Please add my new email address

My Dear Friends,

My Hotmail account ( is hacked, please remove the same and mark any incoming Email as spam.


Please note my new email address is


19 July, 2012 23:33

12 July, 2012 04:57

10 July, 2012 23:21

5 July, 2012 21:38

Understanding F-Stops


F-Stop is a unit to express how much light is entering a camera lens. Example f/2, f/4, f/8, etc.


Assuming this post is for beginners I am briefing out the dependent terminologies:

Aperture: Just like our eyes, camera lens has an opening that allows light to enter into the camera. This opening is termed as aperture.

Focal Length: Distance between the image sensor and optical center of camera lens. When you buy a lens for your camera, it will have a number on it, something like 18mm, 55mm, 105mm, etc. These numbers are called as focal length.


Letter “F” in F-Stop is called as focal length. Focal length divided by aperture determines the F-Stop.

Calculating F-Stop

For a 200mm lens with an aperture 50mm:

F Number = Focal Length/ Aperture

= 200/50

= 4

Finally denoted as F/4

For a 200mm lens with an aperture 25mm (decreasing the opening):

F Number = Focal Length/ Aperture

= 200/25

= 8

Finally denoted as F/8

Focal Length Aperture F-Stop Conclusion
200 mm 50 mm F/4 Bigger lens opening results in smaller F-Stops

More light enters when F-Stop is small

200 mm 25 mm F/8 Smaller lens opening results in bigger F-Stops

Less light enters when F-Stop is large

How does this affect your photography?

Change in f number has a…….

Read more? go to

Protecting your Camera’s Sensor from Dust

Just like many of you I am also a believer of “Prevention is better that cure”. If you can prevent your camera’s sensor from getting dusty, you will never have to look for a cure. Here are a couple of important steps you can avoid getting dust into your camera:

– Keep you camera clean. If you can; avoid working in dusty areas.

– After shooting store your camera in a clean bag i.e. free from dust.

– Keep your replacement lens ready before changing the lens. This will at least reduce the time of exposure of your camera’s optics to dust. I have seen people first removing the lens, keeping it aside, grabbing another lens from deep inside of their bag while keeping the camera optics exposed to dust. I personally call it “abusing”.

– Before replacing make sure you dust off the rear of the lens mount of the replacement lens.

– While detaching the lens, face the camera downwards so that any dust particles present in the mirror chamber fall away from the sensor not on the sensor.

– After you have attached replacement lens, put back the end cap quickly on the last lens so as to reduce the dust that might fall on it.

– User blower bulb to dust off your optics. Never ever user compressed air or vacuum.

– Blow off dust before every session else you will have to curse yourself for returning home with those tons of photos containing dust spots that were present on you sensor before you even started.

– If available use your camera’s dust reduction feature. You can specify when to run this feature automatically i.e. at the startup or at the time you shut off your camera. I prefer to run the mechanism at startup as well as at the time of shutting off. The dust reduction mechanism basically produces vibrations on or around the image sensor making dust particles fall off.