October 20, 2014, 12:36:25 AM

Author Topic: New Wide Angles Lenses in 2013 [CR2]  (Read 43351 times)

tron

  • 1D X
  • *******
  • Posts: 1854
    • View Profile
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #180 on: March 13, 2014, 05:36:50 AM »
I got tired of waiting for an announcement and bought the Rokinon 14mm f/2.8.

Sorry Canon, maybe you can pull it together by the time I decide to get a new 50mm.
What kind of lens is it supposed to replace? If you wanted a 14mm Canon already has one.
If you wanted a new UWA zoom then the Rokinon 14mm clearly isn't.

canon rumors FORUM

Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #180 on: March 13, 2014, 05:36:50 AM »

canonographer

  • SX50 HS
  • **
  • Posts: 9
    • View Profile
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #181 on: March 14, 2014, 01:59:21 AM »
I got tired of waiting for an announcement and bought the Rokinon 14mm f/2.8.

Sorry Canon, maybe you can pull it together by the time I decide to get a new 50mm.
What kind of lens is it supposed to replace? If you wanted a 14mm Canon already has one.
If you wanted a new UWA zoom then the Rokinon 14mm clearly isn't.

Point taken, but unless you have unlimited funds, a lot of thought goes into buying a lens.  I really wanted a new UWA lens.  I've been anxiously awaiting word of what Canon might have to offer.  A 16-50mm f/4 IS with 77 mm filter threads would have been a perfect fit for me.  I'd heard it was one of the possibilities and have been waiting for an announcement to confirm or put it to rest for 9 months.  Back in June the report was that they would announce within 6-8 months.

In any case, I got tired of waiting and bought the Rokinon.  If it turns out that I like that lens and decide I don't need anything between 14mm and 24mm, Canon won't get my money for a new UWA.  Incidentally, if they keep dragging their feet with their announcements, I'll probably get Sigma's 50mm too.

AUGS

  • PowerShot G1 X II
  • ***
  • Posts: 59
    • View Profile
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #182 on: March 14, 2014, 06:03:20 AM »
The f stop value of a lens is defined by the focal length of the lens divided by the diameter of the objective lens (front element). so a 300mm lens with a 100mm front element has an f stop value of f2.8. That's how it works.
I'm not sure you are correct.  By this formula, the new 24-70LII has an f stop of about 24/64 = 0.375.  But its a 2.8 lens.  While the approximation approaches this as the focal length gets longer and the angle of view becomes narrower (telephotos and telescopes), it is not true for all focal lengths, and especially the wide angles.
My understanding is the f stop is calculated from the focal length divided by the apparent iris aperture via the optical formula of the lens (which includes all the magnifications of the optics).
I may be wrong, so I'd be happy to be corrected.

privatebydesign

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2564
  • Ermintrude says "moo"
    • View Profile
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #183 on: March 15, 2014, 12:32:39 AM »
AUGS you are 100% correct.
The best time to plant a tree is twenty-five years ago. The second best time is today.

9VIII

  • 5D Mark III
  • ******
  • Posts: 650
    • View Profile
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #184 on: March 15, 2014, 10:20:54 AM »
The trick here is you have to realize that optical designers can do very funny things with focal length, like making an 800mm lens that's only 461mm long, or "retrofocusing" design with an effective focal length that exists entirely outside the lens.
The "focal length divided by aperture" rule is true, but the definition of focal length is more than meets the eye.

I'm sure the video guys here would point out we would all be better off using T-stop anyway.
-100% RAW-

GMCPhotographics

  • 5D Mark III
  • ******
  • Posts: 728
    • View Profile
    • GMCPhotographics
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #185 on: March 18, 2014, 07:08:36 AM »
The trick here is you have to realize that optical designers can do very funny things with focal length, like making an 800mm lens that's only 461mm long, or "retrofocusing" design with an effective focal length that exists entirely outside the lens.
The "focal length divided by aperture" rule is true, but the definition of focal length is more than meets the eye.

I'm sure the video guys here would point out we would all be better off using T-stop anyway.

The word "telephoto" indicates that a lens' focal length is longer than it's physical length. So a 135L is a telephoto lens, but a 85L isn't. Many photographer's assume that a "tele" indicates a longer focal length, but it doesn't. It is possible to have a fairly wide telephoto lens.   

StudentOfLight

  • Canon 70D
  • ****
  • Posts: 318
  • I'm on a life-long journey of self-discovery
    • View Profile
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #186 on: April 13, 2014, 01:28:47 AM »
The trick here is you have to realize that optical designers can do very funny things with focal length, like making an 800mm lens that's only 461mm long, or "retrofocusing" design with an effective focal length that exists entirely outside the lens.
The "focal length divided by aperture" rule is true, but the definition of focal length is more than meets the eye.

I'm sure the video guys here would point out we would all be better off using T-stop anyway.

The word "telephoto" indicates that a lens' focal length is longer than it's physical length. So a 135L is a telephoto lens, but a 85L isn't. Many photographer's assume that a "tele" indicates a longer focal length, but it doesn't. It is possible to have a fairly wide telephoto lens.

I learnt something today. So the 40mm pancake is in fact a telephoto lens. Who knew?
Fantasy Gear:
TS-E: 45mm f/2.8 L-II,  EF: 40mm f/0.8,  100mm f/1.4,  35-85mm f/1.8, 
EF with 1.4xInt: 100-300mm f/4 ,  500mm f/5.6 L

canon rumors FORUM

Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #186 on: April 13, 2014, 01:28:47 AM »

GMCPhotographics

  • 5D Mark III
  • ******
  • Posts: 728
    • View Profile
    • GMCPhotographics
Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #187 on: April 17, 2014, 06:18:17 AM »
The trick here is you have to realize that optical designers can do very funny things with focal length, like making an 800mm lens that's only 461mm long, or "retrofocusing" design with an effective focal length that exists entirely outside the lens.
The "focal length divided by aperture" rule is true, but the definition of focal length is more than meets the eye.

I'm sure the video guys here would point out we would all be better off using T-stop anyway.

The word "telephoto" indicates that a lens' focal length is longer than it's physical length. So a 135L is a telephoto lens, but a 85L isn't. Many photographer's assume that a "tele" indicates a longer focal length, but it doesn't. It is possible to have a fairly wide telephoto lens.

I learnt something today. So the 40mm pancake is in fact a telephoto lens. Who knew?

Yup! While the 50mm f1.4 USM isn't a telephoto either!

canon rumors FORUM

Re: New Wide Angles Lenses in 2013 [CR2]
« Reply #187 on: April 17, 2014, 06:18:17 AM »