Tag: What are three pillars of photography

4. Shutter Speed and the Holy Trinity of photogrpahy

Hi there all…today the final part of the basics, shutter speed…
Shutter speed, as the name suggests is how fast or how slow the shutter will open up and close down. Lower the shutter speed, slower is the shutter movement and hence more time for the sensor to gather light.
The speed is denoted by notations like 1/250, 1/500 ranging upto 1/4000 commonly, upto 1/16000 are also found in very high end models. And on the slower side, speeds go 1/10, 1/2, 1′, 10′ generally up to 30′ and then there is a “bulb” mode. In the bulb mode, the shutter will remain open as long as the shutter button is pressed, no time limit to it.
Please note, 1/250 means, shutter will remain open for 1/250th of a second. Similarly, with a shutter speed of 2′, the shutter will remain open for 2 seconds. A faster shutter speed will allow you to freeze motion, make your photos less susceptible to camera shake and other disturbances while a slower one will allow you to show motion in form of trails, or ghost images.

     1/20     1/125     1/320

Now that we know the 3 basic pillars of making of a photo, namely, ISO-Aperture-Shutter Speed, we must now understand how these three are related. Let me explain below.

Assumption: we want a properly exposed, unblurred and negligibly noisy photo

1. With increase in shutter speed, chances of blurry image is less, and also the amount of light available decreases. So, for a properly exposed photo, we need to either slow down the shutter speed, or open up the aperture or increase the ISO.
We try opening up the aperture to the maximum to let in more light and also, we increase the ISO setting to make the sensor sensitive…then, the limiting factors become, how much DOF do you want, and how much noise can your camera handle.
For settings where you control the shutter speed and let the camera handle the rest, switch to the Shutter Priority mode, denoted by the “S” button on the dial in Nikon Cameras.

2. With a wide aperture, you get ample light to work with, but a very shallow DOF. Suppose you want a deeper depth, you ll need to stop down the aperture a few stops. This, in turn causes the light available to decrease, and hence, the need arises to lower the shutter speed or increase the ISO. As stated earlier, lower shutter speed will cause blurriness due to camera shake and higher ISO will cause noise. Hence, the limiting factor basically becomes, how slow shutter speed can the lens accommodate with the Vibration Reduction (VR) systems and/or how steady your hand is.
For settings, where you control only the aperture, switch to the “A” (Aperture Priority) mode in Nikon Cameras.

3. There will be conditions, where the aperture value is maxed out, and the shutter speed is as slow as feasible and still not enough light, that is when we need to increase the ISO out of compulsion, in my opinion that is. The sensor becomes more sensitive and we get better exposure, but the chance of a grainy pic is always there.
For this mode, where you get to change only the ISO, dial in to the “P” (Program Auto) mode in Nikon Cameras.

These modes are tried and tested over the years of SLR history and they deliver impeccable results with an appreciative hit rate, its a huge advantage to know how they work. But then, there are those, who want to have total control over the Trinity. If you are amongst those who are not afraid to take complete control of your camera, have a lot of misses and very few hits initially, learn to read the photo histograms, understand the range finder and then take a shot…then switch to the Manual mode, “M” on the Nikon bodies. As an afterthought, sooner or later, you will have to shift to the Manual mode to grow…so I ll suggest, get friendly with the Manual mode early on, but do know the quick settings that might be handy in a jiffy.

Once you get cool with the modes, shots like these, are going to be easy.

  15s  1/250

1/200

Next up, the first photo effect and some shots of a very common and very beautiful, Bokkeh!

Cheers!

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3. Aperture (F-stop) and Depth of Field

Hi there all, today, its all about dilation and depth…Aperture and DOF (Depth of Field)
Aperture is the slit or opening through which light enters the camera through the lens. The aperture is the characteristic of the lens and not the camera body. It is denoted by the F/- numbers, in the format of f/2, f/3.6, etc.
You might have heard people say, photos taken at “widest aperture” or “aperture fully open”, what they essentially mean is that the aperture is open at the maximum to open the maximum amount of light. The smaller the f/- number, the wider the aperture. The below photos show the apertures at various f/- numbers.

  f-1.8    f-5.6    f-11    f-22

The wider the aperture, to get a shot properly exposed, you get more light coming in at an instant…so that reduces the need to increase the ISO. Another way of saying this would be, suppose at f/5.6, you need ISO 400 to properly expose a shot, other conditions remaining constant, then, if you open up the aperture to f/1.8, then ISO 100 would cater to the shot adequately. How is this helpful…it reduces noise that are introduced with higher ISO.
Now, the other factor that is directly related to aperture values, is depth of field (DOF).
DOF refers to the part of the photo that will remain in focus when you take the shot. You might have seen and marveled at the photos, where the subject is in sharp focus and the background is a dreamy blur…that is to say, the DOF extends over the subject only. With the increase in the F/- numbers, the DOF increases i.e region of photo that will show up in sharp focus increases.
There might and will be times, when we want some of the background to show up, we would just increase the DOF, that’s all. This also acts as a buffer for the people who are unsure while using manual focus. You focus to the best of your ability, and have a fairly deep DOF, chances are very high that the subject will be in focus, but this technique is generally avoided and discouraged.
Similarly, for a shallow DOF, dial down the aperture value and hence open it up and you have yourself a very isolated subject..perfect for those portraits of your loved ones 😉

These photos below have been taken varying only the F stops to give an idea of what it is.

    f/1.8     f/3.2     f/4

        f/7.1     f/22     f/14

Now, in the following ones, are more like real situations where, with the change of F stops, DOF changes , and so does the amount of light coming in. With increase in F stops, light entry will decrease proportionately.

 

  f1.8     f2.5     f3.2

 f5     f7.1

Now, with tweaking the ISO and changing the F stop numbers (that’s what F/- numbers are called, by the way), you can manage the photos all right, the photos of still life objects, landscapes, basically, objects which wont move. How do you take a noiseless photo, with nice DOF and proper exposure too? Or how do you capture or restrict motion…that’s where shutter speed comes into play. Coming up next…
Cheers!

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2. ISO

Hi all…today, the first basic concept of the image…ISO
Some of you might know and remember ISO stands for International Organization for Standardization and they set some standards, namely, ISO12232:2006, for determining sensitivity of a camera sensor, hence the name ISO. Not going into all the technicalities, long story cut short….ISO lets you change the sensitivity of the sensor.
Lower the ISO number (say ISO 100/200, even up to 400 on some cameras) better will be the clarity of the picture, this is kind of a thumb rule. So, why would we want to rise from these numbers at all, set the camera to the lowest ISO and snap away…we always want the sharpest of pictures right? The argument is true, Yes, we do want the sharpest photos but every now and then, we are in situations where we do not have decent amount of light. Bumping up the ISO, lets us deal with this issue. When we are increasing the ISO number, we are increasing the light sensitivity of the digital sensor. The ISO system today, in digital cameras is equivalent to what film speeds were in the film cameras. Remember the numbers written on the film rolls, and how a 400 or a 800 speed film would be pretty costly and hardly be given to us, when we were younger, while the 100 or 80 speed ones were cheaper and more dispensable. Back then, the film speeds reflected how sensitive the film were to low light conditions, more sensitive, more pricey.
But, the sensitivity comes with a trade off too…noise, digital noise. Digital noise is what causes tiny grains to appear on the photos. Sometimes we do put on a film-grain effect on the photo to make it look different, but if they come up in the original photo, it is undesirable. Now, with increase in the sensitivity, the noise also increases. To counter this, the cameras generally have a noise reduction system in them. These systems, take care of the noise till ISO 800 with ease, some take handle it up to ISO 6400 too, but beyond that, the noise overwhelms the anti-noise system and they appear in the photos.
Below are a few photos, which are almost 200% crops of bigger photos, taken of a pillow cover at various ISO to show the difference. Notice that in ISO 100, 400, and also in 800, the strands are pretty much visible separately but once beyond that, they start getting smudged in the photo…this is being caused by noise and in ISO6400 and ISO12800, the details are almost non existent.

The high end DSLRs provide with ranges near ISO204800. Agreed, at that high range, your picture will be noise and noise only, but the sensitivity will allow you to shoot at pitch darkness and your camera will see more than your eye can and give you some outputs, in theory at least…need to try this in practice someday..
Now, even in the entry level DSLRs, the noise reduction system is good enough that on a general viewing, the noise might not be a distraction to the great photo that you have taken. But as and when you start printing them, say at 100%, the noise will show up and believe me, you would want to avoid that.

To avoid the noise from creeping in and ruining your shot, you ll need to handle the aperture ( F stop) and the shutter speed….topics coming up on the next posts..

Cheers

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