These days zoom lenses are used mostly for convenience — to adjust focal length as needed. Non-zoom "prime" lenses are sharper and faster, but zoom lenses are so handy that for everyday purposes many photographers rely on them entirely. In moderate ranges, such as 35-105 or 70-200, they are often quite sharp. The first two panels show how 24mm can differ from zooming in to 105mm. I shot the first to establish how the shot was set up; the second is the actual intended photo. And I didn't have to go through the time-consuming annoyance of changing lenses.
When zooms first showed up, most photogs could not resist the zoom effects you get when you zoom WHILE you expose. That look got so overused that you almost never see it anymore, but I felt it was necessary to include that technique, for better or worse. Like any blur technique, it is difficult to predict exactly what you will get when you zoom during a slow exposure, so it is just plain fun to goof around with. And fun IS allowed — for some of us — at certain times.
Bottom Line: Zoom lenses are usually too handy not to use, although you do lose some sharpness and speed compared to non-zoom "prime" lenses.
I doubt anybody thinks much about the focal length — by number — while shooting; you just zoom to where you like what you see. But it interesting to check what focal length you actually use with your zoom. If you are ALWAYS at the widest point, you might want to switch to a non-zoom wide-angle and save weight and gain speed.
Left
Right
This is using the 24mm end of the zoom range to shoot the general set up. Compare to the "actual" shot in the next panel.
24mm, Canon 24-105 zoom, f8, studio flash
Zooming in to the 105mm end of the zoom range sure looks different than the 24mm shot in panel 1. To some extent all photos are like movie sets - what is out of the frame no longer exists.
105mm, Canon 24-105 zoom, f8, studio flash
In a "reporter" sort of shoot, or a "grab" situation, a zoom lens can be really handy because usually you can't get as close or far as you like. Here I shot at 115mm with a 70-300 zoom lens, but still got more "stuff" in the frame than I wanted. Compare to frame 4.
1/60 second, f4.5, 70-300 zoom lens, ISO 1600
Here I zoom just to 150mm and was able to isolate Nicole's face. Compare to frame 3.
1/45 second, f4.5, 70-300 zoom lens, ISO 1600
Here we have the freaky look that you can get by zooming during the exposure. (Using a tripod will keep the camera steady so that your zoomy look will be more neatly linear, rather than swirly.
I did make this look a bit freakier by balancing the color toward the green, which makes the face blue-ish purple.
1/3 second, f22, 24-105 zoom lens, ISO 200
NOTE: Point-and-shoot cameras do not allow you to zoom during the exposure, so you can't do this.
This is a mix of a long zoom exposure with a flash at the end (or beginning) of the zoom. Nicole was standing in a doorway facing inside. The outside trees zoomed nicely, then the flash exposed her face, with no effect on the trees 50 yards away.
1/2 second, f16, 24-105 zoom lens, ISO 125, flash above camera
NOTE: Point-and-shoot cameras do not allow you to zoom during the exposure, so you can't do this.
This is zoom done entirely in the computer, starting with a crisp non-zoomed image. Just to make the point that you CAN do this later on.
But there is that point of view that says if you create an image in the camera, with one click of the shutter, then it is a different thing (a more pure thing?) than something created later via computer.
Camera data doesn't mean much once you get this wacky on the computer. Below is the original that was zoomed in computer.
This is a long exposure where we zoom while shooting, but Nicole also turned her head, producing a somewhat soft cubist-like double image.
(What do we suppose Picasso would have done with computer graphics had be been born 100 years later? And who is the Picasso of the computer?)
1/2 second, f16, 24-105 zoom lens, ISO 125
NOTE: Point-and-shoot cameras do not allow you to zoom during the exposure, so you can't do this.
This is using the 24mm end of the zoom range to shoot the general set up. Compare to the "actual" shot in the next panel.
24mm, Canon 24-105 zoom, f8, studio flash
Zooming in to the 105mm end of the zoom range sure looks different than the 24mm shot in panel 1. To some extent all photos are like movie sets - what is out of the frame no longer exists.
105mm, Canon 24-105 zoom, f8, studio flash
In a "reporter" sort of shoot, or a "grab" situation, a zoom lens can be really handy because usually you can't get as close or far as you like. Here I shot at 115mm with a 70-300 zoom lens, but still got more "stuff" in the frame than I wanted. Compare to frame 4.
1/60 second, f4.5, 70-300 zoom lens, ISO 1600
Here I zoom just to 150mm and was able to isolate Nicole's face. Compare to frame 3.
1/45 second, f4.5, 70-300 zoom lens, ISO 1600
Here we have the freaky look that you can get by zooming during the exposure. (Using a tripod will keep the camera steady so that your zoomy look will be more neatly linear, rather than swirly.
I did make this look a bit freakier by balancing the color toward the green, which makes the face blue-ish purple.
1/3 second, f22, 24-105 zoom lens, ISO 200
NOTE: Point-and-shoot cameras do not allow you to zoom during the exposure, so you can't do this.
This is a mix of a long zoom exposure with a flash at the end (or beginning) of the zoom. Nicole was standing in a doorway facing inside. The outside trees zoomed nicely, then the flash exposed her face, with no effect on the trees 50 yards away.
1/2 second, f16, 24-105 zoom lens, ISO 125, flash above camera
NOTE: Point-and-shoot cameras do not allow you to zoom during the exposure, so you can't do this.
This is zoom done entirely in the computer, starting with a crisp non-zoomed image. Just to make the point that you CAN do this later on.
But there is that point of view that says if you create an image in the camera, with one click of the shutter, then it is a different thing (a more pure thing?) than something created later via computer.
Camera data doesn't mean much once you get this wacky on the computer. Below is the original that was zoomed in computer.
This is a long exposure where we zoom while shooting, but Nicole also turned her head, producing a somewhat soft cubist-like double image.
(What do we suppose Picasso would have done with computer graphics had be been born 100 years later? And who is the Picasso of the computer?)
1/2 second, f16, 24-105 zoom lens, ISO 125
NOTE: Point-and-shoot cameras do not allow you to zoom during the exposure, so you can't do this.
