As you may very well know, long exposure photography is a method by which you expose a sensor to a scene for an extended period of time. But in this 15-minute video, PiXimperfect asks the question, then isn’t a video just a long exposure? Well, not really, but you can use a video to make long exposure photos.
PiXimperfect has two examples in this video where he shows off this method: one with moving clouds, the other with stars. In either case, you’re going to need both Premiere Pro and Photoshop to pull it off.
The first step is to export a short video sequence as a JPEG. You can do this easily in the export pane where you can tell Premiere to export as JPEG. Remember, if your frame rate is 24p, that’s 24 frames for each second of video. For this method, you’re therefore not going to want too long of a video clip or it will take longer to export and leave you with a ton of clips to work into the next step.
Once you have each frame exported as a JPEG, import them into Photoshop by going to File, click on Scripts, and then click Load Files into Stack.
Select the images you want to import and bring those files into Photoshop. In this step, you’re not going to want to exceed 500 images or you’re going to significantly hamper your computer (unless you’ve got a serious workhorse of an edit machine). The loading process is going to take some time, but after they’re all in as individual layers, you can start to work with them.
Next, select all the layers and convert them all into a single smart object. Then go to Layer, Stack Mode, and select Mean. What this will do is have Photoshop take a look at all the images in the stack and find the mathematic mean of them all and display that as a single image.
The result will give you blurred motion without changing any parts of the image that remained constant, like buildings, mountains, or other stationary objects.
For a star trail image, follow pretty much the same steps as outlined above, but instead of selecting the Stack Mode of Mean, select Maximum.
Looking at the results here, this is a really stellar trick to getting long exposure images without using the traditional methods. The only downside is you will be limited to working JPEGs (unless you shoot RAW video) and your image size will only be your video resolution. Still, you can get some really great results quickly and easily.
If you are a fan of timelapse work, you can translate many of his steps to working with full-size images in Lightroom. Once you’ve gotten your edits in Lightroom done, you can export those images as JPEGs and bring them into Photoshop as a smart object, much the same as he did with the video file, and get similar results but with full size finished images.
For more from PiXimperfect, make sure you check out his YouTube Channel.