[Easy Photoshop] Photo stitching – 85mm as a Wide Field lens

Photoshop and Lightroom are two mainstream programs in photo processing with very different characteristics. Photoshop is complex, but provides unlimited tooling to manipulate individual pixels. Lightroom is simple, intuitive and easy management on the massive amount of photos. Mixing them makes powerful, yet easy to use photo processing workflow, called ‘EasyPhoShop’

Determining the Lens Focal Length to use

Below photo was taken with 85mm lens in a single shot. In this distance, only the upper body of the model can be recorded. What do you do if you want to take a full-body shot? A vertical photo will generate a longer downward, but narrower in width obviously. The distance in between photographer and model was too close to take a full-body shot with an 85 mm lens.

Then, (1) change lens to a wide-angle, e.g. 35mm (2) Or move a couple of steps back with the current lens, 85mm could be an option.

However, (1) Wide angle lens makes ‘lens distortion’, also includes more background (a lot of people and facilities in the event in this case) which I want to avoid absolutely.

(2) And I could not step back. About a dozen photographers are crumbled shoulder to shoulder on this spot. I had to shoot the photographer’s head instead of the model if I did so.

Enlarge the sensor area, mimic a large format photo

Another way is to take several pictures of ‘small part’ of the model and merge them into 1 photo later in Photoshop. It is Panorama stitching which mimics the bigger film area of a medium or large format camera.

The screenshot shows the ‘small parts of the model’ in LightRoom. I chose four among them (bright gray) and transfer to Photoshop.

 

In LightRoom menu, select;

  • Photo> Edit in> Merge to Panorama in Photoshop

Here it is, merged photo

35mm f1.4 lens would take the same area as of this photo in one shot, but 35mm lens will make foot bigger, head smaller, and include messy background which is not shown in the 85mm shot in here …

I often use 35mm f1.4 lenses in portraits, but the photo expression is completely different from 85mm. The 35mm presents a dynamic frame with exaggerated perspective and personality with the surrounding environment. 85mm lens delivers a calm and static mood, and emphasize the person itself separated from the surroundings.

Check stitched photo

When photo merged, sometimes stitched lines are clearly visible which looks unnatural & fake. It happens more often when using a wide aperture lens, like 85mm f1.2 but hardly any problem in landscape photo where smaller aperture used in general.

  • Select layer mask
  • Select brush with flow 10 -20%, softness100%
  • Brush out the sharp edge of the layer mask to make sure the top and bottom layers are smeared each other

‘Before’ shows stitched line sharp and clearly visible ‘After’ stitched line is not visible

Adjustment in Photoshop

  • Select Layer > flatten layers
  • CTRL + J (copy layer)
  • Adjustment layer > Curve > Auto (exposure control)

I use ‘Curve > Auto’ in Photoshop often because it delivers a better result than LightRoom’s Auto level, even though the difference is subtle and not always working as expected. It is a little bit of personal preference…

Use the Crop tool to cut out the protruded area, and use Fill function to add pixels in empty areas.

Press Save.

Then, photo returns to LightRoom automatically as below.

Develop this photo in the Lightroom is the same as any other raw file processing.

Color temperature (white balance)

The key factor to color photography is literally the color. As a very first step of post-processing, you have to decide what color you want to use for the picture with.

It was late afternoon I shoot this photo, sunlight comes from the model’s backside at a slanted angle, not backlighting situation though, and muted in warm and mild color. But in the camera raw file, I cannot see such a mood at all. The camera captures the color temperature simply based on mid-gray (18% reflection) in most of the time.

Here I adjusted the color temperature to +15 so that late afternoon mood gets into.

Adding Highlights

To express the slanted sunlight behind the model, I added a couple of circular tools with boosted temperature (+30) with Yellow / Magenta. Just one circle does not make realistic expression, somewhat awkward and fake look. I stacked 3 large and small circles with slightly different temperatures.

Usually, this effect (called flare or light leak effect) dealt in Photoshop, with a Gradient or Overlay tool. But it is not difficult to reproduce the same effect in the Lightroom as shown here.

Other than these 2 adjustments (color temperature and highlight), I do not have much to do. Auto exposure in Photoshop curve took care most of the adjustment work already.

After merging 4 shots of 42M pixel files from A7R II, the photo becomes 112 megapixels, which equals 3 times bigger sensor area compare to full frame, something like 6X6 Rolleiflex or Hasselblad in the old days. 85mm lens works as a Wide Field lens (a lens project image into a larger area of film or sensor)

Final result

 

(Reference) More details about Panorama stitching methodology

http://opeanut.com/panorama-stitching-portrait-simulate-large-format-why-how/

 

 

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