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GH2 to super-8 cinema format
  • I'm trying to setup a patch to make the GH2 as similar as possible to a super-8 cinema camera. On the hardware side I have mounted an angenieux 8-68 f1.9 and it's all good with the ex tele mode.

    I would like to change the sensor coverage of the MJPG mode, but it's hard for me to find a way.

    The patch i'm starting with is flowmotion 2. Sensor coverage is great on ex-tele combined with both "cinema 24P mode" and "HBR" mode. On MJPG and 720p the sensor coverage is smaller than the above, and this is what i'd like to fix.

    What I'm trying to achieve, at the end, is a final result of film 3:2 aspect ratio 1920x1280 frame, possibly @24p or 25p.

    Any suggestion?

    thanks in advance

  • 13 Replies sorted by
  • so the 8-64 covers ex-tele fov ? That's surprising...although it now starts around 42mm. I'd look for a 6-66 ang. It's got better glass, but not guaranteed to cover. Everything else is probably impossible except in post. There's a video where they use an eos m to create super8esque look. Google. It's just re-framing, coloring, and adding some grit. But he's using magiclantern raw if memory serves me right, and probably one of their fov changes.

  • The GH2 has a native sensor resolution of 4592x3056, and a sensor size of 17.3 x 13.0 mm. If you crop into 1920x1280, you'll be using 41.8% of the sensor, or a frame size of 7.2mm x 5.4mm.

    Since Super 8 frame size is only 5.79mm x 4.01mm, the lens will be unlikely to cover GH2's ETC sensor crop.

    Btw., I might be the guy who shot the EOS-M in ML Raw mode and an adapted Schneider Super 8 zoom lens to achieve a Super 8 look:

    Nowadays, you can do the same with the BM Pocket 4K: Set it to 1080p sensor window mode, frame guides 4:3 and safe area 80% for a correct frame preview on the display, and in post, crop the image to 1250x866 pixels.

  • @cantsin yes that's u on the thread at eoshd, where I saw it. If @agaraster has mounted the 8-64ang and says it covers the etc frame ....well, my first question would be...does it cover it in all focal lengths...because the 12-120ang coverage on the bmpcc is focal length and fstop dependent, which I've tried. And playing the devils advocate, the lens could very well have greater coverage than the s8 frame size. I own the 8-64 as well as the 6-66 and have thought about removing the beaulieu zoom and exp servos, which is the only way to mount them on a cmount adapter, but the idea seemed fruitless, esp after my tests with the 12-120 as well as the 10mm angeniew, both of which were far less than sharp. I'd like to hear from @agaraster that it really does cover the etc mode in all focal lengths, if he's willing to further test, because I've heard the 6-66 is the sharpest s8 lens ever, and the servo mech looks easier to remove. Beyond all this, which I finally decided was ludditical, I think using grain overlays made from s8, and doing everything in post would arrive at an acceptable product. I remember when kinefinity was testing their s8 sensor and the results were very good...like s8 but better. Shame they didn't pursue it.

  • I started the thread because of a problem with the hack, and here some example that will define some questions:

    1) Do the lens cover the ex tele sensor? Yes, on 24p, HBR and AVCHD 1080i it's perfect, on AVCHD 720p and MJPG it became more tele than the above formats, and that's a pain in the arse.

    image

    2) what is the field of view of the lens in ex tele mode? It looks like something like 24-180, see the picture below.

    image

    3) is it worth the efforts? Yes, definitely yes, I love the taste of the footage I'm shooting, I'll post some video here asap

    4) How can I improve the experiment? Since 720p and MJPEG svga modes are the only settings that can be modified on PTOOL, I would like to give them the same crop factor of the other setting, but it looks like they crop more, and that is unlikely, also because the amount of noise on that is too much.

    @kurth just 4 screws on the bottom side of the servos and you can mount it. Be careful with the backfocus leverage.

    test3.png
    820 x 305 - 398K
    test2.png
    565 x 418 - 295K
  • @agaraster not exactly sure what you're saying with the images. If you shot the 19mm sigma in normal mode , I believe the gh2 had about 2.1x crop factor. That means that the sigma is 40mm thereabouts in normal 1080p on the gh2. The crop in etc mode is over 5x compared to 35mm fov's. So the 8-64 will be something like 42(44) to 320mm more or less. If you want wider , you'll need a quality wide angle adapter on the front end. A .7x would give you about 5.6mm or about 28-30mm in 35mmfov on the wide end. That's why I was more interested in the 6-66mm optivaron, coupled with a .7x WA adapter, it would be around 22-23mm at the wide end. I have a sony hd .7x, just need to take the sony mount off. As for ptools, @vitaliy would know, but I never saw fov being able to be manipulated in any hack I saw. I look forward to seeing samples nevertheless. As I said my tests with the angenieux 12-120 and 10mm 16mm lenses was less than optomistic. I did that on the bmpcc and the g6 which would give similar results although it's not a multi-aspect sensor like the gh1&2. I'd be pleasantly surprised that the s8 lenses were sharper/thanks

  • FYI, the GH2's crop is ~x1.9 (in 16:9)

    Sensor dimension are 17.3mm x 13mm for 4:3, 18.8mm x 10.6mm for 16:9 and around 7.3mm x 4.1mm when in ETC.

  • @brudney...still gives a 5x fl factor for etc more or less. Actually because of the multi aspect sensor, it was even a little less than 1.9. thanks https://luminous-landscape.com/panasonic-gh2-11-mode-revealed/

  • Thank you for the answers but, For smoke sake, guys, try to keep the focus on the topic. This is a thread about the Hack, not about anything else. I have a super-8 Beaulieu camera with a 6-68mm zoom and I have it for 20 years, I made video clip and commercials with it, then I moved to 16mm and now I'm on digital cameras, so I can say I have some experience.

    The GH2 in ex tele mode is giving me back almost the same field of view of the super-8 camera, so I'm perfectly fine with it. No matter what you say about crop factors and comparing super-8 lenses with full frame. There are specific forums out there about that, but this is not the point.

    My simple damned question is: Why the sensor crop factor in ex-tele mode is different from CINE24/HBR to MJPEG and 720p. POINT. I need to use 720p mode because I can modify the resolution with PTOOL but I want the same sensor usage of the CINE24 mode.

    That's it.

    If you want to test the lenses yourself: Get a super-8 camera, make a shot on something, take the lens and mount it on your gh2 in ex tele mode, take the same shot from the same distance, and voilà, you get almost the same field of view. that's it.

  • hey man@agaraster....it's a free world. A thread has its own life. Concerning your principle concern....etc mode is different in 720p, because etc mode is a one to one pixel file. 720p etc either processes the pixels differently ,or more probably, crops 1280x720p out of the sensor, which would do exactly what you're complaining about. One or the other. Seems there might have been a gh1 hack that uprezzed the mjpeg to 1080....but gh1 had no etc mode. There...and goodluck

  • yeah, free world, sorry. Just a lil frustration. GH2 hack has the same ability and actually my MJPEG SVGA mode is tuned up to 1920x1080 but still, the sensor coverage is smaller than CINE24p. Moreover, the MJPEG HD mode, that I left untouched at 1920x1080 is smaller too. For the moment I'm using CINE24p, i'll post some footage asap, the quality is very good.

  • Does the mjpeg etc mode look to be the same fov and same detail in 1080 and 720 ? If so, then you can assume that no matter what the ptools setting, the mjpeg is always 720p or 480 for the svga, is left untouched. Seems I remember that's the case. PM vitaliy or lpowell and ask them directly if real mjpeg 1080 is even possible, would be my next piece of free advice. I don't think mjpeg res at 1080 was ever possible and your stuck with avchd. If that had been the case , many people would be using mjpeg hacks, and they aren't.

  • yep, thanks mate.

  • out of curiosity I removed the motors , easy 4 screws, from the optivaron 6-66mm and it heavily vignettes at 6mm in fhd etc mode on the g6 but covers in hd mode. It gets pretty close to getting rid of the vignetting around 8mm....I imagine about what the 8-64 angenieux would do. It is sharp in fhd at the center. When the reglomatic control is taken off, the lens has clickless aperture and pretty smooth zoom. I have a question....are all etc modes equal ...the gh2, gh3, gh4etc? Next I'll try putting it on the zcam e1 and see if 4k is sharp in the center. I guess that would mean this lens might be useful with a smaller 4k 1/2" sensor like yi 4k with a cmount adapter, which gets pretty close to a s8 frame. I found this thread that motivated me. There's a guy posting named dan hudgins on vimeo who shot footage with the kinefinity s8 camera. Shame that camera never came to fruition. https://cinematography.com/index.php?/topic/30721-removing-beaulieu-quotreglomaticquot-from-optivaron-666/