wide angle lense

[luv2liv]

im looking at the samples for canon 17-40mm.
some posted closeup photos of tomatoes and flowers. why?
all this time i thought these kind of lenses are good for outdoor landscape and buildings.

http://www.amazon.com/gp/custo...ages_2?ie=UTF8&index=2

 

[Zenmervolt]

Well, to start with, wide angle lenses will usually focus closer than telephotos because it's easier from a mechanical and lens design standpoint to get a wide-angle lens to focus up close.

Also, getting close with a wide angle lens allows you to isolate a subject against a background much more effectively than you can with a telephoto lens. (http://www.mhohner.de/essays/myths.php#focalper)

You do want to avoid portraiture with a wide-angle lens if you are close to the subject, however, as the perspective from being that close (perspective due to positioning, not due to the lens itself) tends to exaggerate the subject's nose in unflattering ways.

ZV

 

[ElFenix]

Originally posted by: Zenmervolt
Well, to start with, wide angle lenses will usually focus closer than telephotos because it's easier from a mechanical and lens design standpoint to get a wide-angle lens to focus up close.

Also, getting close with a wide angle lens allows you to isolate a subject against a background much more effectively than you can with a telephoto lens. (http://www.mhohner.de/essays/myths.php#focalper)

You do want to avoid portraiture with a wide-angle lens if you are close to the subject, however, as the perspective from being that close (perspective due to positioning, not due to the lens itself) tends to exaggerate the subject's nose in unflattering ways.

ZV

well the autofocus thing isn't right. it gives the impression that cameras monitor the phase detectors and stop when maximum contrast is achieved. that isn't how they work. the phase detectors are able to, with just one glance, determine what direction and how far to turn the lens (because a phase detector is actually a rangefinder). at that point, the camera determines only that the lens has in fact turned in that direction and that far. it doesn't check the phase detectors again until the shutter is half pressed again.

actually i should post that to the comments there

 

[troytime]

uh, for a different perspective and wider field of view?

 

[ghostman]

Why not? That's like asking why I might use my steak knife to cut tomatoes. Because I can. It might be used mostly for one purpose, but it doesn't mean it can't be used for other purposes. Don't get too focused on the "rules." Just because a telephoto is typically more flattering for portraits doesn't mean a wide angle can't be used to yield some stunning portrait shots as well.

Not to mention, that photo states that the lens is on a XTi, which means it's equivalent to about 27mm focal length. Wide, but not super wide.

 

[teatime0315]

Originally posted by: ghostman
Why not? That's like asking why I might use my steak knife to cut tomatoes. Because I can. It might be used mostly for one purpose, but it doesn't mean it can't be used for other purposes. Don't get too focused on the "rules." Just because a telephoto is typically more flattering for portraits doesn't mean a wide angle can't be used to yield some stunning portrait shots as well.

Not to mention, that photo states that the lens is on a XTi, which means it's equivalent to about 27mm focal length. Wide, but not super wide.

This. Why not use it if you can? Versatile = win

 

[soydios]

Originally posted by: ElFenix

Originally posted by: Zenmervolt
Well, to start with, wide angle lenses will usually focus closer than telephotos because it's easier from a mechanical and lens design standpoint to get a wide-angle lens to focus up close.

Also, getting close with a wide angle lens allows you to isolate a subject against a background much more effectively than you can with a telephoto lens. (http://www.mhohner.de/essays/myths.php#focalper)

You do want to avoid portraiture with a wide-angle lens if you are close to the subject, however, as the perspective from being that close (perspective due to positioning, not due to the lens itself) tends to exaggerate the subject's nose in unflattering ways.

ZV

well the autofocus thing isn't right. it gives the impression that cameras monitor the phase detectors and stop when maximum contrast is achieved. that isn't how they work. the phase detectors are able to, with just one glance, determine what direction and how far to turn the lens (because a phase detector is actually a rangefinder). at that point, the camera determines only that the lens has in fact turned in that direction and that far. it doesn't check the phase detectors again until the shutter is half pressed again.

actually i should post that to the comments there

Nikon's continue to evaluate the phase detectors during the autofocus operation for faster autofocus, particularly on moving subjects. http://www.nikon.com/about/tec...software/caf/index.htm

 

[luv2liv]

cool
thanx

 

[Zenmervolt]

Originally posted by: ElFenix

Originally posted by: Zenmervolt
Well, to start with, wide angle lenses will usually focus closer than telephotos because it's easier from a mechanical and lens design standpoint to get a wide-angle lens to focus up close.

Also, getting close with a wide angle lens allows you to isolate a subject against a background much more effectively than you can with a telephoto lens. (http://www.mhohner.de/essays/myths.php#focalper)

You do want to avoid portraiture with a wide-angle lens if you are close to the subject, however, as the perspective from being that close (perspective due to positioning, not due to the lens itself) tends to exaggerate the subject's nose in unflattering ways.

ZV

well the autofocus thing isn't right. it gives the impression that cameras monitor the phase detectors and stop when maximum contrast is achieved. that isn't how they work. the phase detectors are able to, with just one glance, determine what direction and how far to turn the lens (because a phase detector is actually a rangefinder). at that point, the camera determines only that the lens has in fact turned in that direction and that far. it doesn't check the phase detectors again until the shutter is half pressed again.

actually i should post that to the comments there

Still, you have to admit that it's much more accurate than the oft-heard comment that AF measures the distance.

I'm very, very impressed if the phase difference detectors are able to tell how far to go with just one look. That's certainly more than I can do with a rangefinder.

I know that with my Minolta and Sony SLRs the AF system will occasionally overshoot and then come back a little. Not in any way that slows focusing, but you can hear the drive motor switch directions. This would lead me to assume that, in Minolta and Minolta-derived cameras at least, the system does continue to monitor the phase difference detectors until is senses a "hit".

Of course, you've schooled me in how AF works before, so I would not be one bit surprised to find that you're correct here.

ZV