The Workflow in a nutshell:

- Shoot 3 shots around, bracketing for HDR (7+ brackets, +-2 EV steps in RAW).
The Agnos 3-shot "angled" head saves a ton of time here. It only takes 3 "DSLR cropped" circular fisheye photos (at 120 deg. increments) to produce a 360x174 deg. sphere! (The missing 6 degrees is on the bottom, inside the tripod legs - not critical for HDR lighting of a 3D object that is resting on a surface, and the tripod legs can be "cloned out" in Photoshop CS2!)

Some "on location" tips for those totally new to HDR photography:

1. You will be shooting in Manual mode, so get to know your DSLR controls! Also, with the Sigma 8mm Fisheye you have *wide* native DOF, so you can "focus" it to infinity or just below and then set it to "Manual Focus" as well. Don't touch it while shooting!
2. Set your DSLR's "ISO" to a lower (100-200) setting and adjust your EV "steps" by changing the Shutter Speed. (Changing the Aperture will also change some optical characteristcs, so only adjust this when your camera's shutter speeds just aren't fast enough.)
3. A good HDR will come from having equally-spaced exposures *on both sides* of a metered, optimal exposure. This doesn't mean the same # of exposures on each side, just a good sampling of each. You will be both under- and overexposing the scene, so just try to imagine what details you will capture and whether you need that information (maybe a few test shots will help as well!). And with the camera in Manual mode any built-in flash shouldn't pop up, which would defeat the purpose of "capturing" the existing light.
4. Layering all of these exposures without misalignments requires consistency when shooting - so shoot all of your various exposure "steps" for one directional "click-stop" of your pano-head and *then* rotate the head to the next section. You also *must* use a sturdy tripod and be careful not to bump it while shooting. It also helps to have a remote release and use "mirror lock-up" to minimize vibrations, but that isn't quite as critical as having a steady tripod and capturing *all* exposures before rotating the pano-head to the next increment.
5. Try to "choose" scenes for HDR capture that have very few moving objects in them. 3 minutes for a full HDR spherical capture is really fast compared to a scanning camera, but things like fast-moving clouds and cars on a highway will be "stair-stepped" or "ghosted" when you combine all of the exposures. Still, don't let this stop you from shooting a scene - maybe use the AEB bracketing function on your camera and shoot very fast for a limited range. In any case you can still use Photoshop CS2 to "fix" a lot of this stuff through retouching in native 32-bit later on.
6. How much range (and how many EV steps) you need for an HDR is based on *your experience* not someone else's forum posts. Even 3 exposures that are 2 stops apart (4 EV range) can produce acceptable results when tonemapped or used for ambient 3D image-based lighting. A 7-shot range at 2 EV apart is what I use for sunny days to get strong directional lighting and minimal color shifts from the sky in my IBL renderings, but each shoot is different.
7. The reason my "system" has a ball-head between the tripod and pano-head is to make it very easy to "level" the head so my captured scene is visually horizontal. There is a built-in bubble level in the Agnos head, so I can loosen the ball and level the head *before* attaching my expensive camera. Also, the quick-release plates on the camera (and base of the pano-head) allow me to set up and disassemble the rig in a few seconds without screwing something on and off repeatedly. The RC2 system isn't perfect, but trust me, you will *want* quick-releases to mount/ dismount the camera at the very least! (Oh, and this makes the tripod very useful for "general purpose" photos, too!)

- Process shots in Adobe Camera Raw for vignette, CA, neutral exposure level.
One bad thing about the Sigma 8mm is the really enormous vignetting (light falloff from center to edge), but this is why I shoot in RAW. You can easily process the images in a RAW converter to remove it (which is neccessary for HDR), along with any bothersome chromatic aberration or sensor noise. Because these images are being batch-processed for HDR, I set the white balance based on the scene and leave all other adjustments in Photoshop's Camera Raw converter at "0." Even the overall tonal curve is a flat ramp. The output files may not be pretty, but they are good for HDR! (You can also save this RAW conversion setting from Adobe Camera Raw and simply apply it to huge piles of shots via the new Adobe Bridge.)

- Stitch one "exposure set" in a PanoTools front-end (PTMac, PTGui, Hugin).
Okay, this is what requires some poking around in the forums for these PanoTools stitchers - don't worry, the forums and lists for these stitchers are really helpful. These stitchers use a library of tools (PanoTools) originally created by Dr. Helmut Dersch specifically to address the remapping and stitching of images from any input type, including the very distorted fisheye images we are starting with. [Why PanoTools front-ends? Funny thing, but a US company has a laughable patent on "fisheye unwarping," and sues (and destroys) major software vendors in this market. Open-source to the rescue!] Fisheye stitching with these GUI wrappers for PanoTools is not terribly complicated (you basically hand-pick matching features in the overlap regions), but getting *great* results from just 3 cropped fisheye images takes some practice due to the minimal overlap. If you want to go with 4 or more shots you will get greater overlap, but multiply each additional shot around by the # of exposures you take! I like 3 around because it takes less time, both "on location" and in software processing later, and it should be noted that your final resolution is tied to the camera and lens, not the # of shots used for the panorama. As for the cost of this "specialized software," PTMac and PTGui are around $50, and Hugin is open-source!

- Batch process remaining 6-10 exposure sets with same PanoTools project.
Hey, if you stitched one exposure set right, and didn't knock the tripod, the rest should fall into place with the same settings in any PanoTools-based stitcher. These image transformations are really just math, not based on the details you can (or cannot) see on screen. Plus, most PanoTools batch stitchers can chew through sets using the latest open-source blending technologies (Enblend, Smartblend), so you can't see any seams in your panos. However, be sure you have plenty of RAM for this kind of automatic blending! [*Special note: Hugin can transform and stitch 32-bit images, so it is possible to combine your exposure sets (see the next step) into HDRs *before* stitching them, but I think some bugs still need to be worked out in this open-source software before it is "production ready."]

- Create HDR composites from these stitched sets in either Photoshop CS2 or Photomatix.
If you were consistent with your EV increments, you could just enter those into either program when making the HDR, but the true shutter speed, ISO, and aperture will generally do a better job. One big problem is that these stitched panos are *new* files - they no longer have the camera EXIF information of the originals, even if only the positions of the pixels changed, not their colors. Not only that, the "Merge to HDR" function in CS2 is seriously crippled in terms of choosing shutter speeds (use EV steps instead), *and* it converts any source file to 8-bit before making the HDR file (sometimes using the wrong conversion settings for RAW files!). However, you can copy the EXIF information from one of your source RAW files or a pre-processed TIFF or JPEG to the respective stitched exposure (with the ISO, Shutter Speed, and Aperture being the critical bits) using either the free EXIFtool or a higher-end image-cataloguer like iView MediaPro. There is also the free Photosphere application from Greg Ward (for OS X only) that can both modify the EXIF information *and* create an HDR file from the stitched exposures, among many other cool things.

There are many other HDR file-creation apps, but the main two that I mention are both cross-platform, and either ubiquitous (PSCS2) or cutting edge (Batch processing RAW files into HDRs by folders? Advanced tonemapping? That's Photomatix!). Photomatix also has a freeware version ("Photomatix Basic") that creates HDRs in batch mode, and the time-unlimited demo of the $100 "Pro" version will create individual HDRs and show you histogram and range information with a live preview, but it will "watermark" tonemapped or blended output. [HDRshop? Uh, have you read the new license agreement? This may be a cheap workflow, but it is also very "commercial."]

So what kind of results can you get?