sorry for being blunt, but if you haven’t shot a single panorama in your life, perhaps you shouldn’t be giving advice. if you’re going to be doing CG on this, just send them a reference file that works for you and say that that is what you are expecting to receive and let them figure out how to produce it. Either the DP figures it out or they bring on a dedicated photographer for this. It’s better than offering advice and not being able to answer any questions – which will backfire.
Now I am going to do exactly what I just said you shouldn’t be doing, and give you advice about nodal heads – without using them myself. (though I’ve done my share of panoramas) A nodal head is a device that goes in between the camera tripod and the camera - camera mounted on nodal head which in turn is mounted on tripod – and offsets the camera and allows it to be turned around it’s optical center. For panoramas, ideally the camera stays perfectly in place, and turns around it’s optical center (along the center axis of the lens, in the very middle of the sensor) , so that each image will perfectly overlap with the others, without parallax. (=nearby objects moving more than further ones which is what you get when you move the camera – if you turn around any point other than the optical center, there is an amount of translation if you will – like in 3D when your pivot isn’t properly centered.) Now most cameras do not have their camera mount along the axis of the lens, and none have it in the center of the sensor obviously. So if you put a camera on a tripod and turn it around , you will never be turning around the optical center and will get some parallax, which will inturn give imperfect overlaps, and stitching errors – more on nearby elements, less on further ones. That’s where the nodal head comes in. Properly setup and tested – you can find the optical center (there might be some indications on the camera but as it’s a point inside the camera in 3D space any markers are only partial info) and then turn around it, while mounted on the tripod. In a landscape where everything is far away it’s not so critical – but if you’re inside a building with lots of geometric detail it’s more important – and on a movie set I would say it’s indispensable. The Nodal head usually has some features to turn precisely and easily along set intervals (eg. 30 degree turns), for example clicks you can feel – which is less often the case with tripod heads. Overall, with a nodal head you can gain time and precision, both while shooting and stitching – so it’s a no-brainer to use a nodal head in production. Hope this helps some, but when the client is going to ask for which nodal head to use – you’re back at square one. Nodal heads come with all kinds of functionality and in all sizes and prices, from a simple 30$ metal bracket up to robotized and software controlled devices that run in the thousands of dollars – and they constantly make new ones. Any nodal head should allow to turn horizontally around the optical center – so for just a single horizontal panorama strip that would do – but if you want several horizontal bands, camera pointing up or down or full spherical coverage you will need nodal heads that allow for this (quite common luckily enough). What nodal head to use also depends on camera size/weight and lenses used. With a 180 degree fisheye, doing a spherical image with just 4 images - you don’t need very minute rotation control, with a wide angle you will need some more. If you want to make gigapixel panoramas (which on set doesn’t make much sense) using a normal lens (or tele if you’re crazy), you’ll need very precise rotation control – and time to waste. There’s also one click solutions – where all camera operation and even stiching is automated – for up to full spherical HDRI – but this comes at a cost – and you are also locked in with the results that gives. For very high resolution you can’t beat “just a camera taking lots of images”. And finally, if it’s “just” for highres landscape panorama’s - HDRI or not – in full daylight - you can even shoot those by hand with a little experience. Though I will never claim its “as good” as with tripod and nodal head - just for the sake of it I’ve done some spherical 360 panorama’s inside – and it can be done – certainly acceptable for reflection maps and/or image based lighting – for use as replacement background plates that would be pushing things. From: Paul Griswold Sent: Saturday, November 30, 2013 10:21 PM To: softimage@listproc.autodesk.com Subject: OT: shooting panoramas Hey guys, I am helping out on a documentary that's being shot in China & the subject of shooting spherical panoramas came up. For what these guys are doing, I don't really think there's a need to shoot HDRI's, but I do think having panoramas would come in handy. The problem is, I'm being peppered with questions by the DP about the subject (things like, "this requires a nodal head, right?") and honestly I've never shot a single panorama in my life. I think the DP is way overcomplicating & overthinking things, but since I have no experience I don't want to give him bad advice or information. I sent him a link to the sIBL tutorial page ( http://www.hdrlabs.com/tutorials/ ) and that just added to the amount of questions I'm being hit with. So I was hoping someone on the list might have some experience with this subject & could share some info & advice. Thanks, Paul ᐧ
