Personal computing discussed
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churin wrote:My question is how can that lens be used as a 18-200mmm lens?
Usable area size of the image by DX lens is smaller than that by FX lens. Based on the difference between the usable image sizes, when DX lens is used the effective focal length is ALWAYS 1.5 times the stated focal length regardless of the camera sensor size being APS-C or full frame.
Is the above correct?
churin wrote:Let me repeat the question in my previous post:Usable area size of the image by DX lens is smaller than that by FX lens. Based on the difference between the usable image sizes, when DX lens is used the effective focal length is ALWAYS 1.5 times the stated focal length regardless of the camera sensor size being APS-C or full frame.
Is the above correct?
JustAnEngineer wrote:The focal length marked on the lens is the focal length of the glass. The focal length of the lens does not change when you swap cameras.
I believe that the real problem is that there are a huge number of people who mistakenly believe that "50mm" is a specification for field of view instead of a measurement of focal length.
jihadjoe wrote:churin wrote:Let me repeat the question in my previous post:Usable area size of the image by DX lens is smaller than that by FX lens. Based on the difference between the usable image sizes, when DX lens is used the effective focal length is ALWAYS 1.5 times the stated focal length regardless of the camera sensor size being APS-C or full frame.
Is the above correct?
Yes, unless you can somehow turn off the auto-crop feature on the FX camera while the DX lens in attached.
churin wrote:Thank you for confirming my understanding.