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RED SCARLET-X Crop Factors and Data Rates, Visualized

11.9.11 @ 9:50AM Tags : , , , , , ,

Anyone considering the RED SCARLET-X camera should check out this great thread at REDUSER by Phil Holland, which takes a look at the crop factors and datarates of the SCARLET-X. Below is a great visualization of the various crop factors; keep in mind the SCARLET-X shoots in a slightly “windowed” 4K, so your lenses will take on a slightly narrower field of view than the true 5K EPIC (though this window is still, for all intents and purposes, Super35 — the EPIC at 5K is actually larger than S35):

Phil also posts other useful charts, detailing for example that a single $1,1800 128GB SSD stores 46 minutes of 4k footage, and that a lens that yields a 50mm field of view on a full frame sensor is an 80mm equivalent on the SCARLET-X thanks to the crop factor of 1.6X (at 4K). Very helpful for planning… for example, you’re going to want some wide-angle lenses for the SCARLET, especially if you plan on shooting at high speeds (when other cameras drop resolution, they typically use the full sensor size, unlike the RED’s “windowed” mode at higher frame rates).

Link: Scarlet X Data Sheet – REDUSER

[thanks, Matt B]


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Description image 33 COMMENTS

  • I’m really sorry to say so, but with that crop it makes the camera really uninteresting.
    Is that the same problem with the EPIC?

    And other than that is there a reason why RED cameras do crop the image at lower resolution?

    - Sebastian

    • Ryan Emanuel on 11.9.11 @ 12:04PM

      Thats a bit excessive, for sub 10k I think 4k 16bit 4:4:4 RAW is still pretty damn interesting.

      Yes, the epic crops just the same.

      • and do you know why they do that image crop?

        - Sebastian

        • The EPIC is different in that you can shoot full motion at 5K (thus no crop at all). The SCARLET, being its little brother, can’t quite handle the datarate (5K is 14 megapixels, after all).

        • I believe to avoid moire/aliasing issues by
          keeping the captured image pixel accurate.

          The sensor is 5k, so if it used the full sensor to record 2k
          then it would either have to ignore or combine pixels.

          Ignoring (or line-skipping) pixels is the common practice
          for DSLRs but creates bad moire / aliasing.

          Combining the surrounding pixels is very
          processor intensive (i.e. hard to do) but would be better.

          That is part of what Canon is trying to get around by
          lowering the pixel count in their new cameras (i.e. XF100/XF300 and C300)

      • RED MX crops similar.

        EPIC you can shoot 5K @ 120FPS
        4k @ 150FPS

        So on and so forht.

        That’s the big deal about EPIC, along with using the full sensor area, etc.

      • Can we dispel the myth already that Red’s shoot RAW? It’s marketing-speak from Red.

        • Well, it’s somewhere in the middle. Is it compressed? Yes. But is it like other codecs, that bake in (for example) white balance into a compressed video file? No.

        • RED does infact shoot raw. People commonly misinterpret RAW as Uncompressed. Sure you can technically have an Uncompressed RAW file but even Canon and Nikon DSLRs don’t do that, their raw files are compressed (lossless).

          The RED records images that has not been de-bayered, therefore a RAW image. The camera does not bake white-balance, ISO, sharpening, contrast, gamma curves into the file. Yes RED does compress these raw files, but so does every other RAW shooting camera. The Red Epic shoots 3:1 which is mathematically lossless compression. You can shoot at a higher compressions which are considered visually lossless.

          KG, maybe you should do some more research :)

  • So all of this is based on an 8 perf (35mm still “full frame”) standard? That’s awesome if that’s the case, it’s an almost Super35 4K image coming out of that…. so it’s like, the same as a real movie?

  • Weird. In 2K mode (60fps) you need a 10mm lens to get FOV of 39mm, which means wide(r) angle shots are actually not possible in this mode (without strong distortion), right?

  • Lliam Worthington on 11.9.11 @ 10:56AM

    David Rasberry posted on RED that 3.9 should be 3.24

  • So it’s the same problem as with APS-C sensors (my t2i, 7D, etc) – everyones is used it in anycase.

    • it’s not the same – the 7d is always 1.6X no matter what resolution you shoot.

      • Wow, I really mangled my words up there. Obviously I should have elaborated… I meant: Canon DSLRs have the same crop factor, excluding slow motion. In any case, slow motion is a side thought. You don’t shoot everything at 60fps.

        • tru….and as for the crop factor i think the canon cine zoom lenses were made for this camera especialy the canon 14 to 60 mm 2.8 constant apeture .especialy if u shoot at 3k ..the last time i checked the whole 4k Resolution thing was to emulate to a certain extent film, where you would shoot at a higher resolution (giving you the option of post cropping , and works very well for live action since it gives u a bigger plate with means more features) and THEN deliver at a lower reses like 1280*72O …who buys a 4 k 15 thousand dollar camera to shoot 1k? And everone is forgetting the one thing that res gives u that u dont get with other cameras FUTURE PROOFING ..come on people did you forget that u UPGRADE ur sensor in the future maybe even posible close to epic standard ..(close not exsact..bit rate loss and all that) with red dragon coming soon who knows were this camera could rather spend 15k on a great camera now and spend a bit more a litlle on and get a better one later that spend 20k on a canon then spend another 2ok in the futuer for a better one..and as for frame rates i think that their is a firmware update coming soon to better them..i think..(dont quoute me)

  • I had no idea the Scarlet did this! Shooting at 2K seems like a real pain if it goes to a 3.9x crop factor – what if you need the higher frame rate (60) AND you need a wide angle? Doesn’t even look possible with this camera, which I find quite shocking.

  • you can just use SUPER wide fish eye lenses at 2k

  • How is it that the viewing window of DSLRs with or without a crop factor (5d, 7D) remains constant whatever the chosen resolution but this much more expensive camera does not? I’m confused!

    • @ Mike, first it all comes down to processing power. More fps = more data rate. Larger sensor = more data rate. So with the 5d mkII being a vista vision sensor at 22MP, what kind of processor(s) could handle a full sensor read out, especially at higher frame rates?

      To date, none in existence, however dual Digic V’s are said to do a full sensor read out at 30fps…

      Therefore, the Canon DSLR’s on the current market throw lines out – line skipping – while still scanning the entire sensor. This keeps the crop factor from occurring but creates a huge problem: aliasing and moire. Parts of the image are literally skipped!

      RED windows the sensor. All lines are scanned, just not all lines of the entire sensor, it scans a smaller section of the sensor, therefore creating less data rate and processing, but retaining detail. However, there is now less area for your lens to project onto, therefore it crops.

      Quite drastically for Scarlet X.

      Seems like the EPIC is the only way to go to manage both scenarios, or for less money, the C300. Sure it has less resolution but not necessarily less sharpness and arguably better ISO and color performance – all at s35.

      In all honesty, since the Scarlet does not take more than 12 fps at 5k (s35), the Scarlet is NOT a s35 camera and especially not when you do slow motion.

  • Can’t you use 16mm PL lenses when you shoot 2k and need higher framerate? I heard that lenses are quite inexpensive on eBay.

    • s16 glass is the go…..

      i shoot a lot of action sports and the scarlet fitted with a nice s16 zoom shooting 2k seems like a good idea to me!

      its not long ago that anyone would have been happy shooting 2k with those kind of frame rates…..

      for me the cost of a camera that will produce the same frame rates as the scarlet is just way too costly and most of what does exist in my price range either drops down in resolution or limits me to certain frame rates…..

      just some thoughts, you could easily have a 35mm lens in your pack for any realtime situations……. if it “had” to be 4k?

      • I thought of the S16 thing too, but I honestly think that’s losing out on the main feature of the RED. 2K images also show noise more than 4K.

  • I you can get the right adapters, I dont see why you couldn’t so you couldnt fit lenses from a 4/3rds or 2/3rd systems when overcranking so as to give you a wide or ultrawide fov. Its a drag that you need a second set of glass but hey, you just saved $20K

  • I believe this could be avoid by shooting at 4K through Samurai Atmos?

  • WHAT? crop of 6.4?? and if you want to buy a set it’s not $10.000, but $20.000!!! Scarlet is not interesting at all!

  • That 1.6 FL factor represents quite a bit of f-stop loss if you will use full frame lenses. Super35 is about 1.5 FL factor compared to full frame 35mm coverage (24mm x 36mm approx). So Super35 lenses would be a closer fit and preserve a more comparable f-stop and look. I am not sure without doing the math whether most 16mm PL lenses would cover the corners of a 1.6 FL factor coverage area or not. I continue to think that Sony, Arri and Panasonic produce cameras with superior image quality … and that to a large degree RED tends to muddy the waters with market hype rather than provide cinematographers useful info on their products. Yes it is cheap. Borrowing someone else’s still camera image sensor is always going to be cheaper than engineering a Super35 sized low noise CMOS sensor and the lenses to match it. But you get what you pay for when it comes to image quality. So, if the film won’t get shot unless you use a DSLR or RED camera, then it definitely makes sense to go the way the budget dictates, but if your goal is best quality image, then these may not be the best choice. IMO

    • Fatzpatrick on 11.11.11 @ 5:24PM

      ED, you are so right! The one’s who make a living doing work day in and day out have to relie on a camera that works with GOOD GLASS!! I know just what I get when I put a Cooke on an Sony, Arri and Panasonic. Take a look at cable and network TV and you will see that thes camera’s are the work horses.