10MP D-SLR Review (Canon, Nikon and Sony)
Wednesday, March 28th, 2007[youtube=http://www.youtube.com/watch?v=Nx9tIpAd_NM]
Archive for the ‘Imaging’ Category
Experiments with Light
Friday, November 3rd, 2006Yesterday there was a black out in our area. It was pouring and my laptop’s battery ran out..as I was sitting in the dark with a candle I thought of some pictures and here are the results.
All Images and text © Praveen Chamarthi 2006
Flora at Lalbaugh Botanical Garden
Monday, October 30th, 2006This weekend I was at Lalbaugh, the largest Botanical garden in Bangalore.
A slight drizzle and heavy over casted sky followed me everywhere. Here are a few shots I managed to take.
Images copyright Praveen Chamarthi
Anatomical 18% gray card
Wednesday, October 4th, 2006Any SLR user (advanced) who shoots in “M” mode must have surely come across the term “18% gray”. So what exactly is this 18% gray and how does it affect exposure?
Mostly all cameras have an in-built light meter, which are calibrated for 18% gray i.e. the reference point for a camera’s light-meter to determine exposure are the surfaces that reflect 18% of the light that if falling on them. It is similar to a thermometer: At room temperature the thermometer stay at 94-97 deg i.e. the mercury in the thermometer remains stable during these temperatures. As the temperatures rise above this point the mercury starts reacting and shoots up the meter depending on the temperature it has been subjected to. So a reference point for a thermometer are the points at which it stays stable. Depending on this you can say if a person has a fever or if there is a drop in temperature. Similarly a camera’’s light-meter is calibrated for, surfaces that reflect 18% light, or in other words, surfaces with 18% reflectance. So the mid-tones in your frame are rendered as surfaces that reflect 18% gray and deflection from this point results in an over or an under-exposed picture.
For instance if you compose a picture with your SLR camera in such a way that the frame is filled with any black material, the famous example is when you shoot a black cat. Place a black cat on a leather couch which is also black in color and then compose and shoot the picture with the whole frame filled with the black cat and the background, the black couch.
The results will be surprising you will see that the camera will fail to understand the shades of black and your picture will have a noticeable layer of gray on it. This is because of the camera calibration to 18%gray. Since the light-meter cannot find any mid-tones it renders the whole picture as gray. Similarly you can try this with your frame filled with only whites and you’ll see that the results are more or less the same.
So, how do we expose correctly for black cats 
or rather when your frame is filled with same colors? The answer is very simple: “Use an 18% gray card/surface to determine the exposure”.
How do I take the reading for a good exposure?
You can place the 18% gray card next to the subject of interest. Zoom in with your lens (or go closer) and now focus the gray card, adjust your shutter speed such that the light meter indicates perfect exposure. Now remove the gray card, zoom out and recompose your frame with your cat or whatever it is, DO NOT CHANGE YOUR EXPOSURE SETTINGS (let the reading be the one that you took off from the gray card) and then shoot et voila you now have a better and most realistic colors and shades of the picture as opposed to the one that the stupid light-meter has decided for you.
So now where do I get a gray card?
You can pick them at any of your local store for a few dollars.
What If I don’t have one or If you forgot one at home?
Most of the camera bag manufacturers (LowePro) provide the adjustable partition strips inside the bags with gray color. you can just strip on these and use it as your gray card. Alternatively an average human palm is supposed to reflect 18% gray so you are never out of options.
Tricky situations can be encountered when you are shooting a landscape with hills, clouds, flowing water, rocks and the green valley. Obviously, one cannot walk up to the hill place your gray card, come back place it on the water and then on the greens, take readings and shoot. The solution for this is quite simple and also complex
keep reading this blog for more on exposure techniques.
Good day people!
The Grand Palace and Wat Phra Kaew
Saturday, September 30th, 200620 Sep 2006
Thanking myself for moving out of K.T Guesthouse and choosing to stay in Banglamphu turned out to be a wise decision. I didn’t need to think twice to get to the palace as I already knew the road that leads to it. The Grand Palace opens at 8:30am and I was there at 9:00. As I walked past through the huge wooden doors entrance I spotted armed guards standing still and staring at you and the also I some tourists taking pictures of them, with them and from them too. I noticed that the guards were sending most of the “scantily dressed” women to the counter where they provide you free shirt (for covering those sleeveless blouses) and trousers(if you are wearing a mini skirt or shorts apparently even 3/4ths are not allowed). I later learned that there was a strict dress code to enter into this sacred site.
“Men must wear long pants and shirts with sleeves — no tank tops. If you’re wearing sandals or flip-flops you must wear socks (in other words, no bare feet.) Women must be similarly modestly dressed. No see-through clothes, bare shoulders, etc.”
What is HDR?
Saturday, September 9th, 2006I think in Photography one thing that cannot be acheived is to capture the full range of shadows, highlights and luminiosity within a single image.
HDR stands for High Dynamic Range imaging
I was introduced to HDR a few months ago through another flickr member.
The first thing you’ll notice in a HDR image is that there was decent amount effort went into pushing the ranges of luminiosity, highlights and shadows. Light is evenly distributed and the tones are more pronunced than a picture exposed using normal digital techniques.
Basically it means when you employ this technique you can produce images with a very high dynamic range for exposures in other words when you expose your picture most of us usually follow the light meter inside our cameras and some of us use external light meters: based on these readings we expose this picture but we will never have an exposure which is technically perfect i.e. we cannot have all the shadows exposed in a way so that every detail in the dark area is visible and at the same time expose all the highlights to avoid burn outs. Basically, it is difficult to acheive this dynamic exposure range using film, slide or digital techniques. HDR helps you to acheive that thus allowing you to create some nice and surreal images.
I hope you guys understood what I wrote up there anyways here is the definition
Definition:
“In computer graphics and cinematography, high dynamic range imaging (HDRI) is a set of techniques that allow a far greater dynamic range of exposures than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to the deepest shadows.”
You can wiki this for more information or read more here.
all right since we now know what HDR means so how do I generate one?
How do I generate a HDR Image
Things you need to generate a HDR image
1.Most importantly your image(s) itself.
You would require an image that has been bracketed for +/-1EV(Exposure Value) i.e. basically you shoot the same picture with different exposure settings, one slightly overexposed(1 stop), one slightly underexposed(1 stop) and one with exact exposure settings as suggested by your camera.
2.A software that can generate a HDR
PhotoMatix Pro is a popular one (HDR, Tone Mapping)
You can also acheive HDR using Adobe Photoshop CS2
Example:
Original Image
HDR Image
Original Image
HDR Image
Some interesting links
http://www.luminous-landscape.com/tutorials/hdr.shtml
http://www.cybergrain.com/archives/2005/05/photoshop_hdr_i_1.html
http://www.hdrsoft.com/examples.html
How to shoot traffic at night?
Wednesday, August 30th, 2006It always fascinates me to see night photographs of traffic esp. those long white and red streaks of light. I have seen many photographs of traffic at night, endless shuffling through those Nat Geo really charges up your gray cells. After being inspired enough I decided to see night life from a different perspective. Whenever I used to travel I was always able to spot a good “night” frame here and there..I guess it’s the warm glow of tungsten on peoples faces and buildings,gates,foodstalls, I guess it’s the fire that lights up in those narrow streets. There is a strange beauty in the night mesmerizing and calm.
After said all that I wanted some good memoirs of night life through my lens
Some points to consider while shooting traffic at night esp if you want those everlasting white/yellow/red streaks of lights, glittering street lamps..
What would you need:
1. A sturdy and flexible tripod.
2. A Shutter release OR IR remote control to release the shutter
3. A good wide angle lens with MF (Manual focus) option
4. Patience and Cool.
1. Setting your ISO
If you are using a Digital SLR then set your ISO to 100/200. I prefer these ISO levels as the color saturation is more and more detail is captured while exposing. If you are shooting with a film/slide then also make sure you have loaded the camera with a ISO 100/200 film. I suggest Fuji crystal for film users and Fuji Velvia 100/100F for slide users.
2. Apertue and Shutter Speed settings
a. Stoop the aperture down to anything above 18 (personally I like 22) this is to allow the light to gradually fill the frame as time passes by.. so you can capture even the most dimly lit areas…if exposed for a long enough time all the street lights will glitter like stars and this is also to avoid those bright blobs in your picture if you were shooting traffic travelling towards the direction of the frame with their head lights on
b. Change to MF (Manual Focus). Now compose your picture. It is better if you a still /stationary object in your frame like a lamp post, sign post, parked vehicle etc., and focus on that This gives the feeling of motion better.
c. Set your shutter speeds to anything above 15″ (secs) (personally I like the BULB setting). Why 15″ ? I’am assuming here that a vehicle would enter and pass the frame (when viewed through your viewfinder) in 15″. If you have continous traffic coming at irregular intervals then it is better to set your shutter to BULB.
Now once your ISO, aperture and shutter speed settings are done then release your shutter slowly using the shutter release…take a deep breath and leave the shutter release to avoid any camera shake.. after you are satisified that enough traffic has passed by then release the shutter back to normal.
During the whole process you can completley forget the cameras readings.
DO NOT compensate for exposure by taking the camera readings into consideration.
You can experiment with different combinations of aperture and shutter speed settings. Interesting shots can be taken by experimenting with different white balance settings. Also do try taking some shots in Black & White and am sure you will be pleased.
Here are some of the pictures I have taken during the last two years.
Street Spotting
Sunday, May 21st, 2006This saturday I was all set to test the capabilities of my new D-SLR the CANON EOS 350D.
So along with a bunch of enthusiasts I decided to shoot people rather kids and families on the streets..and man it turned out a wonderful experience for me. I guess one can understand what “unity in diversity” means from this street. The first thing I spotted was a big gateway/entrance which was colorfully decorated with small sculptures of hindu gods and dieties and the back drop was a tall structure emerging from the mosque which was just a few meters down the lane..I decided to walk into the lane and took the right…a quiet start with people immersed in their daily chores.
Housewives washing clothes and cooking, the elderly lot were just baskin themselves in the sun kids playing marbles youth involved in a serious game of carromboard..the moment the cameras were taken out of the bags one of the kids noticed the same out of nowhere as if the guards were alerted with enemy attack.
There were kids and kids all around me asking me what I was doing there and why I was takin pictures..once those questions were answered everyone wanted their “Single Photos” 
)..anyways…this is what I saw and captured on those lively streets through my lens..
