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Comments : 2

Basics of Digital Photography: Understanding ISO

Posted by Vishal Vasu | Posted on 05-03-2011

Tags: ISO

ISO stands for International Standards Organisation and when releated to photography, it is a industry scale for measuring the sensitivity to light. In today’s world where the film has been replaced by a digital image sensor, ISO basically relates to how much sensitive the sensor get’s to the light that enters the camera. ISO is measured in numbers where the lowest number means least sensitive to light (example ISO 100) while the highest being most sensitive to light (example ISO 3200). Almost all digital cameras today allow to control the ISO settings and so it is important to know what it is and what effect does it have on the snap that you take. After all, we all want to get that WOW factor in our photography – right?

I’ve seen many photographers – including myself – click photographs with the available natural light and avoid the use of flash. This is because the final image looks as natural as possible not to forget the softness it carries as the hard light is avoided. ISO plays an important role under these situations. Before clicking a photo, ask yourself the following:

Is the subject well lit or is there enough ambient light?
Is the subject stationary or moving?
Should I use a tripod?

The above questions help to decide the ideal settings for ISO, Aperture and Shutter Speed. We are going to cover Aperture and Shutter Speed later but in context to ISO, the answers to th above three questions would help to decide the ISO value.

For example, if there is plenty of light, the subject is stationary and the camera is mounted on a tripod, a low ISO setting would be the best. We do not need the sensor to be highly sensitive to light as we can decrease the shutter speed so that more light enters the camera.

However, if it is dark, the subject is moving and a tripod is not available, a higher ISO is required. Reason, we need a high shutter speed to avoid blur or camera shake as the subject is moving and so we need the sensors to be more sensitive to light.

Below are some samples clicked at different ISO settings while keeping the same Aperture and Shutter Speed.

Let’s take an example. Assume that the ISO setting is at 100 and the light meter says that the camera should be set at f/4 and 1/60 second for a well exposed picture. But the subject is moving or our lens only opens to f/5.6.

In this case, 1/60 of a second will not stop the motion of a moving object and if the lens only opens to f/5.6 we are surely going to have an under exposed and blury photograph. Now is the time to step up the ISO setting. If we step up to ISO-200 then we can move one of the other elements one full stop. Your setting would now be f/5.6 and 1/60 or f/4 and 1/125. Bust since the subject is on the move we’ll probably need more than one stop to freeze the motion so we will set our ISO to at least ISO-400. This will give us the ability of setting our aperture at f/4 and the shutter speed at 1/250.

So what is the trade off when using a high ISO? Noiser picture! Better quality pictures are achieved at a lower ISO. Higher ISO pictures capture lot of light and look grainy. Digital noise can be seen a sort of speckley effect in areas of similar colour, like skies or dark shadow areas.

ISO Comparison

Try keeping the ISO set to the lowest number and use aperture and shutter speed to get the right exposure. If the result is not good with aperture or shutter speed, move up to the next ISO setting and try again.

Comments : 7

Basics of Digital Photography – Exposure Triangle

Posted by Vishal Vasu | Posted on 17-02-2011

Category : Photography

Tags: DSLR, Exposure, Photography

First things first – I’m not a pro or a guru of photography and my learning curve still rises with every single photo that I take. It all started with a summer vacation course in photography when I was about 10 years old. It was really an awesome experience as I found a new dimension to explore my creativity. My grandfather’s Zenith SLR camera (fully manual Russian camera), which was locked up by my father and well preserved, could not have proved more helpful then ever during my 6 weeks of training.

It was the first day at the institute and ofcourse the first chapter was to understand the parts of an SLR camera. Interesting! But my mind started to bog when complicated words like Aperture, ISO and Shutter speed were being thrown at me. “Want your shutter to be open for one-thousandth of a second? Then your camera’s shutter speed should be set to 1000. Want it to be 2 seconds? Look for 2″ sign on the dial. What’s bigger? An aperture setting of f1.4 or f16?” – Go ahead – scratch your head. Even I did the same.

All this might make sense to professional photographers who have become professional after years of experience. For a newbie it is rocket science. But trust me, it’s not that hard. One might not get it the first time, but once you start taking snaps, analyze them and play with these settings, the results will speak. Let’s start by understanding the basics of the three main elements of exposure in photography:

Aperture
The aperture controls the size of the lens opening. It is like the iris in your eye. If an environment is too bright, the iris contracts to restrict the amount of light entering our eyes and if it gets dark, it expands and more light enters. Similarly, the aperture is the iris of a camera. The aperture settings also determine the Depth-Of-Field (DoF) – a very important aspect if you want to shoot some great photographs.
- Remember:
  - A smaller number means there is a larger lens opening, thus allowing more light into the camera
  - A larger number means a smaller lens opening, thus allowing less light into the camera
Shutter
The shutter controls the amount of time the camera has to let light in and time to capture movement. This is the eyelid of the camera system.
- Remember:
  - A smaller number means shorter exposure time, thus “freezing” any action. It also means less light will get in
  - A larger number means longer exposure time, thus “blurring” any action. It also means that more light into the camera will get in
ISO
ISO controls the sensitivity of sensor to light and the amount of grains on the picture. It is like a magnifying glass on a photo. The closer you get, the grainer the image (thus the higher the ISO, the grainer the picture).
- Remember:
  - A smaller number means the sensor will be less sensitive to light (allowing in less light) and have a finer grain on the final picture
  - A larger number means the sensor will be more sensitive to light (allowing in more light) and have rough grain on the final picture

To summarize, the ISO controls the amount of light that falls on the sensor and controls the light required to obtain an image. By changing the Aperture, you change depth of field. By changing the shutter speed, you decide how the motion is captured. These three elements of exposure are inter-connected and changing the value of one has a direct effect on the other two. The exposure triangle diagram here would help to understand that better:

A well exposed photograph is a result of the correct Shutter speed, the correct ISO and the correct Aperture. The exposure triangle defines the relationship between all three of these photographic aspects. No single setting is just right or called an ideal exposure. The best way to learn this is to go out and shoot some photographs while taking notes of the exposure settings. Note down the time of the day or night (gives you idea about ambient light), the Aperture value, the Shutter Speed, the ISO setting and the Camera Mode (Auto, Manual, Aperture Priority, Shutter Priority, etc.). Come back home, download the photos on your computer and analyze them. The exposure settings noted down while you shot the photograph will certainly help here.

In the next series we shall discuss these three elements in more detail, preferably with some examples. Yes, your read it right – with examples because a picture is worth a thousand words.

Comments : 1

Microsoft Windows InTune

Posted by Vishal Vasu | Posted on 07-02-2011

Category : General, Microsoft Windows Server

Tags: Network Monitoring, Patch Management, RIM

Microsoft recently announced the beta availability of a new cloud-based subscription-based remote infrastructure management solution for mid-sized businesses called InTune. Microsoft Intune allows admins to manage computers from any location instead of forcing them to be at their own console, and it’s not just an enterprise-scale application, either. Windows Intune simplifies how businesses manage and secure PCs using Windows cloud services and Windows 7—making it easier for IT staff to manage and secure PCs from virtually anywhere.

For instance, Intune highlights the ability to manage updates released by Microsoft, as well as block malware using Microsoft’s Malware Protection Engine. The buck does not stop there. It also enables technical support personnel in an organization to monitor PCs and provide remote desktop support for their users. Additionally, Intune also includes tools for tracking hardware and software inventory, including the ability to monitor assets, licenses, and compliance. It also has remote management tools like remote desktop initiated by the client through the Intune service could be very helpful for consultants and corporate IT when a remote user calls with an email problem.

From the first looks of it, the interface seems to be good which is built in Silverlight. Going to give this beta a try and see how it goes.