Friday, November 1, 2013

Lights.... Camera.... Fireworks!!!!

With the festive season around the corner, i am often confronted with questions regarding fireworks and colourful festive low-light photography. Since its been quite some time since I wrote, I thought why not add line or two on these...

The world of Fireworks...

Fireworks have always fascinated me and capturing the colours and the grandeur of fireworks is what I have always liked. Certain points to be noted here though...

Things needed...

  • Shoot RAW - absolutely necessary here since we are living in regions where the sky and ambient color keeps changing. raw shooting helps a lot in post processing like white balance, exposure, noise, etc. unless you really like orange skies to be captured
  • Strong/Heavy Tripod or fixture - this one is another absolute necessity unless you have really really steady hands (read not possible). the camera's position in the 3 dimensions needs to be fixed and why so, we'll come that in a bit.
  • Wide Angle Lens - preferably 18mm and below to get the whole landscape
How to...
  • typically on a dark night of diwali, you would want to set-up your shooting on a tall structure (building terrace, hill, etc.) near lots of action
  • mount your camera on the tripod and align your camera to get the composition you like
  • set your camera on Manual, with shutter at around 10sec (not 1/10sec) and take a click at whatever other settings the camera is at
  • with hardly any movement, other than strong winds, you should be getting a bright image of the otherwise dark cityscape
  • notice the orange tinge (ideally for polluted cities like Mumbai), if you like it then no issues, otherwise a Tungsten White-Balance can remove the orange tinge
  • a camera wireless remote or wire-triggers to reduce camera shakes
  • I would preferably shoot at
    • Shutter - 5sec to 20sec 
      • depending on the speed of the fireworks (you dont want overlapping fireworks else it will be a ball of white light)
      • remember, longer the shot, more time for the camera to process and hence more of missing action
      • also longer times are good if the fireworks are happening on a wide area and not starting from the same place
    • Aperture - f8 - f11
      • depends on the first shot you took; if it isnt sufficiently bright move to higher apertures
    • ISO - 100 or lowest values
    • WB - Tungsten
    • Long Exposure Noise Reduction - OFF
      • if your cam has this, better to keep it off and remove the noise in PP
  • once the fireworks starts.... what are you waiting for... just SHOOT!!!

Shooting People & Low-Light Photography

This one's interesting, since these would be mostly candids and missing the moment is missing the shot. Very rarely would get another chance with the same expressions and emotions. So you need your camera to capture as much details as possible in the shot.

Photography is all about capturing and light and for such quick moments, you need a fast lens - one with a large aperture. f2.8 and lower I mean. And that's because, you need a higher shutter speed for capturing moments and if you recall my last article, shutter speed and aperture are inversely proportional, so you need a large aperture.

Another way is to use flash to freeze the motion and yet this doesn't always work. Flash power and its light's spread is limited.

Finally, you can compensate for smaller apertures and higher shutter speeds by using higher ISO speeds. Limitations for higher ISO is the digital noise, which can be cleared off in post processing only to some extent.

Okies enough of the gyaan here... the most important part of photography during festivals is DO NOT keep the camera INSIDE your bag or you lose the moments.

Keep clicking... and Happy diwali...

Wednesday, January 9, 2013

Photography 101 - The DSLR, Aperture, Shutter and ISO

In most of my discussions about photography in general and cameras and lenses in particular, one thing that I have realized is that there is a mixed reaction towards the Manual Mode of the camera. While I can easily attribute it to laziness, a bit of introspection and inspection made me realize that there is a partial understanding of the basic concepts in the first place. While most of my friends have had the liberty to discuss these topics openly, many haven't had that chance or a medium perhaps.

So here are the basics of photography... Photography 101... for the sake of argument, this article is limited to Dslrs and Slrs, but the techniques can be applied to any type of photograph recording device.

Lets attack unarguably, the most common term in photography - A Dslr
Digital Single-Lens Reflex (camera) is basically digital cameras which use the (old) Single-Lens Reflex (SLR) technology and replace the film with a digital back (sensor). The Single-Lens Reflex is of interest to us at this point since we are going to use it further in this article and manipulate it in subsequent topics. To think about it in simple terms, think about a periscope, only in this case, the light is first bounced off a 45 degree mirror into a condenser lens finally into a Penta-prism before emerging out of the view finder. When the shutter release button is pressed all the way down, the mirror retracts and the sensor sees what you essentially saw earlier through the view finder. Hence, the term Single-Lens Reflex. Based on the sensor (film) size, they can be categorized into Crop Sensor (APS-C), Full Frame (35mm format), Medium Format and Large Format cameras. Most of us will be wielding a crop sensor camera with a crop factor of 1.5 for Nikon and 1.6-1.7 for Canon. I am going to restrict our discussion to crop sensors and full frames for ease.

The terms and concepts that follow have certain uniqueness. Each of them can be attributed to a part of the entire camera and normally aren't swapped or mixed.

Shutter - Body function
Aperture - Lens function
ISO (ASA) - Sensor (Film) function

Whether Film or Digital, it has always been the amalgamation of these 3 things that takes the snaps. Lets dive a bit into each of these.

Aperture and Depth of Field (DoF)
When light travels, through the camera lens, it is actually travelling through a tunnel or a pipe. How much light reaches the other side is determined by the size of the hole or the opening. Aperture when loosely translated means a opening. Based on the size of the opening, the volume of light hits the sensor. The concept of aperture has been developed from the pupil in the human eye. Brighter the light, smaller the pupil to avoid irritation. Lesser the light wider the pupil so that we can see better. The second concept of Depth of Field or DoF is again borrowed from the pupil. Bigger the pupil, more the optical aberration and hence 'messier' the image, while smaller the pupil, sharper is the image and also the distance over which the image is sharp. If we extend it to the camera lens, bigger the hole size (aperture), more the light and optical aberration and hence shallower the DoF, while smaller the aperture, less light, more is the distance over which the image looks sharper and hence greater is the DoF.
This Ladybug is around 5mm in length. Notice how the head region and the body in that plane is sharp. The back and the grass in front are all blurred out

Aperture Priority or Aperture Value Mode - A (Nikon), Av (Canon), AV (Pentax)
In this mode the Aperture value is fixed and the camera processor decides the shutter speed for the correct exposure. When you turn the dial, what essentially happens is that the diaphragms in the lens open up or close down to control the size of the hole. In film cameras this was done by an aperture ring on the lens itself. In dslrs, this is done from the camera body. But finally the lens opening is only adjusted through a small lever extending from the camera body. The visible figures on the screen look something like this - f4, f4.5, f5, f5.6, f6.3, f7.1, f8, f9, f10, f11, so on and so forth. Interesting to note here are two things -
  • amount of light decreases with increase in aperture value and vice versa; ie f4 allows more light than f5.6 and conversely f11 to f8 allows more light
  • f4 is half of f8 while f5.6 is half of f11. So there are two mathematical series going on here. 
Without going into the mathematical (geometric) progression (beyond the scope of this article), please remember that f4 to f8 progression is 2 stops similar to f5.6 to f11. Hence, f4 to f5.6 is one complete stop. Now here is the most important part - every time you change one whole stop, the light changes by half or double. So from f4 to f5.6 the light has halved while f11 to f8 the light has doubled.

Most of the cameras these days have the provision of breaking down the complete stop into 3 steps, but the relationship remains. The above confusing relationship is what will be widely used further for proper exposures. It is confusing in the beginning but as you practice more, it becomes much easier.
This is taken at f2.8. Notice the narrow plane of focus. The mushroom head and some grass below it is in focus.

For DoF, lenses with F1.4, F1.8 and F2.8 are called fast lenses since their apertures are very wide. For these lenses, at the Max aperture (smallest aperture value = Max hole size) the focal plain will be few centimeters wide and hence everything else will be blurred, giving a wonderful appearance. Since such aperture sizes are difficult to manufacture repeatably, such lenses are very costly. Similarly at aperture values approaching f6.3 to f8 and beyond, the DoF is several meters wide which means most of the photograph will be in focus and sharp.
This is taken at f16. Notice the sharpness which extends right up to the structures way behind.

From application stand point, Higher Aperture (smaller f value), More Light, Lesser DoF. Lower Aperture (higher f value), Less Light, Higher DoF.

Shutter and Shutter Speed
Essentially, the dslr sensor is like the film. Moment you expose it to light it will start recording data. Whether you are at the right focus or frame or is the light sufficient; it simply doesn't care. So what we have essentially here is a curtain; a piece of black cloth on a spring, which hides the sensor (film) from light till we feel we are ready to click. Hence, you might have observed that the Shutter release button has 2 stops - first, at half way, it adjusts focus (in case of auto-focus) and finally it clicks when you press all the way through. Shutter Speed would then literally mean, the speed at which we open and close the curtain to allow the light to fall on the sensor (film). This brings us to the next term.

This is the D7000 Shutter assembly. Important to notice is the marked region which shows several shutter curtains.

Shutter Priority or Time value Mode - S (Nikon),  Tv (Canon), TV (Pentax)
In this mode, the camera allows us to fix the value of the shutter speed. What you control is the rate at which the curtain opens and closes the sensor (film). In turn, what you control is the amount of time for a volume of light (determined by aperture) falls on the sensor (film). When you use the wheel or the dial for the Shutter speed, the numbers either increase or decrease on the screen. What you see for example is 250, 320, 400, 500, but what it means is 1/250, 1/320, 1/400 of a second. Now the important part in this part of the discussion - 1/250 of a second is 1/2 of 1/125. Hence 1/250 lets the same volume of light to fall on the sensor for 1/2 the time of 1/125. Hence 1/125 to 1/250 is one full stop and exposure time is half. Similarly 1/60 to /30 is again a full stop while exposure time has doubled. The series goes something like this - 1", 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, so on and so forth. Newer cameras give 1/3 stop arrangements so you can get something like 1/60, 1/80, 1/100, 1/125, 1/160, 1/200, 1/250, so on and so forth. Even though, 1/60, 1/125, 1/250, is the original series, the relationship between 1/100 and 1/200 is the same.

Fireworks - it is a 87 seconds exposure (motion blur)
Water drop - taken at 1/320 of a second (freeze motion)

From application stand point, Higher Shutter Speed, Lesser Light and Motion Freeze. Lower Shutter Speed, More Light and Motion Blur

The final of the triangle, ISO, as pointed out earlier is a sensor (film) characteristics. It is basically a medium to gather more light. Loosely, ISO can be compared to worker ants. More the number of ants, faster is the food collected. Say it is a bright day outside. For the same brightness of the image, keeping the other settings the same, the amount of light collected by ISO 100 will obviously be less than ISO 200 and so on. However, as your ISO increases, so will the digital noise. This is primarily because ISO produces brightness artificially through pre-written algorithms. Lower ISO is a darker smoother image, Higher ISO is a grainy image. A balance needs to be set and each camera has its own sweet-spot.

Here is a cheat sheet summarizing the above.

So long for now. Happy clicking and experimenting...

- Abhishek 

Tuesday, January 1, 2013

Voices of Nepal...

"the best way to overcome a temptation is to succumb to it.." once said my English teacher in school.

being assigned the lead for the project, i had the unsaid privilege of.... hush hush... traveling to the installation locati... psst psst...

nevertheless, this time, my work took me for a pleasure ride into Nepal via Patna right across the border at Raxaul, crossing over to Birgunj... phew...

none of the world-class technologies at Google could save me from the suffering that lay en-route Patna-Birgunj... a mere 250 km... Google reassured a 3-4 hour journey... we did it in 9... and trust me when they joked that they can transform Shanghai into Bihar in 10 days... they were damn correct....

anyways, we moved into Nepal did some office work and moved to the next site in Kathmandu - the land of the Gods...

yeah Birgunj's heat and hotel's chilled water did give me a 100 deg fever and i carried that straight into Kathmandu's chill, but that didn't really stop me... somewhere deep down, there were voices which kept me pushing... The Voices of Nepal indeed...

as advised the first thing we did in Kathmandu post work was a visit to the famous Pashupathinath temple... the temple stood in pure magnificence... the evening "aarati" amazingly captivating... the enthusiasm was in the air... psychologically you feel the strength just sitting there for some time... and once again Einsteins Relativity plays tricks with you - you just wouldn't know how the hour hand moved from 7 pm to 8 pm...

the banks of the idly flowing Bagmati river below the Pashupathinath temple, is a gateway for heaven for all the deceased Nepali folk... the cremation process fills one with awe... but the temple bells chiming far away gives all the hope and courage needed...

with time the spiritual visit further metamorphosized into a much glamorous one...Thamel, one of the shopping   centers of Nepal was waiting to treat us... you could just find anything here - from the extreme trekking stuff to mild and soft shawls. i got some shawls for home... claimed to be pashmina - i dunno; aint an expert...

some of the weird things the place had to offer to eat  included buffalo momo and hot beer called thungba... bon appetit...

Post completion of the work, the next day a brief visit to the King's palace (now museum) was exquisite...took about an hour to get through the palace. it showed what it is to live life king size!!! only one question that lingered in my mind - if the king and queen stayed in separate rooms, then.... never mind....

the final trip of the day was the Darbar Square... 3 hours flat and yet we couldn't finish it all... the place is huge with huge structures and with a huge number of people... there were huge old buildings resembling pagodas... temples, a kumari palace and museum too.... about the museum - built in 1770 it is made of wood and earth and nine storeys high... beat that!!!! tired as we were, we finished the evening with a late lunch and returned to the hotel...

the next and last day was a quick trip to the work zone and then straight to the airport. airport security is funny in Kathmandu... the'll will touch you everywhere to check if you are carrying something that doesn't belong in the flight.... anyways...

all in all, with the fever, with work, the trip went extremely well... we didnt plan any time for any of these places; thought that work wouldnt allow us... but i guess we were extremely efficient...

For more pictures please visit