What is a DSLR (Digital SLR)

DSLR stands for “Digital Single Lens Reflex”. In simple language, DSLR is a digital camera that uses mirrors to direct light from the lens to the viewfinder, which is a hole on the back of the camera that you look through to see what you are taking a picture of.

1) What do DSLR cameras consist of?

Take a look at the following image of an SLR cross section (image courtesy of Wikipedia)

  1. Lens
  2. Reflex mirror
  3. Shutter
  4. Image sensor
  5. Matte focusing screen
  6. Condenser lens
  7. Pentaprism
  8. Eyepiece/Viewfinder

2) How do DSLR cameras work?

When you look through the viewfinder on the back of the camera, whatever you see is exactly what you are going to get in the photograph. The scene that you are taking a picture of passes through the lens in a form of light into a reflex mirror (#2) that sits at a 45 degree angle inside the camera chamber, which then forwards the light vertically to an optical element called a “pentaprism” (#7). The pentaprism then converts the vertical light to horizontal by redirecting the light through two separate mirrors, right into the viewfinder (#8).

When you take a picture, the reflex mirror (#2) swings upwards, blocking the vertical pathway and letting the light directly through. Then, the shutter (#3) opens up and the light reaches the image sensor (#4). The shutter (#3) remains open for as long as needed for the image sensor (#4) to record the image, then the shutter (#3) closes and the reflex mirror (#2) drops back to the 45 degree angle to continue redirecting the light into the viewfinder.

Obviously, the process doesn’t stop there. Next, a lot of complicated image processing happens on the camera. The camera processor takes the information from the image sensor, converts it into an appropriate format, then writes it into a memory card. The whole process takes very little time and some professional DSLRs can do this 11 times in one second!

The above is a very simple way to explain how DSLR cameras work.

To read a lot more about DSLRs, check out this great article at Wikipedia.

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Photoshop CC2015.1.2 What’s New

Photoshop is a primary tool for many photographers. Some photographers prefer Lightroom because it easier to learn. I think Lightroom has limited use and almost everything in Lightroom can be done with more control in Photoshop. The bottom line is that both programs come for one price about $9.95 US\month as subscription to the cloud. A monthly subscription means you don’t have to shell out $700 plus for Photoshop, but it also means you have to pay as long as you use it. The price can go up anytime, but I think if that happens many photographers will search for an alternative. There are free alternatives to Photoshop like GIMP.

I have been teaching Photoshop at local colleges for almost two decades. One of the good things is that now each college classroom will have the latest version of the software. Some colleges would only upgrade the software every few years or use free 30 day download and that made it frustrating when I taught advanced courses.

Photoshop is a primary tool for many photographers. Some photographers prefer Lightroom because it easier to learn. I think Lightroom has limited use and almost everything in Lightroom can be done with more control in Photoshop. The bottom line is that both programs come for one price about $9.95 US\month as subscription to the cloud. A monthly subscription means you don’t have to shell out $700 plus for Photoshop, but it also means you have to pay as long as you use it. The price can go up anytime, but I think if that happens many photographers will search for an alternative. There are free alternatives to Photoshop like GIMP.

I have been teaching Photoshop at local colleges for almost two decades. One of the good things is that now each college classroom will have the latest version of the software. Some colleges would only upgrade the software every few years or use free 30 day download and that made it frustrating when I taught advanced courses.

Once you subscribe to the cloud you can download the software on two computers, and one can be a PC and the other a Mac. Also if you want more copies, you need to register with a different email for each package that you purchase. I have 2 accounts – a total of 4 copies of Photoshop CC. The Mac vs PC issue doesn’t interest me, neither does the Nikon vs Canon or any other brand – it’s the photographer that matters not the hardware – folks. As for Photoshop vs Lightroom – well I believe those that want more control will choose Photoshop.

New Photoshop CC 2015.1.2 Features

In this article I am going to show some of the new features that have been added to Photoshop. The first new feature when you open Photoshop is a new start screen. I find this screen annoying and turn it off in Preferences. Edit > Preferences > General > uncheck show Start Workspace When no documents are open.

The second feature that stands out is the modified tools panel. It can collapse into a single column which provides users with more editing space on a laptop and this has been around for several versions, but since I have used Photoshop since 1989, I prefer to double it up. The new feature is the ability to modify the tools palette as you like by clicking on the “…  ” 3 dots – hold for about 3 seconds and a new palette appears shown below or just click the … and select edit tool bar. You can drag tools from the right side into the left where you want them to appear. Nice feature, but I was fine with where the tools were. In addition on my PC but not my Mac – the Quick selection mask was disabled and I had to click on it for it to appear on the tools palette.

A new feature added to Photoshop Cloud is the Camera RAW filter. By selecting Filter > Camera RAW filter it is easy to open a .jpg or .tif file in Adobe Camera RAW. This is quite a nice feature as you can now quickly modify the white balance or exposure and several other features of a .jpg. You can upsize the image in Camera RAW like you can a  RAW file. I am not saying you can now photograph .jpg instead of RAW files, but often I am given .jpg file to work on. I still recommend you shoot in Camera RAW most of the time if quality and flexibility is crucial.


Oil Painting Filter – its Back!

While its possible to use the Mixer Brush tool to simulate an oil painting, this takes time and sometimes I want a quick way to convert a picture to a simulated oil painting. The feature was added, then removed and I presume after receiving complaints it was brought back. To apply the filter you simply open an image and select Filter > stylize > Oil paint – and play with the sliders in the pop up box. Nice, quick and easy.

Artificial Trees

This feature allows you to add a variety of trees to a landscape. I imagine this was done for folks working on computer games and architecture. If you are going to add trees to a picture you should first create a new layer so you can resize and position the tree where you want – otherwise it will appear in the center of the image and won’t be editable. To add a tree Select Filter > Render > Tree.  You can select quite a variety of trees, change their branching pattern and color of the leaves. They look OK, but its easy to see they are not real trees and hopefully this feature will get better in future versions.

Add Frames

It’s not difficult to create and simulate a picture frame in Photoshop and there are many tutorials on the web.  Still Adobe has made it even easier to add a picture frame to your images. Select > Filter > Render > Picture Frame – and modify the various sliders to get the type and size of frame you want.

Dehaze Filter in Camera RAW

To use this filter open a RAW file in Camera RAW Select > fx tab > and then slide the Dehaze filter to the right to remove haze, to the left to add haze. I like this filter because it can remove haze, or add it to a photo to add mood. Below are a few examples.

White Balance

Color Temperature

To understand the concept of White Balance, you need to first understand the concept of color temperature. Color temperature is a characteristic of visible light. It provides a method of describing these characteristics and is measured in Kelvin (K). A light having higher color temperature will have more blue light or larger Kelvin value as compared to lower light, which has a smaller Kelvin value. The following table shows the color temperature of various sources of light.

How does the Light Affect the Color

You must have noticed some photos turn out with an orange/yellow cast if shot under tungsten lighting or a bluish cast if shot under fluorescent lights. This occurs because each source of light possesses a different color temperature. A digital camera can measure the colors in the red, green, and blue light of the spectrum, as reflected to its sensors. In a photo taken under the midday sun there is the whole spectrum of light (which makes up “white” sunlight). Under these conditions, the colors in an image appear nearest to the “true” colors. An image taken under tungsten bulb (a normal household incandescent bulb) without adjusting the digital camera for white balance produces the dull orange shade as it spreads the biased light. Similarly, an image taken under the fluorescent lighting produces a brighter bluish cast. However, it is possible to shift the color in the desirable direction, provided you have a good understanding of your digital camera and its settings.

Why to Adjust the White Balance?

Since different sources of light have different color hues, a picture taken with a normal white balance under artificial lighting conditions transmits the low heat to the camera’s sensor. This light touches the red bits of the spectrum, which results into dull yellow or orange shades in the picture. Though the human eyes can automatically adjust to different lights and color temperatures to sense right color, a camera needs to be adjusted to different lights for accurate color reproduction. By adjusting the white balance setting of your digital camera, you can alter the required light or temperature to produce the most accurate colors in a digital image.

Preset White Balance Settings

Auto – The Auto setting helps in adjusting the white balance automatically according to the different lighting conditions, but you can try other modes to get better results.

Tungsten – This mode is used for light under a little bulb like tungsten, and it is often used while shooting indoors. The tungsten setting of the digital camera cools down the color temperature in photos.

Fluorescent – This mode is used for getting brighter and warmer shots while compensating for cool shade of fluorescent light.

Daylight – This mode is for the normal day light setting, while shooting outdoors. Many cameras do not have the Daylight mode.

Cloudy – This mode is ideal for while shooting on a cloudy day. This is because it warms up the subject and surroundings and allows you to capture better shots.

Flash – The flash mode is required when there is inadequate lighting available. This mode helps pick the right White Balance under low light conditions.

Shade – A shaded location generally produces cooler or bluer pictures, hence you need to warm up the surroundings while shooting shaded objects

Manual White Balance

You can also adjust your digital camera manually by setting a white object as the reference point. This is done to guide the camera how white the object would look in a particular shot. It is advisable to manually adjust the white balance when taking a picture to compensate for the changing lighting conditions. As the daylight changes during early morning and late evening hours, the varied light intensity is easily perceived by the camera. Therefore, you need to correct the white balance regularly while shooting during these times of the day. To manually set the white balance in your image, you first point your camera at a pure white object, set the exposure and focus. Now, activate the white balance on the object by pressing the button. It may take few seconds for the camera to perceive the shot, but it will this color setting until the next white balance is performed.