Histogram

I am back.... :)

After spending a lot of time on this topic and after a lots of experiments , I come to know what is Histogram means. Its not a compulsion for a photographer to use it. But now a days almost every camera provides this tool and with the help of this you can improve your photography. With the help of this you can easily come to know the tonal range present in your image. About the more detail of Tones and Contrast below is one tutorial. It will defiantly helps you to understand the concept of this. Camera Histogram : Tones and Contrast.

WHAT IS HISTOGRAM:

The histogram is simply a graph that tells the tones in your image from black (on the left ) to white (on the right). Higher the graph at any point the more pixels of that tone that are present in the image. So a histogram with lots of dark pixels will be skewed to the left and one with lots of lighter tones will be skewed to the right.

Lets look these histogram.

This histogram indicates you have most of your pixels toward the dark. The pixels also touch the left edge, indicating underexposure.

This histogram indicates you have most of your pixels toward the highlight. The pixels also touch the right edge, indicating overexposure.

This histogram depicts a correctly exposed picture with the pixels mostly in the middle, i.e. neither too dark nor too bright. Notice a few pixels touch the dark edge, so we should also expect a few very dark spots in the picture.

Now let me explain you the difference of this with the help of some examples.

under exposed
shutter speed =1/1600 sec, Aperture value =F8.0, exposure =-2.0, Recording mode=ProgAE

over exposed
shutter speed =1/250 sec, Aperture value =F8.0, exposure =2.0, Recording mode=ProgAE

correctly exposed
shutter speed =1/500 sec, Aperture value =F8.0, exposure =0.0, Recording mode=ProgAE

Similarly below one also helps you.

Over exposed
shutter speed =1/2.5 sec,Aperture value =F3.2, exposure = 1.0, Recording mode AP

Correctly exposed
shutter speed =1/8 sec,Aperture value =F3.2, exposure =- 0.66, Recording mode AP

Under exposed
shutter speed =1/20 sec,Aperture value =F3.2, exposure= -2.00, Recording mode AP

From the above two example I think its become easy to know the difference.

There are some more links which can help you if you have any confusions. :)

1. Understanding Histogram (by Luminous Landscape)
2. Watch your histogram (by Digital Outback Photo)
3. Understanding Histogram (by Digital Photography school)
   

SHUTTER SPEED

I am using the Panasonic-FZ8.
I am also in my initial stage still what ever I learnt from the book/web , I tested those things and hope helps to every one.

ToDay- Lesson is Stutter Speed.

The shutter is a mechanism that controls the exposure time of an image. This time can be manually set by using the shutter priority shooting mode from your digital camera. The numbers you'll use will look probably like this:

8, 6, 5, 4, 3.2, 2.5, 2, 1.6, 1.3, 1, 0.8, 0.6, 0.5, 0.4, 0.3, 1/4, 1/5, 1/6, 1/8, 1/10, 1/13, 1/15, 1/20, 1/25, 1/30, 1/40, 1/50, 1/60, 1/80, 1/100, 1/125, 1/160, 1/200, 1/250, 1/320, 1/400, 1/500, 1/640, 1/800, 1/1000, 1/1250, 1/1600, 1/2000 sec.

These numbers represent how long the light will be allowed to hit the digital sensor in order to capture the image.

The shutter is the device that controls the exposure time of the photo. The exposure time usually begins at 1/2000 sec. and goes up to 30 sec.

At 1/250 sec. exposure time, the shutter will let in 2 times more light than at 1/500 sec. and 2 times less than at 1/125 sec.

The exposure time determines how a photo will look, if it will be "shaken" or crystal clear.

Below is some example , you can also try this.

There are two picture of moving fan. Its on full speed but due to the difference of stutter speed in one pic you can easily see the wings of the fan and in other there is only a impression of wings.

Shutter Speed=1/2000 sec

Shutter speed= 1.0 sec

Similarly You can see these two (below) also. A short exposure (of 1/2000 sec.) will "freeze" the water droplets in mid air; the detail of every droplet will be clearly visible in the photo. A long exposure time (of 1/25 sec.) will create a special effect where the falling droplets traces unite to create streams of water.

Shutter Speed=1/2000 sec

Shutter speed =1/25 sec