All posts by alisterchapman

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FCP-X, My first look.

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OK, I took the plunge and tried FCP-X to see for myself what it’s like, despite all the negative comments about it I though I would give it the benefit of doubt and try it for myself..
It’s very fast, the way you scrub through clips in the bins is impressive and the built in filters are a good start. I also note that decklink now have drivers for most of their cards so HDSDi out is now available, certainly things are strating to come together with FCP-X.

BUT… I wanted to add a simple colour correction to a clip, no problem with that using the colour board, but then I tried to add a keyframe so the correction would change slightly of the duration of the clip. Simple, basic stuff…. But you can’t. You can’t keyframe the majority of FCP-X’s effects, only the motion effects and a couple of others. This is such a simple, fundamental thing that I take for-granted with every other pro edit package. It’s not an advanced feature and yet it’s completely missing. FCP-X is not ready for me yet, too much stuff missing to make it useful as my NLE of choice. If I can’t keyframe effects then for me this is not a “Pro” edit package, it is a consumer product. Perhaps over time it will mature and things like this will get added. But I have on-going projects and who knows how long it will take to get FCP-X up to speed, it could be a year or more. So I either stick with now somewhat long in the tooth FCS or jump ship to Premiere CS5.5 which looks better and better by the day or maybe leave the Mac platform altogether and go with Vegas or Edius. Of course Avid is still an option too.

cameras

Motion “Judder” on the FS100 and other video cameras at low frame rates.

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There have been a number of threads in various forums about the way the images from the new Sony FS100 appear to judder or stutter when shooting at 25P or 24P. Most of the complaints appear to be coming from PAL areas where shooting 25P is common. This is not an issue unique to the FS100, in fact motion judder is often more noticeable with video cameras than film cameras even though the frame rates and shutter speeds may be exactly the same. Why is this?

One of the key issues here and I believe a very strong clue to what is going on is that most complain that the issue is most pronounced in areas of high contrast.

Our visual system picks up edges and other areas of high contrast to detect motion, in areas of high contrast any non-smoothness of the images motion will be more noticeable. The higher the resolution/contrast or more precisely the higher the MTF of the camera system the more we will notice judder and stutter.  Just take fast motion in an Imax film as an example, it stutters like crazy.

The FS100 and similar high contrast/resolution cameras will appear to stutter at low frame rates more than a low contrast/low resolution camera. Edges in film are almost never instant changes from black to white, there is almost always some smoothing or dithering caused by the grain structure of film. So when you consider the FS100’s near complete lack of noise, which through it’s random nature will help mask judder and stutter and you have a worst case scenario. A camera with sharp edges and no noise.

Another strong contributing factor is the use of detail correction that adds a very definite, hard, non-motion blurred black or white edge around any areas of medium to high contrast, so unlike the very slightly dithered edges we would see in film we have instant light to dark or dark to light transitions occurring over a single pixel. In the case of a pan that hard edge is going to step uniformly from one position to the next, it won’t have any motion blur and it will increase edge contrast compounding the images judder as our visual system will notice these hard edges jumping from one place to the next.

The PMW-F3 although it uses the same sensor is less prone to this effect as it has a more sophisticated DSP and uses less detail correction and more aperture correction for image sharpening. Aperture correction blurs with motion as it is a type of high frequency boost and as you pan the camera the motion blur of the image reduces high frequencies so the amount of correction also drops thus helping smooth edges as you pan.

You also need to consider the results of watching 25fps video on a computer monitor typically running at 60hz. You will get judder as 25 does not go into 60 evenly, this helps explain why this “issue” is getting more airtime in Europe than in the US where 24P with pull up to 30P is common and of course 30P will display on a 60Hz monitor with no additional problems.

So in the case of the FS100 (or other cameras exhibiting this effect),  I would suggest turning off the detail correction circuits or at the very least reducing the detail level if you are shooting high contrast images or anything with a lot of motion. It would also be interesting to compare similar pans at different speeds with some gain added to see if that helps.

I don’t think this is, as claimed by some, to be camera fault, more likely a result of a very clean, detail corrected image. Even an EX1 or EX3 will do similar things if your detail settings are too high. It’s not unique to the FS100, just one of those things that can happen when you have sharp pictures. When I watched the Sony F65 4k demo film “The Arrival” I noticed a similar increase in motion judder compared to film, again I put this down to high edge sharpness catching my eye and making me notice the cameras motion more acutely. Ohh that F65 stuff looked stunning!

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Why using negative gain can be bad, unless you have an F3.

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One way to reduce the noise in a video camera image is to reduce the cameras gain. We all know that increasing the gain to lets say +6db will increase noise and generally the reverse holds true when you reduce the gain, the noise typically reduces and this may be helpful if you are going to do a lot of effects work, or just want a clean image.

However in most cases negative gain reduces dynamic range as it will artificially clip your low key parts of the image. The brightness range is restricted by the cameras DSP (Digital Signal Processor), it only has so many bits of data to sample the sensors output, from dark to light. If you reduce the gain the highlight handling doesn’t change (DSP bit depth limited) but your entire image get shifted down in brightness and as a result you will clip off some of your shadow and dark information, so your overall dynamic range is also reduced. Dynamic range is not just highlight handling, it is the entire range from dark to light. 3db is half a stop (6db = 1 stop) so -3db gain reduces the dynamic range by half a stop.

So for cameras like the EX1 and EX3 or even PMW-500/PDW-700 using negative gain can be a bad thing to do. You need to be aware that there is a trade off of noise against dynamic range and need to be sure that the small noise benefit are worth the sacrifice of some latitude. The problem is further compounded on the EX1 and EX3 where the use of -3db gain also reduces the peak white recording level by 3db and with Cinegamma 2 this will prevent you from actually reaching peak white (unless you change the gamma curve gain).
Interestingly the PMW-F3 has an excess of dynamic range for the normal gammas and cinegammas and the processing appears to take advantage of this to keep the images very clean. When you shoot with the standard gammas and cinegammas on the F3 the cameras base ISO (sensitivity) is 400 asa at 25p. This gives a very clean, ultra low noise image with 11.5 stops of dynamic range. When you switch the camera to S-Log, which gives a greater dynamic range (approx 13 stops by my estimation) the base ISO increases to 800 asa.  Looking at some of my S-Log test footage a clear increase in under exposure latitude can be seen when you use S-Log. I suspect that the “0db” point in the F3 is actually 800 asa as used by S-Log, where maximising dynamic range and using the full sensor range is the priority. Meanwhile with standard gammas, which are limited to 11.5 stops anyway, you can reduce the gain by 6db (1 stop) sacrificing one stop of underexposure but still have the full 11.5 stops but with 6db less noise.

lenses

Adaptimax Lens Mount Adapters for PMW-F3, Canon and Nikon.

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Adaptimax F3 to Canon and Nikon lens mounts

I was sent a couple of Adaptimax lens mount adapters to test on my PMW-F3. I have used some of their EX3 adapters in the past and these worked very well. The new PMW-F3 adapters are finished with a very nice hard black anodised finish and look very smart indeed. I had 3 adapters to try, one F3 to Canon and two F3 to Nikon adapters. The Canon adapter is a “dumb” adapter, so there is no way to control the lenses iris. If your using Canon lenses this means using a DSLR body to set the iris before using the lens on the F3. Obviously this is not ideal, but you do have to consider that there is a massive range of lenses that can be used with this Canon adapter via a secondary adapter ring.

Canon’s flange back distance (the sensor to lens distance) is the shortest in the DSLR world. So this means that there is space to adapt to other lens mounts with longer flange back distances such as M42, Nikon, Pentax, Pentacon etc. This opens up a whole world of possibilities as now you can use those nice M42 Zeiss lenses that can be picked up cheap on ebay by adding a cheap M42 to Canon adapter.

Nikon 50mm f1.8 with Adaptimax F3 Mount.

If you have already invested in Nikon fit glass then you can use a Nikon to Canon adapter or you can use one of Adaptimax’s purpose built F3 to Nikon adapters.

There are two varieties, the original Adaptimax and the Adaptimax Plus. The Plus version includes a long screw that pushes the iris pin on the rear of the lens to give you iris control even when the lens does not have an iris ring. While this is not as elegant as MTF Services rotating adapter barrel, it works fine and the simplicity of the design means the adapter is a little cheaper. The standard version has no iris control, so you need to ensure your lens has a proper iris ring. Priced at £255 for the standard adapters and £265 for the plus versions these are good value for money.

cameras, Travel, Uncategorized

Night Flyers. Shot with PMW-F3 in Singapore

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I’m currently in Singapore staying at Clarke Quay. Most evenings a group of radio control kite flyers from a local store (goflykite.com) bring out their illuminated kites and fly them in the local park. It’s very pretty and seemed an interesting thing to try and shoot with my F3. As I’m travelling light, trying (and failing) to keep within a 20kg baggage allowance, I don’t have a tripod and I’ve only got a couple of lenses, my trusty 50mm Nikon f1.8 and my Tokina 28-70mm f2.6 zoom. Most of this was shot with the Nikon lens at +6db. I really wish I had a tripod and a longer lens! I did a little bit of grading work here and there to balance out the very orange street lights a little.

 

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Today3D Electronic Follow Focus and 3D Rig Controller. FIZ

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Today 3D FIZ Controller

Here’s a very exciting new product I was first given a sneak preview of at Cinegear in LA a couple of weeks ago, but now I have had a slightly longer look and a chance to take some pictures at Broadcast Asia. It comes from a new name to the market, Korean based Today 3D, but don’t let that worry you, I know some of the guys behind this and they know what they are doing. In addition many of the products coming out of Korea in recent years have been very good, like the NextoDI range of media backup devices. The device is a full wireless electronic follow focus designed primarily for 3D applications. There will be different models capable of driving up to 8 motors for full stereo focus, zoom, iris, interaxial and convergence control down to an entry level 2D wireless follow focus.

Today3D controller screen

The hand controller is beautifully well built, machined out of a solid block of alloy and it feels reassuringly solid, if just a little heavy in your hand. On the right side there is a nice big, silky smooth focus control that sits nicely in your hand. On the face of the controller there is a slide control that would normally be used for the other functions such as convergence or most commonly interaxial. The unit is full programmable via a small joystick and menu system with a multicolour display giving you information about your focus distance, zoom position and interaxial etc. It runs off rechargeable Canon DSLR batteries which easy enough to get hold of wherever you may be. The final price has yet to be announced but I have been reassured that it will be extremely competitive, probably a lot less than a comparable C-Motion controller. It won’t initially come with motors but it has the industry standard motor interface so can be used with motors from Heden, Preston, M-One etc. It’s a great looking piece of kit that really feels built to last. I’m hoping to get hold of one for a full review and test drive in the near future. There are also some other interesting 3D products coming from Korea including some innovative transparent alignment charts! Watch this space.

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PMW-F3 S-Log and Cinegamma quick look.

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Hello from hot and steamy Singapore. I’m at broadcast Asia doing some presentations on the PMW-F3, FS100 and 3D. On the Sony booth they have a PMW-F3 with all the options installed including S-Log and what also appears to be the 3D link firmware (mission for tomorrow – investigate 3D link). So I decided to quickly grab a couple of test shots with both S-Log and Cinegamma 1 to see how much of a difference there was. I was only able to record to the internal SxS card, but the results were quite enlightening. This was all done very quickly, so it’s not particularly scientific or accurate, but it does prove beyond any doubt that S-Log brings a significant boost to the dynamic range compared to the cinegammas. I estimate it gives you between 1.5 and 2 more stops to play with. Given that the F3 is already tested and shown to have around 11.5 stops with the cinegammas, this means that the F3 with S-Log is in the 13 to 13.5 stop range, very impressive indeed.

The shot is a pan from the darker side of the Sony booth to the very bright camera set. Exposure was set using the bright end of the shot and setting the iris so that the hotspots  in the image were just below clipping, the idea being to look at what was going on in the shadows to get a feel for the dynamic range. Click on the images below a couple of times to get to the full resolution version if you want to see that.

Cinegama 1 Bright Part
S-Log, bright part, un graded.
S-Log bright part, graded.
Cinegamma dark part.
S-Log Dark Part

What’s most striking is the difference in the shadow areas in the S-Log footage. Given that the peak white exposures were roughly the same (108ire) there is a huge difference in the darker shadow areas with much more information in the S-Log. It also surprised me just how well the bright part of the S-Log clip graded. Do remember that these clips were taken from recordings on the SxS cards, so they are 8 bit, 35MB/s.

I’ve put together a sequence of these clips for Vimeo. Click Here to go to the video on vimeo. The final test that I did, which you will see in the vimeo clip is to try to grade the shadow areas of the Cinegamma to bring them up to match the S-Log. The result was nowhere near as pleasing as the S-log as lifting the blacks introduces a lot of extra un-wanted noise and it still does not have the contrast range of the S-log.

cameras, Uncategorized

Sonnet SDHC to SxS Adapter Review.

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I recently reviewed the rather excellent Sonnet QIO I/O device that allows you to very quickly ingest material from SxS cards, P2 cards as well as SD cards to your computer. Along with the QIO I was sent a Sonnet SDHC to SxS card adapter to take a look at. Now I’m going to lay my cards on the table here and say that I strongly believe that if your going to shoot with an XDCAM EX camera you should be using SxS cards in order to get the best possible reliability. However as we all know SxS cards are expensive, although a lot cheaper now than they used to be, I remember paying £600 for an 8Gb card only 4 years ago!

So ever since the launch of the XDCAM EX cameras, users including me have been trying to find alternative recording solutions. I found that it was possible to use an off-the-shelf SD card to express card adapter (the original Kensington Adapter) to record standard frame rates on class 6 SD cards in the EX cameras.  However the SDHC cards stick out of the end of the generic adapters so you can’t close the doors that cover the card slots in the cameras. Following that initial discovery various companies have brought out flush fitting adapters that allow the use of SDHC cards. Then about two years ago Sony openly admitted it was possible to use an adapter in the cameras and released their own adapters (MEAD-SD01 and MEAD-MS01) as well as making some firmware changes that made using adapters more reliable. The key point to consider when using an SxS adapter and SD cards is that the media, the SD cards, are consumer media. They are produced in vast quantities and the quality can be quite variable. They are not made to the same standards as SxS cards. So I choose to shoot on SxS whenever possible and I’ve never had a single failure or unexplained footage loss. BUT I do carry a couple of adapters and some SD cards in my camera kit for emergencies. You never know when you might run out of media or find yourself in a situation where you have to hand over you media to a third party at the end of a shoot. SDHC cards are cheap and readily available. You can buy an SDHC card just about anywhere. I’d rather switch to SDHC cards than try to do a panic off-load to a backup device mid-shoot, that’s a recipe for disaster!

Sonnet SDHC adapter for SxS Camera Slot

Anyway… on to the Sonnet SDHC to SxS adapter. It feels as well built as any other adapter on the market. It is mostly metal with plastic end pieces that are made from a nice high quality plastic. I have other adapters that use a very brittle plastic and these can break quite easily, but this one appears to be well made. The SDHC card slots into a sprung loaded slot in the end of the adapter making a reassuringly positive sounding click when it’s latched in place. Once inserted the SDHC card is slightly recessed into the adapter. This is good as it helps prevent the SDHC card from being released from the adapter as you put the adapter into the camera. It means that as you push the adapter into the camera you are pushing on the end of the adapter and not on the SDHC card like some other adapters I have used. To remove the SDHC card you simply push it quite firmly, further into the adapter until you hear another click and it then pops out far enough to be pulled out. This is certainly one of the better made adapters that I have come across.

To test the adapter I used some Transcend class 6 SDHC cards as well as some Integral Ultima Pro class 10 SDHC cards. I used the adapter in my PMW-F3 with firmware version 1.10 as some user have reported problems with other adapters and this firmware revision. I was able to completely fill the cards shooting using S&Q motion at 50fps or 60fps using long and short clips with lots of motion. This is I believe the toughest test for these adapters as the recording bit rate is close to 70Mb/s. I had no issues at all with either type of SDHC card and there was very little delay between finishing a recording and being able to start the next, a good indicator of the cards high performance. I also tested recording very long clips to ensure that there would be no issues when the camera breaks the recording into 4Gb chunks. Again, no problem.

So if you are going to use SDHC cards and an SxS adapter I would suggest you consider the Sonnet SxS adapter. It’s certainly cheaper than the Sony adapter. Sonnet are a large business with a wide range of products and a global distributor and dealer network, so you should have no problem finding a local supplier.

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Can you see the difference between a 8 bit and 10 bit camera output?

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The question is can you see a difference between a camera with a 10 bit output and one with an 8 bit output? This is being asked a lot right now, in particular in relation to the Sony FS100 and the Sony F3. The FS100 has an 8 bit output and the F3 is 10 bit.

If your looking at the raw camera output then you will find it just about impossible to see a difference with normal monitoring equipment. This is because internally the cameras process the images using more than 8 bits (probably at least 10 on the FS100, the EX3 is 12 bit) and then convert to 8 or 10 bit for output so you should have nice smooth mapping of graduations to the full 8 bit output. Then consider that most LCD monitors are not able to display even 8 bits. The vast majority of monitors have a 6 bit panel and even a rare 8 bit monitor wont display all 8 bits as it has to do a gamma correction at 8 bits and this results in less than 8 bits being displayed. 10 bit monitors are very rare and again as gamma correction is normally required there is rarely a 1:1 bit for bit mapping of the 10 bit signal, so even these don’t show the full 10 bits of the input signal.  So it becomes apparent that when you view the original material the differences will not normally be visible and often the only way to determine what the output signal actually is is with a data analyser that can decode the HDSDi stream and tell you whether the 2 extra bits actually contain useful image data or are just padding.
Where the 8 bit, 10 bit difference will become apparent is after grading and post production. I wrote a more in depth article here: Why rendering form 8 bit to 8 bit can be a bad thing to do. But basically when you start manipulating an 8 bit image you will see banding issues a lot sooner than with 10 bit due to the reduced number of luma/color shades in 8 bit. Stretch out or compress 8 bit and some of those shades get removed or shifted and when the number of steps/shades is borderline to start with if you start throwing more away you will get issues.