Author Topic: D.I.Y. HDRi?  (Read 9466 times)

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D.I.Y. HDRi?
« on: May 23, 2016, 12:27:00 pm »
I like the HDRi files that came with Keyshot and I’d like to make my own.   ;)

Posting to double check my research with the rest of the Keyshot user base and see if anyone can offer suggestions.

First off I’m doing this as a hobbyist, not making a profit off of anything. 

Gathered the best solution for me happens to be a DSLR + fisheye lens + nodal tripod mount on a tripod + stitching software.  With an existing tripod and DSLR the cost can range from approximately $1000-2000 USD.   ???
Hoped there would be a simple push button solution within this price range.  (If there is something great that I haven’t listed please let me know.)
Tried alternatives such as:
  • iOS app Google Streetview.  Despite using a tripod and a steady hand it isn’t consistent when it comes to stitching 44 photos together into one image.  Objects in frame need to be 20 feet away or more to avoid parallax.
  • Ricoh Theta S.  Created multiple exposures, made a slew of HDR files and imported to Keyshot.  And they were serviceable but really noisy. 

Otherwise photography sites seem to lean towards using the most expensive gear possible when taking spherical panoramas.
In my case I own a canon DSLR and I’m perplexed as to the differences between fisheye lenses.  Is a $150 (brand I’ve never heard of) bad and a $1200 Canon lens good?  Noticed fisheye lenses that range from 165 to 185 degrees.  There are circular non circular lenses.  There are sunex lenses and mounts that offer 185 degree fisheye lenses that can get full coverage in 3 shots.  (And yet very few reviews on this product.)

Experimented with a demo version of PTGui and sample images from different lenses.  Current results seem to indicate taking four shots instead of three seems to create larger more detailed HDRi files. 

Does anyone have personal experience they can share on the creation of HDRi files?

Offline cadjockey

Re: D.I.Y. HDRi?
« Reply #1 on: May 25, 2016, 10:48:21 am »
+1 I'd like to know more too

Offline Will Gibbons

Re: D.I.Y. HDRi?
« Reply #2 on: May 26, 2016, 08:10:35 am »
Richard Funnell or Steve Talkowski may be able to help out here.

Ricoh Theta S is the best way I've seen as far as working as a hobbyist goes. It's far cheaper and it's fast. The next camera they release should be higher resolution and hopefully will export RAW data. Do you compile your bracketed shots from that camera in Photoshop? There's a HDRI toning option within PS as I understand that nearly automates the process and gives you a good result.

What I've learned from Steve and Richard is being sure to take photos with a DSLR and a nice piece of glass to go along with your HDRI. You use your HDRI to provide lighting, but then use your high-res DSLR image backplate actually in the rendering, rather than relying on the HDRI for image quality.

You may've already done all this, but just wanted to share what I know in case it's helpful.

Offline DMerz III

Re: D.I.Y. HDRi?
« Reply #3 on: May 26, 2016, 09:03:28 am »
+1 on the Ricoh, it does all the stitching for you and is pretty quick at doing so. We have one of the first models, and it's pretty cool for quick environments, but the newer models with higher res are the ways to go, especially if you're planning on rendering highly reflective objects with sharp reflections.

Re: D.I.Y. HDRi?
« Reply #4 on: May 26, 2016, 05:17:49 pm »
Thank you for getting back to me.

For context, purchased the Theta S last month, in less than a week I returned it.  I was heartbroken that it just didn’t have the crisp quality I was looking for.  Mine in particular had a focus issue, (a problem noted in the Ricoh forum) but there is a common issue of image noise found in all Theta S cameras.  I loved the design, the weight, quick charging, and how it interacted with an iPhone.   But spent that entire week trying to determine why the image quality was undesirable no matter what the ambient lighting happened to be.  Lots and lots of photos turned into HDRi and tested in Keyshot.  Even adjusting the exposure down, there is an overexposed quality, and an overall grainy quality. 

This snippet is the result of five 'bracketed' shots combined in Photoshop to form a HDR image.  Perhaps one of the nicer ones.

I enjoy using HDRi images as the backdrop in Keyshot but the only way I could get my Theta S shots to work was to use a the camera depth of field lens blur.  Here we have one of my daily zbrush creations with a Theta S based lighting/background.

Not saying the Theta S is bad, I just want more quality from a similar product.  That is why I wanted to explore other options of 360 all in one cameras, or stitching DSLR fisheye shots.

Thanks again

Offline richardfunnell

Re: D.I.Y. HDRi?
« Reply #5 on: May 27, 2016, 06:57:22 am »
Hi UnexpectedToy,

As Will mentions above, you never want to use your HDRI as the background/backdrop. Shoot backplates in the same locations and you can achieve great results. Even high quality, professional environments are still accompanied with high resolution backplates for this reason. You'll never replace a 15k, professionally shot environment with one created using a Theta, but the results are good enough for simple renderings.

Alternatively, you can use the Environment Editor in KeyShot to help with lighting. That way I can shoot a single sphere (or the simple HDRs) with the Theta S, then add more lights using the HDRI Editor. I also boost lighting in Photoshop, the attached image was enhanced using a bright brush to boost the sun. Both the backplate & environment are available in the KeyShot Cloud Library.
« Last Edit: May 27, 2016, 07:00:16 am by richardfunnell »

Offline DMerz III

Re: D.I.Y. HDRi?
« Reply #6 on: May 27, 2016, 11:55:23 am »
Richard forgot to mention that  you can snap a photo for the ground plane as well and use that as an image pin at the bottom of your HDRI to help with reflections where the object sits. Eliminating the tripod/sliver of theta base. I learned that trick from Mr. Funnell  ;)

Sorry to hear the Theta S wasn't working out for you. We did do some research on 360 cameras about a year and a half ago, and there are some high-res but very expensive options, or....the theta.  But that's really when the technology was in its infancy. Other companies are developing them now, and I'm sure within the next two years, there'll be a surge in quality for this type of camera. Please let us know what you decide on!

Re: D.I.Y. HDRi?
« Reply #7 on: May 28, 2016, 12:28:49 pm »
Thank you all.

Getting back to the original question. The recommended method for creating large detailed HDRi photospheres is to use a DSLR with a fisheye lens, right?

What kind of fisheye will yield the best results and why?  Different features include: a circular image vs an entire frame, coverage from 165° up to 185°, etc.

Otherwise the rest of the package would be a nodal ninja, tripod level, and stitching software like PTGui?

As for backplates...

Discovered once a Keyshot environment HDRi reaches a certain size the rendered images work fine without backplate.  (Hence my interest in large detailed HDRi images.)  For example this HDRi was generated with Google Photosphere @ 10240 x 5120 and resulting renders at 2000 x 1307 are fine.