Exposure Parameters : Part I - ISO

If you own a digital camera and a little curious you would definitely not have missed ISO, Though the name sounds so technical this is one of the easiest parameters which you can start controlling , ofcourse in the long run this does not make any difference if not used with Aperture and shutter speed , but nevertheless a good start.

Now what is ISO and why should you bother? In digital photography terms it is how sensitive your camera sensor is to light.
Normally ISO that are supported are 80 100 200 400 800 1600 , Having said that what do those numbers mean ? Do higher number mean better quality ? No! Less is more in this case.

A photograph taken with a Lower ISO is of better quality than that of the photo taken with Higher ISO.Why ? By increasing the Number from 100 to 400 what you are doing is making the sensor more sensitive to light,but sadly it is equally sensitive to noise and thus results in the granularity of the picture.
Now if you have the question as to , Both me and a friend of mine have same megapixel camera and both are taking pictures at same resolution at same ISO but still my pictures look grainier than his/her , Yes that is possible and the culprit is the camera sensor, Bigger the sensor for a given megapixel better is the quality ie lesser is the noise, so next time you are going to buy a camera please make sure you check that along with the megapixel.
but then if lower ISO is always good and higher ISO bad and grainier why set higher ISO at all, Reason is you will need it in low light conditions,Though the picture appears a little grainy you still will be able to take photos ,better than not taking one right, Also this allows you to control wider range of shutter speed and aperture values thus aiding photography at night/low light.
You may ask why not flash ? using flash against a reflective surface will result in loss of information and unwanted glare,even on regular surface there will be unwanted glare in line of flash portions where as other regions will overly under lit.So rule of thumb is flash is bad unless you have a strong reason to do so.
After all the explanations , What to set ? If the scene is sufficiently lit and please set the ISO to the lowest value supported by your camera (say ISO 80), as mostly the calibration of the sensor would be for lowest ISO.
If the scene is not sufficiently lit whether it is night or indoors or concerts,you higher ISO accordinly and see the best fit , for instance start off from ISO 200 as higher the ISO higher is the noise.

Now that you have taken a night shot with higher ISO and see a lot of grains,there is some post process you can do.
There are some easy tools which are available:
http://ndnoise.free.fr/
http://www.neatimage.net/
But for all the GIMP users ,who dont want to use any other Application, Here is a cool plugin:
http://gmic.sourceforge.net/gimp.shtml

These software's will help in reducing the noise in the Image.

Photo Editing software - GIMP , Picasa and Irfanview

Not always you are at your best and take the best of photos , ligthing or other parameters also add to bad photography, Not to mention photos taken while you are travelling!.That would be worst nightmare (As not much help on motion blur is available).

Yet another use of photoediting is you can create some really artistic photos , like in smoke photography using photo editors.

Photo editing , though cannot help you if the information itself is not captured (say in a hugely overexposed image all you see is bright light and as the information of that scene is not captured you can do nothing to restore it), it can definitely help to enhance the image quality or lighting or say resize it to different size. 

I have listed 3 really good photo editing tools which are free to use but at the same time can really make a difference to your photo.How to use and how to enhance will be covered in future.

1) GIMP - any day it is one of the best editing tool which is open source with lots of features, comparable to that of photoshop or lightroom.I guess a hard core techy would go beyond and try to write a new plugin or fix bugs meanwhile.

I will explore features of GIMP in following articles, Its really fun to explore.

Download link : http://www.gimp.org/windows/

2)Picasa - A free google tool with very good user interface , best suited for basic fixes like fill light , auto contrast or for getting some special effects like B&W , sepia , hue and saturation etc.It Also provides easy option to upload to web and signatures/watermarking.

Download link : windows :  http://picasa.google.co.in/ 

linux   : http://picasa.google.com/linux/download.html

3) Irfanview - Very simple tool , extremely easy to use , works well for cropping , image resize  is the best , really good for upscaling (ofcourse lack of information will be a constraint)

Download link : http://www.irfanview.com/

Printworks Matte 8-1/2 x 11-Inch Photo Paper 50 Sheets (00471)

Megapixel and its influence on photography and prints - what and why

Now before going to the effect of megapixel on photography lets understand what is megapixel .

Megapixel never was a parameter in film camera's right ? yes this is purely a digital camera parameter and it has been hyped and used as a big time marketing strategy for selling the camera be it in a phone or a full fledged camera , If so what is it and what do we need?

Now consider that you draw a 4"*6" rectangle and then you start pouring sand inside (rather spread to cover entire space). Initially they look too granular and spread across but as you fill in and once a layer is formed not matter how much sand you fill inside the space it still will look the same right , that's exactly the job of pixel's on a photograph.

In layman terns pixels are the dots drawn in placed in the resolution of the picture chosen by you.Now that we have known this then what is the use of a higher megapixel camera ? Now take the same sand inside rectangle example , but now make a bigger rectangle say 5"*7" and then spread the same amount of sand (Which was the threshold of 4*6 ie beyond which it did not make difference), Now suddenly it looks grainier right .. so filling some more sand would help.Higher mega pixel have exactly the same benefits.

I have put up a pictorial example below (click on the image to get enlarged view). The left side of the image is 200% scaling(zoom) of a 1600*1200 image and a certain portion is cropped and right side is that of a 640*480 image. When you do this you definitely see that the quality of left side is far better .Below that you can original picture.
Thus if your aim is to put up photos on istock or publish it in magazine or make a huge blow up then go ahead and take picture of higher resolution.But if your goal is to print a 4*6 or 5*7 photos you can set medium resolution.





Now you may ask when i have a better megapixel camera why shouldn't i take a picture of higher resolution, that is because pixels are memory intensive.Now consider you have a SD card of 1GB.Assuming that your camera stores it in RAW format(That is not normally the case , standard is jpeg).Consider a 1600*1200 image , this will take up 1600*1200*24(assuming 24bits per pixel)/8(bits per byte)*10^6 , It will take about 6 MB of space(JPEG would be around 500-800kb). so that would mean you can store about 170 pictures whereas if the resolution was 640*480 it would be about 900kb.(jpeg would be roughtly 50-60kb).which would mean you can store roughly 1100 photos , roughly 6 times more for the higher resolution which you dont need.
Now that you have a 10Mega pixel camera , does all the pictures taken will be at 10Mpixel? No that's not the case if you take a 640 * 480 picture it will be a 0.3 Mega pixel image, The highest image size in you camera would be the maximum pixel supported by the camera. say 3264 * 2448 would be using 8 Megapixel.
Now you can decide for yourself what megapixel image or quality you want based on your requirement.Normally for a magazine or high quality prints you would need 300 pixels per inch so if you are taking a picture at 1600 * 1200 then the best picture you would get is of size 5.3" * 4 " but for a regular home prints it would be 200 pixels per inch with a good quality printers so you can easily get a 8" * 6 "

Calculation to find memory used for raw image :
Resolution is x(width) by y(height) then( x*y*No of bits per pixel) / (8(No of bits per byte) * 10^6) to get in Megabytes
Calculation to find the size required for printing an image :
x/ppi * y/ppi
x is width y is height
pixel per inch (PPI) which can be 300 for high quality 200 for medium quality

Photography and Imaging - What , How and What Next ?

‘I have no special talents. I am only passionately curious.’

This was told several decades before by Albert Einstein.

No matter what, you are always curious about things you are passionate about , You always checkout clothes of brand you are fond of , books of author you like , similarly i am drawn to photography and post processing/imaging, Though I've not no special talents in taking photos , it doesn't stop me from longing to try out different things wrt it.

Though art and science are considered as two different subjects , they converge to form photography.Photography not only wakes up the artist but also the science freak in you..

Irrespective of whether you want to capture the moment you cherish or scence which moves you or just try out all the options available in your new digi cam, Photography provides a vent.

Now not all the shots taken will be excellent may be because of bad lighting/shake or any of the 101 reasons for bad photography or you might just want to make it more artistic there comes the role of imaging/post processing.

Also not always you need a SLR to capture a great photo, so the topics that will be covered in this blog are photography tips and tricks, Parameters involved, How to edit photos it will mainly with free tool GIMP.Also some trials and techniques that i try out.

Now how is this blog different from already existing one's?

It is mainly from a perspective and learning's of a passionate amateur photographer, so I will try to annul most of the problems i face when i read other websites or blogs , Also yet another benefit is I will mostly try to use all the free tools available for any of the editing :) .I
have a decent non SLR , canon S5 IS , so i understand grievance of all non SLR holders and thus parameters i mention in my blog will hold good for most of the digital camera's rather than privileged few..
Also atleast i havent found a blog yet which addressess all the above issues.

Ah so much for introduction , its all action from next post :).