Tonight’s photo is a bit of an experiment, with a questionable level of success, and I’m going to tell you how I produced my first focus stacked HDR landscape image. I had an image in mind of the grapes hanging on their vines in front of the dome off in the distance. This required some careful lining up as in order to make the dome large enough in the frame I had to use my 300mm lens and stand a fair distance from the grapes. I also had the problem that there was a bit of breeze and the leaves were moving about. As a result I needed a fast enough shutter speed to freeze the leaves motion. However, I wanted to take bracketed exposures to produce an HDR image. As the HDR process creates a lot of noise in the image I was reluctant to increase my ISO to get the shutter speed up. This meant I had to increase my aperture to the point where I couldn’t get the depth of field I needed to keep the grapes and the dome in focus.
I had the term “focus stacking” in my mind. I wasn’t sure where I’d heard it but assumed it was some method for combining a number of images focused at different points into one fully focused image. With this in mind I set about taking bracketed images adjusting the focus from the front of the image all the way through to the back. It resulted in me taking the following 21 images (My gallery import isn’t working, you can see them here until I figure it out):
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Naturally, this was a daunting task. I did some reading on how to focus stack and discovered it was relatively easy. You simply upload the images to Photoshop and click on the following:
- File >>Scripts>>Load Files into Stack
- Edit>>Auto-Align Layers
- Edit>>Auto-Blend Layers
Then, like magic you have a tack sharp image from front to back. Well, at least that’s what the articles I read led me to believe. I set about to try this, with my regularly exposed images. After clicking Auto-Blend Layers Photoshop whirred away and did come out with a pretty magical result. I have no idea how it does it. It was good but it wasn’t perfect.
I had a number of areas that were still blurry and assumed I must have missed focusing on certain areas. I wasn’t sure how I could have done this as I adjusted the focus by such small increments. That was a few months ago and I had actually given up on this image. Tonight, I asked my travel partner what she thought I should work up tonight. I do that when I need some inspiration. Naturally, she always picks one of the places she visited with me. Tonight she said Italy. I’ve actually processed all of the Italy photos I expected to process, but then I remembered this one and decided to try again.
I did the s
ame thing I did last time, started by attempting to focus stack the regularly exposed images. I got the same result, blurry around the edges and with a few areas of the photo out of focus. Then I had an epiphany. I use Photomatix to produce HDR images, but I don’t trust the program to get it right, I go in and fix problem areas. I could do the same with this focus stacking stuff.
So, after combining the seven images that would become my one regularly exposed image I layered the result on top of the original 7 images and searched for in focus areas to replace the out of focus portions of the image. Once I found them, I masked through to the original photo to sharpen up the blurry areas. This worked pretty well, though I did still have some areas that I just failed to focus on – I did say it was an experiment, the results aren’t perfect.
Once I got this technique down I decided that I could do the same with the 7 underexposed and 7 overexposed images to produce the three different exposures I needed to create my HDR image. This went well and I was left with three images bracketed from -2 to +2. Once I had these three images I was able to process them in Photomatix and Photoshop as usual.
Read about how I do that in my Free HDR Tutorial.
I don’t think that I can really call this photo a success except for the fact that Iv’e got a few thoughts to take away from it. The biggest issue I had was the movement of the leaves. As you can see in the result, the areas that are still blurred are surrounding the leaves. This is due to the fact that in the photo where those areas were in focus, the leaves were blocking the view. I cuold have taken a similar approach to removing people from Charles Bridge and shot multiple shots at teh same exposures and focus. This would have increased my chances of catching all the areas of the final image in focus.
Another option would have been to make note of the spot and wait for a time when it was less windy. However, when travelling with limited time this could likely result in just giving up.
I also wish I had shot this at a higher ISO, to see if I could control the noise in post-processing. As it turns out, carrying out so many steps has resulted in a lot of noise in the final image anyway. I could have bracketed the images and, rather than using Photomatix to combine them simply masked the correctly exposed dome onto the correctly exposed vines.
That being said, I’ve enjoyed the process and think I’ll keep exploring the possiblities available with focus stacking. I do really like watching the magic of Photoshop as it combines the variously focused images into one.
