Whenever we hear about cameras there are certain parameters which draw everyone’s attention. One of them is aperture. What is about aperture that its an important part of every camera’s or it’s lens’s spec sheet? And what if you want the beautiful ‘Bokeh’ effect in your photos and how aperture can help you to achieve that? Today lets talk about that.
Just like our eyes a camera lens has the iris in it. That iris in the lens is usually states as diaphragm. It is made of multiple curved metal blades which move inward or outward as per the aperture setting on your camera. Take a look at the picture below, there you can see six blade diaphragm. In this picture you can understand how the camera or lens adjusts its aperture.
Higher the number of blades in diaphragm, smoother the ‘Bokeh rings’ will be.
Aperture defines how much light a lens will allow to pass through it and reach the camera sensor. It is defined with f stops. For e.g f/1.8 or f/6. A lens with f/1.8 has bigger aperture than the one with f/6. Confused?
Look at the picture below
Here we can see that f/1.4 has bigger opening than f/11 even though the number on the later is bigger. Its because these numbers are actually in the ratio of 1 i.e. f 1:1.4 and f 1:11. And as we know the higher the denominator, lesser the final number. So a lens with f/1.8 will allow more light to the camera sensor than the one with f/4. Hence while shooting a low light scene one prefers to use a lens with fixed and bigger aperture.
“Now wait, bigger aperture is fine but whats with this ‘fixed’ aperture” you ask. Zoom lenses often come with variable aperture. These lenses tend to decrease the aperture value when their focal length is increased. NIKKOR 70-300MM F/4.5-6.3G is one fine example of that.
Whereas if you are shooting a low light scene then this may not be the best zoom lens you can choose as at 300MM focal length it has the max aperture value of f/6.3. Bokeh lovers will also get disappointed by the end result of that as f/6.3 is quite a narrow aperture for good quality bokeh. And the rule is – higher the aperture the more tighter the focus area be and more the Bokeh you’ll get.
But we are covered here as there are zoom lenses with fixed and bigger maximum aperture for their entire focal range. These lenses are quite COSTLY than their variable aperture brethren. But boy those are worth it! Two of the finest example of these lenses are –
Canon EF 70-200mm f/2.8L IS II USM
NIKKOR 70-200MM F/2.8E FL ED VR
Both of these lenses have the max aperture of f/2.8 for their entire focal range. Which is quite nice.
So today we learned something about aperture.
- Smaller the f stop number looks the bigger the maximum aperture
- Want to shoot low light? or Want a nice milky Bokeh in your pictures? Go with a lens with the bigger maximum aperture
Don’t know what ‘Bokeh’ or ‘Bokeh rings’ are? Don’t fret, an article explaining those will follow soon.
Have a question or different opinion on this matter? Leave a comment.
Good day friends!
