It's really easy to do in Photoshop. You figure out what the sharpest opening is for your lens, lets say F8. Then you take a series of pictures that will give you a plane that is in focus in the foreground, then advance the focus a little further back, overlapping the first image a bit.Then repeat until you have taken the image that represents the rearmost plane that you want to have in focus. For example, if you have a landscape scene where you have something that needs to be sharp that is only 4 ft in front of the camera, yet you need to have the trees in the background in perfect sharpness.You are using a 28mm lens. In the simplest of terms you would take a shot at 4 ft. Using a depth of field calculator like DOF Master or a chart, you will see that your depth of field is 3.22 ft to 5.28 ft. Your next image will be focused at 5 ft which will extend your rear focus to 7.2 ft. Your next image will be taken at 6.5 ft, which will give you a rear focus depth of 13.9 ft, and finally you would focus at 16.2 ft which is the hyperfocal distance - or the focus distance that will give you the greatest depth of field, which in this case would be from 8.1 ft to infinity.You could stop here, or take one last image focused on the trees in the distance, just to ensure that everything from 3.22 ft to infinity will be in focus.
Next, you take your 4 or 5 images and open them all at the same time in Photoshop. In the file menu, you pick Scripts, Load Files Into Stack. In the next dialog, you specify "add open files" and "attempt to align." This will create a new file, with each image file loaded as its own layer.
Once this is completed, you select all the layers at once, go to the edit menu, and pick auto blend layers, and check box options in the resulting dialog box. This will create individual layer masks that reveal the sharpest part of each image and when all the layers are viewed at once, the image will have the depth of field you envisioned.
If you are working at close distances, as in less than 2ft in macro, then you are better off moving the camera and lens forward and backward to change the focus point. The reason is that focusing at close distances with internal focus lenses (lenses which do not change length as you focus) will focus the focal length as you focus closer. A lens that is 150mm at infinity can shrink to around 100mm at its closest focusing distance. This will change the image magnification, as will the subject to focal plane distance. Photoshop will need to work harder to take into consideration changes in magnification coming from lens focal length and distance. If you move the camera forward, the image magnification remains constant at the plane of focus. Hope this helps.
Thanks for a detailed write up Gene. I didn't quite get the last part. Say I have a some flowers in the landscape that I wish to exaggerate using a wide angle lens. Let's say that they are less than 2 ft away. How does this work?
If you want to consider spending some money, a fellow by the name of Chip Phillips has a video that covers many aspects of image editing, including focal and exposure blending. His instruction is excellent. He also covers luminosity masking which has become a routine now for me in editing. Sean Bagshaw is another fellow you may want to check out. He has a series of various videos that covers a huge variety of editing task.
Thanks very much for the input. Gene's write up got me fairly clear about the Photoshop side of things. My questions at the moment relate to in field techniques that will help bring back the desired set of images that need to be DoF Blended. Particularly, what do I do when I have an ultra close foreground with a distant background. When I want end to end sharpness, what is the way to focus and what are the pitfalls I need to be aware of
Sairam, I think the last paragraph of Gene’s explanation is for macro or close ups only, not for landscape photography.
The first three paragraphs of his explanation describes the field shooting and Photoshop process of focus blending for landscapes, where one wants to have the foreground as well as the background in sharp focus. A popular example would be a clump of flowers a few feet in front of the lens and the mountain in the background, all in sharp focus.
As I understand Gene’s explanation, to obtain the necessary exposures for depth of field blending, simply take a series of photos at different points of focus. The first would be focused on the clump of flowers, the next would be focused on the middle ground and the last would be focused on the mountains. Depending on the focal length and distance of components in the comp, one may need more than three exposures. For most wide angle comps at higher f-stops three may be enough. At longer focal lengths like 50mm, one may need more than three exposures in order to have everything in focus.
Things to pay attention to: Be sure to shoot in manual mode as you will need the shutter speed to remain constant for all of the exposures. Also when shooting with a zoom lens, be careful to not accidently adjust the zoom ring on the lens as you adjust the focal ring.
I have yet to try focus blending, but after reading Gene’s explanation I will give it a try.
I have also purchased the Chip Phillips instructional / tutorial vid and think it’s good. I bought it for the luminosity mask blending but it also includes focus blending as well.
My only concern is that if I want the clump of flowers to be closer than a few feet from the camera, then I may not be able to focus that close. I wanted to know what one would do then?
As for the post processing part, I'm quite excited about trying Gene's suggestions. I already use luminosity masking in my workflow, and I absolutely love it.
I suppose one is limited by the minimum focus distance of the lens. Now you have peaked my curiosity about how close one can focus a wide angle. I just tried with my 5d MKII and the 16-35mm @ 16mm. At f-22 I was able to obtain sharp focus at 2.1” from the front of the lens to the subject, at f-5 the closest was 4” from the front of the lens to the subject. I used live view and the DOF function for the test.
This tells me that through focus blending or “focus stacking”, one can stack exposures from 2” to infinity with this lens on the 5D. I would bet that one would need to stack a lot of exposures for the first few feet of the comp,more at larger apertures, fewer at smaller apertures.
I thought only Marc A did creative stuff like this.
We expect an extreme near-far post from you soon. Your assignment is due by the end of the month.
Thank you, Sairam for posting your question. And many thanks to Gene, Richard and Ken for their generosity in sharing resources and techniques. Very much appreciated!!
Discussion
10 repliesI've seen a lot of images here in the galleries where the photographer talks of using DoF blending.
I looked around online and found some tutorials that talk about it as applied to macro work.
Does anyone have some good tutorial that explains how it's done for landscape photography. Specifically:
1) How to set up the shots in field for a later blend
2) The actual blending process in photoshop
3) Things to pay attention to (artifacts, etc)
I'd appreciate your inputs very much! Thanks
Next, you take your 4 or 5 images and open them all at the same time in Photoshop. In the file menu, you pick Scripts, Load Files Into Stack. In the next dialog, you specify "add open files" and "attempt to align." This will create a new file, with each image file loaded as its own layer.
Once this is completed, you select all the layers at once, go to the edit menu, and pick auto blend layers, and check box options in the resulting dialog box. This will create individual layer masks that reveal the sharpest part of each image and when all the layers are viewed at once, the image will have the depth of field you envisioned.
If you are working at close distances, as in less than 2ft in macro, then you are better off moving the camera and lens forward and backward to change the focus point. The reason is that focusing at close distances with internal focus lenses (lenses which do not change length as you focus) will focus the focal length as you focus closer. A lens that is 150mm at infinity can shrink to around 100mm at its closest focusing distance. This will change the image magnification, as will the subject to focal plane distance. Photoshop will need to work harder to take into consideration changes in magnification coming from lens focal length and distance. If you move the camera forward, the image magnification remains constant at the plane of focus. Hope this helps.
Thanks very much for the input. Gene's write up got me fairly clear about the Photoshop side of things. My questions at the moment relate to in field techniques that will help bring back the desired set of images that need to be DoF Blended. Particularly, what do I do when I have an ultra close foreground with a distant background. When I want end to end sharpness, what is the way to focus and what are the pitfalls I need to be aware of
The first three paragraphs of his explanation describes the field shooting and Photoshop process of focus blending for landscapes, where one wants to have the foreground as well as the background in sharp focus. A popular example would be a clump of flowers a few feet in front of the lens and the mountain in the background, all in sharp focus.
As I understand Gene’s explanation, to obtain the necessary exposures for depth of field blending, simply take a series of photos at different points of focus. The first would be focused on the clump of flowers, the next would be focused on the middle ground and the last would be focused on the mountains. Depending on the focal length and distance of components in the comp, one may need more than three exposures. For most wide angle comps at higher f-stops three may be enough. At longer focal lengths like 50mm, one may need more than three exposures in order to have everything in focus.
Things to pay attention to: Be sure to shoot in manual mode as you will need the shutter speed to remain constant for all of the exposures. Also when shooting with a zoom lens, be careful to not accidently adjust the zoom ring on the lens as you adjust the focal ring.
I have yet to try focus blending, but after reading Gene’s explanation I will give it a try.
I have also purchased the Chip Phillips instructional / tutorial vid and think it’s good. I bought it for the luminosity mask blending but it also includes focus blending as well.
My only concern is that if I want the clump of flowers to be closer than a few feet from the camera, then I may not be able to focus that close. I wanted to know what one would do then?
As for the post processing part, I'm quite excited about trying Gene's suggestions. I already use luminosity masking in my workflow, and I absolutely love it.
I understand.
I suppose one is limited by the minimum focus distance of the lens. Now you have peaked my curiosity about how close one can focus a wide angle. I just tried with my 5d MKII and the 16-35mm @ 16mm. At f-22 I was able to obtain sharp focus at 2.1” from the front of the lens to the subject, at f-5 the closest was 4” from the front of the lens to the subject. I used live view and the DOF function for the test.
This tells me that through focus blending or “focus stacking”, one can stack exposures from 2” to infinity with this lens on the 5D. I would bet that one would need to stack a lot of exposures for the first few feet of the comp,more at larger apertures, fewer at smaller apertures.
I thought only Marc A did creative stuff like this.
We expect an extreme near-far post from you soon. Your assignment is due by the end of the month.
Marc A does some really amazing DoF stuff so I'll probably start slower
Thanks for trying out the technique and reporting your findings!