Tuesday 29 November 2011

wide-angle lens (Photo imaging equipment and materials (205))

What is wide – angle lens? From a design perspective, a wide angle lens is one that projects a substantially larger image circle than would be typical for a standard design lens of the same focal length.
It refers to a lens whose focal length is substantially shorter than the focal length of normal lens for the image size produced by the camera.

Longer lenses magnify the subject more, apparently compressing distance and (when focused on the foreground) blurring the background because of their shallower depth of the field. Wider lenses tend to magnify distance between objects while allowing greater depth of field.
My images is maybe not the best examples, but surely you get the picture what I'm talking abut.

On the beginning of this course I get new addition to my photo equipment WIDE ANGLE LENS  Tamron's SP AF 10-24mm F3.5-4.5 Di. With the wide zoom this lens certainly looks like a tempting prospect for photographers in search of sweeping vistas. 

 

Manufacturer description: Wider and longer than others in its class, this compact, lightweight, high-performance lens for DSLRs with APS-C size sensors provides 35mm equivalent coverage from 16mm ultra-wide to 37mm semi-wide, a remarkable 2.4X zoom ratio. With a maximum coverage of over 108°, this state-of-the-art classic is the perfect solution for expanding your visual horizons.

Construction:
There are two different varieties of wide-angle lens: short-focus lenses and retro focus lenses.


~Cross-section of a typical short-focus wide-angle lens.
Short-focus lenses are generally made up of multiple glass elements whose shapes are more or less symmetrical in front of and behind the diaphragm. As the focal length decreases, the distance of the rear element of the lens from the film plane or digital sensor also decreases. 
 
~Cross-section of a typical retro focus wide-angle lens.
The retro focus lens solves this proximity problem through an asymmetrical design that allows the rear element to be further away from the film plane than its effective focal length would suggest. 
 
 
 
 
The basic comparison of impression between different types of lenses:
 
The image shows how different lenses affect the perspective. The wider the angle the shorter the stronger the difference in the sizes of the elements in the photograph.
  
One of the most interesting features of wide-angle lens is -the capability to stretch perspective- when you look through a wide-angle lens, it seems that the distance between objects has extended. The objects that were not so distant could appear too far away. And the proportion of objects dramatically increases, so the one that close to the camera look enormous, but those, which are father away almost, disappear in the distance.
 
 
When I bought this lens I didn’t quite understand how it works till I saw what it can do, how these lens make photograph complete different, how beautiful sky looks captured with wide angle lens. In one image you can capture such amount what human aye just not see. I still getting used to it as is a lot things need to be explored, but this lens is worth having, I would say essential for everyone interested in landscape photography.
The only downside probably for me is losing sharpness - if you have a wide angle zoom lens so is less sharpness at the very wide angle, especially with the widest aperture, which very hard to avoid. And also when I’m using a filters - filter holder on a widest setting applier in the edges - causing vignetting. But that’s something what you can’t avoid unless if you forget about filters, what is not a best of ides as the filter can transform any dull, plain day photograph into impressive image, but I will be closer discussing filters on my fallowing posts.
Returning to wide angle lens ability…I have only one thing to say…if you don’t have one - get one, even if it is pricey it`s worth to have.

Some useful sites to explore: