Understanding light: Surface Appearances

Surface Appearances

All surfaces produce diffuse, direct, and polarized reflection in varying degrees. We see all of these reflections, but we are not always conscious of them. That is because of our brain.

Psychological image vs photo-chemical image

The psychological image in the brain may be quite different from the photo-chemical image the eye actually sees. Psychologists have not completely explained why this difference exists. Movement certainly has something to do with it, but not  everything. Some visual defects are less disturbing in a motion picture than they might be in a still photograph, but not much… Photographers know that the brain cannot edit an image of the scene as well as the scene itself. We discovered that fact when we learned how quickly we could spot defects in our images, even though we could not see them at all when we carefully examined the original scene.

When we photographers make a picture we have to consciously do some “editing” onto the “original scene” that other observers do unconsciously.

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What’s Important in a Photograph, and What Isn’t

(John Sherman, May 2016). You know the drill.  You pick up a magazine or browse a website and flip through the photos.  Most you look at for less than a second, but a select few grab your attention and demand a longer look.  What’s different about these select photos?  What makes some photos great and others mediocre?

Verm-California-Condor-Vermillion-Cliffs-3918-2

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Portrait Vs. Headshot

There’s a fine line between a portrait and a headshot. The main difference being that a headshot is a professional representation of the subject for the desired use of the photograph, while a portrait tells more of a story. It doesn’t have to be a complicated story either, just something that makes you wonder what’s going on. Dramatic lighting, coloring, and expressive poses can take the same subject wearing the same outfit with the same hair and make-up and transform the image completely.

Amanda_Cruz_Portrait

The photo above is of Amanda Cruz (photo by Joseph W. Nienstedt), who came by to get this headshot made for her new real estate business:

Amanda_Cruz_Headshot

These shots are only a few moments apart – The difference in her pose and expression coupled with a change in the lighting setup and you have a completely different product. Sometimes the difference can be subtle, so the best way to determine whether you’re making a headshot or portrait is in the story. Is the photo showing the subject being themselves? Is it displaying something in their character? Then it’s most likely a headshot. On the other hand, if the shot is implying an emotion, or leading you to imagine a scenario that is playing out for or in view of the subject, then you’re most likely looking at a portrait.

 

SMD LED Brand Comparison

2014 Comments from Functional Utility Inc

CREE and Epistar are the most popular chips/drivers used in the automotive LED light bar industry, although there are actually more than a dozen different brands that are commercially available.

CREE, Inc. was established in 1987 and is based in the USA. They hold thousands of patents in more than twenty countries around the world and are universally accepted as the LED industry’s most prolific innovators. CREE makes the best LEDs, but other manufacturers are in a close second place when it comes to LED quality. Epistar Inc. (a Taiwan based company) and Nichia Corp (a Japan based company) produce good quality LEDs as well. It is important to note that CREE licenses the use of its patents to others, and all three of the leading LED companies manufacture most of their LEDs in China.

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LED SMD 5050 VS 2835 VS 3528

LED SMD 5050 vs. SMD 2835 vs. SMD 3528

So what do these numbers mean? Is one better than the other? Well, the numbers actually represent the package size.

SMD TYPE DIMENSIONS WATT
SMD5050 5.0mm x 5.0mm 0.24
SMD 2835 2.8mm x 3.5mm 0.15
SMD3528 3.5mm x 2.8mm 0.08

SMD stands for Surface Mount Device. SMD 2835 is the newest SMD configuration and offers the best cost / performance. It is significantly smaller than the SMD5050 and has better heat dissipation.

Advantages of SMD 2835 vs 3528

  • Chip direct conduction fins improve the heat dissipation performance allowing it to withstand higher current (40-60mA)
  • 2-3 times larger heat sink than 3528, allowing excellent heat dissipation
  • Slower light decay of LED chip life
  • Oversized light-emitting surface improves the rate of light up to 90%.
  • Ultra-thin structure solves the 3528’s long-standing problem.
  • 2-3 times higher luminous efficiency than 3528; capable of up to 90-100 Lumens per Watt.
  • The costs have been reduced by up to 20% vs the older 3528 design.

Core Advantage of 2835 LED:

  • The vertical structure: Chip direct conduction fins to improve the heat dissipation performance, which can withstand the higher current (40-60mA)
  • Large heat sink: larger than 3528 heat sink 2-3 times, excellent heat dissipation design, light decay of LED chip life more secure; ,
  • Oversized light-emitting surface: to improve the rate of light: up to 90%.
  • Ultra-thin structure: to solve the 3528 been long-standing problem spot;
  • High optical efficiency: higher than 3528 luminous efficiency 2-3 times the luminous efficiency of up to 130LM / W (@CRI>80);
  • Super stability: low light fades material, process, process maturity and stability.
  • The high cost: to achieve the same luminous flux, than 3528 costs reduced more than 20%

Main different:

  • SMD3528 is old, usually we say  SMD 2835 is update version for SMD3528 and SMD3014
  • Lighting area: SMD2835 is 9.18mm, 3528 is 4.5mm only.
  • Light View Angle: SMD2835 have 120degree light view angle, SMD3528 have 90 degree only.
  • Heat dissipation: SMD2835 have big heat sink for heat dissipation, SMD3528 light source do not have heat sink.So SMD2835 is better
  • Cost: SMD2835 cheaper than SMD3528.Typical 0.2W SMD2835 LED power is approximately equal to 3pcs 0.06W SMD3528.