newb question...

Justin Ly · July 27th, 2007, 11:27 PM

i notice a lot of people here use adaptors with (nikon) prime lenses. i know the benefits of primes are that they can achieve incredible dof and faster f-stops. now, my question is.. if one has enough available light, why don't shooters use the convenience of zoom lenses more often?

Bob Hart · July 28th, 2007, 01:37 AM

Justin.

For a given f-stop and focal length setting on the zoom, the same depth-of-field effect can be achieved.

Prime lenses are chosen also for there being fewer pieces of glass inside, therefore fewer glass-to-air surfaces which may reflect stray light which loses deep contrast. Fewer pieces of glass also mean in most cases a sharper image.

Some still-camera zooms may not hold focus through the zoom range.

Chris Hurd · July 28th, 2007, 09:23 AM

Plus, many zoom lenses tend to breathe -- that is, they change focal length slightly when the operator changes focus, which isn't desirable. A prime lens won't do that, since by definition it can't change focal length.

Justin Ly · August 1st, 2007, 07:23 AM

Quote:

Originally Posted by Bob Hart

Justin.

For a given f-stop and focal length setting on the zoom, the same depth-of-field effect can be achieved.

Prime lenses are chosen also for there being fewer pieces of glass inside, therefore fewer glass-to-air surfaces which may reflect stray light which loses deep contrast. Fewer pieces of glass also mean in most cases a sharper image.

Some still-camera zooms may not hold focus through the zoom range.

thanks bob! that totally makes sense. less glass = better pictures.

July 27th, 2007, 11:27 PM	#1
Justin Ly New Boot Join Date: Feb 2007 Location: Vancouver, Canada Posts: 8	newb question... i notice a lot of people here use adaptors with (nikon) prime lenses. i know the benefits of primes are that they can achieve incredible dof and faster f-stops. now, my question is.. if one has enough available light, why don't shooters use the convenience of zoom lenses more often?

July 28th, 2007, 09:23 AM	#3
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 21,311 Images: 535	Plus, many zoom lenses tend to breathe -- that is, they change focal length slightly when the operator changes focus, which isn't desirable. A prime lens won't do that, since by definition it can't change focal length. __________________ CH Search DV Info Net for quick answers \| The best in the business: DV Info Net Sponsors \| ...Tuesday is Soylent Green Day!

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July 28th, 2007, 01:37 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 2,385	Justin. For a given f-stop and focal length setting on the zoom, the same depth-of-field effect can be achieved. Prime lenses are chosen also for there being fewer pieces of glass inside, therefore fewer glass-to-air surfaces which may reflect stray light which loses deep contrast. Fewer pieces of glass also mean in most cases a sharper image. Some still-camera zooms may not hold focus through the zoom range.