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Top frame of a panoramic stitch

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Bottom frame of a panoramic stitch

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Panoramic stitch

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Panoramic stitch distorted

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Panoramic stitch cropped

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Panoramic stitch cropped and retouched

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Panoramic stitch retouched

The strategies above are not limited to panoramic stitches.

We’re responsible for everything that’s in the frame. We’re also responsible for everything that’s not in the frame. Deciding what’s in the frame and what’s out is a critical decision that can make or break an image.

Here are two essential framing strategies.

One. Use the frame to eliminate distracting information around a subject(s). Take extra care with image information that touches the frame, as it will draw extra attention. Do this with significant compositional elements.

Two. Eliminate excess space around a subject(s) to focus the attention of the viewer. A lot of surround space between the subject and the frame can be used to use to call on psychological associations with space, such as freedom or isolation. Some space between the subject and the frame can give the appearance of the subject resting gracefully within the frame. Touching the subject with the frame strongly focuses the attention of the viewer and may seem claustrophobic. Cropping the subject with the frame can focus the attention of the viewer on specific aspects of the subject and/or give an image a tense quality, evoking evasion and incompleteness – this often seems accidental if less than half the subject is revealed.

Cropping is extremely simple to practice. (While cropping techniques are simple to practice, the reasons for their application and the choices made about how to apply them as well as the final effects may be exceptionally complex.)

Here are two cropping choices.

One. Reposition the frame before exposure.

Two. Contract the position of one or more of the borders of an image after exposure, generally with software.

Because distorting an image during post-processing, by expanding or contracting one or more sides or corners, is a relatively new possibility, most people don’t think of exercising this option. Ironically, anyone who uses lens profiles distorts their images in post-processing to correct lens distortion. Consider this a creative supplement to and extension of that practice. While cropping potentially changes the aspect ratio of an image, distortion does not.

Here are two distortion choices.

One. Use Photoshop’s Edit > Transform to distort an image. Push the areas you wish to crop outside the frame. Move one or more sides by pulling the point in the middle.

Two. Use Photoshop’s Edit > Transform to distort an image. Push the areas you wish to crop outside the frame. Move one or more corners by pulling the corner point while holding the Command key.

Retouching used to be complex. Today it can be simple. Never before, has retouching been so easy to do or the results so sophisticated. (To be certain, not all retouching is simple. You can make retouching as simple or as complex as you choose to make it. Retouching is an art that continues to be elevated on a daily basis. But what once required specialized tools and a Herculean effort can now be done with standard software in seconds.)

Here are four retouching choices.

One. There’s cloning. Simply use the Clone Stamp Tool set to Current and Below on a new blank layer. (This will ensure that any retouching can be removed or redone at a later date.) Hold the Option/Alt key and click to sample information to copy, then move the cursor to the area you’d like to copy the information to and click and drag. Repeat until a desired effect is achieved. Typically, donor information is drawn from the same document but you can also clone from one image or file to another.

Two. There’s healing. Use the Healing Brush Tool as you would the Clone Stamp tool. Or, use the Spot Healing Brush, which will automatically select the information sampled for you and can be used within a selection to contain the results. Or, finally the Patch Tool, which will copy information selected with it from or to (depending on whether you check Source or Destination) wherever you drag it to. Healing can’t be done on a transparent layer, so work on a copy of the layer you’d like to retouch. Click on the layer and select Duplicate Layer from the Layer menu or palette. If you need to heal image material contained on multiple layers, create a new composite layer by holding the Option/Alt key select Merge Visible from the Layer palette.

Three. There’s copying and pasting. Just select a region of an image with any selection tool. Copy it. (Edit: Copy) Paste it. (Edit: Paste) Then move the resulting layer into play and mask as needed. (Click the mask icon at the bottom of the layer palette and use a black brush at varying opacities to hide the information.)

Four. There’s filling. Select a region. Fill with Content Aware fill. (Edit: Fill and select Content Aware from the drop down menu in the dialog.) (This feature was introduced with Photoshop CS5.) Photoshop will automatically create an appropriate random texture in the selected area. Like healing, this feature won’t work on transparent layers/areas so, again, use it on a new merged layer.

Software routines such as lens correction and panoramic stitching may distort the frame, subtly but sometimes significantly distorting a composition, and requiring additional measures to restore a rectangular frame. When solving this challenge, you may get better results if you don’t contract the frame as aggressively as you once did and retouch rather than crop to fill in the gap and/or eliminate distracting elements.

Your choice of practices or their application may or may not change the nature of the artifact that you finally create. And, whether the means you choose is appropriate for your objective, the practices you adopt may or may not be accepted by the community of artists you choose to work within – some are more permissive than others. Nevertheless, you should explore your options. You simply won’t know whether it’s for you until you try it for yourself.

Learning to think within the frame is an essential skill for creating strong photographic compositions. But today, learning to think within the frame is only the beginning. You can learn to think outside the frame as well.

It’s a new mindset. Once it becomes second nature, you’ll not only find you have more options for visual problem solving but you’ll also find your visual horizons will have expanded – significantly.

Learn to see in new ways. Combine them with old ways. You’ll find you’ll make images that you once passed by, leaving them unmade or even unnoticed. As a result, you’ll make many more successful images.

Read more in my Exposure lessons.

Learn more in my digital photography and digital printing workshops.

Reflection XXXVII

high noise / low noise

Noise happens. There is always some degree of noise present in any electronic device that receives or transmits a signal. Though noise is unavoidable, it can become so small relative to the signal that it is no longer visible. It’s all about a good signal to noise ration (SNR). The image is the signal. The capture and carrier mediums’ biproducts are the noise. (Film grain is noise.)The higher the SNR the more the image overpowers the noise; the lower the SNR the more the image becomes confused with noise. While some noise increases the apparent sharpness of images, the vast majority of noise found in images degrades quality. It’s best to avoid it.

There are a number of things you can do to reduce noise in your digital images at the point of capture.

1       Expose to the right

2       Use lower ISO settings

3       Use bigger sensors

4       Use faster exposure times

5       Keep equipment cool

Start here. Use software to reduce the appearance of noise only when needed. (Of course, reducing noise may not be the only deciding factor when selecting conditions, tools, and techniques. As with all things, you will have to balance many concerns simultaneously. Adhere to the above principles when practical.)

Knowing how noise is produced will help you avoid it.

histograms_zones_caution

avoid the red zone, caution in the yellow zone, go for the green zone

ETTR

Underexposure results in more visible noise. Darker regions contain more noise than lighter regions in digital capture; the opposite is true of film. This is because the darker regions are recorded with fewer photons and less bits of data. It stands to reason that darker regions of images are produced with fewer photons. But why are they recorded with less bits of data? Digital cameras record data in a linear progression. If a digital sensor is capable of recording 14 bits of data (or 16,384 shades of gray) with a dynamic range of 8 stops, the lightest stop contains half the data in the file; the next lightest stop contains half as much data; and so on; it generates this progression from dark to light – 32 / 64 / 128 / 512 / 1024 / 2048 / 4096 / 8,192. This means you want to expose to the right. Avoid the lower 2 stops whenever possible; they contain less than 1% of the total data in the file. With so little data the signal becomes confused with the noise; the signal to noise ratio is very low. What’s more, when these tonal regions are adjusted, brighter or contrastier, the noise contained there quickly becomes more pronounced and with so few bits of data it also has a tendency to posterize. In addition, significant under exposure greatly increases the chances of producing Bayer pattern noise, a type of noise that is seen in larger areas and is more challenging to remove in post-processing. You’re much better off making a light exposure and darkening the Raw file during post-processing; this way your shadows will be represented with much more data and contain less noise. When light becomes challenging, which should you choose – under expose (without clipping) or raise the ISO? The precise cut off point is different for every camera, but in general avoid the lower 20% of the histogram. You’ll get less noise if you boost ISO and move the histogram up.

ISO

Higher ISOs amplify noise. ISO (International Standards Organization) is a descriptor that signifies absolute sensitivity to light. A digital sensor has one native ISO. Higher ISO settings simply boost the resulting signal. This is useful, but not ideal. When the brightness of the image is boosted, the noise is too.

Use “Shorter” Exposure Times

Longer exposures generate more noise. Hot pixels become hotter. All sensors have a few pixels that heat up faster than others, producing brighter than expected values. Some even have a few dead pixels that never fire, producing only black pixels. During longer exposures hot pixels are given more opportunity to heat up, growing brighter still; slightly hot pixels not visible at shorter exposure times become visible. As digital sensors age, hot pixels may become hotter and more pixels may become hot. Hot pixels produce a consistent fixed pattern of noise that can be recorded for given exposure times, making it easy to reduce. There is a duration at which a sensor suddenly produces a lot more noise; in older models this could be seen in exposures lasting only one minute, but with newer sensors this is greatly extended and most users will not encounter this; if you’re making very long exposures it’s useful test this and find the duration at which this happens for a your specific camera.

Use Bigger Sensor Sites

When it comes to noise, bigger is better – theoretically. Bigger sensors have more light gathering capacity, producing a higher signal to noise ratio, or cleaner images. More isn’t necessarily better. Cameras with more photosites (yielding more megapixels) packed into smaller areas tend to produce a lower signal to noise ratio, or noisier images. That said, a stronger signal does not necessarily guarantee lower noise. It’s the relative amounts of signal to noise that determines how noisy an image appears. The way a camera processes the file it makes has a significant impact on the final quality. Consequently, many medium format cameras that produce beautiful files in daylight typically produce noisier files than DSLR’s with smaller sensors in low light.

Stay Cool

High temperatures exacerbate noise. Thermal energy (leakage current) in semiconductors can generate an electrical signal that is difficult to distinguish from the optical signal. Ambient temperature increases leakage current by a factor of 2 for every 8 degrees Centigrade. Whether due to ambient temperature (You might start to see some effect over 90 F / 32 C degrees.) or storage (Don’t leave your camera in the sun, especially on a car seat, for long periods of time.), your camera can get hot and this will increase noise, which you can reduce by cooling off and keeping your camera cooler.

The best way to avoid noise is to produce as little of it as possible during exposure. These five tips will help you do just that.

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Different HDR renderings accentuate different artifacts

HDR (high dynamic range) imaging captures extreme contrast ratios and subsequently renders them for LDR (low dynamic range) devices, monitors and / or prints. The very things that make HDR renderings appear natural can make them appear unnatural if taken too far.

Midtone compression

You can’t avoid midtone compression, they get caught in the middle when the relationships between highlights and shadows are compressed. But you can take steps to minimize it by being sensitive to this when choosing compression settings and amounts and by taking subsequent steps to expand it.

Tonal inversions

Some compression routines and settings can be so aggressive that they create inversions or solarizations of specific tonal relationships. Avoid this, there is no subsequent cure. If you like the overall effect of an aggressive setting and the inversion is contained to one area of an image you can render an image twice, once for the overall effect and once for a specific area, and then blend the two together using Photoshop’s layers and masks. 

Saturation Distortions

Saturation changes when lightness shifts but color stays the same. Because HDR produces effects that can be aggressive and localized to specific set of tones, the saturation shifts that accompany tonal compression often appear unnatural. Selectively adjusting the saturation of specific hues, with tools like the HSL panel in Lightroom or Camera Raw, can often convincingly cure a majority of these side effects and hide the rest.

Halos

HDR softwares help restore midtone contrast by accentuating contours. When used aggressively this edge contrast can produce halos.

Over the years, these algorithms have dramatically improved their ability to treat the halo (light line) separately from the line (dark line), suppressing the first more than the second. Sometimes, to avoid distracting halos at the border of skies, you may want to make a second rendering for the sky and blend it with another rendering using Photoshop’s layers.


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8 HDR Myths Debunked

December 12, 2016 | 2 Comments |

illuminationxxxviii_425

There are many misconceptions surrounding the practice of high dynamic range (HDR) photography. Here are eight – debunked.

HDR is new

Within the first five years of the invention of photography photographers began bracketing exposure to extend the dynamic range of photography. They used chemistry to process their negatives instead of software to process their files – but they still bracketed exposures to capture contrast ratios that exceeded paper, glass, and film.

HDR is hard

High dynamic range imaging has become so commonplace that cameras and software make it increasingly easy to practice HDR techniques – auto-bracketing, merging and rendering.

HDR requires the use of a tripod

While there are times when the use of a tripod is required, when exposures are long in duration, in a majority of cases current cameras’ auto-bracketing features and softwares’ image alignment algorithms make hand-held exposure bracketing highly practical.


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canon_autobracket_back_425

back LCD menu

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top LCD menu

It’s easy to set your camera to auto-bracket. The hardest part of this process is navigating a camera manufacturer’s menu. Once you find it – and do it several times – you won’t forget it.

Here’s how to do it on current Canon cameras – the steps are similar for other cameras but the buttons and menus vary.

First, set the number of frames made in each bracketed sequence. Press the Menu button. Use the main command dial (top) to cycle through the menus on the LCD screen (back) Go to the 4th tab (small camera) > 1st list and then the use the jog wheel (back) to select the 5th item. Press the set button to select it. Use the jog wheel to select the number of shots and press the set button once again. While 3 is the most commonly used, it’s not unusual to use 5 or even 7. Because 3 is the most commonly used number, it’s likely that once you set this, you’ll reset it infrequently.


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salinas1_425

Today’s cameras have the ability to generate HDR merges on the fly. The problem is that they produce JPEGs with a smaller gamut (lower saturation), lower bit depth (fewer shades of gray), and compression artifacts (noise and jagged edges) and they offer no control over the tone mapping process.

If you want a better HDR file, choose to make multiple bracketed Raw files, then merge and tone map them manually. Remember, aside from exposure settings, in camera settings that affect the look of your image have little or no affect on Raw files, which can be processed any way you want to process them.

In camera HDR JPEGs can offer a fast and convenient preview of potential HDR results. You can get the convenience of one and the quality of the other by setting your camera to produce both JPEG and Raw files simultaneously.

Read more on HDR techniques here.

Learn more in my digital photography and digital printing workshops.


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