p.1 #1 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
On this and other forums the question is often raised as to how well the Kenko Pro telextenders work with this, that, or the other lens. Since these telextenders are often purchased for use on other than top-of-the-line lenses, I thought it might be useful to show how the combination of lens with these telextenders does, versus the lens alone, and how the combinations with different lenses/types of lenses might work out. Accordingly I designed and shot a pretty rigorous test for this purpose and have posted it in pBase, here:
p.1 #2 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
I probably should add that a few years ago when I owned a Nikon 300mm f/2.8 AF-S I, I did a similar test...bare, and with the two extenders. I published it on NIkon Cafe...can't remember if I did it here as well. Needless to say, with a top of the line lens both telextenders performed superbly well.
p.1 #4 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
I very much appreciate you doing this, there's not that many comparisons like this on the net. I was primarily interested in the performance of the 70-300VR with the Kenko TC. It is apparent with your examples that the IQ of the 2.0 TC is better than the 1.4 TC, which is not logical, so is there a chance you transposed those examples? Thanks.
The IQ degradation with a fixed focal lens like the Nikon 300mm f/4 plus a 1.4 TC can be negligible, but with a zoom is another thing. I personally see noticeable degradation with the zooms and TC combination, some more than others. Most times cropping renders equivalent or better results IMO, but that determination is totally subjective...
p.1 #5 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Drive by the Brass Cat just about every day, but rarely stop in (i'm not much of a drinker anymore). My son and his band occasionally play a gig there, and I have the son, a niece, and an ex-girlfriend who all live within three blocks. Small world, eh? What's your connection to the 'Cat?
p.1 #6 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Lora, you have good eyes and so I went back to the source and traced the sequence from Nefs, to cropped nefs, to tiffs, to large Jpegs, to transfer into pbase.....and no change....the order was correct.
So, the possibilities are that the autofocus didn't work very well for some reason (although I picked the best of two), or that somehow with the particular lens combination, the middle (upsized crop, some degradation) was not as good as the base (no degradation, very sharp, but upsized crop) nor the 2X reach (some degradation, and only a small downsize). That's all I can come up with.
But, glad you liked the effort otherwise. Thanks for your keen observation.
p.1 #7 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
I uses to live in Easthampton, and was a custom furniture designer and maker in Cottage Street. Used to have lots of friends in town and at the Cat. they have some good music there on the weekends. I'm in Amherst now and at UMass.
p.1 #8 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Harry, I would respectfully ask you to check your workflow sequence again:
- Nikon 300mm AF @ 600mm.JPG - EXIF indicates: Nikon D300 ,Nikkor 80-200mm f/2.8D ED AF 1/80s f/8.0 at 600.0mm iso720 (different lens)
- Sigma 18-200 @ 400mm.JPG - EXIF indicates: Nikon D300 ,Sigma 18-200mm f/3.5-6.3 DC 1/100s f/8.0 at 400.0mm iso200 (At 200mm this lens is f/6.3, so it can't do f/8 with a 2x teleconverter)
- Nikon 70-300 VR @ 600mm.JPG - EXIF indicates: Nikon D300 ,Nikkor 70-300mm f/4.5-5.6G IF-ED AF-S VR Zoom 1/80s f/8.0 at 600.0mm iso200 (At 300mm this lens is f/5.6, so it can't do f/8 with a 2x teleconverter)
The results for the Sigma 70-300 @ 600mm, shot at 1/80s f/13.0 at 600.0mm iso500 seems correct and is more like what I would have expected from this class of lens with a 2x teleconverter - soft and mushy.
p.1 #9 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Albert, not to speak for Harry here but there is an explination for the conflicts with aperture in the exif. I have always noticed Nikon exif gives the lens' working aperture for the image, not the effective aperture with light loss from the tele. I've even noticed that my Kenko 1.4x on the 300/4 always reads 300mm in the exif on a D90, 60, and 40. Don't know why.
p.1 #10 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Sorry to be so negative, but I really think Harry must have gotten his images somewhat mixed up. Just look at the Nikon 70-300 VR series at 300mm, 420mm and 600mm at "Original" size. To my eyes, the image quality improves rather than degrades with the 1.4X teleconverter and then magically improves even more with the 2X teleconverter.
p.1 #11 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
's okay, Dennis. He started and front's a band called "Trials and Tribulations". Voted best folk-rock band in the Valley two years ago. He also plays with his best friend Ben in The John Bobbitt Experience, an electro-disco band.
p.1 #12 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Thanks, Albert and Dennis, for your comments.
Dennis is right about the aperture....on an AF lens, the readout is for the lens by itself...no correction of aperture or of focal length.
On the other hand, Albert, I agree that something seems amiss. I did go back to the original download, which seemed to be in the order I shot (I use markers)...and I checked focal lengths from there. But I see no reason why the wrong lens should be assigned, so somewhere something happened. I'll check it out, make whatever corrections are warranted, and let you know. BTW, my Opanda doesn't seem to give a lens read-out....just focal length...so I had to rely on NX2 for that.
p.1 #13 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Sorry, Albert but I have triple-checked everything right back to the original nefs and can find no problems. Just to be sure, I replaced the 300 f/4 AF shots with a fresh set (although they appear identical) that I KNOW are exactly correct in sequence....and the EXIFs underneath say 300mm AF f/4.
Two of your three complaints were explained by Dennis....is it possible that you opened the wrong file when you saw the 80-200 EXIF. I coud find no such descrepancy throughout all my checking.
p.1 #14 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Albert wrote:
- Nikon 300mm AF @ 600mm.jpg - EXIF indicates: Nikon D300 ,Nikkor 80-200mm f/2.8D ED AF 1/80s f/8.0 at 600.0mm iso720 (different lens)
Thanks for replacing the 300 f/4 AF shots with a fresh set. The EXIF in the image caption which is what I was referring to (i.e. not the "Full EXIF Info" box) is now correct.
Albert wrote:
- Sigma 18-200 @ 400mm.jpg - EXIF indicates: Nikon D300 ,Sigma 18-200mm f/3.5-6.3 DC 1/100s f/8.0 at 400.0mm iso200 (At 200mm this lens is f/6.3, so it can't do f/8 with a 2x teleconverter)
- Nikon 70-300 VR @ 600mm.jpg - EXIF indicates: Nikon D300 ,Nikkor 70-300mm f/4.5-5.6G IF-ED AF-S VR Zoom 1/80s f/8.0 at 600.0mm iso200 (At 300mm this lens is f/5.6, so it can't do f/8 with a 2x teleconverter)
Harry wrote:
Dennis is right about the aperture....on an AF lens, the readout is for the lens by itself...no correction of aperture or of focal length.
Interesting! That must be the way Kenko teleconverters work. My only experience has been with Sigma teleconverters on Sigma lenses, and the combo reports both the resulting aperture and focal length correctly.
However, then, the Sigma 70-300 @ 600mm, shot at 1/80s f/13.0 at 600.0mm iso500 (which I commented on above) would have a resulting aperture of f/26? The resulting diffraction at f/26 on this lens would explain the "mushiness" I observed.
p.1 #15 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
Albert -
What you say about the light transmission of the Sigma is true, but I believe the quality of the lens image is a function of the physical lens aperture setting iteself, eg. f/13 is f/13 for image quality. Can anybody help me out here?
ps. The Kenko telextenders do read AF-S lenses and Sigma's with similar function correctly....it is the older screw-drive lenses that they do not report accurately.
p.1 #16 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
As fat as I know, the aperture of the lens dictates the effects of diffraction. Adding a teleconverter will not change this. The "effective aperture" involves only the amount of light hitting the sensor/film. Light loss happens through the action of the optics and the additional extension. Any degredation of IQ I believe comes from the optics. Any additional difraction also come directly from the optics.
Harry, I know of both those bands, though I've never heard either live.
p.1 #18 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
As fat as I know, the aperture of the lens dictates the effects of diffraction. Adding a teleconverter will not change this...
That's not quite correct, Dennis. The diffraction effects will be twice as large with the 2X teleconverter. See Q34 at http://photo.net/photo/optics/lensFAQ
p.1 #20 · Five Lens rigorous test with Kenko Pro 300 1.4x and 2.0x Telextenders
It can be sharper if the lens is sufficiently sharp to work well with the telextender vs. the loss of detail involved in the upsizing process of the 300mm "bare" file.
That is where pixel-peeping can be misleading. Is individual pixel clarity reduced by a teleconverter. Yes. Is this enough to offset the loss of clarity from having to do a 4X upsize from use without the teleconverter? That depends on the lens.
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