Photo – A Kolkata Sunset

 

Its been some time since I’ve been writing this blog and a lot of readers pointed out that I had not posted a single photograph I clicked.

So without much ado, here’s my first photo on my site.

This was during a visit to Kolkata and a boat ride across the Hoogly river. The iconic Howrah bridge was downriver and I was hoping I’d get a good shot of it. However with poor lighting, it got extremely difficult to catch from the distance I was at. However the beautiful sunset near the Vidyasagar Setu made a much prettier picture.

As usual, comments and suggestions are welcome.

Understanding Camera features - Zoom

 

Since we checked out the myth of Megapixels in a past post, you know what to look for in terms of megapixel count for the new camera you want to buy.

Today we look at another of the camera salesman’s favourite buzzwords – The camera zoom.

Zoom, in terms of a camera, is the ability of the camera lens to focus on a subject at progressive distances from the camera. The ability of the camera to magnify the subject so as to capture greater detail or to very simply, get close to the subject, which in reality can be very far off.

In my past post about focal lengths, we saw how zoom or subject magnification actually worked. By varying the distance between the lens and the image sensor, the angle of viewing is narrowed down. This focuses the camera’s image sensor on a smaller portion of the subject, thus causing it to magnify.

So very simply, the greater the ability of the camera to magnify subjects further away, the better the zoom capability of the camera.

However there is a catch. There are in reality two types of zoom in digital cameras, optical zoom and digital zoom.

Optical zoom or mechanical zoom is the method of zoom explained above. The magnification is achieved by physically changing the distance between the lens and the image sensor. This needs a mechanical way to move the lens and is most commonly done using a telescopic mechanism like the one pictured below.

Because the optical zoom does not manipulate the captured image in any way, the result is a clearer and sharper magnification.

Digital Zoom is the cheaters way to zoom, available only to digital cameras. As there is no film in the digital camera and the captured image is electronic information, this allows the camera to manipulate the electronic image in many ways which were not possible with film.

The magnification of the picture is done by image manipulation rather than any physical movement of the lens. The area of interest in the digital image is cut out and magnified by expanding the pixels. Now while this technically works for a small expansion, doing this too much causes the picture to blur and lose focus, not to mention giving it a very grainy look.

As an example of the quality difference, look at the picture below. 

(Picture courtesy: Bob Atkins)

As can be seen, while a optical zoom would give you a sharper clearer magnified image, the digital zoomed image is blurred and pixellated. Even though the image is magnified to the same extent, the usability of such an image greatly reduces.

So, when you go out to buy a new camera, ask for one which has a larger optical zoom. Never settle for only a digital zoom even though these cameras are a lot cheaper. Most of the time the camera salesman may not know what type of zoom is present in the camera. In that case, ask to see the specifications of the camera and look for the word “Optical Zoom”.

Nowadays, most cameras have a combination of optical and digital zoom. The zoom range begins with optical zoom [with the telescopic mechanism coming out] till about 4X – 6X and then goes further to digital zoom. While this effectively would give you a large combined zoom range, remember that the useful zoom is the optical part. The digital zoom for around 2X more would help, but anything more than that is a gimmick.

Usually 4X to 6X optical zoom is good for any point and shoot camera and should cover most photography situations. Special prosumer cameras, called super zooms, feature optical zoom ranges of up to 20X. These are useful for the hobbyist.

dSLR cameras have the option of interchangeable lenses. As a result, special lenses and lens attachment combinations enable the camera to have an incredible zoom factor. These lenses have the telescopic mechanism within and allow fine adjustment of the zoom to enable tack sharp images. Some of these lenses cost more than the camera body itself !!!

The rule of thumb in the shop is – Buy as much optical zoom that is possible within your budget.

As always, please leave your comments. Until next time……………………

Technical terms - Focal Length

 

If you were to read through the specifications of a camera or even a lens, one of the first things you would notice is Focal Length. Engineers in the audience will immediately be taken back to their Physics class in Optics, and sometimes even they will not be able to clearly remember what this term means. Trust me, I’m an engineer :)

Very simply put, Focal length of a lens is the distance between the lens and the image sensor, while focussing on the subject. The image sensor is where the photographic image is recorded inside the camera.

Let’s look at the picture below:

There are three lens positions in this diagram. Position 1 or X, is the closest the lens can be placed next to the sensor. In camera terms, this is the base focal length. Notice that when the lens is in this position, more of the subject is captured on the sensor due to the wide angle of viewing.

Position 2 or 2X, is about 2 times the base focal length. This causes a smaller angle of viewing, thus capturing a smaller portion of the subject to fill the whole image sensor. As a result, that particular portion of the subject appears magnified or zoomed.

Position 3 or 4X is about 4 times the base focal length. This position narrows down the viewing angle even more, causing more magnification of the subject.

Hence the position of the lens determines how much of the subject is captured on the area of the image sensor. Farther away from the sensor means less of the subject is captured onto the whole sensor, giving the effect of magnification.

The most common way a camera manufacturer can introduce a variation in focal length in a camera is by installing a telescopic lens mechanism like the one shown below:

This mechanism telescopes out to change the distance between the lens at the front of the telescope and the mage sensor housed inside the camera body. The result of this movement can be seen on the LCD screen behind as a magnification of the subject. 

While looking for a camera, it is best to buy one with a good range of focal lengths. This would allow you to zoom closer to the subject without physically moving close. A range of 3X to 6X is good in a compact point and shoot camera.

We shall dwell on the matter of zoom in another post.

Its not about the camera

I was watching the Michael Jordan Nike ad the other day. And for us photographers there’s nothing that’s more true…

Its not about the camera

Its never about the camera. A good camera is important, but just having a good camera does not automatically result in you taking stunning photos. The camera sees what you see. What YOU see. The camera is a mere tool, the creativity, the composition, the moment is yours and yours alone.

Sure a big zoom lens will get you close to the action, but is there a better perspective by not zooming in? Sure, more megapixels and high end lenses will get you a sharp image, but did you get the emotion of the moment?

Professional photographers will take close to 100 shots, before they get that one shot that just might make it to National Geographic, and even then that’s optimistic. So don’t fuss that you’ve not got that fancy dSLR with all those buttons and settings. When you take pictures, focus on that, taking pictures. And take lots of them. Trash lots of them. Proficiency comes with practice, not with great tools alone.

If you’re going to go out and buy a new camera, stop a while if you’ve already got one. Pull out that old one, see all the setting options. Did you use all of them?? Do you know what each one does?? Did you do something creative with that camera? Did you experiment with all the settings?? Now postpone that new camera purchase till you’ve done all you can with the old one.

Its never about the camera. Its always about the eye behind the viewfinder and the finger that presses the button.