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Category: New Questions

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Photography Question 
Jerry Cocuzza

member since: 6/6/2004

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!

6/6/2004 12:50:22 PM

Dave Cross

member since: 4/8/2004
  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.

6/7/2004 7:16:30 AM

Jerry Cocuzza

member since: 6/6/2004

Thanks for your input!

6/8/2004 4:05:29 AM

Jon Close
BetterPhoto Member

member since: 5/18/2000
  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

6/8/2004 11:02:34 AM

Jerry Cocuzza

member since: 6/6/2004

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


6/9/2004 4:53:59 AM

Michael McCullough

member since: 6/11/2002
  I highly recommend any Kiron 1.5X five element or 2X seven element converters. They are outstanding and reasonably priced in the used market!!!!

6/9/2004 10:32:49 AM


member since: 7/6/2001
  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.

6/9/2004 4:35:45 PM


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