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  1. Member
    Join Date
    Apr 2006
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    United States
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    I have an upcoming project and could use some advice on finding a suitable camera.

    I need to take live video of the touchscreen on a car's dashboard, send it over SDI to display on a projector.

    I've been experimenting with a Marshall CV350 (http://www.lcdracks.com/servers-cameras/HD-SDI-cameras/CV350-minicamera.php) which isn't bad, except I have problems getting the exposure set correctly so it doesn't blow out the light parts. More troubling, it's grainy at low light levels and I have problems with the picture rolling or flickering at lower brightness levels, I assume it has something to do with the refresh rate of the touchscreen but adjusting the shutter speed doesn't seem to help. Note that the camera is limited to 29.97 and 59.94fps.

    Has anyone done this successfully before? Or can anyone recommend a source for more information on the best gear and setup to make this work? It's somewhat unique so I'm having trouble finding people to ask.

    It's preferable that the camera have SDI out, but I can work around it as long as I can convert the output to SDI for a 100' run.
    - Dave
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  2. Member Cornucopia's Avatar
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    Oct 2001
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    1. No matter what, you WILL have problems with pic rolling/refresh flicker unless both your touchscreen (monitor) and your camera were genlocked to the same master clock source. $$$.
    Even with both operating at, say nominally 60Hz, they will drift because of independent inexpensive crystal sync clocks, plus getting them to start their cycle EXACTLY at the same time is rare. That's why the genlock.

    I say find a setting that is common & acceptable. Most monitors refresh at 60Hz, so try a cam that can do 59.94 AND exactly 60 and take whichever works best.

    2. Light the interior of the car to bring up close to level of outside the car. That will both make the contrast be less of an issue, and also push the sensor into a much less noisy range.

    Scott
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  3. Member
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    There's no way that I can genlock the car's screen because these are just production cars. I don't have any special access to them beyond what a regular driver will have.

    Your recommendation is basically what I plan on doing, but am looking for advice on cameras that will have that flexibility. It seems that many have 25/30/50/60 and others have 29.97 and 59.94, but none seem to cover everything. Since I'll be shooting a variety of cars I want to have the most flexibility I can get in case there are differences between vehicles.

    Agree that lighting the interior is important. I will do that the best I can. The problems start to occur when pushing the exposure high enough to see the detail in the black buttons and knobs around the screen. Usually that requires enough of a boost that the screen itself blows out, even with a fairly bright interior.
    - Dave
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  4. Member Cornucopia's Avatar
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    How many do you need to shoot? If not too many, I recommend RENTING a pro/broadcast HD video or cinema camera that has widely adjustable zoom & great exposure latitude, where you can adjust the knee&shoulder to get a flatter contrast source which you can tweak in post. Or similarly if it has RAW or HDR capability.
    Also, many of those higher end Sony & Panny broadcast cams SPECIFICALLY have a "clearscan" or similar feature for combatting problems just like this.
    Alternately, you could try some of the Blackmagic or similar indie dig-cinema cams, as they are quite flexible in setting their shooting framerate, IIRC. Maybe a specialty scientific cam, designed for wide range of realworld subjects.
    Most, if not ALL consumer cams, DSLRs & sport cams just aren't up to scratch for this, and that is especially true of security cams. Unless maybe the top of the line with 4k & HDR/WDR. Won't even talk about phonecams with their VFR editing nightmares.
    Any cam with an output can be adapted to work w SDI.

    Shoot from immediately behind back window (to avoid extra glare/reflection - too bad you can't ditch the window). Drop front seats as much as poss. and put lights at sharper key & fill angles than normal to get better chiaroscuro, but then temper it with a minor fill-in light at the cam such as a ring light.
    Scrim/gauze your lights to make them very soft. Possibly add dusting/matte spray on subject to reduce hard glare further.

    My suggestions are pushing you toward the higher/pro end for a reason: this specialty, exacting kind of gig is the kind of gig that requires pro gear, pro mindset & skills.

    Hope that helps,
    Scott

    ...or you could just cheat like Hollywood would do it and shoot a reference set of clips and then shoot the screen "Blue'd" out and composite a clean/synthetic graphics overlay and a matted hand if needed in the shot.
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  5. Member
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    This isn't for a recording... this is a live shoot, or a series of live shoots. The green screen trick isn't an option here.

    But I think you're spot on... I need to look at a pro-level broadcast camera and really focus on the lighting to keep everything smooth and even.

    Thanks.
    - Dave
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