Discussion about the now-retired Photosynth Apps for Windows Phone and iOS.
I stumbled upon the new Tech Preview, watched a few Spins, Walks, and Walls, and immediately enamored with the new synths. I noticed the Preview is closed to new sign-ups. But my real question is when will the mobile apps be updated to allow such feature rich synths? I am having a difficult time waiting....
I'm only your fellow Photosynth user, so can't give you a specific timeframe as to when to expect the updated mobile apps which actually make photosynths (rather than only stitched panoramas, as the current mobile apps create), but I expect Photosynth 2 to move out of Technical Preview within the 2014 calendar year.
You can get a general sense of the order of events that the Photosynth team planned out regarding Photosynth 2 from David Gedye's reply in this discussion: http://photosynth.net/discussion.aspx?cat=00581351-82d8-438d-a37b-7eadb3fb4991&dis=f6e164e4-fe47-4ab6-9252-758c5a6be545
Note that the Technical Preview should be open to all Photosynth.net users (new or old) at this point.
You may want to subscribe to Photosynth's blog over at http://blogs.msdn.com/photosynth for more news or to get a sense of what news there has been about the Tech Preview and mobile apps so far.
If you haven't already watched them, here are some videos which will inform you about some of the history of the Photosynth 2 technology.
Stories from 2011: Microsoft Research's TechFest in February and Microsoft's MIX conference in April
http://channel9.msdn.com/events/MIX/MIX11/RES06#time=00h03m57s (3:57 - 14:40)
Photosynth 2 videos from 2014:
http://channel9.msdn.com/Events/Build/2013/4-072#time=00h01m41s (1:48 - 2:15)
:: Understanding photosynths and panoramas ::
One thing that is important to understand is that photosynths and panoramas are two different things.
The original Photosynth desktop application for Windows that launched with Photosynth.net in 2008 only calculates photosynths.
:: Understanding Panoramas
Stitched panoramas had existed before Photosynth and Microsoft Research had their own panorama stitcher (called Image Composite Editor or 'ICE' for short) whose technology was integrated into Windows Live Photo Gallery in 2008, as well as a panorama viewer called HD View.
Panorama stitchers, though, only work well when the camera taking the images for the panorama keeps its camera lens at the exact same latitude, longitude, and altitude while pivoting the camera on its lens to look in all directions. This is because panorama stitching works in 2D so it depends on foreground lining up with background the same way in every photo. http://www.johnhpanos.com/epcalib.htm
In 2010, the Photosynth team worked with Microsoft Research's ICE + HDView team to add panorama hosting to Photosynth.net and also added the ability for ICE to export panoramas in a format that Photosynth's desktop application could upload to Photosynth.net for viewing. http://bit.ly/icetopsblogmsr | http://bit.ly/icetopsblogps
Later in 2010, the ICE + HDView team created a plugin for Adobe Photoshop which could publish stitched panoramas to Photosynth.net via the Photosynth desktop application for Windows for people who wanted to manually edit their panoramas before uploading (something that ICE does not allow for). http://bit.ly/pstops | http://bit.ly/pstops-wlps
We also got a glimpse at a mobile panorama stitcher app that Microsoft was working on in late 2010: http://youtube.com/watch?v=hzWT9ClzeVk
In 2011, this would launch as Photosynth's mobile app for iOS and Windows Phone, however the app did not create or even view photosynths, but rather only panoramas.
The release of Windows 8.1 also saw the realtime panorama capture viewfinder built into Windows' default Camera app. http://youtube.com/watch?v=3FOktNd9G0c
All of these ways to create panoramas (Microsoft ICE, Adobe Photoshop, Photosynth's current mobile apps for Windows Phone and iOS, and finally Windows 8.1's Camera app) do not create photosynths, even if the panoramas are stored on Photosynth.net
:: Understanding Photosynths
When Photosynth began to be worked on in 2006, it did something that no panorama stitcher ever had before.
Instead of trying figure out how images overlapped each other in 2D (like panoramas do) photosynths studied the input photos for unique features, then tried to find these same features in other images of the same things taken from different points of view + calculate how far away from each other + the camera those observed features were.
This resulted in a rough 3D point cloud model of stationary things + 3D positions of the photos.
What Photosynth 2 is doing that is different than Photosynth 1 is that instead of projecting each photo onto a flat rectangle in front of the 3D point cloud, Photosynth 2 tries to project the photos onto a simplified version of the depth in the point cloud.
Another difference is that Photosynth 1 allowed people to move the camera however we wanted as long as we followed some basic guidelines like making sure not to move too far in between photos - whether we were moving toward or away from something or moving around something. Photosynth 1 also allowed you to put many more photos together in a single synth.
Photosynth 2 is a little more constrained because the Photosynth team wanted the new synths to be easily navigable on a touch screen.
For this reason, Photosynth 2 photosynths are a single line of camera positions.
Spin = Single inward arc of photos
Walk = Single Line of photos
Wall = Single Line of photos
'Panorama' = Single outward arc of photos
By contrast, a Photosynth 1 photosynth could combine multiple spins, walks, strafes, and pans all in a single synth.
:: Understanding how (stitched) Panoramas + Panorama-style Photosynths are Different
The 'panorama' style photosynths in Photosynth 2 are not the same as the stitched panoramas made with ICE or Photosynth's mobile pano apps.
When shooting stitched panoramas, you want to keep the camera's lens in a single position (to line up foreground and background the same way in all the shots and reduce stitching errors) like this: http:/youtube.com/watch?v=6XYSJPbwBT4
However, when shooting a panorama-style photosynth for Photosynth 2, you want to hold the camera at arms' length and orbit the camera around you to make sure that foreground and background *do* line up differently in different shots, as shown in both the Photosynth 1 and Photosynth 2 video tutorials. http://bit.ly/howtosynth | http://bit.ly/howtosynth2
More overlap between photos is also best.
Also, a stitched panorama is capable of using multiple rows and columns of photos to cover the inside of an entire sphere, whereas a panorama-style photosynth in Photosynth 2 is limited to either a single row or a single column of photos.
The point of a panorama styled photosynth is to capture a familiar panning movement, but intentionally capture the 'parallax' between foreground and background objects so that they move independent of each other and provide a sense of the depth of the scene.
Anyway, I'm sorry to make my answer so lengthy, but I did point you to the closest thing to an answer that the Photosynth team has given us regarding when to expect Photosynth 2 mobile apps up at the top.
Also note that if your mobile web browser allows you to select multiple photos for an upload form, you could use the Technical Preview website to create new photosynths from your phone or tablet.
If your mobile web browser supports WebGL, then you can view them too.
If you have any other questions, or want me to try to explain something more clearly, please feel free to ask.
Your fellow Photosynth user,