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p.1 #5 · Ultra Wide EF-S Prime? | |
Hi Will, thanks for commenting.
The 15 is actually a good compromise, but still not f2 fast... That big old front element sure is awfully exposed too... But I have used it, and it worked purdy well.
As to the size issue, an EF-S lens that is that fast would be much smaller than an EF lens, simply because the image circle would be so much smaller, so the optical elements are not nearly as big. I am no optics expert though, but it seems like it wouldn't be that difficult to put together a fast wide prime for a cropped sensor. Maybe it is though?
For example on weights, a 17-55 2.8 is similar to a 24-70 in FOV and aperture on their respective bodies, but the EF-S weighs 1.4lbs, compared to 2.1lbs for the EF version. Or compare the 50-150 2.8 Sigma with a 70-200 2.8 Canon. Sigma is 1.7lbs. Canon is 2.8lbs. Canon 10-22 is 13.6 ounces, the 17-40 is 17.5 ounces. Not perfect comparisons, but it shows the difference is significant.
That is one of the reasons I would like to keep the crop sensor around, it should allow for lighter weight systems. I guess my question is this: is there a reason why a fast ultrawide digital lens hasn't been designed yet? Is it that the engineering is just that much more difficult?
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