How to Stitch and Blend

Bracketed Panoramas

The difficulty experienced exposure blending bracketed images can vary from easy to quite complicated. We can add additional layers of complexity to the process when we are dealing the bracketed panoramas. Bracketing our exposures is a technique we use to ensure we’re capturing the entire dynamic range of the scene, and is commonly used. Therefore, translating this into a panoramic series seems logical and you’d think just as easy, but it’s not.

This tutorial uses a previous version of our luminosity panel, the techniques are still relevant with our current panel.

Taking the images in the field is the easy part. But, how often do you get home only to end up choosing just one set of exposures to work with, because the process of stitching and blending is to complicated. We’re often asked which we should do first: blend each set of exposures, or stitch the panoramas and then blend?

This is an easy question to answer, if you understand how the tools work that you’ll be using to do the stitching and blending.

 

Using Photoshop or Lightroom for Stitching Panoramas

Blending the exposures prior to stitching is a viable solution and is a requirement the majority of the time, if you’re using programs such as Photoshop to do the stitching. Photoshop does not allow the user to save a stitching pattern or algorithm, meaning that stitching before blending is not a viable option. Therefore, when you use Photoshop, Lightroom or most other stitching software you should blend your images first. If you’ve done a lot of blending of exposures, you’ll realise this is not desired, as it will require you to do the exact same blending technique for each set of exposures. If you don’t use the same technique, the exposures will not match properly when stitching. Also, we often don’t want to use an automated blending process, instead we want to blend in the areas we believe need it.

The issue we face when using most stitching software to stitch our panoramas before blending is that they do not apply the exact same stitching pattern to each set of images. What this essential means is that when you stack them to start blending, the features of the images will not be aligned. If the images are not aligned, it will be impossible to blend, and the Align tool in Photoshop does not fix the problem.

 

Using PTGui for Stitching Panoramas

PTGui is a stand-alone software used for stitching panoramas, and is far more advanced than most other stitching software on the market. If you find yourself in a tricky stitching situation, if used properly this software will get you out of trouble most times. For the purpose of this exercise, we don’t need all the bells and whistles, just one. PTGui has the ability to save a template for a stitch. This allows us to repeat the exact same stitching pattern across multiple stitches. What this then allows us to do is stitch each set of the bracketed exposures and blend afterwards. As a result, we can manually blend the images, choosing which areas we want more or less detail.

 

In this tutorials we show:

  • Why Photoshop & Lightroom don’t work for stitching bracketed panoramas.
  • How to stitch and blend bracketed panoramas in PTGui.
  • Use Luminosity Masks to blend exposures.
  • Additional techniques to create balanced exposures in your blended images.