PTGui tutorial part 7: Viewpoint Correction

[@CNL-tz4rn]

It had been a while since I last used viewpoint correction, was lost for a moment but wow, this is even better, easier! Great job!

[@geoffhodgson2492]

These are really good tutorial videos. I’m guessing by Florian Knorn ? Please keep up the excellent work. PTGui is a great program but until now lacked serious tutorials.

[@piermane6134]

Thank you so much for your tutorials on PTGui; they help a lot. I wonder if we are taking a pano on the fly, without a tripod, and also without the string with the weight technique, in essence introducing parallax error, would we turn on a change of viewpoint on all images?

[@ptgui]

Hi, yes if you shoot hand held there will be some parallax. Enabling viewpoint correction can help a lot. But it's important to enable viewpoint correction for all images except one. That one image will serve as an anchor for what's the actual viewpoint of the panorama. The other images will have their viewpoints updated against this reference. So pick one image (in the center perhaps) and set its VP correction option to 'Reset'. All other images can be set to 'Optimize'. If you have more questions, don't hesitate to post to the PTGui forum; this is the place to get technical support: ptgui.com/forum

[@BoonOng]

what happened if this is the top, zenith? I am using 12mm, the alignment still go out everytime.

[@marktaylorza]

Well done. Clear concise and easy to follow. Can you please provide a link to the offset image so that we can play around with the masking.

[@ptgui]

Good to hear that! You can get the images here: www.ptgui.com/images/tutorial7.zip

[@FredrikLindee]

Thanks a lot for these tutorials! I'm a d850 shooter using a nikon 10,5 mm lens, and PTgui gives me perfectly fine 360 images out of tree images. But I've starting to use a bit bigger (and more stable) tripod. It would be great with a tutorial on best practice on removing the tripod replasing it with the forth ground image.

[@pruutus]

'tilted tripod' method of shooting the nadir. facebook.com/groups/panoramicphotographers/permalink/4257611204282958/

[@ChrisArmstrong194]

Hi, im getting poor alignment using the same type of google 4 turn 8mm sigma with a d850 set up. I did not move the tripod and i use the same 4 turn google style pano head that you have in these videos. I shoot in A mode, auto iso and shutter and the auto zoom readjusts each time i take a picture. I managed to align my images in the end, however it was not a perfect alignment as you would expect from a 8mm sigma using a google panohead and PtGui. Im really trying to figure out what ive done wrong and why its getting poor alignment? Could it be that the camera is refocusing as the image does change in and out a little? Could it be that i did not use the bubble to level the tripod, i would not think that would be an issue using the set google style head as you have as it always turn around the nodel point? What i did to align before blending odd minor miss alignments. 1.I plotted my own points 2.Masked out an insane amount to guide the stitch line around detailed objects that stand out too much. 3. Viewpoint correction on down view, followed by every other view, this Really helped get the closest alignment. 4. After the viewpoint alignment the image became very de-leveled!, I had to now set vertical points and it brought the alignment and level back quite well. Ive spent 4 days playing with everything, watching videos on YT and even saw a guy get great aliment with an 8mm on full frame using a peice of string and no tripod. Please help as you seem to be the person with the very best knowledge. Many thanks in advance.

[@ptgui]

Hi Christopher, just upload a set of images to dropbox, wetransfer, google drive, etc and post a message to the PTGui support forum: groups.google.com/forum/#!forum/ptgui We can probably see what's wrong at a glance, you shouldn't have to struggle for 4 days. To give some general advice: - if you shot an off-axis nadir image (with the intention to use viewpoint correction), first try stitching the panorama without the nadir image. - if you can't get a good alignment despite tweaking control points for hours, often the problem is parallax. - if the alignment problems occur specifically in small rooms and less in panoramas taken outside, the problem certainly is parallax. - a pano head must be setup correctly for the camera/lens combination. See for example kzbin.info/www/bejne/sHbKfZqImqaFrtU - disable autofocus! Focusing slightly changes the projection of the lens, this may be what's causing the trouble here. - use manual exposure (M mode of your camera), fixed ISO and fixed white balance. Expose such that the highlights are not blown out. See you in the support forum.

[@jimnewberry]

Do you not manually add control points for nadir shot? I didn't see that in the video, I can't get my stitch to work without adding manual CPs...

[@ptgui]

Hi Jim, it depends on the scene. Sometimes PTGui will find control points, sometimes it won't. In particular if the nadir shot is taken far away from the no-parallax point, PTGui may have difficulty finding control points. Also, often the floor of a panorama is plain colored or it has repeating patterns, in which case you may need to help PTGui a bit. If you need help with a panorama just post to the PTGui support forum, I'll be happy to help.

[@jimnewberry]

@@ptgui Thanks...adding manual CPs is working.

[@Gasteraner]

great programm- i love it - thanks for that - happy easter to you and take care

[@bjnslc]

The interface encourages the wrong workflow, which I have seen for the first time in this tutorial.

[@Paolo.Dalprato-AI]

Really very useful and well done, thanks! One question, how approximately flat should the floor be? Is a meadow or country road flat enough? I mean like this goo.gl/maps/PkVmoGaf8yUFPB7WA

[@ptgui]

Hi Paolo, that should work fine. It's nearly flat and grass is very forgiving to small stitching errors.

[@Paolo.Dalprato-AI]

Thanks @@ptgui for the answer. In the meantime I did some tests (I should have done them immediately, I know) and I confirm