The f-stop is a function of both focal length and aperture of the lens - Focal length divided by aperture diameter.

Since larger sensors require longer lenses to achieve the same angle of view, it is far hard to make such lenses with a low f-stop.

For a smaller sensor you are, in effect, condensing the light onto a small area, increasing the intensity. However, larger sensors tend to be more sensitive and produce less noise due to their larger photosites. Therefore the advantage of smaller chips is often lost.

DOF is dictated by actual aperture. Since the actual aperture in a f3.5 35mm lens is still far larger than a f1.4 1/3" lens (of the same angle of view), the 35mm will still produce far shallower DOF.

Your point about zoom ratio is pretty true though - there are any 35mm still lenses with the flexibility of video zooms.

Does anyone know for sure if it uses a VBR? I contacted Michael at Luminous Landscape and asked him about the 47 Mbps rate he showed for it. He said that was a mistake in the figures Canon had sent him along with the advance 5D he was loaned for testing. He said he corrected it on his website. I didn't see anything about the bit-rate on the Canon website other than the 38.6 Mbps rate they listed.

Has anyone been able to download the sample 5D video he has posted on Luminous Landscape? I tried twice, using 6 Mbps broadband and after 75 minutes, it still hadn't finished. I'm not sure it was even loading at all, as there was no progress indicator showing on my screen.

I'm more than aware how hard it is to focus a 35mm full frame lens, anyone who has been using a Letus or Brevis 35mm adapter knows its not easy. But you can do it on run and gun, especially if you stay wide. Have a look here Rice farmers of the Philippines on Vimeo

Photojournalists have gotten used to changing lenses frequently on the move, I have something like 15 different ones and kit out according to the job at hand.

That said I'd plan on the 5dmkII tripping up many people who don't really understand what they are getting into or just can't adjust their style from having an all in one video lens as before. I can still see plenty of occasions when a regular video camera is more usable than the 5DmkII, that's why I'm not planning on selling my Sony EX-1's just yet. In fact I am going to set them to 1080/30p and see if I can try and match the 5dmkII and Sony colours when it ships. That way they can be used interchangeably.

I think that's exactly the point Tom is making. What's the point in making a bigger sensor, with a two stops sensitivity advantage for a given f-stop....... if you can then only realistically make a suitable lens that's f3.5 instead of f1.8? Effectively, they both then require the same amount of scene illumination. In the still world, you may be able to just say, OK, 1/125s instead of 1/500s - that's not possible with video.

The bigger sensor may provide shallower dof, which may or may not be an advantage, but is likely to need bigger, heavier, more expensive lenses, with a likely much smaller zoom range.

A much smaller, un-motorized zoom range. Maybe not a big deal for some filmmakers who use a zoom as an adjustable prime, but a definite challenge for anyone wanting to change focal length during a shot.

And zoom photo lenses tend to breathe quite a bit... another challenge for anyone wanting to pull focus with one during a shot.

where a large sensor shines is with wide angle lenses with shallow depth of field. for example... here's a shot I took the other day on a 1ds3 with a 35mm f1.4.....


please note that a 35mm on a full frame 35mm still body gives an angle of view of 63 degrees. Canon has a 24mm f1.4 as well... fantastic lens..... and their 14mm has a angle of view of 114 degrees... and it's not a fisheye ( distortion )

http://www.witzke-studio.com/_W8E4057.jpg

many wildlife photogs I know prefer the smaller aps size sensors so they get more reach out of their longer lenses..... horses of courses

I agree it terms of zoom ratio but larger chips are far better in terms of low light sensitivity/noise and DOF control. My 2/3" camera wipes the floor with my 1/3" cameras even though my 2/3" lenses have a higher f stop.

If Canon could make a video camera with 35mm sensors which made the same step up again, it would be very interesting. I'm tempted to get the 5DMKII as a wide angle and low light tool. Even with a few lenses, it would cost less that a broadcast wide angle lens.

You're right; it's just such agonizing working conditions some of us want to enjoy—with the fillip of remaining independent of corporate financing and its attendants!

I've got an XH-A1, and I've pre-ordered the 5DmkII with the expectation that it may well replace the XH. One big factor in this is that with the 20x zoom I've found far more situations where I wished for much wider angle rather than longer zoom. In fact I can't think of a situation where I used the zoom that I couldn't have just moved in closer if the zoom was shorter (I don't shoot wildlife or sports where that would be difficult). I have however run into several situations where I couldn't move any further back (small rooms, etc) and the lens just wasn't wide enough - which shouldn't be a problem with the 5D.

This is exactly my situation - I rarely use the zoom other than for composition. In the very few instances where I have used a slow pull in a shot I'm pretty sure I can figure out a way to deal with it with the 5D - or just shoot the scene differently. Ultimately I think the suitability of the 5D for video has a lot to do with your intended subject. It won't be good for one-off, run & gun type shooting - but for staged, dramatic work I think it's going to be great because you can easily work around the weaknesses of the camera and really emphasize it's strengths.

The 5D apparently does drive the autofocus in video, but it uses a slower contrast detection mode since the mirror is locked up while shooting. I believe Vincent Laforet mentioned in one of his blog posts that it worked but was slow to react... hard to know what this means since he's primarily a still photographer and DSLRs in general have much faster autofocus than most video cameras. I'm also pretty sure one of Canon's promo videos shows the face-detection mode working while shooting video, which could actually make it more useful than that on many video cameras - it would be less likely to do things like shift between the foreground subject and background. It'll be interesting to see if you can do things with this like select which face to focus on in a scene... might allow for automatic rack focusing between two people.

I'd like to see a lot of the contrast detection techniques used in P&S cameras make their way into camcorders and the LiveView/MovieMode of DSLRs. Focusing is the hardest on these higher resolution cameras, and right now, the best solution is to buy an external HD monitor.

The Live view AF speed should be similar to the EOS50D, have a look at the end of this video YouTube - Canon EOS 50D First Impression Video by DigitalRev

Should give you an idea.

Dan

Raw video from the Reverie short is up now:

Canon Digital Learning Center - EOS 5D Mark II: Full-Resolution Video Clips

Pretty great looking stuff. Looks every bit as good as my Sony EX1 without having to lug around the big letus attachment on the front.

Any news whether it'll do 25p?

It is 30p only in all regions at time of writing.