Need Help Setting Exposure with a 400mm lens.

Discussion in 'Beyond the Basics' started by Ken Roberts, May 6, 2005.

  1. Ken Roberts

    Ken Roberts TPF Noob!

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    Hi;
    I'm new to the forum. Recently I got back into the older mechanical SLR's and have had no trouble using them (I have a pretty good memory) but I don't know how to set the shutter speed and aperture with a long focal length lens. 400mm. I tried aperture priority & shutter priority and it won't work. I remember that you had to open up the lens alot more, but how much?
    400mm? I attached my 2x converter(bayonet) to my Ricoh KR30 than attached my Soligor 70-200 zoom to the converter. All went smooth. I went to remove the 200mm from the converter and it won't come off. Turns, but stays on. I can live with that but would like to use the "400" mm at an upcoming baseball game. Any help will be greatly appreciated.
    Thanks.
    Ken
     
  2. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

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    Focal length doesn't have an effect on the amount of exposure by itself. Many long focal length lens apertures don't open up as wide as shorter focal length lenses, but if f/8 @ 1/500th (for example) is the right exposure for a 28mm lens, as long as the light doesn't change it would be the same for a 400mm lens.

    Teleconverters decrease effective aperture. I think that x1.4 teleconverters decrease the aperture 1 stop, and 2x converters lose 2 stops, but you better read your manual.
     
  3. DocFrankenstein

    DocFrankenstein Clinically Insane?

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    Mattfish is right about the light reduction and everything else.

    Sounds like you have something broken... either thel lens or the converter.

    Also, my guess is that the soligor is 5.6 on the long end, which would make it f/11 with the TC... A bit slow for football, don't u think?
     
  4. Ken Roberts

    Ken Roberts TPF Noob!

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    Thanks KS and Doc for the replies. I'm going to chuck this particular project and forget that I have the lens!
     

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