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cameras

Raw is raw, but not all raw is created equal.

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I was looking at some test footage from several raw video cameras the other day and it became very obvious that some of the cameras were better than others and one or two had some real problems with skin tones. You would think that once you bypass all the cameras internal image processing that you should be able to get whatever colorimetry that you want from a raw camera. After all, your dealing with raw camera data. With traditional video cameras a lot of the “look” is created by the cameras color matrix, gamma curves and other internal processing, but a raw camera bypasses all of this outputting the raw sensor data. With an almost infinite amount of adjustment available in post production why is it that not all raw cameras are created equal?

For a start there are differences in sensor sensitivity and noise. This will depend on the size of the sensor, the number of pixels and the effectiveness of the on-sensor noise reduction. Many new sensors employ noise reduction at both analog and digital levels and this can be very effective at producing a cleaner image. So, clearly there are differences in the underlying electronics of different sensors but in addition there is also the quality of the color filters applied over the top of the pixels.

On a single chip camera a color filter array (CFA) is applied to the surface of the sensor. The properties of this filter array are crucial to the performance of the camera. If the filters are not selective enough there will be leakage of red light on to the green sensor pixels, green into blue etc. Designing and manufacturing such a microscopically small filter array is not easy. The filters need to be effective at blocking undesired wavelengths  while still passing enough light so as not to compromise the sensitivity of the sensor. The dyes and materials used must not age or fade and must be resistant to the heat generated by the sensor. One of the reasons why Sony’s new PMW-F55 camera is so much more expensive than the F5 is because the F55’s sensor has a higher quality color filter array that gives a larger color gamut (range) than the F5’s more conventional filter array.

The quality of the color filter array will affect the quality of the final image. If there is too much leakage between the red, green and blue channels there will be a loss of subtle color textures. Faces, skin tones and those mid range image nuances that make a great image great will suffer and no amount of post production processing will make up for the loss of verisimilitude. This is what I believe I was seeing in the comparison raw footage where a couple of the cameras just didn’t have good looking skin tones. So, just because a camera can output raw data from it’s sensor, this is not a guarantee of a superior image. It might well be raw, but because of sensor differences not all raw cameras are created equal.

cameras, Uncategorized

XDCAM Picture Profiles and setups, also C300 coming soon.

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I’ve added a new section in the xdcam-user.com forum for listing details of my various picture profiles. You will need to be a registered forum member to view or comment, but registration is free. I hope to add many profiles to this forum over the coming weeks for many of the XDCAM cameras as well as the new Canon C300 once I start to get that dialled in. I’ve started with my EX S-Log style gamma curve.

http://www.xdcam-user.com/forum3/viewtopic.php?f=41&t=194&sid=c233ea884673388efe1e1af8c2ef84c7

cameras, Uncategorized

Canon C-Log on the C300 compared to S-Log.

5 Comments

First let me say that as yet I have not used C-Log in anger, only seen it at a couple of hands on demo events and in downloaded clips.

From what I’ve seen C-Log and S-Log are two quite different things. S-Log on the F3 is a true Log curve where each stop of exposure is recorded using roughly the same amount of data and the available dynamic range is about 13.5 stops. It is inevitable that when you use a true log curve like this and play it back on an uncorrected Rec-709 (standard HD gamma) monitor that it will look very flat and very washed out. This is a result of the extreme gamma miss-match across the entire recording range. If you had a monitor that could display 13.5 stops (most only manage 7) and the monitor had a built in Log curve then the pictures would look normal.

What has too be considered is that S-Log is designed to be used with 10 bit recording where each stop gets roughly 70 data bits ( this roughly means 70 shades of grey for each stop).

Now lets consider the Canon C300. It has no 10 bit out, it’s only 8 bit. Assuming Canon’s sensor can handle 13.5 stops then using 8 bit would result in only 17 bits per stop and this really is not sufficient, especially for critical areas of the image like faces and skin tones. A standard gamma, without knee, like Rec-709 will typically have a 7 stop range, this is a deliberate design decision as this yields around 34 bits per stop. As we know already if you try to do a hard grade on 8 bit material you can run in to issues with banding, posterisation and stair stepping, so reducing the bits per stop still further (for example by cramming 13.5 stops into 8 bits) is not really desirable as while it can improve dynamic range, it will introduce a whole host of other issues.

Now for some years camera sensors have been able to exceed 7 stops of dynamic range. To get around the gamma limitation of 7 stops, most good quality cameras use something called the knee. The knee takes the top 15 to 20% of the recording range to record as much as 4 to 5 stops of highlights. So in the first 0 to 80% range you have 6 stops, plus another 4 to 5 stops in the last 20%, so the overall dynamic range of the camera will be 10 to 11 stops.

How can this work and still look natural? Well our own visual system is tuned to concentrate on the mid range, faces, foliage etc and to a large degree highlights are ignored. So recording in this way, compressing the highlights mimics they way we see the world, so doesn’t actually look terribly un-natural. OK, OK, I can hear you all screaming… yes it is un-natural, it looks like video! It looks like video because the knee is either on or off, the image is either compressed very heavily or not at all, there is no middle ground. It’s also hard to grade as mid tones and highlights have different amounts of squashing which can lead to some strange results.

So the knee is a step forward. It does work quite well for many applications as it preserves those 34 bits of data for the all important mid tones and as a result the pictures look normal, yet gives a reasonable amount of over exposure performance. Next came things like cine gammas and film style gammas.

These often share a very similar gamma curve to standard gammas for the first 60-70% of the recording range, so faces, skin, flora and fauna still have plenty of data allocated to them. Above 70% the image becomes compressed, but instead of the sudden onset of compression as with a knee, the compression starts very gently and gradually increases more and more until by the time you get close to 100% the compression is very strong indeed. This tends to look a lot more natural than gamma + knee, yet can still cope with a good over exposure range, but depending on the scene it can start to look a little flat as your overall captured range is biased towards highlights, so your captured image contains more bright range than low range so will possibly (but not always) look very slightly washed out. In my opinion, if shooting with cinegammas or similar you should really be grading your material for the best results.

Anyway, back to the Canon C300. From what I can tell, C-Log is an extension of the cinegamma type of gamma curve. It appears to have more in common with cinegammas than true S-log. It looks like the compression starts at around 60% and that there is a little more gain at the bottom of the curve to lift shadows a little. This earlier start to the compression will allow for a greater dynamic range but will mean fewer bits of data for skin tones etc. The raised lower end gain means you can afford to underexpose more if you need to. As the curve is not a full log curve it will look a lot more agreeable than S-Log on an uncorrected monitor, especially as the crucial mid tone area is largely unaffected by strong compression and thus a large gamma miss-match.

For the C300 this curve makes complete sense. It looks like a good match for the cameras 8 bit recording giving a decent dynamic range improvement, largely through highlight compression (spread over more recording range than a conventional knee or cinegamma), keeping mid tones reasonably intact and a little bit of shadow lift. Keeping the mid range fairly “normal” is a wise move that will still give good grading latitude without posterisation issues on mid range natural textures.

cameras

Canon C300 open house at Visual Impact. Price £9995!

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Crowds gather around the Alexa, F3 and C300

I spent most of the morning at the Visual Impact C300 open house. They had 3 C300’s on show. One on a camera set alongside an F3 and an Alexa, the other was a very simple handheld configuration for people to play with and a 3rd on a stedicam rig.
What impressed me the most was how nice the camera was to hand hold and how good the rear viewfinder is. You certainly don’t need anything extra to shoot with it.
On the camera set I was a little less impressed. For some reason the C300 looked a little soft or not quite in focus. No matter how I played with the focus, the edges of the image looked soft compared to the F3 next to it. Both the F3 and the C300 had Arri 32mm master primes so they should have been similar. I was told all the cameras were set up with standard gammas, but looking at the C300 it looked quite flat, so perhaps it was setup with the Canon Log gamma and the resulting lower contrast was making the image appear softer. There were so many people at the event that it was difficult to really get at the camera to figure out what was going on. I asked if I could record some footage but was told that this was not possible on this occasion as these are pre-production cameras. Shame, I had a pocket full of CF cards and SxS cards. Anyway I have been promised a test shoot very soon.

I really hope that the softness was a peculiarity of that particular camera or the way it was set up as the C300 would for me be fantastic for my storm chasing and extreme weather assignments. I’d love to take one up to Norway in January to see if it sensitive enough to shoot the Northern Lights without having to resort to slow shutters or long exposures. I’ve done the math, and according to my calculations it should just about be sensitive enough at 22,000iso with a f1.4 lens to shoot the Aurora in real time. It would be really cool to try and stream the Aurora live from Norway in January. On other assignments I could shoot using Canon L series glass or my B4 to Canon adapter and get broadcast ready material without needing an external recorder. I still think the Sony F3 with S-Log and an external 444 recorder is capable of a better image, but that’s a significantly more expensive package and more cumbersome, power hungry etc. It’s horses for courses. The C300 for me looks to be fantastic for simple, fast, easy shoots where shallow DoF is desirable, while I would continue to use the F3 where the extra bulk of an external recorder and the slightly more complex S-Log workflow will not be an issue as I think the ultimate image quality will be better. I might just have to place an order for one, especially as the price will be less than anticipated. The price I was offered from Visual Impact today was £9995, available from mid January…. Just in time to take to Norway????

cameras

Canon C300 open house at Visual Impact. Price £9995!

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Crowds gather around the Alexa, F3 and C300

I spent most of the morning at the Visual Impact C300 open house. They had 3 C300’s on show. One on a camera set alongside an F3 and an Alexa, the other was a very simple handheld configuration for people to play with and a 3rd on a stedicam rig.
What impressed me the most was how nice the camera was to hand hold and how good the rear viewfinder is. You certainly don’t need anything extra to shoot with it.
On the camera set I was a little less impressed. At the beginning of the day when I first quickly looked at the 3 monitors I could see no obvious difference between any of the cameras. The monitors were fairly small 20″ Panasonic monitors. However when I went back to take a closer look, for some reason the C300 looked a little soft or not quite in focus. No matter how I played with the focus, the edges of the image looked soft compared to the F3 next to it. Both the F3 and the C300 had Arri 32mm master primes so they should have been similar. I was told all the cameras were set up with standard gammas, but looking at the C300 it looked quite flat, so perhaps it was setup with the Canon Log gamma and the resulting lower contrast was making the image appear softer. There were so many people at the event that it was difficult to really get at the camera to figure out what was going on. I don’t think something was quite right, I’ve seen better from the C300. I asked if I could record some footage but was told that this was not possible on this occasion as these are pre-production cameras. Shame, I had a pocket full of CF cards and SxS cards. Anyway I have been promised a test shoot very soon.

I really hope that the softness was a peculiarity of that particular camera or the way it was set up as the C300 would for me be fantastic for my storm chasing and extreme weather assignments. I’d love to take one up to Norway in January to see if it sensitive enough to shoot the Northern Lights without having to resort to slow shutters or long exposures (Stop Press… I’ve placed an order and hope to have one in time for Norway). I’ve done the math, and according to my calculations it should just about be sensitive enough at 22,000iso with a f1.4 lens to shoot the Aurora in real time. It would be really cool to try and stream the Aurora live from Norway in January. On other assignments I could shoot using Canon L series glass or my B4 to Canon adapter and get broadcast ready material without needing an external recorder. I still think the Sony F3 with S-Log and an external 444 recorder is capable of a better image, but that’s a significantly more expensive package and more cumbersome, power hungry etc. It’s horses for courses. The C300 for me looks to be fantastic for simple, fast, easy shoots where shallow DoF is desirable, while I would continue to use the F3 where the extra bulk of an external recorder and the slightly more complex S-Log workflow will not be an issue as I think the ultimate image quality will be better. I might just have to place an order for one, especially as the price will be less than anticipated. The price I was offered from Visual Impact today was £9995, available from mid January…. Just in time to take to Norway????

cameras

Canon C300 open house at Visual Impact. Price £9995!

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Crowds gather around the Alexa, F3 and C300

I spent most of the morning at the Visual Impact C300 open house. They had 3 C300’s on show. One on a camera set alongside an F3 and an Alexa, the other was a very simple handheld configuration for people to play with and a 3rd on a stedicam rig.
What impressed me the most was how nice the camera was to hand hold and how good the rear viewfinder is. You certainly don’t need anything extra to shoot with it.
On the camera set I was a little less impressed. At the beginning of the day when I first quickly looked at the 3 monitors I could see no obvious difference between any of the cameras. The monitors were fairly small 20″ Panasonic monitors. However when I went back to take a closer look, for some reason the C300 looked a little soft or not quite in focus. No matter how I played with the focus, the edges of the image looked soft compared to the F3 next to it. Both the F3 and the C300 had Arri 32mm master primes so they should have been similar. I was told all the cameras were set up with standard gammas, but looking at the C300 it looked quite flat, so perhaps it was setup with the Canon Log gamma and the resulting lower contrast was making the image appear softer. There were so many people at the event that it was difficult to really get at the camera to figure out what was going on. I don’t think something was quite right, I’ve seen better from the C300. I asked if I could record some footage but was told that this was not possible on this occasion as these are pre-production cameras. Shame, I had a pocket full of CF cards and SxS cards. Anyway I have been promised a test shoot very soon.

I really hope that the softness was a peculiarity of that particular camera or the way it was set up as the C300 would for me be fantastic for my storm chasing and extreme weather assignments. I’d love to take one up to Norway in January to see if it sensitive enough to shoot the Northern Lights without having to resort to slow shutters or long exposures (Stop Press… I’ve placed an order and hope to have one in time for Norway). I’ve done the math, and according to my calculations it should just about be sensitive enough at 22,000iso with a f1.4 lens to shoot the Aurora in real time. It would be really cool to try and stream the Aurora live from Norway in January. On other assignments I could shoot using Canon L series glass or my B4 to Canon adapter and get broadcast ready material without needing an external recorder. I still think the Sony F3 with S-Log and an external 444 recorder is capable of a better image, but that’s a significantly more expensive package and more cumbersome, power hungry etc. It’s horses for courses. The C300 for me looks to be fantastic for simple, fast, easy shoots where shallow DoF is desirable, while I would continue to use the F3 where the extra bulk of an external recorder and the slightly more complex S-Log workflow will not be an issue as I think the ultimate image quality will be better. I might just have to place an order for one, especially as the price will be less than anticipated. The price I was offered from Visual Impact today was £9995, available from mid January…. Just in time to take to Norway????

cameras

Canon C300 open house at Visual Impact. Price £9995!

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Crowds gather around the Alexa, F3 and C300

I spent most of the morning at the Visual Impact C300 open house. They had 3 C300’s on show. One on a camera set alongside an F3 and an Alexa, the other was a very simple handheld configuration for people to play with and a 3rd on a stedicam rig.
What impressed me the most was how nice the camera was to hand hold and how good the rear viewfinder is. You certainly don’t need anything extra to shoot with it.
On the camera set I was a little less impressed. At the beginning of the day when I first quickly looked at the 3 monitors I could see no obvious difference between any of the cameras. The monitors were fairly small 20″ Panasonic monitors. However when I went back to take a closer look, for some reason the C300 looked a little soft or not quite in focus. No matter how I played with the focus, the edges of the image looked soft compared to the F3 next to it. Both the F3 and the C300 had Arri 32mm master primes so they should have been similar. I was told all the cameras were set up with standard gammas, but looking at the C300 it looked quite flat, so perhaps it was setup with the Canon Log gamma and the resulting lower contrast was making the image appear softer. There were so many people at the event that it was difficult to really get at the camera to figure out what was going on. I don’t think something was quite right, I’ve seen better from the C300. I asked if I could record some footage but was told that this was not possible on this occasion as these are pre-production cameras. Shame, I had a pocket full of CF cards and SxS cards. Anyway I have been promised a test shoot very soon.

I really hope that the softness was a peculiarity of that particular camera or the way it was set up as the C300 would for me be fantastic for my storm chasing and extreme weather assignments. I’d love to take one up to Norway in January to see if it sensitive enough to shoot the Northern Lights without having to resort to slow shutters or long exposures (Stop Press… I’ve placed an order and hope to have one in time for Norway). I’ve done the math, and according to my calculations it should just about be sensitive enough at 22,000iso with a f1.4 lens to shoot the Aurora in real time. It would be really cool to try and stream the Aurora live from Norway in January. On other assignments I could shoot using Canon L series glass or my B4 to Canon adapter and get broadcast ready material without needing an external recorder. I still think the Sony F3 with S-Log and an external 444 recorder is capable of a better image, but that’s a significantly more expensive package and more cumbersome, power hungry etc. It’s horses for courses. The C300 for me looks to be fantastic for simple, fast, easy shoots where shallow DoF is desirable, while I would continue to use the F3 where the extra bulk of an external recorder and the slightly more complex S-Log workflow will not be an issue as I think the ultimate image quality will be better. I might just have to place an order for one, especially as the price will be less than anticipated. The price I was offered from Visual Impact today was £9995, available from mid January…. Just in time to take to Norway????

cameras

Canon C300 open house at Visual Impact. Price £9995!

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Crowds gather around the Alexa, F3 and C300

I spent most of the morning at the Visual Impact C300 open house. They had 3 C300’s on show. One on a camera set alongside an F3 and an Alexa, the other was a very simple handheld configuration for people to play with and a 3rd on a stedicam rig.
What impressed me the most was how nice the camera was to hand hold and how good the rear viewfinder is. You certainly don’t need anything extra to shoot with it.
On the camera set I was a little less impressed. At the beginning of the day when I first quickly looked at the 3 monitors I could see no obvious difference between any of the cameras. The monitors were fairly small 20″ Panasonic monitors. However when I went back to take a closer look, for some reason the C300 looked a little soft or not quite in focus. No matter how I played with the focus, the edges of the image looked soft compared to the F3 next to it. Both the F3 and the C300 had Arri 32mm master primes so they should have been similar. I was told all the cameras were set up with standard gammas, but looking at the C300 it looked quite flat, so perhaps it was setup with the Canon Log gamma and the resulting lower contrast was making the image appear softer. There were so many people at the event that it was difficult to really get at the camera to figure out what was going on. I don’t think something was quite right, I’ve seen better from the C300. I asked if I could record some footage but was told that this was not possible on this occasion as these are pre-production cameras. Shame, I had a pocket full of CF cards and SxS cards. Anyway I have been promised a test shoot very soon.

I really hope that the softness was a peculiarity of that particular camera or the way it was set up as the C300 would for me be fantastic for my storm chasing and extreme weather assignments. I’d love to take one up to Norway in January to see if it sensitive enough to shoot the Northern Lights without having to resort to slow shutters or long exposures (Stop Press… I’ve placed an order and hope to have one in time for Norway). I’ve done the math, and according to my calculations it should just about be sensitive enough at 22,000iso with a f1.4 lens to shoot the Aurora in real time. It would be really cool to try and stream the Aurora live from Norway in January. On other assignments I could shoot using Canon L series glass or my B4 to Canon adapter and get broadcast ready material without needing an external recorder. I still think the Sony F3 with S-Log and an external 444 recorder is capable of a better image, but that’s a significantly more expensive package and more cumbersome, power hungry etc. It’s horses for courses. The C300 for me looks to be fantastic for simple, fast, easy shoots where shallow DoF is desirable, while I would continue to use the F3 where the extra bulk of an external recorder and the slightly more complex S-Log workflow will not be an issue as I think the ultimate image quality will be better. I might just have to place an order for one, especially as the price will be less than anticipated. The price I was offered from Visual Impact today was £9995, available from mid January…. Just in time to take to Norway????

cameras

Canon C300 open house at Visual Impact. Price £9995!

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Crowds gather around the Alexa, F3 and C300

I spent most of the morning at the Visual Impact C300 open house. They had 3 C300’s on show. One on a camera set alongside an F3 and an Alexa, the other was a very simple handheld configuration for people to play with and a 3rd on a stedicam rig.
What impressed me the most was how nice the camera was to hand hold and how good the rear viewfinder is. You certainly don’t need anything extra to shoot with it.
On the camera set I was a little less impressed. At the beginning of the day when I first quickly looked at the 3 monitors I could see no obvious difference between any of the cameras. The monitors were fairly small 20″ Panasonic monitors. However when I went back to take a closer look, for some reason the C300 looked a little soft or not quite in focus. No matter how I played with the focus, the edges of the image looked soft compared to the F3 next to it. Both the F3 and the C300 had Arri 32mm master primes so they should have been similar. I was told all the cameras were set up with standard gammas, but looking at the C300 it looked quite flat, so perhaps it was setup with the Canon Log gamma and the resulting lower contrast was making the image appear softer. There were so many people at the event that it was difficult to really get at the camera to figure out what was going on. I don’t think something was quite right, I’ve seen better from the C300. I asked if I could record some footage but was told that this was not possible on this occasion as these are pre-production cameras. Shame, I had a pocket full of CF cards and SxS cards. Anyway I have been promised a test shoot very soon.

I really hope that the softness was a peculiarity of that particular camera or the way it was set up as the C300 would for me be fantastic for my storm chasing and extreme weather assignments. I’d love to take one up to Norway in January to see if it sensitive enough to shoot the Northern Lights without having to resort to slow shutters or long exposures (Stop Press… I’ve placed an order and hope to have one in time for Norway). I’ve done the math, and according to my calculations it should just about be sensitive enough at 22,000iso with a f1.4 lens to shoot the Aurora in real time. It would be really cool to try and stream the Aurora live from Norway in January. On other assignments I could shoot using Canon L series glass or my B4 to Canon adapter and get broadcast ready material without needing an external recorder. I still think the Sony F3 with S-Log and an external 444 recorder is capable of a better image, but that’s a significantly more expensive package and more cumbersome, power hungry etc. It’s horses for courses. The C300 for me looks to be fantastic for simple, fast, easy shoots where shallow DoF is desirable, while I would continue to use the F3 where the extra bulk of an external recorder and the slightly more complex S-Log workflow will not be an issue as I think the ultimate image quality will be better. I might just have to place an order for one, especially as the price will be less than anticipated. The price I was offered from Visual Impact today was £9995, available from mid January…. Just in time to take to Norway????