So you have this idea for a photograph where you’ve smoothed out the water on a lake using a long exposure, but want to capture the wildlife swimming on said lake frozen in place – or something similar? I had that same vision and I’m going to show you how I accomplished it below, so you can follow along.
When trying to capture this kind of photograph in a single frame you’re pretty much out of luck. You can either capture a long exposure shot to smooth out the water, OR increase your ISO and capture a shot using a faster shutter speed to freeze your subject. No matter what you do in camera though, one piece of this puzzle will be out of line with the other.
So how do you freeze your subjects in a long exposure scene? Simple – with a little bit of post production.
Part One – Photograph Two Different Images
You will need two frames to work with in post production; one with a fast shutter speed to freeze the moving subjects, and one with a long exposure to smooth out the water in the scene. You don’t want to change the Depth of Field between the two frames, and need to make sure that the overall exposure remains the same, so you are left with changing the ISO setting to achieve the results you want.
The long exposure shot will be taken at ISO 100 and whatever settings will be required to get the optimal exposure for the scene in front of you and the faster shutter speed shot will be taken with a higher ISO setting allowing you to achieve a fast enough shutter speed to freeze the motion of the subject you want stationary.
In the example photograph the long exposure was taken at 1.3 seconds, and the high ISO photograph was shot at ISO 4000. This allowed me to get an exposure of 1/30th of a second (still fairly slow, but workable for the desired result).
Part Two – Combining the Images in Photoshop
Here’s the first, unprocessed image, straight out of camera. Before you get to freezing the moving subjects you need process the original photo. I will be working in Lightroom 4 to demonstrate.
After applying a few graduated filters, some adjustment brushes, and playing with the basic sliders I was able to achieve a result that is pleasing. If you’d like to see exactly how I created this – you can watch the entire process here.
Now that you’ve got the photograph properly exposed you’ll notice that the problem is very evident in the photograph – the moving subjects just wouldn’t sit still for the long exposure. So it’s up to post production magic to solve this issue.
Use Lightroom’s “sync” feature in the Develop Module to bring the settings from the photo above over to the high ISO photo that you will be using . This will allow you to make sure everything stays the same (color, contrast, tone, etc.) between the two images when you get to creating the composite later.
I suggest applying some minor adjustments to the high ISO image to get the subjects to stand out more (as they are going to be the only piece of the high ISO used in the final version).
One of the main areas of focus for this example image was to create lines that are as hard as possible for the subjects, so that they stand out very nicely in the composite. To do this, go into Lightroom’s detail section and push up the sharpening quite a bit. You may also want to do some noise reduction to try and compensate for the high ISO exposure with increased noise.
While Lightroom is great for processing photos, it is limited in that you can not create composites or work with layers, which is exactly what is needed to finish this project.
Therefore it’s time to bring out the big guns and jump on over to Photoshop. Below, I’ve loaded the two files as layers, (select the two thumbnails in LR, right click on them, and choose “edit in>Open as layers in PS) with the long exposure layer on top and the high ISO layer on the bottom.
I like to clean up the long exposure shot as well as I can first, so I went ahead and got rid of the blurry geese by performing a simple clone job. Go ahead and do that on your image as well if suitable.
Next reduce the opacity of the long exposure layer (which I’ve arranged as the top layer). This will allow you to see the high ISO layer as a reference point, while still being able to see most of the long exposure shot as well.
With the high ISO layer selected, use Photoshop’s selection tool to make a rough selection of the subjects in the frame. Next add a layer mask to the long exposure layer, which you will be using in the next step.
Once the subjects have been roughly selected, fine tune the edges of the selection to make sure you’ve got everything you need. Then select the layer mask you added to the long exposure layer and fill in the selection with a black paint bucket fill (make sure your swatches are set to default black/white and use the tool at 100%). This is a very crude way of getting the geese into the long exposure shot, but does the job quickly and it works.
Now that you have your subjects visible within your frame, bring the opacity of the long exposure layer back to 100% and start the clean up. I recommend you work in broad strokes first using a wide brush with the color white selected. This will allow you to get most of the areas between the subjects from long exposure frame back, instead of the noisy high ISO frame.
Once you have a basic rough clean up done, it’s time to zoom closer and use a finer point brush to do the detail work. It’s a time consuming process. But, this must be done, or the final image will end up looking like two images put on top of one another, and not one cohesive, final image.
You’re on the home stretch now!
Do one final check of the image by hiding the high ISO image (click the little eyeball next to the layer). By doing this, places the mask has been applied will now be transparent, and you’ll easily be able to tell if there were small areas that need fixing.
After the final touch up and a few other minor tweaks in photoshop you’re ready to merge layers, save the image and show your friends. (you can also save a layered version if you think you might want to edit it more later)
Summary and more reading
I hope you got something out of this step by step walkthrough – for more information on how to mask in Photoshop, which is really what this entire process boils down to, check Photoshop Masks 101. If you’ve ever created a long exposure, high ISO composite, I’d love to see it in the comments!