sony camcorder does...
 
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#7
Ok, so I think that's aliasing (jaggedness) that you're talking about. This is one of those areas where a camcorder will actually perform better than an SLR. Canon could probably improve the situation with better algorithms, but no point having that discussion since it won't help you solve your problem today.

You can try lowering the "sharpness" setting all the way down on your SLR like I suggested and see if that reduces the problem for you.

That's not to say that the Sony frame grab is not without its own problems. For example, the lens seems much inferior to what you were using on the SLR, so you have severe CA near the edges of the frame, and also quite severe barrel distortion. It comes down to figuring out what's more important to you. Personally, Sony footage would probably bother me more than aliasing on the 60D, all things considered, but it's subjective.

You could also consider using SLR footage for closeups with shallow DOF, and Sony footage for wider shots where aliasing is more likely to be a problem.
 
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#8
Ok so after googling "aliasing" I found out it is definitely my problem.
So maybe shooting in 1080? I'll try tomorrow for sure!
I have a little question about focusing if you don't mind.
With my 60D, can I just leave it on a tripod having "everything in focus" the whole time, like my sony cam does.
I find it very difficult to have everything in focus. Is it impossible or there is a mode that does that?
 
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#9
joecaster said:
With my 60D, can I just leave it on a tripod having "everything in focus" the whole time, like my sony cam does.
I find it very difficult to have everything in focus. Is it impossible or there is a mode that does that?
Click to expand...

The larger the sensor, the shallower the DoF. The 60D has a much larger sensor than the camcorder (APS-C is well over 10x larger than the 1/2.9" sensor in the Sony). To get a similar 'everything in focus' depth of field, you'd need to set your 60D to a much narrower aperture (which also cuts down on the light, meaning higher ISO will be needed).

There are online DoF calculators, such as DoFMaster, that can tell you what DoF you get with a given aperture, focal length, and focus distance.
 
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#10
sb, we posted at the same time.
Yes the raynox lens is really not great and blurrs the image a quite a bit.
My lens is the 18-135 that's sold with the body by the way.

neuroanatomist, thanks a lot for that information!
I'll have a look at that tomorrow.
Until now I've used that sony that was doing everything for me without having to worry about aperture, ISO and all these things. I'm totally new to all that.
 
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#11
joecaster said:
Until now I've used that sony that was doing everything for me without having to worry about aperture, ISO and all these things. I'm totally new to all that.
Click to expand...

It's not simple. Keep in mind that for video, the consumer camcorder is analogous to a point-and-shoot camera for stills, whereas a dSLR for video is like, well...like a dSLR for stills - but one without the green square mode.
 
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#13
First of all, if your shooting at 720p why are the shots you are posting not 1280 x 720? Upscaling will make aliasing much more obvious.

Secondly, I would be much more bothered by the massive Chromatic aberration on the edges of the video camera frame than some minor aliasing.
 
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#14
It will also help your DoF problem if you shoot at 18mm. If you start zooming in your DoF will get more and more narrow. I know it's new to you so we will try not to get too complicated but if you shoot at 18mm and f6.3-f8.0 you should fine most things in focus at a reasonable distance.
 
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#15
Well this was shot at 18mm. I'll tweak the aperture to see what happens.
I filmed all day yesterday outside and I had absolutely no aliasing.
That just happened today shooting in my studio.

@Sdiver2489: yes I wanted to make it even more obvious to make sure we were talking about the same thing.

Thank you all for your help and advices!
 
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#16
let's see...

* that's aliasing; wait for moire, you'll love it

* 720p is 1280x720

* 720p60 and 720p50 are a lot worse, in terms of aliasing/moire, than 1080p24, 1080p25 and 1080p30

* it looks like you're shooting a music video; if that is so, you should shoot at 24 frames per second (like the pros do); because that's the film frame rate, and anything higher looks like a soap opera; more here:
http://www.macvideo.tv/camera-technology/interviews/index.cfm?articleId=3213230

* the last two things point towards 1080p24 as the best option

* the bigger sensor has a lot of advantages; shallow DoF is one of them; unless you don't want it, then it is a problem; you'll need a very narrow aperture if you want everything to be in focus; more here:
http://www.similaar.com/foto/doftest/doftest.html
http://www.similaar.com/foto/dof/dof.php
 
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#17
It's definitely caused by aliasing and shooting at 720. A lot less obvious at 1080 but won't be eliminated. That's a weak point of the 60D like SB said. Supposedly, the Panasonic GH2 doesn't have that problem. Overall, the GH2 is really a better camera for video. Switch off all of the automatic functions of the camera like auto white balance, sharpening. For more depth of field, shoot with a good wide lens and stop down. That might mean you'll have to light the scene better.
 
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#19
NormanBates, thank you so much for this wonderful interview that really enlightened me!
I was shooting at 720 because my videos go directly on youtube or they would be watched on a computer anyway. So I thought 720 is "big enough".
Then I thought it was a good thing to choose the more image per second option, thinking "more detail", "more quality" if you will...
Now that I saw this video I realized it's not.
@Cornershot: what did you mean by "stop down"?
@Hurtinminorkey: I'm planning to do slow motion stuff of me walking so that's the other reason why I chose 60fps. 24 fps might be enough for that and I won't do any slow motion drumming anyway!

I'm starting to see clearer thanks to you guys ;)
 
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#20
if you have the time, check out the other parts of that interview, Stu Maschwitz is a very inspirational guy:
http://www.macvideo.tv/editing/interviews/index.cfm?articleid=3212651
http://www.macvideo.tv/motion-graphics-vfx/interviews/index.cfm?articleid=3219946
http://www.macvideo.tv/motion-graphics-vfx/interviews/index.cfm?articleid=3227613

this is his blog:
http://prolost.com/

where you'll find things such as these:
http://prolost.com/blog/2007/10/22/hue-are-you.html
http://prolost.com/memorycolors/
 
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