View Full Version : CMOS and 24p
Stuart Mannion September 27th, 2006, 06:53 PM It's a tough call between the Canon and the Sony. Any suggestions on the critical differences for indie filmmaking? I'm really attracted to the CMOS idea because of its lack of smearing and to my eye, smoother image. The CMOS images I've seen from DSE look more like my digital SLR. I am impressed with shooting into the sun with no vertical smear. Anyone know how the latitude of V1 CMOS chips compare to the Canon's XH A1 (same as XL H1) CCDs?
That said the Canon seems sure to have the better lens.
Does anyone know if either of them have macro lenses?
(Would mean could use a 35mm adapter without an acromat)
Jason Strongfield September 27th, 2006, 08:11 PM Well, just by the physical size of te sensor alone, 1/4 vs 1/3, the canon will give out a shallower depth of field. Heres a good CCD vs CMOS article http://www.dalsa.com/shared/content/Photonics_Spectra_CCDvsCMOS_Litwiller.pdf
I hope that these cams will have a "flip" feature, so that i dont have to get an external lcd monitor to use with the redrock m35 adapter.
ANother issue is that the Canon is not a true 24f/p progressive. Ironically, the sony is a pure 24 progressive though.
Also the Sony is lighter and smaller in size compared to the Canon.
Douglas Spotted Eagle September 27th, 2006, 09:11 PM It's a tough call between the Canon and the Sony. Any suggestions on the critical differences for indie filmmaking? I'm really attracted to the CMOS idea because of its lack of smearing and to my eye, smoother image. The CMOS images I've seen from DSE look more like my digital SLR. I am impressed with shooting into the sun with no vertical smear. Anyone know how the latitude of V1 CMOS chips compare to the Canon's XH A1 (same as XL H1) CCDs?
That said the Canon seems sure to have the better lens.
Does anyone know if either of them have macro lenses?
(Would mean could use a 35mm adapter without an acromat)
It's not *really* a tough call yet, because neither camera is shipping.
Having had my hands on both though...it's a tough call. I'm glad we'll end up with both, but also understand that not everyone has that resource.
Both are exceptionally fine cameras.
As far as form factor....guys, they're so close overall that when I saw the V1, I literally said to the Sony guys, "You're sure you and Canon aren't working together on this stuff?" They're VERY similar in very many ways. Sony has em' seriously whomped on the LCD panel, but then Sony has everyone whomped on that one.
The bigger decisions are CCD vs CMOS, and opinion won't get you anywhere on that one; only your eyes can make your own determination.
24p vs 24f is likely a big one, especially realizing that the Sony is 1080p, not 540p. Canon has a really nice iris control, zooms are about the same, focus very similar. I wish I had them both in my hands at exactly the same moment to know for certain which one I think I prefer. Those fleeting exposures to a new camera are so tough to recall, because they're as much emotional as they are technical and specific.
Canon has a great eyepiece, Canon has a really sweet layout, but the Sony is very PD-like, which means I'm already familiar with it.
But...it's not a tough call until they start shipping. ;-)
Thomas Smet September 27th, 2006, 09:24 PM ANother issue is that the Canon is not a true 24f/p progressive. Ironically, the sony is a pure 24 progressive though.
The SONY may have more overall progressive detail because of true 24p but the Canon has better progressive chroma. This will matter if you plan on doing any chroma key work. I will explain shortly in another post. I am putting together some examples to show this because it is very hard to explain without showing it.
Steve Mullen September 28th, 2006, 12:56 AM Thomas, wouldn't you agree it's even harder to correctly/accurately explain a position on a camcorder that you don't have available for testing purposes?
As you said earlier -- each field is separately encoded. Every other field carries Cb and Cr. Unless you lose a field :) all fields arrive and are decoded. Once decoded, they are baseband YUV data. Makes no difference if they were sent as frames or fields -- they all arrive.
IF you use reverse pulldown, all ABCD frames each get their original chroma and luma information.
It's true that you've got to do some work, but the problem frame C -- gets both Cb and Cr.
I've got a V1 sitting right next to me so I will be running tests. But I'm not sure that even running test(s) will answer the question you pose. We are looking at issues where test variability may swamp results. And, that's from someone who thinks tests are important.
Floris van Eck September 28th, 2006, 01:52 AM I think we are not the only people that are going to choose between the HVR-V1 and the XH-A1. Those cameras will have to compete fiercely. For me, the Z1 might also still be an option. Although logic tells me that these camcorders will outperform it because they are much newer, which means they will probarbly use more sophisticated techniques. Anyway, we'll see.
And what's up with all the names? First Sony has an A1, now Canon has an A1. Can't they come up with something original? It is really confusing.
Marvin Emms September 28th, 2006, 02:01 AM I think to be fair there are a limited number of number and letter only names you can give to products without confusing people.
It doesn't make sense to give a camcorder a name that will be culture specific. Here the V1 was a flying bomb launched against greater London in WW2. So maybe Sony arn't being abstract enough.
Floris van Eck September 28th, 2006, 02:16 AM If Sony sees greater london as Canon, it's a well-chosen name. I think you are right, but i just believe they could make it easier for themselves.
Why A1, G1? What's the logic? They could just pick a line... let's say HVR or XH and then they could brand them as 1, 100, 1000 (1 being the top model)... and then a replacement the 2, 200 etc.. like with digital reflex camera's.
Z1, V1, A1, H1.... it just doesn't make sense to me.
Marvin Emms September 28th, 2006, 02:21 AM I'm guessing here but with so few HD camcorders I suspect they don't feel the need for as many digits as dSLRs.
The problem with sticking to one line is that you have to define a pecking order. The V1 does not replace the Z1, but it is newer and has features the Z1 does not. If its not a cut down version, and its not a replacement, then the numbering system breaks down.
Thomas Smet September 28th, 2006, 02:26 AM This kind of reminds me back in the day when the VX1000 and the XL1 were always compared and tested against each other. At that time if you did DV chances were you had one of those cameras. Of course there weren't a whole lot of options then for 3 chip DV cameras. I think there was a litle SONY TRV-900 and that useless Panasonic thing that looked like somebody bent the poor camera in half by accident.
Anyways I still do not think there is the one true perfect HDV camera. SONY has done some good things but at the end of the day it is still HDV and it has it's limits just like every other HDV camera. All I can say at this stage is to not put any money down on any camera and wait and see what they look like. There are valid pros and cons of every camera.
Stu Holmes September 28th, 2006, 09:12 AM And what's up with all the names? First Sony has an A1, now Canon has an A1. Can't they come up with something original? It is really confusing.Floris - Well to be fair to Canon they don't have a camera called the "A1" (they DID in the 1980's make an SLR with that exact name..) but they do have a camcorder called "XH-A1". I think it's just that people tend to abbreviate things and so "XH-A1" often becomes "A1", so yes i think people should say "XH-A1" or maybe "Canon A1" so as to avoid confusion with Sony A1E / A1U etc.
The letters will probably all stand for something. - "V" is obviously a popular choice for Sony, with the VX1000, VX2000, VX2100, V1E / V1U etc.
As someone else said, names are a nightmare as they are not globally applicable, they are often copyrighted (car names are all like that..) and so they stick to combinations of letters and numbers. Shorter is better. Who wants their camcorder to be called the "VRT700-X2a" or something ?!?!
One final example of how "bad" global naming of products can be :
The Toyota MR2 is a smallish sports car that Toyota make. Now then, in France, how is "MR2" said ???? VERY similar to a rather rude French word.........
so you see the problems..
Floris van Eck September 29th, 2006, 06:11 AM Haha, I see the problem. Branding is a difficult thing.
But what is the differen between this camera's 24p and let's say Canon's 24F. For the last two years, everyone is always talking about 24p, 24p, 24p and I still do not get why this is so important. Especially if I read that Sony's V1 24p uses some sort of in-camera interlacing. So what's the difference?
Furthermore, why do you want 24p? Is it suited for broadcast, documentary, film -- are there differences between PAL and NTSC models?
Thomas Smet September 29th, 2006, 08:19 AM You see 24p everywhere:
1. Every single movie is shot at 24p.
2. Most music videos on MTV, VH1, BET, CMT, bla bla bla are shot at 24p.
3. Most TV dramas such as 24, CSI and Weeds are shot at 24p.
4. A lot of TV sitcoms are shot at 24p.
5. Many national level TV commercials are shot at 24p.
Really the only stuff that is interlaced is:
1. The News
2. Reality TV shows
3. Live concerts although some have been shot at 24p
4. Low budget local TV commercials
5. Soap Operas
6. Live events such as weddings, graduations, Bar/Bat Mitzvahs, sporting events.
Some people will try to tell you that 24p is useless unless you plan on going to film but that just is not true. Most 24p people see during the week is on TV during prime time.
The main reason why 24p is important right now is that it is the best way to get high quality from DVD's on a digital display. interlaced DVD's will get deinterlaced and/or bobbed which reduces the quality on large digital displays such as plasma TV's. a 24p DVD will playback as progressive and look a lot better on a digital display. Since many people are moving to digital displays and will eventually have to have some form of a digital TV it makes sense to give them what will have the highest quality. The reason why Hollywood DVD's can still look good on a plasma HDTV even though they are still only SD is because they can playback as progressive scan. This is something interlaced DVD's will never be able to do. Now if we had a way to give clients a HD disk then 1080i might be fine but we are a few years away from that point yet. Even if we do get a clear format that wins the HD war it will be a long time before everybody has a HD-DVD/Blu-ray player. Some of your clients will still DVD's and 24p will just look better and cleaner.
Note: This is also true for a 25p or 30p DVD but 24p is a better choice than a 30p DVD in my opinion.
Marvin Emms September 29th, 2006, 08:20 AM When movies are shot on film, the rate is 24 frames per second. Interlaced video on the other hand has a 'look' oweing to feathering of the two interlaced halves during movement and other reasons. 1080p24 can potentially get you an utterly jawdropping picture quality, arguably better than what most see in the cinema (several generations down from the original negitive) and it doesn't have to have a video look to it.
Most dramas, wildlife documentaries, anything that is supposed to look like a film is shot in 24p, or 25p.
Its not well suited to a lot of fast movement, for that we have 720p60 and 720p50 depending on where you live and 'bad old' 1080i that seems to be the only common HD broadcast method in Europe.
Eventually 1080p50 and 1080p60 or possibly 1080p48 will come along, and if we are very very lucky will be broadcast.
Tony Tibbetts October 2nd, 2006, 12:35 PM Floris - Well to be fair to Canon they don't have a camera called the "A1" (they DID in the 1980's make an SLR with that exact name..) but they do have a camcorder called "XH-A1". I think it's just that people tend to abbreviate things and so "XH-A1" often becomes "A1", so yes i think people should say "XH-A1" or maybe "Canon A1" so as to avoid confusion with Sony A1E / A1U etc.
Actually Canon made a Hi8 camcorder called the A1 also. It was kinda cool for it's time.
Chris Hurd October 2nd, 2006, 01:01 PM There were I think three different iterations of the old Hi-8 Canon A1 Digital. Using it was my first experience with Canon video. And I agree that the chosen nomenclature is already confusing enough... now we'll have to be sure to specify Canon A1 vs. Sony A1.
Stuart Mannion October 2nd, 2006, 06:05 PM Sony's Bob Ott implied the CMOS sensor could increase the latitude of the image by somehow treating each pixel separately.
Very exciting - latitude is the biggest issue with current digital video (especially when shooting in the harsh Australian sun).
I'd like to know if treating the pixels individually can actually increase the latitude of the sensor. If there was a way to simulate like a tiny ND filter for each pixel that would be very cool. Could this be what Bob was talking about? Can anyone who has played with the camera comment on the latitude? From the para glider footage it seems to be better than normal.
Marvin Emms October 2nd, 2006, 06:22 PM I can think of one theoretical method. If you read (and reset the value of) pixels you know are going to be bright more often than ones you know are going to be dark, then add together all multiple reads within one frame period, that will increase the total lattitude.
A good idea of which pixels are going to be bright could be had from the previous frame.
This sounds a bit implausable in a camera, but if only done for small area blocks like highlights it might work.
Stuart Mannion October 2nd, 2006, 10:49 PM Marvin you're right! In fact the 'bright' pixels wouldn't even have to read multiple times if there was a way to sense how much light had already accumulated in the sensor.
So for example once the sensor's pixel-light-pot was almost full of light it could switch off therefore stopping the light from 'spilling over' and overexposing the pixel. If you could monitor each pixel like that you could stop a sensor from ever over-exposing... therefore making a camera with enormous latitude! (if not light sensitivity). Wow should I patent this idea? : )
Marcus Marchesseault October 2nd, 2006, 10:52 PM There is a better way to do it, but my lawyer said not to elaborate on it with anybody, including him, until I can put together a patent. Seriously. How would you like a camera with another 5 f-stops of latitude? I've done the math, but don't have the technology to make a prototype.
Stuart Mannion October 2nd, 2006, 11:02 PM Really Marcus, a better way... hmmm, are you sure it's not just the way cited above and now you're slapping a patent on it?
: )
Marvin Emms October 3rd, 2006, 06:35 AM Provided you don't lose the timing for when the pixel switches off, that method would indeed work for lattitude. Without the timing you just get a whole load of pixels all at the same value with no way of working out what value they would have had. Given the timing it would work.
One of the disadvatages to this method is that the degree of motion blur, would over a per pixel basis depend on the brightness. You could have an object with a highlight moving in front of the camera with the correct level of motion blur for the frame rate, but the highlight would be sharp and move in jagged steps.
Reading multiple times would avoid this, as every pixel is exposed for the same length of time, and also improves the SNR. The disadvantage to this, apart from electronics that have to be very clever, is that the sensor needs to have a unused pixel bandwidth.
Marcus,
5 stops is a lot more lattitude, and this is actually easy if you design the sensor to need more than 30 times the amount of light in order to fully expose it. You may find it useful to calculate the ISO to fully expose the sensor as well as the signal to noise ratio of the resulting image. There are intrinsic issues with the light level, the quantum efficiancy of the sensor, the amount of stored charge and the noise level. Lastly a lawyer who tells you to write a patent yourself is not your friend. If what you have is valuable enough to justify a patent then you need a dedicated patent lawyer.
Edit,
Additionally, you should try the method with discrete componants. Say a single photosensor. Almost anything that can be done on silicon can be demonstrated with real componants - even if its a 1 pixel model.
David Ziegelheim October 5th, 2006, 09:32 AM Well, just by the physical size of te sensor alone, 1/4 vs 1/3, the canon will give out a shallower depth of field. Heres a good CCD vs CMOS article http://www.dalsa.com/shared/content/Photonics_Spectra_CCDvsCMOS_Litwiller.pdf
I hope that these cams will have a "flip" feature, so that i dont have to get an external lcd monitor to use with the redrock m35 adapter.
ANother issue is that the Canon is not a true 24f/p progressive. Ironically, the sony is a pure 24 progressive though.
Also the Sony is lighter and smaller in size compared to the Canon.
That's a pretty old CMOS vs CCD article (2001). All of the Canon SLRs are CMOS. The SI 1920 is CMOS. Its only a draw here because Sony, for some strange reason, used a 1/4" instead of 1/3" CCD. It made the viewing angle smaller and added depth of field.
While th Canon is using an interlaced imager, I believe its is not de-interlacing. Therefore, for practical purposes, it is progressive, albeit at a lower resolution. It is in resolution, especially in 24p/24f, that the Sony has an advantage. The pics on their website highlight this.
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