Camera Test: 7D & GH1 skew comparison

Luis Caffesse

Luis Caffesse

Admin
Had a chance to play with a GH1 and 7D today - so figured I'd check to see how the skew compared. Figured you guys might be interested - so I put together a split screen in FCP to make it easy to see.

It's pretty self explanatory... I'll keep my opinion to myself for now.
Just check it out and see what you think.



I did this out of pure curiosity because I thought it would benefit me to know what I was dealing with on both cameras.
This isn't about arguing that one camera is 'better' than another.
(figured we could use a preemptive warning there)

Oh - and yeah, both cams shooting 1080/24
Both shots were transcoded to ProRes.


EDITED TO ADD:
PLEASE don't judge the image quality - crunching this video down for vimeo, followed by the vimeo compression, is killing the image completely.
But the angles of skew are the same... so just look at this for that one particular aspect.
Thanks.
 
This footy doesn't look "filmic" at all.

And if you hadn't told me which was which, I'd have no idea. Skew between the two looks pretty similar to me. I forget, was that 1080/24p or 720p/60?
 
Wow- GH1 skew is quite a bit more pronounced- though I would kind of expect that.

Noah
 
Honestly, I expected the 7D to be much more pronounced in the skew department...given the bad rap the 5D has gotten on skew, and how much better the GH1 is with skew according to most reports....

Looking through it frame by frame, I really can't tell a difference between the two, which was interesting to me.

Oh, I should note that this was a 30mm prime on the 7D, the GH1 was shooting with the kit lens, zoomed in to 30mm as closely as I could to try to get the same FOV.

What I'm taking away from this is - if you're debating between buying a 7D or a GH1... skew shouldn't factor into your decision, other than to decide whether or not you can deal with it overall... but at 1080/24p one cam doesn't seem to be any better than the other in regards to skew. Not to my eyes anyhow.

EDITED TO ADD:
By the way, if the GH1 seems skewier (is that even a word) it's probably due to the OIS being left on the lens by mistake...if you notice, the frame floats a little at each extreme of the pans... i think that makes it seem like it has more skew... it was also sitting on top of the 7D on the hotshoe...so it was more prone to vibration.

When I get a moment I'll pull some stills from the raw comparisson and post them up so you can see.
 
looks pretty similar most of the time... couple of times the top image looked like it might have been worse off...

I wonder if the difference in focal length between the two cams makes a difference in "perceived" skew as well... Would bet it does.

EDIT: I guess the focal length is about the same on the two... just looks like one has a wider angle of view or something or something... distance to subjects looks the same,, but at the same time the edges aren't matching up... I don't know what I'm talking about :)

Later,
Jason
 
See? It's just like I predicted...
That brings us to the 7D. When the first sample videos were released, there were conflicting views on the jello; indeed, the jello seemed to vary from clip to clip. It was about as bad as the 5D on some clips, but in the fast motion clips in "Line of Sight," the jello was missing. Quite possibly, this is an indication that the 7D's rolling shutter (and clock) behaves a lot like the GH1's. In fact, I predict that that is exactly what we'll find once we get our hands on the camera.
Click to expand...

BTW, thanks for doing this Luis. It saves me from doing the same test.
 
thnx for the test Luis, one less thing to think about :)

EDIT: NOW could you put both of those cams on top of an EX1 that happens to be on top of a shoulder mounted RED1 and go running down 6th street at midnight, that would pretty much take care of the rest of my ponderings that keep me up at night. Oh and try and keep the ISO, aperture and effective FoV the same, thnx you're a doll :)
 
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Good news is it looks like a little cc in post and you'll be able to match these cams up pretty nice. No need to part with either.
 
johnny cola said:
now could you put both of those cams on top of an ex1 that happens to be on top of a shoulder mounted red1 and go running down 6th street at midnight, that would pretty much take care of the rest of my ponderings that keep me up at night. Oh and try and keep the iso, aperture and effective fov the same, thnx you're a doll :)
Click to expand...

lol
 
ChipG said:
Good news is it looks like a little cc in post and you'll be able to match these cams up pretty nice. No need to part with either.
Click to expand...

I would guess you should be able to get them to match up pretty well in camera if you wanted to - I didn't even try to get them to match up contrast/color wise.
 
When doing a skew test, it helps to set the shutter as short as possible so that the lines that we do see are crisper and not hidden under motion blur.

That said, from this test it does look like they're pretty much comparable, and that's a big relief. I was expecting the 7D to be a lot more rubbery, but it doesn't look like it is!
 
Good point, Barry - the shutters were set the same, but i can try to do this again tomorrow with a higher shutter speed.
Might be interesting.
 
Hey Luis...great test.

I also have the GH-1 and I am waiting for the 7d to arrive tomorrow. Have to ben able to color correct the footage and see which image holds better?

As first impression, which cam do you like to shoot with most? I love the GH-1 but I wonder what your first impression is?
 
Super8 said:
Hey Luis...great test.

I also have the GH-1 and I am waiting for the 7d to arrive tomorrow. Have to ben able to color correct the footage and see which image holds better?

As first impression, which cam do you like to shoot with most? I love the GH-1 but I wonder what your first impression is?
Click to expand...

Well, I'd like to keep this thread specifically about skew...otherwise every thread in here is going to become a general GH1 vs 7D thread. :)

That said - it is by no means a slam dunk in either direction as far as I'm concerned.
I am 100% on the fence right now to be honest... but it all depends on what kind of shooting you do and what your needs are.
I'm not trying to be diplomatic here... honestly I really wish one were obviously 'better' for my needs...

Thing is - one may be obviously better for YOU depending on what you're looking for and what you need -
What is important to some people may not be important to others -

But at least from what I saw today I feel like skew is one of the things we can take out of the equation between the two cams.

(you like the way I worked it back around to skew?)


As far as color correction - I haven't played around with it enough to really draw any hard conclusions. That's on the list of things to do...
 
I wonder how anyone ever got the impression that the GH1, in 24p mode, was that much better than the 5D in terms of jello. Was it because everyone was concerned about the mud issue instead? I guess that if there's one good thing to come from the mud, it's that people were scared of doing quick camera moves, which also happened to minimize the jello. :grin:

Jeez... Assumptions, assumptions. Let's try to be careful about them now.
 
Thanks for this test Luis!

If possible, can you please test the 7D skew @ 50P/60P vs the GH1 skew @ 50P/60P (since you're in NTSC land, I guess it'd have to be 60P for GH1 anyways).

Thanks again for this test! Much appreciated!
 
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