If I use a 1.4X teleconverter with my Canon EF100-400mm f4.5-5.6L lens on my Canon 50D body, what is the 'effective' focal length that I end up with. I can get as far as 140-560mm but I'm not really sure what effect the camera has on the calculations if any. Many thanks in advance of any help on this.
Effective focal length
- Thread starter Bluenose
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- Richard
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I think the answer you are looking for is 1.4 x 1.6 = 224-896mm.
The actual focal length becomes 140-560mm with the 1.4x TC, at f/6.3-8.
Then if you put it on a 1.6x crop format camera, the effective focal length becomes multiplied to 224-896mm, relative to full frame. F/number remains the same.
That is because the actual field of view is equivalent to what you would get with a 224-896 zoom on a full frame camera, due to the crop factor.
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Or if you have never shot 35mm full frame, ignore the x1.6 part. It shouldn't really mean anything to you.
The important issue to remember (given that the change in focal length is a bit obvious) is that your max aperture is affected. Hoppy says f4.5-5.6 becomes f6.3-8 which I'll take his word on.
The important issue to remember (given that the change in focal length is a bit obvious) is that your max aperture is affected. Hoppy says f4.5-5.6 becomes f6.3-8 which I'll take his word on.