Need Lens Help

starky987starky987 Registered Users Posts: 86 Big grins
edited April 12, 2008 in Cameras
I have 2 lenses now after receiving one from a friend as a gift.

1. Canon EF 75-300
2. Tamron 18-200

I was told by someone at my local camera store that the tamron lens range of 18-200mm was not already converted based on the crop factor and that my canon WAS already converted. What I took this to mean is that once I would convert my tamron lens based on my crop factor it would have a range of around 300mm max. If this is the case and the canon is already adjusted for the crop then I believe both these lenses have the same maximum zoom. If someone could confirm this for me that would be great because I won't open the canon lens and will try to sell it. I obviously don't need two lenses that are completely identical for the telephoto end. Any help would be appreciated.

Comments

  • ziggy53ziggy53 Super Moderators Posts: 24,132 moderator
    edited April 11, 2008
    starky987 wrote:
    I have 2 lenses now after receiving one from a friend as a gift.

    1. Canon EF 75-300
    2. Tamron 18-200

    I was told by someone at my local camera store that the tamron lens range of 18-200mm was not already converted based on the crop factor and that my canon WAS already converted. What I took this to mean is that once I would convert my tamron lens based on my crop factor it would have a range of around 300mm max. If this is the case and the canon is already adjusted for the crop then I believe both these lenses have the same maximum zoom. If someone could confirm this for me that would be great because I won't open the canon lens and will try to sell it. I obviously don't need two lenses that are completely identical for the telephoto end. Any help would be appreciated.

    The person at the store is wrong. Both of those focal length ranges are actual millimeters.

    You simply have an overlap of the 70-200mm range but I guarantee that they will not be identical quality through the range. I suggest you run some tests and decide when you should use one lens over the other.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • pyrypyry Registered Users Posts: 1,733 Major grins
    edited April 11, 2008
    All lenses are marked with actual focal lenghts - a lens doesn't know the size of the sensor behind it. The canon would give a field of view equivalent (the actual focal lenghts don't change, it's a crop not a teleconversion) of 120-480 mm.

    The diffence is that the Tamron lens was designed to be used with aps-c sized sensors (ie. crop factors of around 1.5-2). This doesn't change how the focal lenghts are marked, but does effect the focal lengths it's designed for, these lenses are made shorter, hence the 18 mm. This is a re-design of the 28-300 lenses out there.

    Another difference is that the image produced by these lenses isn't big enough to cover a full sized sensor or film. It doesn't need to be, which means the lens elements can be smaller, and therefore the lens is smaller and lighter.

    Hope this helps!
    Creativity's hard.

    http://pyryekholm.kuvat.fi/
  • starky987starky987 Registered Users Posts: 86 Big grins
    edited April 11, 2008
    this helps very much. i guess ill probably keep both lenses unless someone advises against it. Thanks very much.
  • i_worship_the_Kingi_worship_the_King Registered Users Posts: 548 Major grins
    edited April 11, 2008
    If it matters... I have a 70-300 and want an 18-200. The 70mm is just a hair too long for a good walking around lens (just like today, matter of fact, at spring fling...). However 200mm would have been more than enough to get any of the zooming I did walking around today so the 300 was just waste.

    Then when I shoot sports I use the 300 and wish there was another 300 on the end of it.....

    If you get good shots out of them I'm sure you'll prefer different ones for different tasks with time.

    Happy shooting! :D
    I make it policy to never let ignorance stand in the way of my opinion. ~Justiceiro

    "Your decisions on whether to buy, when to buy and what to buy should depend on careful consideration of your needs primarily, with a little of your wants thrown in for enjoyment, After all photography is a hobby, even for pros."
    ~Herbert Keppler
  • RobinivichRobinivich Registered Users Posts: 438 Major grins
    edited April 12, 2008
    I'm assuming the 75-300 was the gift? I expect it'll be comparable if not better quality (we're talking relative terms, of course) from 75-200, after that quality drops off, the key difference is that those 100mms can help out, also it's probably got somewhat better autofocus, particularly at the long end. The 18-200s tend to be f6.3 at the long end, which is usually outside of the normal autofocus working range.

    If in doubt, take the 18-200 with you, the convenience is the entire purpose of this lens, if you know you'll be photography subjects from a distance, go for the extra reach of the 75-300, a lens has to be really soft before 200mm will get more detail than 300mm (not out of the question, but I doubt it). Given the resale value of the 75-300, I'd personally hang onto it for the time being, but if you find yourself using telephoto much, you'll want a better lens down the road and might as well sell it while it's still "BNIB" if that's the case
    http://taylorinlight.com
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