Extending Format – You Can Use It For More Than Panoramas

Technique - MultiShot  Comment
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Left

2_Right

Right

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Panoramic stitches combine both

Think Outside The Frame

No one needs to learn to “think outside the box” more than photographers. The frame, literally a box, is often our greatest ally. Learning to see photographically is in part learning to see within the limits of this box and use them creatively. But there are times when this limits our vision unnecessarily. Once we’ve learned to see within the box, we then need to learn to also see outside the box – and start extending the frame with multiple exposures to perfect select compositions. Extending format techniques aren’t just for panoramic image formats. They can be used to give you the extra inch that can make all the difference in the world for your compositions.

Hand-held Exposure Techniques

While the best way to make exposures for panoramic merges is to use a dedicated panoramic head on a tripod, this may not be practical – or necessary. (There are three significant benefits to using panoramic tripod heads; one, they keep the camera level and without rotation throughout an exposure sequence, two they calculate the number of and overlap between exposures, and three they pivot the camera around a lens’ nodal point minimizing parallax.) Today’s software packages work miracles making what was once impossible possible. Several practices can help you make better hand-held exposures for panoramic merges.

Keep the horizon level in all the exposures; varying rotation can cause improper alignment and/or excessive cropping and/or retouching.

Shoot a little loose. Perspective correction in these types of photo merges often resulting in irregular borders that beg cropping – or retouching, if this is appropriate. The extra wiggle room you gain from shooting loose will allow you to crop the final results more precisely.

Don’t shoot the separate exposures edge to edge. Instead, overlap your exposures by a third for medium lenses, a half for wide-angle lenses, and two-thirds for fisheye lenses.

Make exposures with the opposite orientation as the final image orientation; if you’re making a horizontal composition shoot with a vertical camera orientation and if you’re making a vertical composition shoot with a horizontal camera orientation. This does two things. One, it increases the number of frames, and thus vanishing points, reducing the tendency for the required perspective correction to produce distortion artifacts. Two, it increases resolution – a tendency that becomes compounded with each added pass in multi-column or multi-row exposure sequences.

Once focus is set, turn off auto-focus during the bracketing sequence. Unwanted shifts in focus may ruin an exposure sequence. For this same reason, consider shooting all exposures in a single sequence at the same aperture setting, as significant variances in depth of field between frames may be challenging to merge convincingly.

Consider using manual exposure. While software can convincingly blend exposures with significantly varying exposures, if brightness across a scene remains fairly constant keeping the same exposure settings between different shots can aid the blending process. (The same is true for white balance, which can be set either during exposure or during Raw processing.) On the other hand, if brightness varies dramatically, bear in mind that simultaneous HDR exposure bracketing is not out of the question; it just increases the number of exposures needed.

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Lightroom’s Panorama Merge Preview

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Auto Crop checked

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Boundary Warp slid to 100

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Adobe Camera Raw’s Panorama Merge Preview

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Auto Crop checked

ACR_BoundaryWarp

Boundary Warp slid to 100

Stitching / Merging
Merge to Panorama in Lightroom and Adobe Camera Raw

You can perform panoramic merges in either Adobe Lightroom or Camera Raw. Their interfaces may look different but they’re the same.

There are three advantages to making panoramic merges with these Raw converters. First, it creates a new combined file in DNG format and allows future access to the Raw data in the files. Second, they offer simple but powerful post-merge distortion (Boundary Warp) and Auto Crop options that Photoshop’s Photomerge doesn’t. (This means you’d only choose Photoshop when you wanted to use its additional merge projection options Collage and Reposition.) Third, the DNG file takes up less space than the PSD or TIFF file Photoshop generates.
How do you do this?
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Use Multiple Exposures To Remove Unwanted Objects With Photoshop

Technique - MultiShot  Comment
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Combine 3 or more exposures into 1

MergedOut_Mean

Remove moving objects using Photoshop's Smart Objects

Use the Stack Mode Mean

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Keep moving objects using Photoshop's Smart Objects

Use the Stack Mode Minimum

It’s a perfect shot! If only those unwanted objects (cars, birds, people, etc) in the scene would disappear. As long as the unwanted elements in your frame move, even just a little, you can make them disappear from your image, by taking two or more shots and using Photoshop’s layering and blending capabilities.

You don’t have to retouch your image. Blending is different than retouching. The unwanted elements aren’t covered over with new information, by hiding them with replacement information similar to the surround, either from the same source or another. With blends, the information behind the moving subject is revealed. How? It’s contained in the other shot(s).
You can even do this with exposures that are made with slightly different angles of rotation or framing, so you can use this technique with handheld exposures, not just those made with a tripod. Camera motion may make manual registration difficult, but Photoshop will automatically align and in some cases distort the separate exposures so that they register precisely. In some of these cases, you may need to crop the final result to restore a rectangular frame.

You can even remove stationary objects with blends – if you move. In situations where there is sufficient parallax between foreground and background elements, by varying your angle of view, you can cause significant shifts in position of foreground elements without causing significant changes in position of background elements. Make multiple exposures from multiple angles of view and you can blend out the elements that appear to move. When using this technique, shoot loose, planning to crop more after the merger.

If you have only two exposures you’ll need to manually mask the top layer. If you have three or more layers Photoshop will automatically blend the layers.

So how do you do this with Photoshop?


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Extend Depth of Field With Focus Stacking

Technique - MultiShot  Comment
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Foreground in focus

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Background in focus

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Two exposures combined to achieve infinite depth of field

How deep would you like your depth of field to be? The choice is yours. Today, there are virtually no limits. You can extend depth of field beyond the physical limitations of any lens/camera system with multi-shot exposure practices and software – by compositing multiple exposures.

To do this you first need to make a set of focus bracketed exposures, optimizing focus in different image areas. How many exposures you’ll need will depend on how much depth of field a scene contains. At a minimum, make two exposures; one focused on the foreground and another focused on the background. Making three exposures is better; one each for foreground, middle ground and background. When dealing with extreme depth of field, like macro or microphotography, you’ll want to make more exposures, at least three, probably six, possibly more. When in doubt, make more exposures than you think you’ll need; you don’t have to use them all when you stack the separate exposures, but they’ll be there if you need them. Unlike bracketing for HDR, it’s almost impossible to automate these types of bracketing sequences in camera as focus needs to be adjusted for each frame. However, for tethered shooting, you can use software such as Helicon Remote to take control of your camera and automate this process and other bracketed sequences like HDR and time-lapse. Whenever possible use a tripod to make focusing during exposure more precise and registration during post-processing easier. While using a tripod always delivers more reliable results, don’t let this stop you from trying this technique hand-held, especially with simpler sequences, like those used in landscape. You may notice that In cases involving extreme depth of field, you may notice the relative size of objects may change between individual exposures. These effects will be automatically adjusted during the merging process.

Before you combine a set of focus bracketed exposures, make all the Raw conversion adjustments you’d like to make to the final file. It’s quick and easy to process a focus bracketed series of files; process one file in the series ideally and then Sync the other files to it. Once a Raw file is rendered, you can’t re-access the data in it, such as ‘recovering’ highlights or ‘filling’ shadows, without re-rendering it. While, you can adjust lens distortions after stacking with Photoshop’s filter Lens Corrections, it’s much easier, faster and more robust to apply Lens Corrections during raw conversion, before focus stacking 16-bit TIFFs.

Once you have a processed set of focus bracketed exposures you can automate the process of stacking and blending them into a single file in Photoshop. (Unlike HDR and Panorama merges, you can’t make a focus stacked merge in Lightroom – currently.)

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Photoshop’s Auto-Blend Layers dialog

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Photoshop’s auto-masked layer stack

Take these four steps.

1          Using Adobe Bridge highlight all of the files you’d like to combine.
2          Go to Tools > Photoshop > Load Files Into Photoshop Layers
3          In Photoshop’s Layers palette highlight the layers
4          Go To Edit > Auto-Blend Layers, check Stack Images and click OK

You can then further refine these results, including manually adjusting the automated masks or distorting layers, but this is rarely necessary. Photoshop does a fine job for a majority of applications.
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Helicon Focus’ main window

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Helicon Focus’ Autoadjustment panel

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