2x Converter?

Discussion in 'Digital Discussion & Q&A' started by bazza, Sep 23, 2007.

  1. bazza

    bazza TPF Noob!

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    I've just bought a used Sigma 50mm macro lens for my 400d but I find I have to get really close to a subject to get the result I want. I also have a 2x tele-converter that I can add to the macro lens.

    Will this make it the same as a 100mm macro??

    What are the dissadvantages of doing this??

    I would have got a 100mm lens if it was affordable but I got a good deal on the 50mm.
     
  2. Keith Gebhardt

    Keith Gebhardt TPF Noob!

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    you might get noise with the tele on the macro

    "but I find I have to get really close to a subject to get the result I want"

    Your shooting macro.. wouldnt you say your kinda controdicting yourself here.
     
  3. Garbz

    Garbz No longer a newbie, moving up!

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    Ehhh not really. Firstly a teleconverter is glass. Noise is the only thing it won't add to an image :S. Also with a 100mm macro lens to get 1:1 you need to focus at 38cm. With a 50mm it's much closer and you're more likely to spook your subject if he is of the living so it makes perfect sense.

    The use of a teleconverter depends a lot on the lens. You will suffer 2 main problems. Firstly a 2x teleconverter will cost you 2 stops of light. So forget shooting without a flash, or quadruple your ISO (err yes so it does increase noise). The other problem is you're effectively cropping the centre of the glass elements. What this means is that if you have a poor lens you will get no better results then digitally upsampling the image. The sigma is pretty sharp to begin with http://www.photozone.de/8Reviews/lenses/sigma_50_28/index.htm so you shouldn't lose too much quality. As a graphed example have a look at this http://www.photozone.de/8Reviews/lenses/nikkor_300_4/index.htm the Nikkor 300mm which was reviews stock and with 1.4 and 1.7x teleconverters to see how the graphs change.

    Other than that drag your lens and camera into the shop and see if they'll let you try it.
     
  4. usayit

    usayit No longer a newbie, moving up!

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    Garbz is right... noise has little to do with the lens or the converter. It is more a factor of the sensor, ISO, and image processing (if any).

    One of the factors of shooting macro is working distance (min focus distance). Shooting really close to the subject is not necessarily the result you may want.
     
  5. bazza

    bazza TPF Noob!

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    Thanks all..

    Just wanted to try and increase the working distance between the subject.. especially with those that are easily spooked.

    Thanks again..
     

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