Some notes on aliasing, camera support & meters
Aliasing.... with the default settings, aliasing and moire patterns can be nasty (you don't need to hunt for artifacts, they pop out when complex geometric patterns or horizontal lines are in focus). However, after turning sharpness down a few notches, I didn't notice any problems at all with today's footage (shot in a variety of contexts). It would be interesting to learn how much perceived or actual resolution is being lost by decreasing sharpness, but from today's experience I'm going to keep it turned down.
Camera support.... today I shot using a monopod and lenses ranging from 24mm to 135mm. With my XH-A1, I frequently shoot with a monopod (or indeed handheld) to good effect, even at much longer focal lengths. With the 5d it's a different story. Anything over 50mm IMHO requires a tripod or steadycam as rolling shutter bites hard with even the slightest jerk. Having said that, rolling shutter is not an issue with smooth, controlled movements. One caveat - I haven't tried an IS lens, which may improve the situation somewhat. But with primes, I won't be using a monopod beyond 35mm, or 50mm at a pinch. Also note (someone else mentioned this earlier and I can confirm), Smoothcam (the FCP filter) will not work with 5d footage as even minute rolling shutter causes havoc in the render. So we have a very portable unit that demands very controlled movement. Light meters.... I've never used a light meter, having always relied on my camcorder's internal exposure info. However, I've just ordered a Sekonic as I think it would be very difficult to expose correctly with the 5D without one. In order to set the camera to a desirable ISO, shutter speed and aperture, one has to perform any number of tricks (well documented elsewhere) to get the camera to behave. In the course of which, the camera ends up giving us exposure data out of context, unaware that there won't in fact be a torch in frame during the shot, or your hand covering the frame, or that you're about to stack ND's on the lens, or whatever. I am missing something, or do we all need light meters? |
Do you have video frame captures with and without sharpness, showing the problem ?
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I'll try and get you something tomorrow. Jim Jannard posted a chart over on the Red user forum demonstrating the effect (I can't find it just now but there is a link to it on this forum). Of course, there's no issue with soft textures, natural environs, skin and the like, but when fine/horizontal lines enter focus it's not pretty, and the moire is much worse than anything I've previously encountered in video.
Don't let it put you off though. This camera has a lot more strong points than shortcomings - I'm really enjoying it so far. |
Great read. Thanks for the info.
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BTW, do we know how the cam perform the video scaledown ?
I mean, from the full sensor resolution down to 1920x1080, does it gently smooth using some bilinear/bicubic/.. filter, or a simple "nearest neighbor" method (which would explain the problems with thin horizontal/vertical lines). I was a bit disappointed when I read Red was simply cropping into the sensor when shoting 2K. |
What's fairly clear is that alternating lines per frame are used when reading the sensor frame to frame. That seems to cause the problems with horizontal lines. In the future if they can read every line and downsample noise should be less. Since they apparently are reading every other line the downsampling algorithm is probably non standard. Add to that how they might build the different frame types and it gets very complicated.
One advantage of DOF control is allowing blurring of non critical elements. This caqn certainly help with both artifacts and perceived sharpness. Beyond exposure control I'm not going to be working hard to get this camera to do things it doesn't do well.The testing being done here is very helpful in understanding the limitations of this model. Considering even the sub $1000US single chip cameras now produce excellent images in good light, I'm thinking about the HF11 to shoot with the 5DII and go completely tapeless. I'm still unclear if AVCHP plays nicely with FCS, however. |
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Even if we had full manual control I don't know that there's much use of a light meter in terms of setting camera exposure for video - I mean you can see exactly what you're getting on the monitor. The only thing I'd use one for is checking ratios for lighting - although even then final decisions are probably going to be made based on what the camera sees. |
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The camera is a light meter before we start messing with the video processes. Using manual exposure in photo mode the target exposure values for the scene can be determined. That's all a separate light meter is going to do anyways.
For people who have shoot film, it a normal process to decide how to get to the exposure value needed. It doesn't take too long to do this easily. |
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