7D Someone tell me about skew

dory_breaux

dory_breaux

Todd Wannabe
I'm seriously considering the 7D as my move up from the DVX; I'm loosing clients because I am unable to shoot HD, but I dont have the budget for having two dedicated cameras (still and motion), let alone a Scarlet.

My biggest issue is that I shoot a lot of action sports (skiing and mountain biking mostly), and one of my things is fast pans following the skier/rider from the side, which seems like its just asking for skew/wobble. I've been looking at some samples of the 7D, and its pretty noticeable. Then again, those are videos shot specifically to show skew (handheld, a lot of vertical lines, high contrast etc etc).

My question is this; am I being paranoid about skew/wobbling?

I'd love to hear from anyone whos been in the relatively same situation, and if anyone has any skiing (or snowboarding) or mountain biking footage I'd like to see it.

Thanks for any insight!
 
You should probably look into buying an HMC-40. Excellent Resolution + camera that works perfect in bright areas such as skiing /snowing. Also just for trick shots you can buy a go pro and mount it to your helmet for some really cool shots.

Finally if you can't afford a $1500 camera than your not really losing clients, because you don't have any.....
 
the jello-vision thing is definitely a probability if you expect to use your dslr the same way you use your dvx
if i were going to move to an HD cam from a dvx. and didnt want to have to rethink the way i shoot. id look into an hpx170. its still a CCD camera, so all of the rolling shutter cmos stuff is no worry. but the P2 price can be prohibitive for some. so maybe an hmc150?
 
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Thanks for the input guys!
The Zacuto test was pretty extreme, but really helpful.

wgzn, the 170 is one of the others I'm considering an option. Just not totally psyched about another fixed lens camera...
 
You are being paranoid. I haven't had issues with rolling shutter ONCE, and much of this camera's use is half-assed filming (ie shakey). Reference the following:

 
personally I believe the 7d can do it...it takes some discipline but it can be done. I shoot action with it all the time (with a very capable shoulder rig). However for a cheaper alternative why not a t2i or 600d ? Heck if i were you i'd really try to get an hmc40 AND a t2i. best of both worlds, plus they share the same media. Maybe you can pick up a used hmc40 to help things out. You can get that combo (used) for the total of about $2000 i'm sure. you may however have to wait a while to add some lenses to that t2i (maybe a nifty fifty to keep costs down). Depending on your budget the hmc10 is an excellent choice...but you wan interchangeable lenses...so hmc40 and t2i seems the best fit.
 
You are being paranoid. I haven't had issues with rolling shutter ONCE, and much of this camera's use is half-assed filming (ie shakey). Reference the following:
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the clip presented isnt a good example of lack of a "skew" issue. the camera doesnt do a lot of fast panning in this footage. and the wide angle lens masks a good bit of what may have been there otherwise. now the GOOD point in this clip is that the OP may also be frequently using the same kind of wide angle. so depending on how you plan to shoot. it may minimize the variable.


However for a cheaper alternative why not a t2i or 600d
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the OPs question is about COMOS / rolling shutter skew. BOTH of these cameras are as likely (or more) to show it as any other.
about the ONLY way to avoid skew issue entirely is use a CCD / global shutter camera.
 
The skew/jello can be pretty bad on the 7D the more telephoto your lens. I own a 7D and have worked around it for a long time. If you can swing it, I'd say save up for the AF100 or FS100. Both of these have a sensor that reads twice as fast as the 7D practically (a little less) so it's a lot more forgiving in fast pans or shakes of the camera.

In fact, you can test any of the 60D, t2i, t3i which have the same read/reset as the 7D probably at a local store to see just how much it will be. If I had to track fast motion with a tighter lens, the 7D would be the last camera I would use.
 
wgzn said:
the clip presented isnt a good example of lack of a "skew" issue. the camera doesnt do a lot of fast panning in this footage. and the wide angle lens masks a good bit of what may have been there otherwise. now the GOOD point in this clip is that the OP may also be frequently using the same kind of wide angle. so depending on how you plan to shoot. it may minimize the variable.
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How is that not fast panning? The camera had to pan pretty quickly to keep the skiers in frame. Besides, in my experience there will never be a situation where you'll have to pan any faster than in that clip. Sure the wide angle masks it a bit, but shooting skiing is largely split between UWA and telephoto. In the latter case, a good set of sticks will eliminate any rolling shutter artifacts.

Will a CCD be less prone? Definitely. But I firmly believe people are paranoid about rolling shutter. A smooth hand and solid stabilization will virtually eliminate it.

To further prove my point, watch the shot at 1:46. I was literally a foot and a half away from the skier, who was moving approx. 40mph into the jump. While some invisible amount of skew may be present just knowing it was filmed with a CMOS sensor, for all intents and purposes there is none.
 
How is that not fast panning? The camera had to pan pretty quickly to keep the skiers in frame.
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like i said. the wide angle masks any skew that may have been there.

im not saying your footage isnt good. its great footage. its just a bad example of skew probability because you have things going on that would compensate for it aesthetically.

and your other clip with the skier at 1:46. SAME THING. the wide angle camouflages any skewing that might have occured.

again. not dissing your footage. i just dont think it does anything to progress a discussion about rolling shutter issues.
 
Haha no worries; I'm not saying you're "dissing" my footage. I'm saying that "jello cam" practically doesn't exist and that people are paranoid about it. The reason I posted those videos is to show that at wide angles/fast movement, skew isn't an issue.

Even at telephoto (which I use more often than wide), there is no skew when I'm shooting skiing because the speed at which one follows the skier isn't fast enough to induce it. Shooting skiing with long focal lengths requires very slow tripod movements, so the ONLY way a person could possibly get skew is if they're using a crappy tripod, in which case CCD footage will look just as bad. I made my start shooting skiing, and the first thing I noticed when shooting my first narrative was how quickly I had to pan when using a tripod. Not once in 10 years have I encountered a scenario where a fast telephoto pan is needed, let alone during the time I've shot at 200mm on my 7D.

Trust me, 90% of my work is filming skiing with both CMOS and CCD cameras and I've come to the conclusion that as long as you aren't having a seizure while holding a DSLR, there is no skew. The only time I've seen skew is when people shoot a DSLR with a 50mm or longer either handheld or with a cheap tripod, but then again who would consider that acceptable "support" in the first place?

I don't deny that jello-cam exists altogether, I'm saying that it's not nearly enough of an issue to make or break your DSLR purchase, especially considering their biggest flaw (moiré), which you should be concerned about, if anything.
 
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all due respect. but tripod quality has absolutely NOTHING to do with skew. skew happens simply when the camera moves faster than it is able to capture the full image from top to bottom. |////////|\\\\\\\\|

and that is as likely to happen on a $6000 sachtler as it is on a $100 best buy slik
 
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wgzn said:
all due respect. but tripod quality has absolutely NOTHING to do with skew. skew happens simply when the camera moves faster than it is able to capture the full image from top to bottom. |////////|\\\\\\\\|

and that is as likely to happen on a $6000 sachtler as it is on a $100 best buy slik
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Well yes and no because I cheap tripod that doesn't move slowly and jerks can DEFINITELY exhibit jello in the image. I know, when I was starting out with my 7D oh so long ago my $25 tripod was horrible. When you get to a better tripod, the slower smooth controlled movements do help to prevent those sudden jars of the camera.

I have shot with the 7D since it's release, and I can tell you, anything about 50mm hand held is asking for trouble. If you follow the recommended pan speeds for objects moving in and out of frame, as Barry Green has in a few of his books, then you really don't get too much an issue. Following certain things, like a skier moving at 40mpg with a tighter lens, the background is gonna skew, but if that background is not something that easily shows rectilinear slants, you won't notice it as much. Also, if the pans don't slow down fast to no movement, it will hide it as well.
 
all due respect. but tripod quality has absolutely NOTHING to do with skew. skew happens simply when the camera moves faster than it is able to capture the full image from top to bottom. and that is as likely to happen on a $6000 sachtler as it is on a $100 best buy slik
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You're right that skew is the result of the camera moving faster than it can capture (rolling shutter). Cheap friction heads (Manfrotto 701/501/503/etc.) mixed with shaky legs do two things:
1. Friction heads operate poorly in cold weather, and make irregular movements. This causes the footage to become jerky at long focal lengths, inducing skew.
2. Bouncy legs don't supply the camera with enough support to counteract micromovements caused by handling the camera/tripod. Pulling focus will make the entire image "jump" due to your hand even touching the lens. This is the very reason I upgraded to a Sachtler Cine DSLR with Miller Solo DV CF legs, with my 70-200 mounted via lens collar. I previously had a Manfrotto 503 head with 055xb legs and mounted the camera straight to the tripod, and let me tell you, it was unusable footage. With my new setup I can pull focus and touch the camera all I want, and playing it back on a theatre screen there is ZERO skew. To say that a Sachtler is no more effective at eliminating skew than a $100 tripod is just plain wrong because it is negligent of a very basic physical concept.

With all due respect, who is he going to believe: somebody from Texas (where I'm sure there is plenty of skiing), or somebody from Alaska who currently makes his income off of filming professional skiers with a DSLR?


Following certain things, like a skier moving at 40mpg with a tighter lens, the background is gonna skew, but if that background is not something that easily shows rectilinear slants, you won't notice it as much.
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True, but for stylistic reasons, you rarely film skiers with a tight frame because you often want to include the feature or surrounding on/in which they're riding. Ultra-tight framing in ski videos is for corndog Warren Miller Entertainment films and nothing more (which is what my first video parodied). If there WAS skew, it wouldn't be evident because of both the irregular/natural shapes that make up the background, and the shallow DOF at such focal lengths.
 
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Bouncy legs don't supply the camera with enough support to counteract micromovements caused by handling the camera/tripod.
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yes and no because I cheap tripod that doesn't move slowly and jerks can DEFINITELY exhibit jello in the image.
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To say that a Sachtler is no more effective at eliminating skew than a $100 tripod is just plain wrong because it is negligent of a very basic physical concept.
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yeah. ok. those situations are almost certain to introduce skew. but ANY shot started and stopped with a jerk or wobbled because of substandard sticks is useless anyway (unless you wanted it jerky for some artistic purpose), so i dont consider these being a factor in a discussion of the propensity for skew.

what you guys are talking about is like saying putting your memory card in a blender is a cause of data loss. well yeah. you'll almost certainly lose your data. but i wouldnt bring that situation up in a conversation about data card integrity. i mean with shaky support, the the shot is wrecked before you even get to the point of discussing skew...

im just arguing semantics at this point. so i'll just shut up. i think people will understand what we all mean ; )
 
You'd think having a solid tripod would be a given, but sadly it isn't with many people (I see way too many people with $10k camera setups with awful tripods supporting them). My point is that if quality support is in fact supplied, skew isn't evident, or even an issue. Hell, I'd go so far as to say that it isn't even worth taking into consideration.

Of course a shot will be ruined with a bad set of sticks whether it has a CCD or CMOS, that isn't the point. The point is that in order to induce skew on a quality tripod, you'd literally have to be trying to do so. Assuming OP actually has his head on straight and understands the importance of good support, being concerned about rolling shutter issues is just plain silly. Any complaints about skew almost always comes from inexperienced hobbyists who either shoot longer focal lengths handheld, use cheap support, or are just plain awful at handling their camera.
 
Hey hey don't hate the tight closeups. If you use them properly they still work great, even if they are overly WME.

Anyways, thank you everyone for your input, really very helpful. After watching a lot of 7D footage (righteous your stuff is RAD definitely got me pumped up, although I do like to use closeups more then you it seems, but that's just personal preference ) I'm seeing not as much skew as I thought I would based on some of the replies, but still its present.
That being said, I have to agree with righteous that many people seem to be paranoid about skew. NOT TO SAY IT ISN'T PRESENT. It just seems that it is a little blown out of proportion. Im glad I could get you guys discussing it though, ha.
If Panasonic gave me an HPX with interchangeable lens options, I would have bought it yesterday.
Bottom line though I know it will come down to whatever I decide to move on to is going to have SOME limitations, just a matter of what I can compromise on.
 
so what is keeping you from getting an AF100...i mean if you like the hpx and interchangeable lens? the price?
 
Any complaints about skew almost always comes from inexperienced hobbyists who either shoot longer focal lengths handheld, use cheap support, or are just plain awful at handling their camera.
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the thing that gets me about this whole discussion is that ive been shooting [video] for about the last 15 years. and until the last couple of years i never had to entertain discussions with my clients about judder or skew. my camera just captured what i pointed it at, more or less regardless of how i moved it. now granted i shoot a good bit of hand-held, run and gun / ENG stuff so that may be more of an issue to me than other folk.

so simply in the interest of higher res and better low light performance. we now have to deal with judder and skew? the trade off to many is worth it. not sure where i fall in that scale...

but my point is really more of a cautionary tale to those new to the game or evolving from the days of the 3-chip. when you move into the DSLR/CMOS world. you have to reevaluate how you approach your camera.
 
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