FEATURE REQUEST - U12K-style crop UI for P4K, 6K, 6KFF/PYXIS

The crop selection on the Pocket cameras, 6K FF, and PYXIS are strange since some aspect ratios are available at some resolutions and not others and it's weird.

Lets say you're shooting for 4K DCI delivery on the 6K FF or PYXIS: You have 6K and 4K 17:9 options which is great but the only two crops that reach above 60fps are around 2K and they're 16:9. After crop them to 17:9, you're now shooting at close to 1/5th your delivery resolution.

Your options are even worse with any other aspect ratio. If you're shooting 2.4:1, you only have one crop available to you. If you need to shoot above 60fps, you need to drop down to 2112 x 1184 or 1920 x 1080 again but you'll have to crop out even more of it. The resulting footage would be just 2112 x 880 or 1920 x 800. That's just 12-10% of the resolution of the next largest 2.4:1 crop. 6:5 shooters have it the worst with just one full-height crop that limits them to 36 fps and no good options below that that offer to same desqueeze options.

Hell, neither of them have high resolution 16:9 crops above 2.1K at all!

All of this would be solved with the URSA 12K style of choosing resolutions. That would make the resolutions and max framerates look something like this:

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         3:2             16:9          17:9           2.4:1          6:5
6K    6048 x 4032     6048 x 3408   6048 x 3200    6048 x 2520   4832 x 4032
          36              46            48             60            36

S35   4608 x 3072     4608 x 2592   4688 x 2472    4880 x 2032   4064 x 3384
          50              60            60             70            46
         
4K    4096 x 2728     4096 x 2304   4096 x 2160    4096 x 1704   3272 x 2728
          58              64            65             80            58
         
2.8K  2880 x 1920     2880 x 1624   2880 x 1520    2880 x 1200   2304 x 1920
          75              90            96             110           75
         
S16   2048 x 1360     2136 x 1200   2176 x 1144    2272 x  944   1880 x 1576
         100              110           120            150           90


The max FPS under each crop is what I'm pretty sure the sensor achieve based on BMD's own readout claims, the IMX410CJK's flyer, and some math lol.

The 1920 x 1080 has been removed altogether as it wouldn't be needed anymore. Shooting S16 17:9 with 16:9 frame guides would get you 2048 x 1152 at 120fps anyway so it's not needed. S35 and 2.8K crops were added as stop gaps between resolutions so you can more gradually trade resolution for higher frame rates and actually increases the max frame rate the camera can shoot up to 144 fps.

You'll notice that the S35 and S16 crops look a little different than the others in that they don't have consistent horizontal or vertical resolutions. This is because while the current S35 and S16 crops are made to match the sizes of those film-formats, these crops are chosen to take full advantage of the image circles of S35 and S16 lenses. This graphic shows what I mean.

image_circle.png (117.47 KiB) Viewed 24557 times

Because of this, no aspect ratio is a strict sub-set of the others which maximizes the resolutions and field of view you can record with those lenses.

A happy side effect of these extra crops is that you can now shoot 2.4:1 at up to 144 fps at 2272 x 944. That's a 20% higher maximum frame rate at 40% higher resolution than you could before. The S35 and S16 3:2 crops are actually larger then their image circles but by using 4:3 and 15:9 guide, you can shoot for the actual aspect ratios of S35 and S16 film respectively.

Lets see how this would effect the Pocket cameras.

Pocket 6K

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          16:9          17:9          2.4:1           6:5
6K    6144 x 3456   6144 x 3256    6144 x 2560    4148 x 3456
          50            50             60             50

5.7K  5744 x 3232   5744 x 3024    5744 x 2392    3728 x 3104
          50            60             60             60

4K    4096 x 2304   4096 x 2160    4096 x 1704    2880 x 2160
         60             60             70             60

2.8K  2880 x 1620   2880 x 1512    2880 x 1200    1944 x 1620
         120           120             120            120


Pocket 4K

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          16:9          17:9           2.4:1          6:5
4K    3840 x 2160   4096 x 2160    4096 x 1704    2880 x 2160
           60            60            75             80

S16   2728 x 1536   2776 x 1464    2896 x 1208    2416 x 2000
          120           120            120            120

2K    1920 x 1080   2048 x 1080    2048 x  856    1296 x 1080
          120           120            120            120


Obviously both gain a lot of aspect ratio options but frame rates pretty much stay the same so this mainly helps with storage, data rate, and monitoring. However I think this UI can be adapted to make Sensor Area selection in ProRes a lot simpler.

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        Pocket 4K                         Pocket 6K
[  4K   ][  S16  ][  2K  ]        [ 6K ][ 5.7K][ 4K ][ 2.8k]
[ 17:9  ][ 16:9 ] [scaled]        [ 17:9  ][ 16:9 ] [scaled]


Both cameras only allow for 17:9 or 16:9 aspect ratios in ProRes at 4K/UHD or HD resolutions and that's the only time that scaling can be used. So when ProRes shooting is selected, only those two aspect ratios are shown and a [scaled] button would allow the user to toggle between 4K/UHD and 2K/HD scaling. The sensor area used can be picked by just selecting one of the resolutions above it. This would be quicker than cycling sequentially between three options and both cameras would gain 2K ProRes recording.

This would be a brilliant solution to the current problem. The 6KFF/Pyxis are cameras that produce amazing images, but are plagued by resolution and aspect ratio inconveniences strictly the result of far too limited options. These cameras support 5 different aspect ratios but with only 8 total resolution options to select from.

This Ursa-style layout would provide the space to offer all the options at all the different resolutions. For a great deal of my work I deliver in 16:9, so I would really want to shoot in full frame 16:9, but instead my only options are to shoot in open gate which records lots of unnecessary resolution I will not be using which uses up storage faster, reduces possibilities regarding frame rate, and shrinks the image being viewed on any 16:9 monitor including the gorgeous one on the back of the camera itself, or DCI which forces me to crop off 6% of the sides of the frame. Neither of these options are ideal.

Another option I would have posited would be similar to the Ursa-style menu but selecting aspect ratios instead, then resolutions are a sub-category under aspect ratio, but since the structure already exists for a resolution first layout I would be all in favor of implementing that.

So anyway, I just wanted to throw my two cents into this conversation and double down on what is being proposed in this thread as a perfect solution to support the many different filmmakers and their needs with this otherwise excellent product line. More options are always better than fewer options!

Another option I would have posited would be similar to the Ursa-style menu but selecting aspect ratios instead, then resolutions are a sub-category under aspect ratio, but since the structure already exists for a resolution first layout I would be all in favor of implementing that.

Actually, it's not really that you pick one and then the other., they're more like two separate options. So if it's set to 6K 16:9 and then select 5K, it switched to 5K 16:9.

I was looking at other 6K cinema cameras that are cheaper or more expensive than the 6K FF and PYXIS. Most of them offer one or more resolution between 6K and 4K to delay the point where someone needs to shoot at 4K. Very few offer resolutions between 4K and 2K but the P6K (Pro) is among the few that do both so it's very strange than the 6K FF and PYXIS don't.

In this price range, the most comparable are Z Cam's E2-S6 and E2-F6. The F6 looks like it could be using the IMX410CQK, too, but it out-classes BMDs frame rates starting at 4K. It offers 4K DCI at 72 FPS and 4K 2.4:1 at 120 fps. It also offers a "low-jello mode" which makes me think it's making use of the sensor's faster 12-bit mode for higher frame rates and the low-jello mode to get the most out of the sensor. A post I found about Low Jello Mode even says that it speeds the readout by about 30% which is pretty much what the gap in the 12-bit readout modes appears to be on the IMX410CQK.

I'm not sure that the 6K FF and PYXIS can quite match that because BMD claims slower readouts than the IMX410's flier at around 4K (it should get near 72fps at 4K DCI but it only manages 66), but if BMD implements the Ursa style of crop selection and utilizes those other readout modes, they can close the gap significantly in terms of resolutions and frame rates. BMD already has a better OS, better RAW codec, better recording media, and a better screen so it would do a lot.

I like your suggestions here. This would indeed improve clarity in the menu and add some cool options to choose from.

I like your suggestions here. This would indeed improve clarity in the menu and add some cool options to choose from.

Thanks! I'm glad you agree!

Edit: I've updated the original post with new crops that take advantage of the S35 and S16 image circles and took out the mention of the sensor's 12-bit readout modes because it felt to unrelated for the proposal. I'm going to include that info here.

You'll notice that there isn't too much of a reason to use the 4K 16:9 and 17:9 crops over their S35 crops. That's because, for some reason, the readout speeds that BMD got out of this range of crops are a lot slower than the sensor should be capable of. If you look at the IMX410 flyer, you'll see that it a 4160 x 2160 crop should max out at 72.36 fps while the 6K FF and PYXIS only get 66.09 fps out of it: a 9% difference. Readout speeds at higher resolutions are pretty much exactly what they should be but after the 6K 2.4:1 crop things begin to slow down. By the time it reaches the S16 crop (the current one), it should be able to readout at about 135fps but instead it's just 120.63 fps: an 11% gap. If this got fixed, the S16 2.4:1 would be able to hit 176 fps and the 4K DCI crop would have a sub 14ms readout speed.

The sensor does have a second 12-bit readout mode that scales up to ~36% higher with horizontal crops that could readout a 4K 2.4:1 at 122fps (probably with some quality loss but still useful) but if the same issues effect that mode then it would fall short at just 117.

This would be a great addition to these cameras.

This is an excellent idea. I'd love to see something like this implemented in a future firmware update.

I'm sure some people probably didn't get pulled in by the title because they're Pocket 6K or Pocket 4K owners so I decide to see what it would look like if this expanded to them.

Pocket 6K (G2/Pro)

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          16:9          17:9          2.4:1           6:5
6K    6144 x 3456   6144 x 3256    6144 x 2560    4148 x 3456
          50            50             60             50

5.7K  5744 x 3232   5744 x 3024    5744 x 2392    3728 x 3104
          50            60             60             60

4K    4096 x 2160   4096 x 2304    4096 x 1704    2880 x 2160
         60             60             70             60

2.8K  2880 x 1620   2880 x 1512    2880 x 1200    1944 x 1620
         120           120             120            120


I assumed this would be weirder looking at the resolutions it supports but it's not that bad. There's definitely less variance in frame rates but I'm sure these options would all be welcome for people who want to shoot a consistent aspect ratio as they scale up frame rates. The only thing that stands out to me is the 5.7K 6:5 crop. Typically it would be 3880 x 3232 to match the highest vertical resolution in that family of resolution but instead I put the current 6:5 crop because I'm not sure it could maintain 60fps at that higher resolution.

Pocket 4K

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          16:9          17:9           2.4:1          6:5
4K    3840 x 2160   4096 x 2160    4096 x 1704    2880 x 2160
           60            60            75             80

S16   2748 x 1544   2788 x 1480    2920 x 1216    2424 x 2016
          120           120            120            120

2K    1920 x 1080   2048 x 1080    2048 x  854    1296 x 1080
          120           120            120            120


The Pocket 4K is very straight forward. I made the S16 family get maximum use of the S16 image circle so it's 16:9 crop is slightly higher resolution than the current one but it's not enough of a difference that it couldn't reach 120 fps any more. The weirdest thing is the existence of the 2K crops. They don't correspond to any sort of image circle for any lens type and they crop significantly more than the S16 crops with likely next to no benefit in frame rate. The only reason I included them is because there's such a gap in data rate between 2.8K and 2K in BRAW and because that crop is a sensor area option when shooting 1080p Prores shooters.

Speaking of ProRes, if the Ursa-style crop selection was adopted by these cameras, they would be the first cameras with ProRes to support it and I think the layout could allow the Sensor Area option to be merged onto this page. This is what I was thinking:

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         Pocket 4K                         Pocket 6K
[  4K   ][  S16  ][  2K  ]        [ 6K ][ 5.7K][ 4K ][ 2.8k]
[ 17:9  ][ 16:9 ] [scaled]        [ 17:9  ][ 16:9 ] [scaled]


Both cameras only allow for 17:9 or 16:9 aspect ratios in ProRes at 4K/UHD or HD resolutions and that's the only time that scaling can be used. So when ProRes shooting is selected, only those two aspect ratios are shown and a [scaled] button would allow the user to toggle between 4K/UHD and 2K/HD scaling. The sensor area used can be picked by just selecting one of the resolutions above it. This would be quicker than cycling sequentially between three options and both cameras would gain 2K ProRes recording.

I have a feeling nobody would be opposed to the scope of this topic expanding to them so I'm going to. I just need to figure out how to reword the title lol

Edit: Added it to the first post.

I decided to make some pictures that demonstrate what the proposed Super 35 crops (magenta) would be compared to what you could get now (cyan).

S35 17:9 vs 4K DCI


S35 16:9 vs 16:9 cropped from 6K 2.4:1 vs 16:9 cropped from S35 4:3 vs 16:9 cropped from 4K DCI

The inner cyan is what it would be if you shot 4K DCI and cropped the sides, the middle cyan is what you would get if you cropped from the current Super 35 4:3 mode, and the outer cyan is if you cropped from the 6K 2.4:1 mode.

S35 2.4:1 vs 2.4:1 cropped from 4K DCI or S35 4:3


S35 3:2 vs S35 4:3

If you want to shoot 4:3 stilll, you can just shot 3:2 with 4:3 guides. It will take up the same amount of space on the monitor.

S35 6:5 vs 6:5 cropped from S35 4:3


All Super35 crops overlayed

I'm reading you Mark. Very interesting. By the way, you had an exchange with John, a while back; about the UMPG2, if I recall. This I believe is the the Fairchild (Now BAe Systems) sensor used (and co-developed, I believe also with BMD) in that camera. It's as John said double gain, 22 bit. It's capable of 240fps, full raster and 600fps HD windowed, but the processing never took it that far. As you can see, and like you suggested, in that implementation, it uses the max ADCs DR capabilities of 88db, or around 14 and a half stops. For a long time it was only exclusively available in this application to BMD, I'm not sure if that's still the case:

https://www.baesystems.com/en-media/upl ... 741700.pdf

Perhaps to the witness - 'It's a small world, but I wouldn't like to paint it...' I was years ago in the military, based within BAe Systems, in the UK.

I'm reading you Mark. Very interesting.

Thank you!

By the way, you had an exchange with John, a while back; about the UMPG2, if I recall. This I believe is the the Fairchild (Now BAe Systems) sensor used (and co-developed, I believe also with BMD) in that camera. It's as John said double gain, 22 bit.

If it's the same conversation I'm thinking of, then it's the one where I said that BMD averages the two 11-bit readouts with 16-bits of precision, which was dumb on my part lol The largest 11-bit number is 2047 so if you just add two 11-bit numbers, the result won't ever been larger than the largest 12-bit number: 4095. So BMD just adds them. Anyway... just wanted to mention that because I realized that afterwards and felt dumb lol

It's capable of 240fps, full raster and 600fps HD windowed, but the processing never took it that far. As you can see, and like you suggested, in that implementation, it uses the max ADCs DR capabilities of 88db, or around 14 and a half stops. For a long time it was only exclusively available in this application to BMD, I'm not sure if that's still the case:

I imagine BMD limited the chip for practical reasons. According to the UMP4.6K's product page, 30fps 4.6K can hit bitrates of up to 274MB/s at Q0. If multiple that by four to get to 120fps, that's 1096MB/s which is already above what you could reasonably write to two CFast cards simultaneously. Of course by the time it's cropped down to 1080p, the bandwidth of the recording media stops becoming an issue but I think once they realized that they couldn't push the higher resolutions any further, they just underclocked the sensor to save power and that limited the frame rates the 1080p window could really hit.

BMD doesn't appear to have done that in the cameras this topic is about though. On the 6K FF and PYXIS, the recording media actually has headroom and could handle more than the cameras can give them.

Speaking of the 4.6K, the Super35 16:9 crop in this proposal for the 6KFF and PYXIS is the exact same resolution as the UMP4.6K. It's image circle is slightly larger than the S35 image circle of 31.11mm but it shouldn't be an issue. BMD uses crops with a much larger image circle (32.79mm) in two of it's S35 9K crops on the Cine 12K. I feel like 32.79mm is unreasonably large so I limited the S35 crops never go above 31.5mm. The S35 16:9 crop is actually just 31.4mm. So yea, if BMD implemented these S35 crops, it would let the 6KFF and PYXIS work kind of like mini UMP4.6Ks lol

Mark, thanks for those images with the comparison magenta and cyan overlays.

Mark, thanks for those images with the comparison magenta and cyan overlays.

No problem! I posted about this on Reddit and Facebook and it seems like a lot of people were confused as to what I was proposing so I figured any visual aids would help.

Speaking of the 4.6K, the Super35 16:9 crop in this proposal for the 6KFF and PYXIS is the exact same resolution as the UMP4.6K. It's image circle is slightly larger than the S35 image circle of 31.11mm but it shouldn't be an issue.

Image circle sometimes and quite often may be an issue, Mark, and limited by photosite size, without recourse to some optical adaption. For example: the Ursa Broadcast G2 achieves 4K '2/3" ' criterion size for B4 lenses, by using the 4K B4 optical 1.5x expander adaptor; the actual UHD photosite target area being considerably larger than a true 2/3" sensor. This adaptor is exclusive to the UBG2, that uses the Pocket 6K sensor. The B4 adaptor available for separate purchase is HD only, since the other sensors cannot easily or readily be adapted optically to provide both a 2/3" 'area, for B4 lenses and UHD resolution at the same time.

Great work on your illustrations.

Image circle sometimes and quite often may be an issue, Mark, and limited by photosite size, without recourse to some optical adaption. For example: the Ursa Broadcast G2 achieves 4K '2/3" ' criterion size for B4 lenses, by using the 4K B4 optical 1.5x expander adaptor; the actual UHD photosite target area being considerably larger than a true 2/3" sensor. This adaptor is exclusive to the UBG2, that uses the Pocket 6K sensor. The B4 adaptor available for separate purchase is HD only, since the other sensors cannot easily or readily be adapted optically to provide both a 2/3" 'area, for B4 lenses and UHD resolution at the same time.

I'm not sure how the expander is related to this though. I'm just talking about a crop from the middle of the sensor just like the 6K FF, Cine 12K, and P4K do with there S35 and S16 crops. The only difference is that I'm suggesting a family of crops that maximize the the usage of the image circle for each aspect ratios instead of being based around a specific resolution (Cine 12K with it's 9K crop) or being a single crop that's loosely based off the format's film size (Mini 12K, 6K FF, and P4K).

In the case of the 6KFF/PYXIS, my proposed S35 crops would also double as bridge resolution between 6K and 4K so that a cinematographer can trade off spatial resolution for temporal resolution in finer increments. In the case of 2.4:1, it would allow them to shoot 70fps at nearly 4.9K instead of needing to drop all the way to the S16 crop. That's a 5.37x resolution increase over how they would achieve that now.

If someone used an expander to make use of the full sensor then they wouldn't need any specific crop modes. Unfortunately it doesn't look like there are many options using expanders with these cameras unless you adapter to PL mount first or use the PL version of the PYXIS. For L mount, this is the only option

https://www.bhphotovideo.com/c/product/ ... r_for.html

Great work on your illustrations.

Thank you!

Edit: Oh! Were you just mentioning that different lenses can produce slightly different image circles and thus had different amounts of vignetting than I showed? However that's true of native Super35 sensors as well because they're all based around a Super35 image circle and not Super35 film. For example, since the Ursa Mini 12K has a 17:9 sensor, it can get away with being 27.03mm wide and it's still smaller than the S35 image circle at just 30.56mm.

The reason I put my limit at 31.5mm instead of 31.11 is just so I could had a little wiggle room to pick resolutions that match almost the exact aspect ratios of the resolutions they'd be scaled to for delivery. So for example, even though 17:9 is 1.888888~:1, I tried to make the S35 crop as close to 1.895:1 as I could in order to match 4K DCI. I figured if I went slightly bigger with the image circle, it would still get the most out of the lens's FOV and if there's any very slight, harsh vignetting, it can be cropped without any issue.

Oh! Were you just mentioning that different lenses can produce slightly different image circles and thus had different amounts of vignetting than I showed? However that's true of native Super35 sensors as well because they're all based around a Super35 image circle and not Super35 film. For example, since the Ursa Mini 12K has a 17:9 sensor, it can get away with being 27.03mm wide and it's still smaller than the S35 image circle at just 30.56mm.

Yes Mark; the requirement for any 'crop' of a nominal size and resolution, is dependent on the often arbitrary selection of off the shelf sensors. Even assuming they are not so arbitrary, as in perhaps the case of the 12K RGBW; they normally have a main target resolution and image circle. Any crop from there, say Super35, will ideally have to exceed 4K usefully oversampling too. This is not always possible in an ideal scenario; and that therefore may compromise the choice of lens too; and in order to achieve a necessary adequate resolution for the crop, the image circle may be way off. This can be ameliorated to some extent by an optical adaptor; for example IBE and Arri make such adaptor for B4 to PL, to take those lenses to full Super35. I confess not having fully studied all your calculations; but this is why often those purely cropping targets may not be always practical.

Any crop from there, say Super35, will ideally have to exceed 4K usefully oversampling too. This is not always possible in an ideal scenario;

These crops do exceed 4K resolution though, by quite a bit.

...and that therefore may compromise the choice of lens too;

Why? The 6KFF/PYXIS already have Super35 crops (4096 x 3072) and (4096 x 2160). The S35 crops I'm proposing are significantly higher resolution than that. Their resolutions are on-par with or greater than what someone could get on the UMP 4.6K but they us more of the S35 image circle so it could look sharper.

and in order to achieve a necessary adequate resolution for the crop, the image circle may be way off.

What's considered adequate resolution in this case? And why would the crop effect the image circle?

This can be ameliorated to some extent by an optical adaptor; for example IBE and Arri make such adaptor for B4 to PL, to take those lenses to full Super35.

Yes, but those B4 lenses still need to cover their target image circle for them to scale up to properly cover a Super35 circle in order to work. If you use an expander to go from S35 to FF then the lens needs to cover a 31.11 area to begin with. If it does then that means it would still work on these crops and provide better resolutions and wider field of view than an Ursa Mini Pro 4.6K, Pocket 4K with a 0.71x focal reducer, and the current 6KFF/PYXIS S35 crops. People were/are happy to shoot with these resolutions on those cameras so imagine they'd be deemed adequate.

When it comes to Super16 crops, I personally feel like the 6KFF/PYXIS are a poor match for them and that a Pocket 4K is a better option if you want to shoot with Super 16 lenses but the cameras already have a Super 16 and 1080p crop so I figured I'd have something to replace them.

I confess not having fully studied all your calculations; but this is why often those purely cropping targets may not be always practical.

I have a whole Calc spreadsheet that maps the current resolutions and readouts of the sensor to a graph and I plot any additional crops along the line on that graph to determine roughly what frame rate could be reached at each crop. I also have columns that calculate each crop's physical width, physical height, image circle, aspect ratio, pixel count, and whether it's full frame, S35, or S16 safe.

Each of those boxes in the illustrations I provided were made at the exact resolution of those crops and placed over a full resolution open-gate image from the 6K FF with an APS-C lens on it. I still have the slightly smaller 31.11 versions of the crops as different layers for my own reference in the Gimp file but they're so close that they weren't worth including.

Just saw a Youtube video of a cinematographer who agrees that the Super35 mode of the 6KFF/PYXIS is really valuable and that they could use some more crops between S16 and 4K. I think this feature request really leans into some of the cameras' strengths and fixes some of their weaknesses to really make the cameras even better for cinematographers like him.

He also makes the argument that the 6KFF is actually is a pretty decent B-cam for the Alexa 35 because it can shoot S35 in at least 4K. It wasn't until then that I considered that, if these S35 crops get added, they would be an even better match because the Alexa 35 shoots at 4.6K, too!

Just decided to add another point of comparison for a 16:9 S35 crop: 16:9 cropped from the 6K 2.4:1 crop. This is currently the least wasteful way to record a 16:9 S35 image circle on the 6KFF/PYXIS. However it still uses slightly less of the image circle than the propose 16:9 S35 crop and it's size on the monitor would only be a 3.8" area on the 6KFF and 3" on the PYXIS.

Looks like the PYXIS has two more crops than the 6K FF now, a 6K and 4K 16:9 crops, so the 6K FF might get those.



https://www.reddit.com/r/bmpcc/comments ... w_options/

Unfortunately, it looks like they're not implementing the Ursa 12K's style of crop UI or doing any lens circle optimized crop families though.

This would be awesome! I hope BM implement this, great work by the way.

Thanks, Metalmonkey! And thanks for voicing your interest!

Looks like the PYXIS has two more crops than the 6K FF now, a 6K and 4K 16:9 crops, so the 6K FF might get those.



https://www.reddit.com/r/bmpcc/comments ... w_options/

Unfortunately, it looks like they're not implementing the Ursa 12K's style of crop UI or doing any lens circle optimized crop families though.

Only missed chance here is that the 4K 16:9 just chops off the top of the 4:3 aspect ratio instead of extracting a wider FOV to give you a, for example, 1.35x field of view.

But given the pixel pitch, an approximate 1.35x 16:9 crop may have used a 4488x2528 frame (1.78:1 aspect ratio) rather than a standard 4K 4096x2304 frame.

That odd size may have presented difficulties in the use of most lenses limited to a traditional Super 35 image circle. The chosen 4096x2304 frame has an image circle of 27.93mm so even Sigma lenses with 28.4mm image circles fit comfortably.

But given the pixel pitch, an approximate 1.35x 16:9 crop may have used a 4488x2528 frame (1.78:1 aspect ratio) rather than a standard 4K 4096x2304 frame.

That odd size may have presented difficulties in the use of most lenses limited to a traditional Super 35 image circle. The chosen 4096x2304 frame has an image circle of 27.93mm so even Sigma lenses with 28.4mm image circles fit comfortably.

The crops I presented in the first post in the Super35 family of crops are all roughly the size of a traditional Super 35 image circle of 31.11mm.

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            3:2             16:9          17:9          2.4:1          6:5
S35     4716 x 3144     4608 x 2592   4692 x 2476    4896 x 2040   4080 x 3400
          33.66 mm         31.4 mm      31.5 mm        31.5 mm       31.54mm

4K      4096 x 2728     4096 x 2304   4096 x 2160    4096 x 1704   3276 x 2728
         29.23 mm         27.91 mm      26.16 mm       26.34 mm      25.32 mm


The reason I aimed for around 31.5mm is mix between needing to have each dimension evenly divisible by 8 and finding a crop that most closely matches the exact aspect ratio of the 4K crops. The 3:2 crop is much larger just so it can replace the 4:3 crop while still giving people who use it something to fall back on. 4608 x 3072 (32.89mm) would work for that, too.

For reference, these are the S35 image circles on other cameras:

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Camera              Width    Height    Circle
Alexa 35 3:2        27.99    19.22     33.95
Cine 12K 3:2        27.29    18.59     32.79
Cine 12K 6:5        27.01    18.59     32.79
Alexa 35 16:9       27.99    15.75     32.12

S35 17:9            27.49    14.56     31.11
S35 16:9            27.12    15.25     31.11

Komodo X            27.03    14.26     30.56
Ursa 12K            27.03    14.25     30.56
Cine 12K 17:9       27.01    14.20     30.52
Pyxis/6KFF S35      24.32    18.25     30.41
Alexa Mini 16:9     26.40    14.85     30.29
P4K 0.71x FR        26.79    14.08     30.19
Cine 12K 2.4:1      27.01    11.21     29.24
Pyxis 6K 4K 16:9    24.32    13.29     27.91
Pyxis/6KFF 4K       24.32    12.83     27.49
Pocket 6K           23.10    12.99     26.50


So you can see that the 6K FF/PYXIS are at the bottom of the list with the Pocket 6K. It's using less than the Ursa 4.6K and the Pocket 4K with a 0.71x focal reducer and obviously it uses far less than the the actual S35 on the Pyxis/6KFF.

That's why I presented separate S35 and 4K families of crops. It gets you the best of both worlds.

Most shows now tend to shoot open gate and crop later. It’s often preffered and asked for on most of the shows I’ve done lately for VFX and re-framing.

I’m not really sure what the real advantage is of shooting actual crops. A bit of data? Maybe a few FPS higher?

JB

John, I’ve been following that practice for all my shoots in the last year or so. Reframing improves the edits between clips in terms of the viewer’s eyes picking up what you want them to notice first.

Most shows now tend to shoot open gate and crop later. It’s often preffered and asked for on most of the shows I’ve done lately for VFX and re-framing.

I’m not really sure what the real advantage is of shooting actual crops. A bit of data? Maybe a few FPS higher?

JB

On the 6K FF/PYXIS, the advantages would be:

• Saving on data like you mentioned. These are cheaper cameras so the idea of shooting outside the image circle is very wasteful for people in this budget. This is especially wasteful if you're using it as an S35 or S16 lens.
• Better use of the LCD screen. If shooting open gate for a 16:9 area, the 5" screen becomes more like a 3" screen. The camera only outputs 1920x1080 so the further the aspect ratio deviates from 16:9, the more letterboxing or pillarboxing is introduced.
• As it pertains to any crop that decreases the vertical resolution, you can shoot at higher frame rates with a crop. Open gate limits you to 39 fps max, while a S35 16:9 would get you up to 60 fps for example. That's way more than a few FPS higher.
  
  Please refer to the table I provided in the original post to see what frame rates would be viable at each crop.

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Camera              Width    Height    Circle
Alexa 35 3:2        27.99    19.22     33.95
Cine 12K 3:2        27.29    18.59     32.79
Cine 12K 6:5        27.01    18.59     32.79
Alexa 35 16:9       27.99    15.75     32.12

S35 17:9            27.49    14.56     31.11
S35 16:9            27.12    15.25     31.11

Komodo X            27.03    14.26     30.56
Ursa 12K            27.03    14.25     30.56
Cine 12K 17:9       27.01    14.20     30.52
Pyxis/6KFF S35      24.32    18.25     30.41
Alexa Mini 16:9     26.40    14.85     30.29
P4K 0.71x FR        26.79    14.08     30.19
Cine 12K 2.4:1      27.01    11.21     29.24
Pyxis 6K 4K 16:9    24.32    13.29     27.91
Pyxis/6KFF 4K       24.32    12.83     27.49
Pocket 6K           23.10    12.99     26.50


Hope people don't mind me bumping this. I'm still beating this horse. I just added more info on S35 image circles for different sensors and crops in other cameras. But I also wanted to add info for S16 crops.

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Camera              Width    Height    Circle
Ursa 12K (6K crop)  13.52      7.13    15.28
Alexa Mini          13.20      7.43    15.15

Super 16            12.52      7.13    14.55

Pyxis/6K FF         12.54      7.08    14.38
BMPCC               12.48      7.02    14.32
Pocket 4K           12.37      7.00    14.29
Alexa 35 (S16)      12.44      7.00    14.27
Pyxis/6KFF (FHD)    11.40      6.42    13.08
Ursa 12K (4K crop)  10.19      4.75    10.19


The image circle I used for my crops is the actual S16 image circle rounded up to the nearest tenth: 14.6mm. You can see that Pyxis 6K and BMCC6K actually get the closest to an actual image S16 image circle of any of the cameras so they do a great job. The problem still remains that it's only available as a 16:9 crop so even a 17:9 crop from that brings the image circle down to 14.18 and brings the resolution down by 6%. A 17:9 sensor crop that maintains a roughly 14.38mm circle only reduces the resolution by 3.5%. Doesn't sound like a lot but it would be noticeable in a 4K project and gets allows the readout to be faster enough for 120fps.

Interestingly, a slightly larger 16:9 crop of 2136x1200 would be exactly 14.55 so I don't get why they didn't pick that.

Mark thank you for all the work and detailed lists. I still dearly hope someone from Blackmagic sees this and implements it.

I only looked at a couple of examples and found discrepancies. My numbers are rounded to two decimal places.

BMCC6K and Pyxis 6K:
sensor pitch 0.00594mm
Super16 is 2112x1184 photosites
frame is about 12.55x7.03mm
16:9 aspect ratio
image circle is about 14.38mm

BMPCC4K
sensor pitch 0.00463mm
Super16 is 2668x1512 photosites
frame is about 12.45x7.00mm
16:9 aspect ratio
image circle is about 14.28mm

I only looked at a couple of examples and found discrepancies. My numbers are rounded to two decimal places.

BMCC6K and Pyxis 6K:
sensor pitch 0.00594mm
Super16 is 2112x1184 photosites
frame is about 12.55x7.03mm
16:9 aspect ratio
image circle is about 14.38mm

BMPCC4K
sensor pitch 0.00463mm
Super16 is 2668x1512 photosites
frame is about 12.45x7.00mm
16:9 aspect ratio
image circle is about 14.28mm

Ah! I had the wrong resolution entered into my spread sheets in two spots. Thanks for pointing that out!

I'm also doing the calculation differently than you are. Instead of doing

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pixel pitch * resolution

I'm doing

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crop resolution / sensor resolution * sensor size

Either methods gets me the same image circle for both of those crops but slightly different dimensions. I don't know which method is more accurate because my method assumes the sensor size is exact but, since pixel pitch is the distance between the centers of adjacent photosites, I think your method might not account for the area of pixels along the edge of the crop.

Across all of my numbers I'm not seeing a variance larger than 0.02mm for the image circles between both methods though.

Mark thank you for all the work and detailed lists. I still dearly hope someone from Blackmagic sees this and implements it.

Thank you for showing interest! I really think these image circle crops can make these cameras feel almost like 2 or 3 in cameras in one.

I agree on that, Mark.

All the overall dimensions are approximate. The only true values are the photosite pitch and the resolution you shoot.

I just updated the resolutions and image circle sizes.

@rick.lang, I'm using your way of computing the crop size but I'm adding one additional column and row to account the size of the edge pixels. The sizes aren't hugely different but resolutions do skew a little lower than I originally had. I also intentionally decided to skew some of the S35 image circles down a little. It still maxes out at 13.5mm but most of the crops are closer to 13.4mm. This is still smaller than the image circles of the Alexa Mini and 35 and below two the Cine 12K's S35 crops.

I also fixed some crops that somehow weren't using resolutions divisible by 8.

Thanks, Mark!