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Category: Camera Lenses

Photography Question 

Jerry Cocuzza
 

More on Teleconverters (Tele-Extenders)


I have a Nikon D-70 with the 18-70 zoom. Does anyone have any experience or comments about using a 1.4 or 2.0 tele-extender? Am I better off with the Nikon unit or one manufactured by Tokina, Tamron or Sigma, for example? Is my money better spent elsewhere? Thanks for your input!


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June 06, 2004

 

Dave Cross
  Hi Jerry. The use of teleconverters (that fit between the lens and body of an SLR) is a "swings and roundabouts" situation.

Roundabouts (gains): 1. Cheaper than an additional tele-lens. 2. Light and small (about the size of a 50mm prime).

Swings (losses): 1. Not so sharp as a "proper" tele. 2. Not recommended at the wide end of your current lens (distortion and vignetting possible).

Personally, I use a x2 with my 28-80 f2.8 when I want to go "light" (without the 70-200 f2.8). It's nice to have that extra length available for use if an unforeseen opportunity arises. I suspect that you will see a significant price advantage if you go for a unit from Tokina, Tamron, or Sigma over the genuine Nikon unit. Watch out for really cheap units with poor optics - they really are not worth the savings.

As with all these things, these are my opinions - your mileage may vary. Cheers.


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June 07, 2004

 

Jerry Cocuzza
  Dave,

Thanks for your input!


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June 08, 2004

 

Jon Close
  In addition to what Dave wrote, teleconverters (TCs) increase the lens focal length, but not the size of the diaphram opening, so the effective aperture is reduced. So attaching a 1.4x TC to your 18-70 f/3.5-4.5 makes it effectively 25-98 f/4.9-6.3, or 36-140 f/7-9 with 2x. With maximum aperture of less than f/5.6, autofocus becomes iffy, and you may not get hand-holdable shutter speeds without upping the ISO to the noisier 800-1600 level.

TCs are most effective when used with prime lenses or large/constant aperture zooms like the f/2.8s. A good 2x TC like Kenko's Pro-300 is about $200. For about $50 more, you could get the Nikon 70-300 f/4-5.6D ED. For $200 or less, you could get Sigma 70-300 f/4-5.6 APO Macro, Tamron 70-300 f/4-5.6 LD Macro, or Nikon 70-300 f/4-5.6G


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June 08, 2004

 

Jerry Cocuzza
  Jon,

I appreciate the feedback. Based upon what you and Dave have said I think I will hold off awhile and eventually go for lens.

Thanks!


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June 09, 2004

 

Michael McCullough
  I highly recommend any Kiron 1.5X five element or 2X seven element converters. They are outstanding and reasonably priced in the used market!!!!


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June 09, 2004

 

Armando
  A full-frame TC is not advised with DX series lenses - remember that the DX has a smaller image circle to optimize it's performance with APS-C sized CCD sensors on Digital SLRs - you'd probably get significant vignetting. There's also the possibility of damaging the lens and/or TC because the two are not meant to be mechanically linked.


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June 09, 2004

 
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