sattler123 Posted November 15, 2007 Share Posted November 15, 2007 I did a comparison test today of those two extenders with my Canon 500mm lens and to my big surprise, the Kenko seems to be quite a bit sharper than the Canon. Attched are two 100% crops of the lower right area of a newspaper that I taped against a wall. I then stood back about 20 yards and took the pictures with the lens tripod mounted. You can easily read the entire paper from that distance. Both were shot at ISO800 at f5.6 and 1/400sec - no sharpening was applied to the image or the crops. Is there such a thing as a bad version of this extender? We always hear about lens issues, but I have never heard anybody complain about the Tele-Extender. Does this make sense?<div></div> Link to comment Share on other sites More sharing options...
sattler123 Posted November 15, 2007 Author Share Posted November 15, 2007 Here is the Kenko version:<div></div> Link to comment Share on other sites More sharing options...
sattler123 Posted November 15, 2007 Author Share Posted November 15, 2007 BTW this was a tiny note next to a picture - the smallest fond I could find on that page in the newspaper. The 500mm lens is absolutely amazing. Link to comment Share on other sites More sharing options...
fourfa Posted November 15, 2007 Share Posted November 15, 2007 what camera? on my 5D in the corners, the Canon added mild red/green CA compared to the bare lens; the Kenko added a noticeably more severe blue/yellow CA. Outside of the corners I didn't see any real sharpness difference. the situation could be very different on say an XTi, which ought to be quite a bit more revealing of pure on-center resolution but will crop out the problematic corners. Link to comment Share on other sites More sharing options...
sattler123 Posted November 15, 2007 Author Share Posted November 15, 2007 Good question: I took them with the 40D - I should try it with my 5D as well - just to see if there was a noticeable difference. Link to comment Share on other sites More sharing options...
don_wilkie Posted November 15, 2007 Share Posted November 15, 2007 I got the same results when I compared my Kenko Pro to a friends Canon TC on a 5D and also on a 20D. The Kenko produced a sharper image. Link to comment Share on other sites More sharing options...
mwaks Posted November 15, 2007 Share Posted November 15, 2007 Will the Kenko allow auto focus when using the 100-400mm L? It can only be focused manually with the Canon Extender. If auto focus is possible, then I would switch to the Kenko. Link to comment Share on other sites More sharing options...
brucecyr Posted November 15, 2007 Share Posted November 15, 2007 Maybe this is not a fluke! I can't provide a link, but I seem to recall a lens test by Bob Atkins where he reported superior performance by a 10 year-old, rinky-dink Tamron 1.4X TC compared to the Canon 1.4X TC (1st version). Tamron and Kenko are basically different marketing fronts for the same products. Link to comment Share on other sites More sharing options...
sattler123 Posted November 15, 2007 Author Share Posted November 15, 2007 No, you'll still have to focus manually. It has nothing to do with the extender, but rather with your camera's autofocus system. Link to comment Share on other sites More sharing options...
grant g Posted November 15, 2007 Share Posted November 15, 2007 Interesting. I'll see if I can duplicate your results with the same combos (except that I have the original Canon 1.4x). And just wondering, but could you also try a shot with them stacked? (Kenko behind the Canon) Link to comment Share on other sites More sharing options...
don_wilkie Posted November 15, 2007 Share Posted November 15, 2007 <i>Will the Kenko allow auto focus when using the 100-400mm L? It can only be focused manually with the Canon Extender. If auto focus is possible, then I would switch to the Kenko.</i><br><br> I have three pins on the Kenko Pro taped over and my Canon 100-400 does auto focus even at 400mm. Link to comment Share on other sites More sharing options...
sattler123 Posted November 15, 2007 Author Share Posted November 15, 2007 Don, which three pins? I'd love to use the Kenko on my 100-400 as well! Link to comment Share on other sites More sharing options...
don_wilkie Posted November 15, 2007 Share Posted November 15, 2007 Forgot to mention above, when used with a 5D or 20D. Link to comment Share on other sites More sharing options...
don_wilkie Posted November 15, 2007 Share Posted November 15, 2007 <i>which three pins? I'd love to use the Kenko on my 100-400 as well!</i><br><br> The first three pins on the left. Link to comment Share on other sites More sharing options...
andrew robertson Posted November 15, 2007 Share Posted November 15, 2007 Did you refocus for the second image? The test should properly be done without any change in lens focus. Extremely minute differences in focus will indeed remove any validity the test has. Link to comment Share on other sites More sharing options...
chris_taylor9 Posted November 16, 2007 Share Posted November 16, 2007 For AF, you could just get a camera that has good low light AF. Several bodies go down to f8 AF. Link to comment Share on other sites More sharing options...
yakim_peled1 Posted November 16, 2007 Share Posted November 16, 2007 FWIW, I once tested my Kenko DG to a friend's Canon Mk I. Results were indistinguishable. Happy shooting, Yakim. Link to comment Share on other sites More sharing options...
yasirnisar Posted November 16, 2007 Share Posted November 16, 2007 Suprisingly enough, I tried my new Canon 1.4x converter Mk II over my old Sigma 400 5.6 telelens mounted on Canon 20D and it was still doing Auto-focusing. Link to comment Share on other sites More sharing options...
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