Rethinking 4/3 Depth Of Field

Started Apr 11, 2013 | Discussions thread
Great Bustard
Forum ProPosts: 20,765
Like?
Re: I'm not convinced...
In reply to Anders W, Apr 13, 2013

Anders W wrote:

Great Bustard wrote:

Rriley wrote:

Ironically, I think shallow DOF with UWA is "da bomb":

24mm FF isnt UWA

I've always thought that 24mm (on FF) was the long end of UWA:

http://www.cambridgeincolour.com/tutorials/wide-angle-lenses.htm

The definition of ultra-wide is a little fuzzier, but most agree that this realm begins with focal lengths somewhere around 20-24 mm [on FF] and less.

If I'm in error on this point, I'd appreciate a link to a credible source with a "less fuzzy" definition.

I am not usually inclined to propose definite limits of anything, but 24 is to me precisely the border line between WA and UWA.

That's basically how I see it, too.  In fact, let me get nerdy (I know, I know -- too late!).  Let's think of focal lengths in terms of stops, with 0 stops being the sensor diagonal, and each stop increase/decrease doubles/halves the area of the scene on the focal plane.  Then, for FF, we have:

  • -4 stops --> 11mm
  • -3 2/3 stops --> 12mm
  • -3 1/3 stops --> 14mm
  • -3 stops --> 15mm
  • -2 2/3 stops --> 17mm
  • -2 1/3 stops --> 19mm
  • -2 stops --> 22mm
  • -1 2/3 stops --> 24mm
  • -1 1/3 stops --> 27mm
  • -1 stop --> 31mm
  • -2/3 stops --> 34mm
  • -1/3 stops --> 39mm
  • 0 stops --> 43mm
  • 1/3 stops --> 49mm
  • 2/3 stops --> 55mm
  • 1 stops --> 61mm
  • 1 1/3 stops --> 69mm
  • 1 2/3 stops --> 77mm
  • 2 stops --> 87mm
  • 2 1/3 stops --> 97mm
  • 2 2/3 stops --> 109mm
  • 3 stops --> 122mm
  • 3 1/3 stops --> 137mm
  • 3 2/3 stops --> 154mm
  • 4 stops --> 173mm
  • 4 1/3 stops --> 194mm
  • 4 2/3 stops --> 218mm
  • 5 stops --> 245mm
  • 5 1/3 stops --> 275mm
  • 5 2/3 stops --> 308mm
  • 6 stops --> 346mm
  • 6 1/3 stops --> 389mm
  • 6 2/3 stops --> 436mm
  • 7 stops --> 490mm
  • 7 1/3 stops --> 549mm
  • 7 2/3 stops --> 617mm
  • 8 stops --> 692mm
  • 8 1/3 stops --> 777mm
  • 8 2/3 stops --> 872mm
  • 9 stops --> 979mm

This thinking leads to the following classifications:

  • Wider than -2 stops:  UWA
  • Between -2 stops and 1 stop:  WA
  • Between -1 stop and 1 stop:  Normal
  • Between 1 stop and 2 stops:  Portrait
  • Between 2 stops and 3 stops:  Short Telephoto
  • Between 3 stops and 5 stops:  Long Telephoto
  • Longer than 5 stops:  Super Telephoto

Thus, 24mm would just miss UWA, and 22mm would be the border.  I'm sure this is exactly what Rriley meant. 

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow