Sony EX1: Used with the Glidecam 2000 - Footage

This particular piece of video was included in my lengthy post filled with footage of the Glidecam models, the Steadicam Merlin, and their combination with various cameras.

However, this clip warrants special note because of the interest users have been showing in the Sony EX1 and its rolling shutter.


Glidecam 2000 Test Footage from Andrew Gupta on Vimeo.

Here, we see the Sony EX1 employed with the Glidecam 2000, and according to the notes on the clip, no stabilization vest or arm, etc.

This struck me as a situation where EX1 users and those considering one would want to know how the shutter performs.

Undoubtedly, many who have or may buy cameras in the $3000-7000 range will contemplate using it with a stabilizer in the Glidecam 2000-4000 / Steadicam Merlin range. As well, given the front-heavy design of the EX1, it is good that some people are out there testing its ability to be counterbalanced effectively.

Just for the hell of it, here is a brief DVinfo FORUM DISCUSSION on the Glidecam and the EX1.

SONY EX1: Stories from the Trenches

Now that the Sony EX1 has been in the hands of the ambitious for a few months, it is being used for narrative storytelling and tales of these experiences are trickling in. With them come the wisdom of hands-on experience with the camera's ergonomics and real-world situational handling.

Below is a three-part diary of a six-day shoot with two EX1's. The entries discuss everything from lighting setups to supplemental equipment, from solutions for 24p flicker to sore thumbs.

PART 1
PART 2
PART 3

More to come.

HVX vs EX1 vs XHA1: Analyzing the Specs (Part 1)

Now, in a PREVIOUS POST, I listed the specs of these three cameras with a promise to delve into the ramifications of what these actually mean. The HVX has 4:2:2 colorspace instead of 4:1:1? Is that a big deal? What for? 16 bit audio sampling? 24 bit? Ummm... Does it really matter how much the codec compresses my footage? Why? CMOS, shmee-moss...

Well, here's some of the specs again, with their real world applications included, with a couple reasonable conclusions.

CHIP SIZE

Half of an inch can be enough to impress the girls. Both the Panasonic HVX and the Canon XHA1 utilize three 1/3" CCD chips. The Sony EX1 uses three 1/2" CMOS chips. Does this 1/6 of an inch really make a difference?

Yes, it does. A one-half inch chip allows the videographer to achieve a shallower depth of field because it is a larger surface on which the image is being projected. Is the difference between 1/2" and 1/3" night and day? No, but it is noticeable. It is significant.

One should also keep in mind, though, that while the EX1 and HVX have 13-14x optical zoom lenses, the Canon goes up to 20x, allowing you to use the "back up and zoom in" trick to greater effect in achieving the appearance of a shallow depth of field.

Also, a larger chip means the ability to receive more light, and as a result, better low light performance and less grain. This can be especially noteworthy if you are combining your camera with a depth of field adaptor, which causes an additional loss of light (usually about one F-stop).

Using a depth of field adaptor makes the depth of field capabilities of a 1/2" chip vs. 1/3" somewhat less critical, but does highlight the great light receptiveness of the chip.

Winner: Sony EX1

CHIP TYPE: CCD and CMOS

This has been done to death, so I will refer you to a couple other posts (POST 1, POST 2) for the analysis on the topic, but suffice it to say that at this stage of chip design, a CMOS chip also means a rolling shutter.

One significant benefit of the CMOS chip is that it does not cause vertical banding when portions of the image are blown out by extreme brightness and high contrast, such as that achieved by a bright light bulb in the middle of a black background.

The cost for avoiding banding is fairly high, though, with horizontal skew on fast side pans, vertical stretching and compression on fast vertical pans, partial exposure with camera flashes and strobe lights, and the potential Jellocam wobbling in high vibration situations.

However, regarding his choice to work with the EX1, I did see the venerable Philip Bloom state somewhere that, at least for his purposes, he has gained more by avoiding CCD banding issues than he has lost by working with a rolling shutter.

The debate continues, and if you delve into the forums, you are likely to see a global vs. rolling shutter war zone. Make sure you bring your bulletproof vest and watch out for Sony and Panasonic die hard suicide bombers (comprised mostly, I would imagine, of quasi-professionals who can't bear to digest the idea that their five-to-six thousand dollars could possibly have been better or even equally-well spent on another camera).

Winner: Panasonic HVX and Canon XHA1

PRICE

Duh, by the time you buy the media necessary to shoot in HD on either the EX1 or the HVX, you will be able to buy two XHA1s for the same price (and record your footage to tape).

On price alone, XHA1 is the clear winner, since you could set two of them up for every shot and double your coverage. However, it has been said since time immemorial that "you get what you pay for."

Winner: Canon XHA1

SONY EX1: CMOS and the Rolling Shutter

You know what, I was going to save this for later in the discussion but let's just get this one out of the way.

As people delve deeper and deeper into these cameras, this one issue has become the keystone consideration and possible deal-breaker in their decision-making. So let's address it now. It's just one of the many things that will come into play decision-wise. But it's a biggy.

The EX-1, unlike its competitors here, utilizes a CMOS chip to capture its images. Now this is both good and bad.

The fact that the CMOS chip is more heat and energy efficient, allows it to be larger - 1/2 inch instead of 1/3. This means great resolution and low-light sensitivity, and the potential for a shallower depth of field. Not 35mm film depth of field, but something a little nicer than 1/3 allows.

Also, the CMOS chip avoids vertical banding when we hit bright light. If you have a camera with a CCD chip, point it at a bright light at night and you'll get vertical bright line from the top of the screen to the bottom. Banding. Gone with CMOS.



But...

All is not perfect in CMOS-land.

The way CMOS chips are designed, they use a rolling shutter, and this can lead to several problems when filming, especially when motion is involved.

While global shutters used with CCD chips take a single snapshot of what is in front of them with each frame - everything all at once - rolling shutters sequentially record the image in rows from top to bottom, one after the other, so that not all parts of the image are recorded at exactly the same time. Therefore, the subject being recorded may actually have moved a bit from when part of one frame is recorded to when another part of the same frame is recorded. This can distort the image.

When the EX1 came out, it was quickly hailed as the "HVX killer." That may or may not be, but many people's issues with the rolling shutter and the artifacts it creates are, at a minimum, keeping the HVX on some pretty strong life support.

Among the problems rolling shutter can create are:

Skew: The image bends diagonally in one direction or another as the camera or subject moves from one side to another, exposing different parts of the image at different times.

Jello-vision: This is most common in handheld shots. The rolling shutter causes the image to wobble unnnaturally and bizarrely. This typically only shows up in somewhat extreme circumstances, but we'll get into that later...

Partial Exposure: This one also sucks. If a camera flash goes off, it may only be present for some of the rows of pixels in a given frame. The top 1/3 of the picture may be brightly lit by a flash, while the bottom 2/3 of the picture is dark and unlit. The difference between the two parts of the frame can be very dramatic and even for a frame, is visible and jarring to the human eye. Similar problems can arise with police sirens, some flourescent lighting, and so on. That makes rolling shutters an issue for things like weddings, red carpet and event filming, and narrative filming situations that involve these issues.

Anyway, take a breather.

We'll get into some real-life examples and clips of the above phenomena in the next posts.

And don't go and eliminate the EX1 from consideration just because I opened with this issue. We're gonna cut rolling shutters apart a little bit, but we'll give this camera a chance to redeem itself.

Additional Links and Readings:

You can also find a good ARTICLE on the subject by Barry Green, an expert in digital video and also a strong proponent of the Panasonic HVX.

Here also is a POST by another video pro on blogspot that goes over CCD vs. CMOS. Tell him JC sent ya.

And ANOTHER...

An ARTICLE on CCD vs. CMOS, and ANOTHER ONE...

And finally, an ARTICLE by Kyle Doris.