Joshua Tree At Night By Wayne Pinkston Via Flickr: Joshua Tree National Park At Night, With The Milky

Thoughts about Contrast

My background is the profession of Radiology. The making of radiographs, Magnetic Resonance scans (MRI), CAT scans, Ultrasounds, etc. share a great deal with the technology of digital photographs. All are digital images, and the issues of getting quality images and good signal to noise is very similar. More signal is good, more noise is bad. More sharpness is good. Sharpness is primarily due to spacial resolution and contrast resolution.  There is one area where the emphasis is different. In MRI scanning and CT scanning we emphasize two things to make good images, spacial resolution and contrast resolution (in radiology we commonly say soft tissue resolution). Both combine to create the perception of sharpness. The spacial resolution is important in Radiology, as long as you have enough, but the size of the pixels is vastly different. For years in CT scanning and MRI scanning we used a matrix of 512 X 512 pixels, as that was all the machine were capable of. It finally advanced to 1024 X 1024 pixels and is slowly moving upwards. This gives a ONE Megapixel image!!! It is less spacial resolution than the earliest Digital Cameras!  

So how could you see or diagnose anything at such low resolutions? Well, it turns out that contrast resolution, or the ability to get contrast differences between normal and abnormal tissues was at least as important, if not more important than spacial resolution. For years most of the research went into getting better soft tissue differentation (contrast resolution) rather than spacial resolution. It was more important. 

In photography we talk a lot more about sharpness, and we usually mean spacial resolution. There is little talk about contrast resolution. Well, contrast resolution does matter. Some lens have significantly more contrast than others, but it is sometimes hard to even find this data. The perception is that they are sharper lens.

How does contrast matter in Nightscapes? Well, the sky at night has tremendous contrast between the dark sky and bright stars. Also, the contrast in the sky is typically increased even further in processing. This creates the Perception of great sharpness. So does the sky need sharpening in post processing? I would argue that the answer is no. Sharpening often makes the stars look “crispy” and harsh. In addition increasing the sharpness in Photoshop or other programs increases the noise in the image. This degrades the image. If anything, it is better to do some noise reduction and decrease the noise and perhaps soften the sky. 

The darker foregrounds are completely different.They usually have more noise and very low contrast (except for the illuminated areas). I typically select the foreground and do generous noise reduction here, and then use the Unsharp Mask in Photoshop to Increase Local Contrast. This is a bit different than regular sharpening. If you use a very high radius of 50-60, and a low amount of 10-20 (threshold of 0), you will increase local contrast and increase the Perception of sharpness, without increasing the perception of noise.

Cheers, Wayne

2015

A Candle Wax Landscape by Wayne Pinkston Via Flickr: Thanks to everyone for the kind comments! This is a panorama from the Bisti Badlands in the NW part of New Mexico, USA. The landscape resembles melted wax in many areas, an is the result of erosion of an ancient sea bed over millions of years. It is "otherworldly" and a unique experience at night. This is a panorama of multiple vertical images shot at 18 mm, f 3.2, 25 sec., and ISO 6400. There is Low Level Lighting, or LLL, to gently illuminate the foreground. This is very dim constant light that attempts to match starlight, so dim you can hardly see it. In this case I have used LED light panels with warming filters turned down very low. Thanks for taking the time to look. Hope you enjoy! Big thanks to the wonderful Flickr family out there. Please join me at: Website Facebook Instagram Blog

Echos of Long Forgotten Times by Wayne Pinkston Via Flickr: Website Instagram Facebook Valley of Dreams, New Mexico Badlands, USA. Hope you enjoy! A big thank you to the wonderful Flickr family for all the support and encouragement! Cheers, Wayne

In Memoriam by Wayne Pinkston Via Flickr: Website Instagram Facebook IN MEMORIAM:, THE SENTINEL: The Sentinel in Bryce Canyon National Park fell on Nov. 25. It is seen here as the lighted spire just to the right of center. This was taken several years ago in an effort to accentuate the Sentinel. The spire was along the Navajo Trail which can be seen in the lower center of the image. The Sentinel was one of the named landmarks in the park. Farewell!

Alcove by Wayne Pinkston Via Flickr: Website, Instagram, Facebook Swipe Left: Large alcove or cave in Central Utah. This is a panorama of multiple images. Several photographers accompanied me to this alcove during the Nightscaper Conference last spring. Note the 3 photographers in the image, 2 on the right, 1 on the left. They give some perspective. There is Low Level Lighting with 2 small Goal Zero Lanterns in the alcove and a LED light panel outside the alcove to light up the far ridge. There are several nice features in this alcove. There are petroglyphs on the left ( not visible on this image), a window in the roof (image to follower), and a small pond in the foreground with reflections of the stars. I’d love to come back some time when the pond has more water. 14 mm, f/3.2, 20 sec., ISO 12,800. Thanks for looking! Wayne

Hoodoos in the Badlands of New Mexico by Wayne Pinkston Via Flickr: Bisti Badlands, New Mexico Thanks for taking the time to look. Hope you enjoy! Big thanks to the wonderful Flickr family out there. Please join me at: Website Facebook Instagram Blog

The Organ by Wayne Pinkston Via Flickr: Website Instagram Facebook This butte is called The Organ, located on the main road in Arches National Park, Utah, USA. This is a panorama of about 12 vertical images (some were cropped off the sides), taken with a Nikon 810A and Nikon 14-24 mm lens at 20 mm, f 2.8,20 sec., and ISO 12,800. Processed in PS and LR. This was taken from the path to "Park Avenue", a nearby area. The main challenge here was to get all the shots without car lights. Arches has become a very popular location for star gazing and night photography, and there is still a lot of traffic on the roads until midnight or so. The milky way was centered over The Organ shortly after twilight, and to get this composition you needed to shoot early. It took about 5 minutes to shoot the whole series, and 5 minutes without car lights was hard to come by. Due to the location near the road, car headlights can light up the formation from pretty far away. This was shot multiple times until I could get a series of photos with only a few interruptions. Anyway it worked out well. After midnight things get quieter in Arches, and most of the stargazers go home, but it's still a busy place for photographers. The butte is dimly lit with what I call "LLL", or Low Level Lighting. It is done with LED light panels (on tripods, and with warming filters) turned down very low to match starlight, and then left on the whole time. People passing by would not be able to see any light on the structure. Thanks for taking the time to look. Hope you enjoy! Big thanks to the wonderful Flickr family for all the support and encouragement! Cheers, Wayne

Milky Way over the Coral Sea by Wayne Pinkston Via Flickr: This is another night shot taken on a beach on the NE coast of Australia, between Cairns and Port Douglas. This is a panorama of 14 vertical images combined in Photoshop, taken with a Canon 6D camera, Canon 16-35 mm lens, at f 2.8, 30 sec, 16 mm, and ISO 6400. As compared to the Northern Hemisphere in April, the Milky Way arches high overhead, and continues to rise as the night progresses, Soon the MW is directly overhead, and it takes a really large field of view to capture . The challenge is fun in a different way. Also the core of the MW is more centered, and is very high in the sky, as opposed to the Northern Hemisphere where it is closer to the horizon. Frequently in the Northern Hemisphere the low positioned core competes with light pollution, or features on the horizon. In the Southern Hemisphere its high position places it in the darker portions of the sky, and detail and color in the core is better preserved. Alternatively, it is harder to get the core and interesting features in the same frame in the Southern Hemisphere. Disclaimer: Unfortunately several unruly pixels were harmed in the making of this image. Hope you enjoy!

The Alien Throne by Wayne Pinkston Via Flickr: Website Instagram Facebook The Alien Throne, New Mexico Badlands. Nikon D810A, 14-24 mm lens, 14 mm, f 3.2, 25 sec., 6400. For more images like this please take a look at my website here . Thanks for all the kind support! Hope you enjoy! A big thank you to the wonderful Flickr family. Cheers, Wayne

From a Watery Origin by Wayne Pinkston Via Flickr: Website, Instagram, Facebook Tufas arising from their watery origins. These tufas are composed of calcium carbonate which precipitates out of the water from springs lying along the lake bed over millennia. Some are seen arising from the lake while others are now exposed on land after the shoreline has receded. Stacked image for the sky, long exposure for the foreground (3 minutes at ISO 1600).