Are big lenses for teleconverters

Discussion in 'Beyond the Basics' started by fraserimagery, Feb 5, 2008.

  1. fraserimagery

    fraserimagery TPF Noob!

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    I have a great 300mm lens that goes down to 4 ap. Should I not get a teleconverter because it will darken my image to much - so that I get an fast enough shutter speed to get a shot.
     
  2. AspiringArchitect

    AspiringArchitect TPF Noob!

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    I shot some 300mm shots at f4 and put a 2x teleconverter and was able to shoot sunny situations at an outdoor soccer game (USA v. Italy) at a reasonable fast shutter. What are you trying to shoot? Action? The moon?
     
  3. keith204

    keith204 No longer a newbie, moving up!

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    If you go with a 1.4x converter, it will reduce your aperture by one-stop. So, your max aperture will be f/5.6. If you go with a 2.x converter, it will reduce your aperture by two stops so your max aperture will be f/8.

    If you're shooting outdoor sports, and are fine with bumping your ISO to 1600/3200, then the f/5.6 should be alright, but f/8 is pretty small.

    Also, have you looked into whether or not there are teleconverters that match your lens's auto-focus? Many lenses lose their auto-focus when paired with teleconverters.
     
  4. Big Mike

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

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    This goes back to Keith's first point. A TC will steal some light...essentially making your max aperture smaller. Most cameras need at least F5.6 for auto focus to work. If you have a 2X TC (making your max aperture F8) then the camera probably won't have enough light to make AF work.

    This is why TCs are best used with fast lenses (F2.8 etc). Although loosing auto focus isn't the end of the world.
     
  5. schuylercat

    schuylercat TPF Noob!

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    I used to shoot auto racing, about 10 years ago. I could never afford long lenses, so I'd rent Canon's 300 f/2.8, shooting with an EOS 1N. On tracks with long views I'd rent the 1.4x, and at tracks with REALLY long views I'd rent the 2x, as well as the 600mm f/2.8. Autofocus wasn't an option - cars would be moving up to 225 MPH, and I had to pre-focus and compensate for shutter lag.

    Never had a problem, except lugging that 600 with the 2x was like carrying a weapon - that's when I realized where Canon got their name. Still, I was always in good light.

    Since it's unlikely you'll be shooting that 300mm f/4 indoors, I assume you'll have the option of available sunlight much of the time. If you don't need to narrow your depth of field and can hold the bazooka steady, it's a very good option!
     
  6. Big Mike

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

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    Was that the 600mm F4? I've never heard of a 600mm F2.8 for Canon.
     
  7. schuylercat

    schuylercat TPF Noob!

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    Duh on me, It was an f/4 - my mistake. You remember that big bazooka? Something like 15 pounds. Rented for $75/day back in 1995 or so.
     
  8. Big Mike

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

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    I've never used one...but yes, it's certainly a bazooka.

    Not quite the 1200mm F5.6...but those are/were something like $90,000 and there are only a few of them floating around.
     
  9. RacePhoto

    RacePhoto TPF Noob!

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    Simple opinion point.

    Fastest way to make a really great lens into an average lens is add a teleconverter. :lmao:

    Some times it's the only answer to get a 600 out of a 300 for $300, but there's no magic that will make it as sharp by sticking another piece of glass in the light path, after the real lens.

    I'd worry more about that problem than losing a stop or two.

    Monopod, pan with the subject, shoot, keep panning! The most common beginners error is that they stop when they push the shutter release, and don't follow through.

    You can shoot with a monopod at a 125th and get a tack sharp image with a blurred out background. So light isn't the biggest problem. Sure you'll get some bad ones and some that are worse than bad, but the good ones, will be wonderful. If you can get a good balance between speed and aperture, it just gets better.

    I guess I'm saying that it's digital and every shot doesn't have to be perfect, your film doesn't cost anything, you don't have to pay for processing blurred blobs, you shouldn't be afraid to experiment and make some mistakes. Then learn from those mistakes.
     
  10. DSLR noob

    DSLR noob TPF Noob!

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    a 300 mm f/4 lens with a 1.4X converter is a 420mm f/5.6 That's still enough to autofocus on a Canon camera, so if you're a Canon user, a bumped ISO would be worth the tradeoff of a 420mm reach.
     
  11. jstuedle

    jstuedle No longer a newbie, moving up!

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    Tele's don't always make a great lens average. A top quality lens with a matched tele-converter still makes a great lens. My 400 3.5 with a TC-301 on it make a killer 800 7.1. The biggest problem is packing the 40 lb. tripod to hold it steady.
     

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