What Lens Specification To Look For Sharpness At Distant Subjects When Cropped??

Started 2 months ago | Discussions thread
ZilverHaylide Senior Member • Posts: 1,156
Re: What Lens Specification To Look For Sharpness At Distant Subjects When Cropped??
1

rpszone wrote:

Take two, different, 200mm lenses, same body and subject at 100 feet. Which one can crop better with sharpness and clarity?

Do I look at "perceived megapixel" rating, "resolving power", what makes one lens better than the other for this task?

If everything else were equal, then almost any sharpness or resolution metric could be used, and would probably indicate better cropability. But it's not equal. Sharpness varies over the field, virtually always better in the center than elsewhere, but falling off at different rates in different lenses, and additionaly, differently-dependent on f-stop and even subject distance. No single number can express that variability. Two lenses might have the same total "perceived megapixel" rating, but lens "A" might be fairly even in performance across the field, while lens "B" might have higher sharpness than lens "A" in the center, but lower sharpness towards the edges/corners. So take your crop from the center of that lens "B" and the result will be sharper than from the same location of the lens "A" image, but take your crop from the outer field of both lenses and the result from lens "B" will be worse than from lens "A".

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