Zoom Lens:
A lens allowing a camera to change smoothly from a long shot to a close-up or vice versa by varying the focal length.
Most entry-level digital SLR cameras are supplied with a zoom lens allowing the user to switch from wide-angle shots through to telephoto. Zoom lens’ are highly flexible, however certain photographers will purchase a specific lens for dedicated purposes.
Focal Length:
(of a lens) having a short focal length and hence a field covering a wide angle.
Telephoto:
a lens with a longer focal length than standard, giving a narrow field of view and a magnified image.
Contact Sheets:
Camera Settings:
I used an 18-200mm lens as this will allow me to illustrate the difference between focal lengths and the effect of this on the subject of the images. I used the pre-set increments on my lens and took a photo for each increment, the other camera settings also fluctuated.
Focal Lengths:
18mm:
Exposure - 1/160 sec
F/8
ISO - 160
24mm:
Exposure - 1/200
F/8
ISO - 160
35mm:
Exposure - 1/200
F/8
ISO - 160
50mm:
Exposure - 1/200
F/8
ISO - 160
70mm:
Exposure - 1/200
F/8
ISO - 160
135mm :
Exposure - 1/200
F/8
ISO - 160
200mm :
Exposure - 1/200
F/8
ISO - 160
I think this experiment was successful. I set out to take photos of my subject at different focal lengths while keeping the same proportion of her in the image. To do this I had to use a tripod and a zoom lens on my camera and gradually move away as I extended the zoom, taking photographs at each increment.
The result of this experiment was that the subject remained in focus and the background became blurred. This focused the viewer's attention on the subject of the image instead of the surrounding area.
This is a similar effect to changing the F-stop. The lower an F-stop is the shallower the depth of field and so the greater the focus on the subject of the image. For example, taking a photograph with a 200mm zoom is similar to taking a photograph with an F-stop of F/2 as the field of view is very shallow in both.
Focal Length:
the distance between the centre of a lens or curved mirror and its focus.
The equivalent distance in a compound lens or telescope.
Wide Angle: The equivalent distance in a compound lens or telescope.
(of a lens) having a short focal length and hence a field covering a wide angle.
Telephoto:
a lens with a longer focal length than standard, giving a narrow field of view and a magnified image.
Contact Sheets:
Camera Settings:
I used an 18-200mm lens as this will allow me to illustrate the difference between focal lengths and the effect of this on the subject of the images. I used the pre-set increments on my lens and took a photo for each increment, the other camera settings also fluctuated.
Focal Lengths:
18mm:
Exposure - 1/160 sec
F/8
ISO - 160
24mm:
Exposure - 1/200
F/8
ISO - 160
35mm:
Exposure - 1/200
F/8
ISO - 160
50mm:
Exposure - 1/200
F/8
ISO - 160
70mm:
Exposure - 1/200
F/8
ISO - 160
135mm :
Exposure - 1/200
F/8
ISO - 160
200mm :
Exposure - 1/200
F/8
ISO - 160
I think this experiment was successful. I set out to take photos of my subject at different focal lengths while keeping the same proportion of her in the image. To do this I had to use a tripod and a zoom lens on my camera and gradually move away as I extended the zoom, taking photographs at each increment.
The result of this experiment was that the subject remained in focus and the background became blurred. This focused the viewer's attention on the subject of the image instead of the surrounding area.
This is a similar effect to changing the F-stop. The lower an F-stop is the shallower the depth of field and so the greater the focus on the subject of the image. For example, taking a photograph with a 200mm zoom is similar to taking a photograph with an F-stop of F/2 as the field of view is very shallow in both.
