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Forum: Pentax SLR Lens Discussion
11-26-2017, 12:52 PM
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The image created by the lens will always correspond to whatever focal length is labeled on the lens. The best way to approach this is to completely forget about crop factor. The only thing you need to know is that full frame will see more of the frame (if the lens covers full frame), so this results in a wider field of view at the same focal length.
The whole "equivalence" thing refers to the fact the 40mm on APS-C would look the same as a 60mm on full frame, if you were using both formats.
In the case of the DA 15mm, if you were to compare it with the full frame Irix 15mm on the KP, the coverage would be identical. On the K-1, the DA would give you dark edges but otherwise the image would be the same in the areas where it does show up.
This animation may help:
You Tube
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src="https://www.youtube.com/embed/KP3w63UDeBw?controls=1" allowfullscreen>
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And an article if you want to go in depth:
The Crop Factor Unmasked - Articles and Tips | PentaxForums.com |
