PDA

View Full Version : HDR -mounting reflective sphere to tripod?



JGary
07-06-2007, 08:45 AM
I'm looking to make a small portable HDR setup using either a Dube 2.875" hollow steel ball or a McMaster-Carr 3" solid steel bearing mounted to a tripod. My question is, how would I mount either of these to a tripod? Would I need to have them machined with a threaded hole, or would a glue like epoxy work?

Links to the two different types of spheres I'm considering.
http://www.dube.com/dube/index.html
www.mcmaster.com/catalog/109/html/3366.html#.

Thanks for any help,

warrenwc
07-06-2007, 11:16 AM
Aside from the attachment problem, a single pole that you can set up will give you less to clean up in the photo.
You CAN just use a silver Christmas ornament.

JGary
07-06-2007, 04:26 PM
Aside from the attachment problem, a single pole that you can set up will give you less to clean up in the photo.
You CAN just use a silver Christmas ornament.

Yes, I've used a Xmas ornament mounted to a wood dowel. Works fine, but I'm looking for something a little more sturdy with the ability to fold-up since I will be hiking around on lava fields in Hawaii with this thing in a backpack. I did find a guy who was able to drill a hole in the Dube hollow steel sphere and mount it to a tripod. Probably will try that and see what happens.

Silkrooster
07-06-2007, 06:09 PM
Yep, if you are going to be near lava, I would definately stay away from using any type of glue.
Any machinest should be able to drill and tap the ball to fit the tripod. Just remember to take your tripod with you so the machinist can determine which tap to use.
If you are not familiar with taps and dies, a tap is used to create threads in a hole while a die creates thread around shaft. Therefore the tab is what created the threads in a nut and a die is what created the threads on a bolt.
http://en.wikipedia.org/wiki/Taps_and_dies
Silk

newsvixen8
07-08-2007, 07:07 PM
HDRI 3D magazine (Issue #2, January/February 2005) had an in-depth tutorial on creating HDR environments, including a spread on a recommended structure for holding the ball. The author, Gregory Glezakos, had a welder build him his base, which consisted of a heavy rectangular base , from which extended a (removable) tubular main arm of about 83 cm in height, which then bends back over the base at what looks like a 30 degree angle. The ball balances in a cuplike indentation on the tip of the arm, so no hole drilling is required.

faulknermano
07-09-2007, 12:01 AM
the ball balances in a cuplike indentation on the tip of the arm, so no hole drilling is required.


that's what i do, but i just used a particular nut i found lying around.. but i suspect JGary's problem will be stability.

newsvixen8
07-09-2007, 05:47 AM
Yes, you're right; the unstable ground really would be a problem. (How come HE gets the fun job of shooting HDR's at a lava flow?) :D

JGary
07-09-2007, 12:39 PM
Yes, you're right; the unstable ground really would be a problem. (How come HE gets the fun job of shooting HDR's at a lava flow?) :D

Hah! Actually it's vacation and I just can't help bringing the hdr sphere along. I'm sure my wife will get really tired of me saying "wait, this would make a great hdr probe" every fifteen minutes, then having to wait while I set up and take the images.

Yes, the unstable ground will defintely be a problem. I've hiked across lava fields in Maui and it's some pretty rough terrain, so I figure getting the sphere set up could be a challenge at times.

newsvixen8
07-09-2007, 07:57 PM
So, I guess it's out of the question to ask your better half to hold up a boom from which to suspend the ball, eh? He He He

Long live Texas!! (Homesick former Dallas resident)

faulknermano
07-09-2007, 08:48 PM
or another thing: why not invest in a super-wide fish eye lens? this would solve many problems regarding the spheres. i myself would like to purchase one, but its specialised purpose doesnt justify it for me at this time...

JGary
08-10-2007, 10:45 AM
or another thing: why not invest in a super-wide fish eye lens? this would solve many problems regarding the spheres. i myself would like to purchase one, but its specialised purpose doesnt justify it for me at this time...

I guess if you used a 180 degree fish eye lens and took two shots, one foward and one backward, you could then somehow merge the two together in a program like HDRshop to make a 360 degree light probe image? Sounds like a cool idea, but seems like the price of a 180 degree fish eye lens would not be cheap.

JGary
08-10-2007, 10:54 AM
I finally have a cheap, usuable HDR rig put together. I ended up buying a Dube 73 mm hollow steel ball ($26) and a cheap Targus 42" tripod ($15) that folds up to only 14". Cool thing is, I was able mount the sphere to the threaded end of the pan head handle and then the hollow end of the handle fits snugly to the top of the tripod area where the pan head was removed. This works great since I'm able to easily pop the handle back off the tripod and pack it away when done. Not sure if my explanation is clear, just check out the pics! Now I just have to figure out how to take GOOD hdr images before my vacation next month.

49163

49164

49165

newsvixen8
08-10-2007, 02:30 PM
I still recommend HDRI Magazine's article on the subject; I can lend my copy of Issue #2 if you can't get your hands on one; P-M me if you'd like to read it...

JGary
08-10-2007, 04:23 PM
I still recommend HDRI Magazine's article on the subject; I can lend my copy of Issue #2 if you can't get your hands on one; P-M me if you'd like to read it...

Looks like I can order a back issue for $14. Worth it?

There's also a book coming out soon that look like it might be a big help:

The HDRI Handbook: High Dynamic Range Imaging for Photographers and CG Artists (Paperback)
http://www.hdrlabs.com/news/index.php (author's website)

newsvixen8
08-10-2007, 07:48 PM
In case the upcoming book isn't out soon enough for your purposes, the magazine article might well be worth the cost of a back issue. It covers sixteen full pages, with detailed explanatory photos, and includes not only tips on building the probe, taking the shots, but processing them in Photoshop into usable HDR images.
Same issue features a piece on reverse foot rigs by the great "Proton" Vaughan, and an interesting use of LW with Photoshop to create fine art, courtesy of Stephen Burns. (Yeah, this was back when Dan Ablan was editor-in-chief...)
If there is a back issue available, I'd say give it a look...

Ztreem
08-11-2007, 05:28 PM
I bought a Steel bearing ball a couple of years ago and I still havn't used it. I bought a magnet to use for mounting it to a tripod.

starbase1
08-14-2007, 05:58 AM
I guess if you used a 180 degree fish eye lens and took two shots, one foward and one backward, you could then somehow merge the two together in a program like HDRshop to make a 360 degree light probe image? Sounds like a cool idea, but seems like the price of a 180 degree fish eye lens would not be cheap.

PT Gui will do great stitching, at a very reasonable price. I often use it with a 28mm equivalent lens - two complete circuits in portrait formatcovers most stuff, though as stitching on clouds is a nightmare IO don't go straight up, or that close to it...

I'm guessing you would repeat the entire panorama at different exposures...

starbase1
08-14-2007, 06:01 AM
I bought a magnet to use for mounting it to a tripod.

Now that's an elegant solution!

JGary
09-10-2007, 10:39 AM
I'm back from vacation in Hawaii and have a sad update concerning the HDR dome images I intended on taking. The backpack containing my HDR dome and two tripods was stolen out of our Jeep the first day we were in the Volcano National Park, so I didn't get to take any lighting probes. When they say never leave anything in your vehicle in Hawaii, not even for a second, they mean it! Fortunately, the thieves didn't get any big ticket items. The backpack and tripods were cheap and I had the camera with me. Despite that incident, I had a great time and did get some great photos. Since the latest earthquake in July, the lava has changed direction and stopped flowing in the park, so we had to take a helicopter to see it. I managed to get a few good shots (thanks to the camera's image stabilizer) and thought I would post a couple here since they make for some good reference (you can never have too many). I 'm leaving these images large to preserve the detail.

50155

50156

50157

50158

50159

I also have some panorama's that I need to put together with PTGui (Canon's free stitcher did a crappy job). I'll post a couple of those when I get them together. Most are in areas where I would have liked to have made HDR lighting domes.

warrenwc
09-10-2007, 11:19 AM
Just an additional thought here:
Photoshop CS3 now has refined Photomerge so well that you can hand hold a bunch of photos(even on auto everything) and the auto setting will blend and merge the photos as well as if they'd been taken with a tripod.
IF you've got CS3, TRY IT!

warrenwc
09-10-2007, 11:27 AM
This photo isn't great but it's ten shots, hand held on auto everything & all I had to do in PS was crop it after the program did it's thing.

JGary
09-10-2007, 11:40 AM
This photo isn't great but it's ten shots, hand held on auto everything & all I had to do in PS was crop it after the program did it's thing.

Looks like it does a pretty good job stitching the photos together. I currently only have CS2, but will definitely try it out when I upgrade (it's on my software to do list). Thanks for showing that feature!

Something I used in Hawaii to help get some quick pano photos was a Kaito retractable hiking pole with a camera mount on top (see image). It made hiking around the rough terrain with a camera readily accessible very easy. When I wanted to take a set of pano images, I simply used the pole as a monopod.

50162

warrenwc
09-10-2007, 11:44 AM
Yeah. It doesn't look like a place you'd want to lug a lot of gear into.
By the way, I forgot to add;
WOW! Nice pics!:thumbsup:

starbase1
09-10-2007, 01:53 PM
I'm a PT Gui fan myself...

JGary
09-10-2007, 05:25 PM
By the way, I forgot to add;
WOW! Nice pics!:thumbsup:

Thanks, It's pretty easy to take great photos in Hawaii, especially using a digital camera! I saw lots of people lugging around really expensive camera's with large lenses and have to wonder if their photos really turned out that much better than my little Canon A710...


I'm a PT Gui fan myself...

I just bought PTGui last night and have to say I'm now a fan as well. Here's some of the pano's I stitched together using it:

Punalu'u Black Sand Beach
50171

Halema'uma'u Crater 01
50172

Halema'uma'u Crater 02
50173

Volcano Places (where we stayed while visiting the park)
50175

Lava Field at Edge of Kilauea Caldera
50176

JGary
09-10-2007, 05:57 PM
Here's a few more panoramas. All of the Kilauea Iki Crater which had a really cool 4 mile hike that went around the edge of the crater and then down through the middle (you can see the path running down the middle). If only a few of these could have been hdr domes...

50178

50179

50180

50181