Sir, Which Lens I should purchase ?


“ Sir, should I buy a new lens ?“  This is a question I am asked very often by my students.

Before I try to answer this ticklish question, I remember a question asked to a candidate appearing for Union Public Service Commission. She was a lady. She was asked “ Diwali is fast approaching, Now tell us whether you will buy a silk sari for yourself ?”

The answer given by this lady, who later on posted as collector was , “ look sir” she said           your question I will rephrase , whether I will buy a  sari this Diwali ?  Now a days, a cotton sari too costs as much as a silk sari does, so it does not matter whether I buy a silk or cotton sari !. The mute point is whether I need  a sari !  My answer is if I really need a sari this Diwali, then I will definitely buy it.”

When you buy your first DSLR, you often get two lenses, typically, 18-55, and 55-250( canon) or 55-200 ( Nikon). These lenses are good enough to hone your photography skills in the first few days of your journey into photography.

Later on, as you progress  you start exploring further, you realize that your equipment is limiting your creativity, and then the search starts, generally this starts in your honeymoon period with your camera and photography !  “ I am not getting good photos of birds in flight…I am not getting enough details while shooting butterflies, small insects I do not get the background blur in my portraits. I do not get wider coverage….These are some of the complaints” these are the points that drive you to think about purchasing new glass…as they call lenses in America !

In these days, the question you should ask yourself is “ what is my main area of interest in Photography ? “ whether I like, shooting wild life or I am content with shooting small insects, small plants, flowers etc, in my back garden or whether I like  shooting, portraits, or street photography.

Hence, Friends, what should drive you to buy a lens ?  You should not buy a lens just because  your well healed friend has it, not because your neighbor has it.  Do you really need it ? whether the lenses you have are enough for your needs ?  whether your physical, mental make-up allows you to go for that kind of photography. After tackling these questions with honest answers, then you should arrive at a decision. OK ?

Once you decide your main area of interest, then go for an appropriate lens for that genre of photography. Do  not go on amassing lenses, just because you have oodles of money, then you will end-up having lenses you rarely use and instead of giving you photographic pleasure these lenses will serve as home for fungus.

Hence friends, it is your real need that should drive your choice for new lens and not anything else !



In good old days when we were in college, we were of impressionable age. There was a very good looking girl in our class. We used to say that her face was her fortune !! Her looks were classic, but what drew attention , was a strategically placed mole just near her lower lip. In those days it was sacrilegious even to talk to girls in college. We the admirers, learnt that such a well placed mole  is considered as beauty spot and is also called as sweet-spot !

Years wore on and with advent of zoom lenses for Single Lens Reflex Cameras, we learnt about another sweet spot……the sweet-spot of any zoom lens we use……….who so ever named it as sweet spot was dead right….as this is what makes the photographers drool over…!

Zoom lenses are complex pieces of individual optical lenses put together in a precise arrangement, just to get you sharp photos….. All lens manufacturers strive to turn out perfect lenses for modern days digital SLRs…..!

I have a question for you. Can you see the glass ? The answer is no……classically you cannot see the glass, the glass is supposed to be transparent ! What you see is the contamination in the glass. And precisely for this reason, lens manufacturers over last century or so, are trying to make lenses which are made up of purest form of glass and which are optically correct. For this they invented different kinds of glass material. And with that they make the lenses you get. The placement of each individual element and their groups has to be so precise.  A fraction of a millimeter here or there will make the image go soft. It is the best endeavour of each lens maker to give you a zoom lens which gives sharpest results at all settings, but many a time it is not so……… some point in its range the lens is the sharpest….razor sharp rather….at all other settings it may be sharp but not razor sharp. The point at which the lens is sharpest is known as the sweet-spot of that lens.

For every lens there is a sweet spot, which you have to explore and find out. The lens at this spot gives the sharpest image. For this you have to try different focal lengths on the zoom lens and that too at different settings of the aperture. Generally aperture F8 or F11 can be explored at different focal lengths. However do not try the focal lengths which are at lower or higher end. Generally these are not the focal length settings that give you sharpest results, as they are amenable to barrel and pincushion distortions respectively. The sweet-spot of focal length may lie somewhere in between these two extremes. As far as aperture is concerned do not go to F22 or F32 as there is going to be another optical problem known as diffraction,which makes the images go softer instead of making them sharper at higher F stops.

So friends, take out your zoom lenses and find out the sweet spot of your lens. If you have prime lenses which give you a single focal length, the sweet-spot can be found out by trying different aperture values………….!

Every time I take out my zoom lenses and try to set it at its sweet spot, I remember my classmate with the precisely placed mole near the lower lip……old habits die hard !!