Are chrome balls a thing from the past?

[panthon]

Hi there!

I've done several chrome balls-based HDR images in the past, but lately im seeing more and more tutos about using a fisheye lens for that purpose. Mainly aiming at 3d objects inside live action footage, I wonder what are the benefits and drawbacks of each setup. A classic example of my needs is when u are allowed to be on the stage where a commercial is being shot, take some HDR pics of the clean plate and later on, use the same lighting on the stage on your 3d models for an accurate and fast match. Here in this HQ diagram , u can see the two setups i can think of without going for a spheron cam.
Any help on this topic will be greatly appreciated! What do u recommend? Can you get same results with both schemes?

Thanks!

[aphex79]

here is a link using fisheye: http://www.cgtechniques.com/tutorials.php

[panthon]

Thanks for the link aphex, i will take a look!

[Clifton Santiago]

I've used the Fisheye method and created the panorama with Realviz stitcher. I think its the best panorama stitcher because it allows you to create a "template" so each panorama exposure is stitched identically.

However, you still end up with mis-alignment errors at the seams, and its practically impossible to get the upward (sky) shot to properly stitch into the lateral shots if you have moving clouds.

I think the best way to go is to hire a good photographer that owns the spheron cam. My guy charges a reasonable day rate and can take several HDRI panoramas at a site visit: www.spheroview.com

[dimo]

Hi,

a big problem with the chrome ball is the uneven resolution. The resolution at the edges of the ball gets very bad. I think it's not a big problem as long as you only need the info for lighting. But if you want to use the map as a reflection map as well you need highres panoramas. Spheron's resolution is limited (But enough for most cases) and it's not as fast as taking several photos with a good Digital Camera on a tripod.

Here's a new one:

http://www.roundshot.ch/xml_1/intern.../d925/f934.cfm


Best Regards,

Dieter

[instinct]

we're not even using fisheye lenses as they introduce a lot of non-linear distortion. we shoot a lot of images, stitch them with ptgui (wich is 50 bucks and has beaten realviz in some pre-purchase tests), and then create multiple exposures. There is some handwork to be done (retouching errors and differences etc) but the results arent bad at all. The cam we're using also outputs 16bit, so we dont need as many exposure passes as with a jpg cam.
SpheroCam has some advantages and a lot of disadvantages. Just to name some :
You get all exposures in one long shot wich is nice, BUT it introduces a lot of problems. If there's moving objects you get really crazy artifacts wich make HDRs unusable sometimes. Clouds or wind in trees is enough to make it no fun. It takes pretty long if you want full res (we did some comparisons for a spot that was shot in norway). The full res pic took 30 mins. That's impossible to do if you need to create HDRs while on set. The crew is going to kill you. And mind you, you would have to close a road for 30 minutes (we're doing mainly car stuff). Full Res means 10k currently. With the stitching method our panos are 30k+ if needed.
Just some thoughts..

Edit: Damnit, Dimo bet me ones more lol

Regards,
Thorsten

[panthon]

Thanks for your answers! I plan to use a canon eos 350 D attached to a laptop while using an automatic bracketing capture program like DSLR pro. I like my chrome ball but maybe it´s time to move forward.

Dimo: that's massive

Clifton: I would like to be able to create the process all by myself, but thanks for your advices regarding stitcher.

Instinct: That's a new way for me and i will take a look at it. On set. photography guys tried once to kill me and destroy my precious HDRBALL because i spent 10 min taking some pics, so go figure...

[dapeter]

Don't even bother trying to stitch them together yourself - you'll go crazy. Plus, every pano you take will need some tweaks to the match points, so it's not like you'll take 1 pano, set up a template stitch, and be able to use that for all the other ones you ever do.

My advice - get the widest angle lens you can get, and PTGui, and something like Panosaurus. PTGui really does work wonders, and you can set it up like this:

Take your series of circular exposures, then create a folder on your computer for each exposure. Rename each image so they all match across the exposures (so, for instance, if the straight up shot is named img14.jpg in one folder, make sure in all the folders the straight up shot is named img14.jpg). Now, stitch one of the exposures using PTGui, and save the PTGui setup file into this folder. Copy the PTGui file to all the other folders, then all you have to do is open this file and it will use the images from that folder in the stitch. So, you only have to stitch 1 series of pano's, then open and render the other ones.

Ohh, and if you think it will be quicker to take the photos, the chrome ball is much quicker. I can probably get a series of chrome ball photos done in 5 minutes (6-8 exposures each from 2 angles). The last rectilinear camera lens pano I did took at least 45 minutes altogether (6 exposures each of 38 different angles).