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http://www.amateurphotographer.co.u...400mm-f3-5-6-3-ii-sample-image-gallery-106876
Looks quite nice, very useful travel lens!
Looks quite nice, very useful travel lens!
Review edited
- Thread starter Andrew Benbow
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Ok so how do I delete this ??
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Why delete it? I for one have been waiting to find out more about this lens, and I thank you for the opportunity to read it. As a Sony A-mount user I was disappointed to note that it has a magnetic diaphragm. Of course that's a technological improvement, but it's not something the mechanical lever Sony A-mount aperture control can currently handle. So there's little possibility of this lens ever being offered for the Sony A-mount.
This lens clearly wins the zoom factor race, having a zoom ratio of 400/18=22.2, whereas Tamron's earlier 16-300mm superzoom is only 300/16=18.75. But is that really the right way to compare these lenses? The field of view changes much more rapidly at short focal lengths than at long. I would argue that perhaps zoom ratios should be calculated in terms of the ratio of angular field of views rather than focal length range. If my use of scantips lens field of view calculator has been correct, then this 18-400mm zoom ranges from diagonal subtended angles of view of 5.5 degrees at the long end to 84.1 at the short, giving a ratio of field of view change of 15.2. Whereas the 16-300mm zoom ranges from 4.13 degrees to 77.4 degrees, giving a ratio of 18.7. By that measure the 16-300mm is clearly the winner -- in terms of the largest proportional range of angular field of view.
Looking at this comparison in another way, the change from 300mm max to 400mm max gives a change of field of view from 5.5 degrees to 4.1 degrees, a decrease of of angle (or increase in "magnification") of 33%, whereas at the other end, a decrease from 18mm to 16mm gives a change of view angle from 77.4 to 84.1, an increase of 8.7%. By that measure, losing an extra 8.7% of view angle at the wide end buys an increase of 33% at the long end. Clearly by that measure the 18-400mm comes out again as the winner. On the other hand, if you have only a maximum of 300mm, and you really want 400mm, you can get there in effect by cropping down to the 400mm view angle, at the cost of slight decrease in sensor resolution. Whereas at the wide end, if you can't fit quite the entire height of a church frontage into an 18mm view from any of the street viewpoints available you're stumped. So a bit extra at the wide end is more generally valuable in terms of image taking versatility than a bit extra at the long end.
Of course in this simple comparison of numbers I've assumed that the detail resolution of both lenses at minimum and maximum are the same, which they probably aren't. Perhaps it's just as well we Sony A-mount users and superzoom fans won't have to make this very complex choice!
This lens clearly wins the zoom factor race, having a zoom ratio of 400/18=22.2, whereas Tamron's earlier 16-300mm superzoom is only 300/16=18.75. But is that really the right way to compare these lenses? The field of view changes much more rapidly at short focal lengths than at long. I would argue that perhaps zoom ratios should be calculated in terms of the ratio of angular field of views rather than focal length range. If my use of scantips lens field of view calculator has been correct, then this 18-400mm zoom ranges from diagonal subtended angles of view of 5.5 degrees at the long end to 84.1 at the short, giving a ratio of field of view change of 15.2. Whereas the 16-300mm zoom ranges from 4.13 degrees to 77.4 degrees, giving a ratio of 18.7. By that measure the 16-300mm is clearly the winner -- in terms of the largest proportional range of angular field of view.
Looking at this comparison in another way, the change from 300mm max to 400mm max gives a change of field of view from 5.5 degrees to 4.1 degrees, a decrease of of angle (or increase in "magnification") of 33%, whereas at the other end, a decrease from 18mm to 16mm gives a change of view angle from 77.4 to 84.1, an increase of 8.7%. By that measure, losing an extra 8.7% of view angle at the wide end buys an increase of 33% at the long end. Clearly by that measure the 18-400mm comes out again as the winner. On the other hand, if you have only a maximum of 300mm, and you really want 400mm, you can get there in effect by cropping down to the 400mm view angle, at the cost of slight decrease in sensor resolution. Whereas at the wide end, if you can't fit quite the entire height of a church frontage into an 18mm view from any of the street viewpoints available you're stumped. So a bit extra at the wide end is more generally valuable in terms of image taking versatility than a bit extra at the long end.
Of course in this simple comparison of numbers I've assumed that the detail resolution of both lenses at minimum and maximum are the same, which they probably aren't. Perhaps it's just as well we Sony A-mount users and superzoom fans won't have to make this very complex choice!
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I wanted to delete because someone else has started the same thread a couple of days ago which I hadn't seen it after I posted
I've got the Tamron 28-300 which is very nice and works well as a walk around lens. The 18-400 won't work for me (full frame) but might make a nice present for my daughter
I've got the Tamron 28-300 which is very nice and works well as a walk around lens. The 18-400 won't work for me (full frame) but might make a nice present for my daughter
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Why not post a link here to the other thread?
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