Effective Focusing

Most people know how to focus a lens, but don't know how to focus well.
In the days of film, lenses didn't have motors and electronic focus confirmation chips, so they had to be manually focused. Today, almost all cameras have Automatic Focus(AF). You can try using Manual Focus(MF) on your DSLR if you feel adventurous, but the focusing screens that come with todays entry level DSLRs are not optimized for MF(they lack focus aids like split screens and micro-prisms. Besides this, they do not resolve finer DoF for apertures larger than f/3.5). Knowing how to use your AF is the key to quick & accurate focusing.
This is what my Canon 400D viewfinder looks like:

It has 9 focus points that you can select(the little rectangles with dots you see). You can select an individual point or use the matrix mode(multi-point). Someone asked me, why I use a single point over multi point. The answer is simple. How is the camera supposed to know what I want to focus on? It just guesses. And as far as I know, when in multi-point mode, the camera focuses on the closest object that lies on any of the focus points.

Another thing to remember is the central point(which is a cross-type sensor) is the most accurate among them all. So I usually prefer to always keep the central focusing point selected, focus and recompose, then take the shot... and I advise you to do the same(unless you are shooting macro or a close object with a wide angle lens, in which case you use the closest focus point to the area you want in focus). Except for the underlined situations, shifting the camera sideways or rotating it about the optical centre after focusing will not throw the point outside the DoF range, keeping it in focus.

To get more control of the focusing, I recommend that you switch to 'back button focusing' rather than half-click the shutter release to focus. Read your camera manual on how to do that. You will then focus by pressing a button on the back of the camera(the '*' button on my 400D)

Sometimes, especially in low light, the camera will struggle to focus. A little insight into how autofocus works will help you here.

When autofocusing, the camera's focus sensor turns the focus ring so as to maximize contrast(the difference between black & white, or colours). You can try focusing on a blank white wall, even if there is lots of light, the camera will struggle to focus. Now try focusing on a speck on the wall. It locks focus immediately!

Here is an example:

This was shot @44mm at f/2.8. The DoF is quite shallow, cause of the large aperture and close distance of the subject. Lets zoom in to 100%

Since 'Canon' is not at the centre of the original image, I used the focus and recompose technique(using the central focus point). In the zoomed in image, you see two possible locations at which I could have kept the central focus point for getting 'Canon' in focus.(the red and green squares). Both lie on the same plane. However, the red square is over pure black area, therefore lacking contrast, and the camera will not focus easily. On the other hand, the green square partially lies on black and partially on white... the camera will easily be able to resolve focus to get the highest contrast. Hence the green square location is preferred over the red square location while focusing.

In short, always place the focus point over an area of contrast.

All Articles

I noticed its a little difficult to navigate through this blog and find what you want, so I decided to make this page which contains links to all articles. I will keep updating this as and when I post more articles. I think you can guess the article name from the address, so no point in adding the title here. These articles are in the order in which they were written, from oldest to newest:

http://photog4beg.blogspot.com/2010/12/what-is-photography.html

http://photog4beg.blogspot.com/2010/12/camera-modes.html

http://photog4beg.blogspot.com/2010/12/aperture.html

http://photog4beg.blogspot.com/2010/12/shutter-speed.html

http://photog4beg.blogspot.com/2010/12/iso.html

http://photog4beg.blogspot.com/2010/12/art-of-panning.html

http://photog4beg.blogspot.com/2011/01/composition.html

http://photog4beg.blogspot.com/2011/05/composition-examples.html

http://photog4beg.blogspot.com/2011/05/why-i-still-love-my-nifty-fifty.html

http://photog4beg.blogspot.com/2011/05/zoom-perspective.html

http://photog4beg.blogspot.com/2011/05/about-histograms.html

http://photog4beg.blogspot.com/2011/05/about-flash-part-one.html

http://photog4beg.blogspot.com/2011/05/about-flash-part-two.html

http://photog4beg.blogspot.com/2011/06/how-to-chose-camera.html

http://photog4beg.blogspot.com/2011/06/pseudo-hdr.html

http://photog4beg.blogspot.com/2011/08/exposure-zone-system.html

http://photog4beg.blogspot.com/2011/10/lightroom-basics-part-1.html

http://photog4beg.blogspot.com/2011/11/lightroom-basics-part-2.html

http://photog4beg.blogspot.com/2011/11/effective-focusing.html

http://photog4beg.blogspot.com/2012/01/lightroom-intermediate-1-tone-curve.html

http://photog4beg.blogspot.in/2012/04/nissin-di466-review.html

Lightroom: Basics Part 2

So now, lets enter the Develop Module of Lightroom where we will spend most of our time.
On the left side you have a navigator preview. When you zoom in ('Z' or Spacebar), it will show you which part of the image you are zoomed into.(using a red box)
Below it, there is a presets pane. You can use factory presets(a combination of specific settings) or you can make you own and use(or download other peoples from the internet). Below that you have 'Snapshot' where you can save how the image looks currently if you wish to try something but come back to the current state later. After that you have 'History'.

One of the best things about lightroom is that it is a non-destructive editor. This means that it does not make changes to your original photographs. The catalog imports images and stores all your changes as 'steps', which it applies to the image when showing you. After making all changes you can export the image. 'History' lets you go back to how the image looked at any point in time since you imported it till the current state! Pretty awesome huh?!
You can also copy settings of one image and paste them on another image.

Below the main photo area, there is an option for viewing Before&After (Its a small box with [Y|Y] ) to compare the original image and the current state.

On the right side is the histogram followed by all the sliders and controls. We'll go over the basic ones now, and cover the more advanced ones in a future article.

I will assume that you know how to read a histogram here; if you do not, then please read it here: http://photog4beg.blogspot.com/2011/05/about-histograms.html or somewhere else before continuing, as it gives you some idea of where to start editing.

Editing Sliders:

Basic

Lets start off with white balance. In case you dint use custom white balance or your auto white balance dint hit the nail, chances are your image has a colour tint to it. You can either balance it manually using the Blue/Yellow and Green/Magenta sliders, or use the colour picker, and click a part of the image that you know was neutral(white or grey). Lightroom automatically corrects the colours of all other pixels in the image.

After white balance, we deal with exposure problems. Our light meters are not perfect, and you will usually end up with a not-so-perfectly exposed image. Even if it is well exposed, it may lack contrast due to the nature of the scene.
I advise you to look at the histogram and observe the changes as you move the following sliders. Then interpret the results and see if they make sense to you.

Exposure: The way it changes the brightness of pixels is similar to what changing the ISO on the camera does, except for the fact you cannot get detail that was in the scene but not captured. It affects pixels of all values 'equally'. However, brightness values are not linear, but follow a gamma function, and so the brighter parts of the image will shift faster than the darker areas, in the histogram.

Recovery: Sometimes when we take a picture, the highlights can get clipped to white or near white in a scene with lots of dynamic range. Recover helps decrease the brightness of the brightest pixels in the image. In other words, it darkens the highlights. Its a very subtle though and is one of the few effects you can use to 100% without making the image look unnatural.

Fill Light: This slider is used to brighten up the shadows(dark areas) of the image while not affecting the rest of the image by much. Be careful as it can make a lot of noise visible if used excessively.

Blacks: It is used to darken the dark areas of the image. Mainly used to set the black-point if the image does not have one. Usually slide it till the first grey part of the histogram touches the left wall (this means the darkest part of the image is remapped to pure black) Helps improve the contrast of the image.

Brightness: Similar to exposure, but it tries not to clip the highlights when increased.

Contrast: When increased, darkens the dark areas and brightens the bright areas of the image.(and affects everything in between)

Clarity: Changes regional contrast. Increasing makes images large edges more clear. Decreasing causes a sort of flat softness look.

Saturation: Increases the vividness or intensity of colour of all pixels by the same proportion.

Vibrance: Like saturation, but increases the intensity of colour of the undersaturated pixels more and the already saturated pixels less. Prefer using it over saturation.

Skip Tone Curve, HSL and Split Toning for now.

Head over to Detail. (You must zoom 100% or more into the image to see the effects of sharpening and noise reduction)

Sharpening: Sharpening Basically tries to make an image look sharper by increasing the contrast of 'edges'. Note that it does not add more detail to what has already been captured. Holt the "ALT" key when moving sliders to see their affect on the luminance channel.(It should appear grayscale when adjusting)

     Amount: It defines how much to affect the edges.
     Radius: It defines the area around detected edges that will get affected (Radius in pixels)
     Detail: Affects sharpening of finer details in the image
     Masking: As you increase it, it masks areas of progressively larger and larger edges(first small, then larger and larger) from the sharpening filter. Hold "ALT" and you will see the areas masked as black and areas that will be affected by the sharpening filter in white.

  
Noise Reduction: At High ISO and/or in low light, camera sensors generate noticeable noise. Lightroom helps you remove this noise while preserving detail in the image. There are two types of noise, i)Chroma or Colour noise-> Random colored specks(like green or blue) and ii)Luminance noise (specks of the right colour, but largely varying brightness, even white sometimes).

Vary the colour slider first and remove as much colour noise as possible without affecting detail too much.(colour noise is easier to see than luminance, so remove it first). Then use the detail slider under it to try and bring back detail that was taken out by mistake by the noise reduction. Use it till you see actual specks on noise beginning to re-appear.

Then target the luminance noise in the same way. It has an additional slider "contrast" which affects larger edges than detail. Try it.

When I get time to write the next article, I'll try and cover the Tone Curve, Channel Mixer(HSL) and Split Toning. Happy Editing. And remember, it very easy to over-edit something.... Everything in moderation!(Subtle improvements are best and most natural)

After making all the changes, export the image: File>Export. Choose your folder and other options and click the export button.

Lightroom: Basics Part 1

So you've taken a picture, hopefully with good composition and exposure. But still there's something missing... it lacks the 'punch' that you see in pictures that professionals have taken. You might start to think your camera & lens are not good enough... or that you've done something wrong when taking the picture.

Well actually, theres one step left in your workflow-> post processing... or simply Editing if you like. Editing is not new to digital photography; its been there since the days of film. But today thanks to our very capable computers, we don't have to toil away in a darkroom for hours.

There is a wide variety of editing software available, and you can choose one that suits your needs.
The most famous is probably Adobe Photoshop, which is extremely powerful for image manipulations of all sorts. It is used by both photographers as well as designers. A free open-source alternative called GIMP exists for the same and is nearly as good.

Adobe probably realized that not everyone requires all the features and power of photoshop, and created a software specially for photographers, Lightroom. It has almost everything a photographer needs, without the extra bells and whistles that photoshop has, allowing a fast workflow. Apple's Aperture is an equivalent software. There are free alternatives, but I found nothing nearly as good.

After that you have Googles Picasa, Apple's iPhoto, etc. They are free or low cost, simple to use, but lack power. I suppose they were made for ordinary people who want one-click-enhance results. If you wanted that, you wouldn't be reading this right?

So then, lets focus on Adobe Lightroom.
Lightroom has 5 Modules- Library, Develop, Slideshow, Print & Web. All controls are organized by function and sorted into these modules. You can select a module on the top right.
Library is used for organizing files.
Develop is used for in-depth editing.
The rest are self-explanatory. I won't cover them here even in future articles.

In the Library Module, you can organize photos into 'Collections'. You can rate photos, flag them, compare them, etc.  In any module, you see all the photos in a film strip.

When you come from a photo trip or something, you may typically have 100s of photos. Not all of them are good. You need not edit them all. Heres where the library module shines.

The first thing I do after importing photos(which you can do by 'drag & drop' when in library module, or file>import) is going through all the images in the filmstrip and clicking 'X'(shortcut for unpick/reject) on the bad pictures(ones you think can't be saved by editing either). After going through all, just click Photo>Delete Rejected Photos. Why waste time editing bad pictures?

Next we will see the Develop module...

** I must mention here that it is preferable to shoot in RAW rather than JPEG to get the most out of your images, and edit them without any significant loss in quality. This is because JPEG cuts down tone variations from the 16bit RAW file(created by 12bit or 14bit A/D converters) to 8bits. JPEGS also have some amount of sharpening, noise reduction, etc done to them in-camera. RAW files are straight from the CCD or CMOS sensor.

Exposure: The Zone System

Cameras use a device called a 'lightmeter'(which is in-built) to measure the lighting in a scene and calculate exposure. They do the latter depending on what "metering mode" you set. Evaluative/Matrix metering checks the whole frame. Centre-weighed metering gives 80% importance to the centre of the frame and 20% importance to the edges. Partial metering measures ~10% of area at the centre while Spot metering measures ~3%. The problem is, the camera will try to expose in such a way that the average of the measured areas has a luminance value of middle grey(18% reflectance). While this is probably the best manufacturers can do for measuring an 'average shot', your exposure gets screwed if you hav a frame full of dark objects or one full of light objects.

Ansel Adams(a very famous photographer in the old film days) developed a system for exposure, which with slight modifications can be applied to digital photography too. Before I explain it, I would like to give you an intuitive idea as to how this system works, from my perspective:
Say I use spot metering on some object which is dark grey. Using exposure compensation, I tell the camera "I see this object like this. I want you to capture it in this very shade, not made it brighter to look like middle grey"

Ansel Adams kept 10 zones in his system (zone 0 to zone 9) with 0 as the darkest and 9, the brightest. The amount of light reflected by each zone is double (1-stop greater) than the previous zone. Zone 5 is middle grey(18% reflectance).

Zone 3 to Zone 7 are of interest to us. Lets place colours into these zones now:

courtesy: photo.tutplus.com

Now to expose correctly, use spot metering over an area of one of the above known zones. Then use exposure compensation as follows:

Zone 3: -2EV

Zone 4: -1EV

Zone 5: 0EV

Zone 6: +1EV

Zone 7: +2EV

Lock the exposure, re-compose and take the picture(Spot metering meters at the centre of the frame). Using back-button focus  and half-click to lock exposure helps here!(For DSLRs only- read your camera manual if you don't know how to do this)

Sometimes the dynamic range of your camera might not be enough for the whole scene. In that case,  meter from something in zone 7(and set+2EV) to preserve highlights or from zone 3(and set -2EV) to preserve shadow detail, depending on what is more important to you in the photo(assuming you are not shooting HDR).

P.S. Zones numbers are written using Roman Numerals. I forgot about that when writing this article and only realized it when I added that picture from another site. Sorry about that, but I'm too lazy to change all the numbers now! :P

Pseudo HDR

Digital Cameras are no doubt brilliant devices. Their tiny CCD or CMOS chips can capture an enormous amount of detail. However, their dynamic range- the range of brightness values they can capture in one picture, is limited, a lot more than the human eye.

You may have noticed a lot of pictures with "washed out"(completely white, lacking any detail) skies or too dark subjects. In some cases, this problem can be fixed by using a flash to balance the lighting. However, you cannot expect to light up a huge building using a flash, to balance it against the bright sky!

HDR or High Dynamic Range technique to the rescue! This technique involves taking the same picture at multiple exposure settings and then merging and tone-mapping them using a computer. Usually 3 photographs are taken, exposures separated by 1 to 2 stops. Most cameras have an "Auto-Bracketing" setting, which takes these 3 pictures automatically when you hold the shutter release down.

There are 2 problems with this technique:
1) you need a tripod or a steady surface to keep the camera from moving between the 3 shots.
2) you cannot have a moving object in the frame, or you will get multiple "ghosts" of the object.

Since I don't like using a tripod and searching for a steady surface can limit compositions, I prefer using another technique called pseudo HDR when needed. This technique doesn't extract as much dynamic range as normal HDR, but it is much simpler and can be used for handheld shots or moving objects.

So basically you shoot in RAW format-> this stores a lot more detail than jpeg(by detail here I mean variation of tones, not more pixels!). You have to underexpose the snap by 1 to 2 stops to preserve some detail in the sky while retaining detail in the shadows.

After this, we have to post process to extract all the detail we can from the shadows and highlights:
Open it in Adobe Camera RAW/ Photoshop/ Lightroom/ Aperture
Change the following settings roughly to these values. Tweak to your taste.
Contrast between 90 to 110
Brightness between 70 to 90
Blacks between 5 to 7
Recovery to 100%
now raise the brightness to about 100-120
use the adjustment tools:
Burn(darken) the sky and dodge(brighten) the rest
use a soft large brush and ~exposure -1.8 for burning and +1.0 for dodging

Use noise reduction, sharpening and a slight vignette for a finishing touch.

What I got was this:

How to choose a camera

Long time no post, and that is because I'm in Chennai, about 500 miles away from home and I don't have my DSLR with me. So I'll try and post on topics which do not require it while I'm here.

Many people ask me which camera should they buy, so I thought of writing an article which could help them make informed decisions on this matter without having to consult me :)

The first thing to see is your budget. How much are you willing to spend? There will always be a better more expensive camera, so you need to draw the line on the price before doing anything else.

The next question to ask is, what will you be shooting most of the while? If you do most of your shooting in daytime and you are on a limited budget, a megazoom camera may be more appropriate than a DSLR, as you will need to spend money on lenses for the latter.
A DSLR will however give you full control over practically everything, besides giving you pixel level sharpness and low noise at high ISO(compared to a compact digicam), besides the flexibility of being able to use various lenses.

For DSLRs:
Check the make. Prefer Canon or Nikon to Sony. I'm not anti Sony or anything, but Canon and Nikon have a much better variety of lenses and their noise profiles are also better than Sony as of date.

Check for lenses and other accessories that you would buy over time and see how affordable they are to you. Check the burst rate of the camera in case you like shooting sports. Try and get the maximum viewfinder coverage and magnification that you can. Check a couple of reviews on www.dpreview.com or www.dcresource.com Finally, go to a shop and see what feels best in your hands.

For Non-DSLRs:
Decide whether you want a megazoom or a good quality compact or a normal digicam. Try and get one with Manual mode, as you would like to have control over your images. Make sure you have manual white balance on the camera. See if the camera if capable of saving RAW files. Forget megapixels, anything above 3 is good, as long as you dont have to print billboard sized images! Try to get as large a sensor as possible. Usually CCD sizes are 1/2.5". Bigger than that is good. 1/1.8" is used in a few good cameras.

Since you have only one lens on this camera, you want to make sure its the best you are getting. Besides Zoom range, you want the lens to be fast, as in have a large maximum aperture. The max aperture range will be quoted like f/2.8-f/5.6
This means that the max aperture when zoomed out completely is f/2.8 and when zoomed in completely is f/5.6. you want these numbers to be as small as possible.

Recommendations:
As of now
Entry level DSLR: Nikon D3100
Megazoom: Panasonic FZ 35
Good semi-pro Compact: Canon S95 or the latest G series