Understanding camera lenses: Add more creative control to digital photography A guest post by Alia Haley
In order to add better creative control over your digital photography, it is important to understand the camera lenses. Selecting a right lens for your camera is daunting task since you have to consider a number of factors like cost, image quality, lens speed, weight and size. However, the below discussion over this subject would certainly enhance your understanding by rendering an introductory overview of concepts pertaining to image quality, perspective, focal length, zoom versus prime lenses and aperture(f-number).
The lens elements and image quality
In any camera you can find lenses which are basically made up of couple of lens elements. Every lens element guides the light rays to recreate an accurate image. The idea here is to reduce aberrations and at the same time using the least and fewest costly elements. The optical aberrations arise when you see the points in the image not translating back onto the single points after passing through the various lenses. This causes reduction in contrast, image blurring and even misalignment of colors.
You can also see the lenses getting affected from things like different uneven, low image brightness or distortion. These all issues can impact your image quality. The loss of contrast can lead to the blurring issue, whereas chromatic aberration can bring in distortion in image. You can find any of these problems with the lenses found in different camera leading respective issues.
Influence of lens focal length
The lens’ focal length decides its view angle which helps in magnifying the subject to the given photographic position. The wide angle lenses carry short focal lengths whereas the telephoto lenses need longer equivalent focal lengths. The focal length does not determine the perspective of any image; however, it only changes with the location as per the subject. The perspective can also change when you try to fill up the frame with the same kind of subjects utilizing both the telephoto lens and wide angle.
The change of perspective is seen since one is compelled to move further or closer from the subject. Also, for these conditions, the large angle lens exaggerates or simply stretches the perspective while the telephoto lens flattens or compresses the perspective. The perspective control is usually termed as the most powerful compositional tool in photography and generally defines your focal length choice. At such point of time, you can click photos from any position.
There are some other factors too which can be hampered by the lens focal length. The telephoto lenses are becomes extra vulnerable to the camera shake issue as you can see even a small hand movement getting magnified in the image which is similar to the shakiness view seen through your binoculars with greater zoom. The wide angle lenses are usually more resistant to things like flare; this is because the designers consider that the sun would come within the frame. Hence it is concluded that the medium and the telephoto lenses usually yield competent optical quality for same kind of price ranges.
The focal length and handheld photos
The focal length of any lens can have some vital impact over the sharp handheld photography. The longer focal lengths would need shorter kind of exposure times to reduce the blurring caused due to hand shake. To avoid this issue, just think of holding a laser pointer in a steady position while shining this pointer over some nearby placed object. The bright spot usually jumps less as compared to the objects kept away. This is considered to be a primary thing since even a slight kind of rotational vibration can be simply magnified to a great extent with distance. However, the side to side or up and down vibrations was seen, the laser’s bright spot cannot be seen changing with increasing distance.
A general thumb rule for determining the pace of exposure requirements for any given focal length is similar to the focal length rule. This means that for any 35 mm camera, the time for exposure should be simply fast enough to cover the focal lengths in seconds. This is required just to avoid the blurring issue during the hand held photography. However, for digital camera users having cropped sensors are supposed to convert into a 35 mm corresponding focal length.
The zoom lens versus the prime lens
A zoom lens helps the photographers to change the focal length within the predefined range; however, this is not seen in prime lens. The basic benefit of using zoom lens is that it helps you to get a number of perspectives or compositions which are important elements required for photo journalism. Zoom lens gives your better flexibility; however, at times you may be required to change your positions.
Even though you have zoom lenses coming in the market, there are some amounts of people who prefer prime lens. Prime lens comes with different benefits over the zoom lens. The basic benefit of using prime lens is they give better optical quality; however the modern day high quality zoom lenses also render this feature, yet can be singled out by some trained eyes especially in a large size print.
The other benefits of using prime lens are that it comes with less cost, speed and weight. In fact, if you consider any high quality prime lens, the image quality it produces would be better than the high end zoom lens. Further, if a small amount of focal length range is required for any zoom lens, then the prime lens with same focal length can be lighter and smaller in size. Lastly, a good quality prime lens generally caters good light gathering capacity as compared to the zoom lenses. This is generally critical for the low light sports or theater photography and where shallow field depth is required.
For any compact digital camera the lenses with specifications like 3X, 4X, or 5X zoom generally designate the ratio between shortest and longest focal lengths. Hence the image with larger zoom simply does not mean that you can magnify it to any extent. This is because the zoom simply carries a wider view angle while completely zooming out. Lastly, digital zoom is different than the optical zoom since the former simply increases the size of any image via interpolation.
Influence of lens aperture (F-number)
The aperture range of any lens generally refers to the quantity which the lens can close down or open up to allow less or more amount of light respectively. Apertures are denoted using f-number term which defines relative light gather area quantitatively. The large size aperture openings can be defined to carry lower f-numbers which are generally a perplexing thing. These two terminologies are usually interchanged due to confusion. The larger apertures lenses are generally defined as faster since for the defined ISO speed, the shutter speed could be made faster to have the same kind of exposure. Lastly, the small aperture denotes that objects which can remain in focus for a wide range of distances which is also termed as depth of field.
When you have to buy any lens, you need to define your requirements first and check the appropriate specifications. Lenses having large amount of aperture settings cater great amount of artistic flexibility both for the depth of field and exposure options. Larger aperture based lenses are used for theater and indoor sports photography since at such places you need faster shutter speed along with narrow depth of field. Lastly, the zoom lenses carrying maximum amount of aperture makes the proper exposure settings more predictable regardless of any focal length.
Understanding camera lenses play a key role in getting right pictures from your digital cameras. The above points pertaining to camera lenses would certainly help you in getting the insight about camera lenses thus helping you decide the best camera for your personal or professional use.
About the author: Alia Haley is a blogger by profession. She loves writing on technology and autos. Beside this she is fond of fancy accessories. She is a tech freak and loves to write on her sites Bornrich and Automotto.
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