2x Converter

Discussion in 'Beyond the Basics' started by Tyler2026, Jun 25, 2007.

  1. Tyler2026

    Tyler2026 TPF Noob!

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    I have been thinking about purchasing a 2x converter, but I have never seen a photograph that was taken with a 2 x converter. Does the converter distort or lower the quality of the photos. I have heard that some quality may be lost but the average Joe would never notice. Just Wondering.
     
  2. keith204

    keith204 No longer a newbie, moving up!

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    I thought about (and am thinking about) purchasing one for my Sigma 70-200 2.8 lens. The responses I got were that the largest aperture would then be a 5.6. You'll want to do a bit of research on the lens/converter combination, because from what I understand, different converters work better for different lenses. Somebody let me know if I'm on the right/wrong track, cause I'm interested in the responses to this topic too.

    Tyler2026-Nice topic idea.
     
  3. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Welcome to the forum.

    Are we talking about a Teleconverter for an SLR camera with interchangeable lenses, or a teleconvertor that screws onto the front of a digi-cam lens?

    Either way, image quality will be negatively affected. Almost anytime you add more glass for the light to pass through, you will be degrading the image quality...and yes, for top quality converters, the difference in quality is slight, and the average Joe may not notice.

    Teleconverters for SLR cameras go behind the lens. A 2X teleconvertor will 'steal' about two stops of light....so it's best to use them with fast lenses (F2.8 or better). If you don't use fast lenses, the view finder will may be too dark to manual focus and that's important because there may not be enough light for the AF to work properly.

    I have a 2X converter that I sometimes use on my 75-300 F4-5.6 lens...but AF usually doesn't work so I have to manually focus.

    If we are talking about the front mounted adaptors for digi-cams...from what I hear, the quality isn't usually that great. You would be better off not using it and cropping an image instead. Of course, using a tripod will help to get sharper shots that are more suitable for cropping.
     
  4. EOS_JD

    EOS_JD TPF Noob!

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    Better with a 1.4x and losing only one stop of light. My 70-200 f2.8L IS is a great 98mm - 280mm f4L IS :)

    What lens did you plan ion using the 2x with? As Mike says using it on anything slower than an f2.8 lens will mean you'll probably lose AF and even if you don't AF is severely hampered by this loss of light.
     
  5. mysteryscribe

    mysteryscribe TPF Noob!

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    Wish you could borrow one to try out. It is very hard to put into words what the difference is. I shot the http://thephotoforum.com/forum/showthread.php?t=85407 to show what MY 2x vivtar does to my 300 mm no name lens on a film camera. Your results will be different.
     
  6. jstuedle

    jstuedle No longer a newbie, moving up!

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    In the "old" days Nikon made converters made for either short or long glass. We shoot a lot of MF glass and one is a 400 f/3.5. With the appropriate converters, either 1.4 of 2/X the quality of the file is acceptable. 13" X 19" prints at proper viewing distances show no ill effects from the increased magnification assuming correct tripod and shooting technique is used. BUT, that said (always a butt) the file close up or viewed at actual pixels does show the affects of the converters. In reality I seldom use them because of the time to setup and we very seldom have a need to go past 400mm. I think the last time it was used with a 2X was to shoot the harvest moon 2 years ago. I personally would never use one on a zoom lens. In that application I am convinced the loss in quality of file would not be worth the extended reach of the glass. I would instead up-sample the file to the desired size.
     
  7. TomHuck-wa

    TomHuck-wa TPF Noob!

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    I have sold several pictures of deer and elk taken with a Canon 20D,70-200 f2.8 IS lens and a Canon 2x extender. No one knows it wasnt a 400 lens if I dont tell them. The degradation to the picture quality is greatly overstated IMHO.
     
  8. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Of course it helps when you start with one of the sharpest zoom lenses avaliable ;)
    The Canon TCs are actually designed only to work with a handful of top quality L lenses.
     
  9. jstuedle

    jstuedle No longer a newbie, moving up!

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    I agree that with the right glass and the made/for converter good or even very good results can be had. But simple physics dictate a loss of quality in the image when extra glass is added to the equation. This is not to say a good print can't be made and sold using a tele, but the image quality can only be better if guality glass of the final focal length were used. I realize we all don't have unlimited budgets, this is why I still use 30 year old lenses purchased in the 1970's. Years ago I used an Air Force optical test target to test lenses and converter combo's. I was amazed to see the combo's I thought great, were only good/very good. I have not used converters very much since.
     

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