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DPChallenge Forums >> Hardware and Software >> Wide Angle Lens Question
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Canon EOS-450D Rebel XSi
Canon EF-S 18-55mm f/3.5-5.6 IS
 09/18/2003 01:58:24 PM · #1
What is the difference between a .45x and a .5x wide angle lens?

I am looking for a good technical explanation if anyone can help.

Thank you!
OM System OM-1
Canon EF 100mm f/2.8 USM Macro
 09/18/2003 02:06:35 PM · #2
I am assuming that you are talking about the adapters. A 0.45x lens will be wider than a 0.5x lens. At any rate, the number is what you multiply the focal length of the lens the adapter attaches to by to get the new focal length of the adapter and lens combined.

Take the example of a 35mm lens; with the 0.5x adapter, it becomes a 25mm lens, with the 0.45x adapter a 22.5mm lens

Hope this helps
Nikon D200
Sigma 30mm f/1.4 EX DC HSM for Nikon
 09/18/2003 02:07:51 PM · #3
Sounds like you are talking about wide angle converters. If that's the case, it's really pretty simple--.45x is simply the factor that you multiply your current focal length by to get the effective focal length with that coverter. So, a 50mm prime with a .45x converter will become an effective 22.5mm lens. The same 50mm prime with a .5x converter will become an effective 25mm lens.
OM System OM-1
Canon EF 100mm f/2.8 USM Macro
 09/18/2003 02:24:47 PM · #4
Originally posted by stephenfaust:
Sounds like you are talking about wide angle converters. If that's the case, it's really pretty simple--.45x is simply the factor that you multiply your current focal length by to get the effective focal length with that coverter. So, a 50mm prime with a .45x converter will become an effective 22.5mm lens. The same 50mm prime with a .5x converter will become an effective 25mm lens.


Yeah, what he said...
Canon EOS-450D Rebel XSi
Canon EF-S 18-55mm f/3.5-5.6 IS
 09/18/2003 04:25:46 PM · #5
Thank you, I think I was looking at a converter, since the lens from my camera does not detach from the body.

Both of those explanations helped me understand.
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