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Topic: Why not more wide angle zoom? (Read 5029 times)
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Patibo
Newbie
Posts: 3
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Something I am wondering about: Canon (for example) has a 10-22mm zoom lens, and a 18-200mm zoom lens. The latter has about 11X zoom. Why do we never see a 10-100mm, or something of that kind? I would find that much more interesting. It would start at 10mm (already exists) and it would have 10X zoom (already exists), so it should be possible, no? Nikon now has a 10-100mm lens, but it's for the 1-system, with a much smaller image circle (sensor).
Why is there not a 10-100mm for APS-C sensors?
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Bob Atkins
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It's just very difficult to design such a lens which maintains high quality across the whole range. It could probably be done, but it would likely be large and expensive.
Designing for a smaller format with a shorter distance between the back of the lens and the sensor makes the design of such a lens much easier. A less extreme retrofocus design is needed at the wide end when the lens is closer to the sensor.
The Nikon 10-100 can use a design similar that would be used in 26-260 zoom for APS-C or full frame, which is something can fairly easily be done.
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Glenn NK
Newbie
Posts: 5
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I've read that as the zoom ratio gets higher, image quality across the image becomes problematic (the weakest part of many zoom images are at the edges and corners). Ratios higher than 4.0 don't seem to be very common in high quality lenses.
Canon's 24-105 ratio is 105/24 = 4.375. And this lens seems to rate quite high (I have one). The other zoom I have is the 17-55 (also has some barrel distortion at 17) but it's IQ is pretty good.
The zooms with ratios of ten or so (Canons' 28 - 300 for example) are really pushing the envelope - it has fairly high barrel distortion at 28 mm, and by 50 mm, it's into pincushion distortion. The IQ seems to not be one of Canon's very best.
The newly announced 24-70 II has a ratio of just under three (2.92), and the initial reports are that it's excellent right across the frame.
Lens technology is advancing and previous limits are being stretched, but there will always be a cost and quality compromise.
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