Featured Ancients: An Anonymous Hero (Phokaian electrum)

Discussion in 'Ancient Coins' started by AncientJoe, Jul 5, 2014.

  1. geekpryde

    geekpryde Husband and Father Moderator

    He is talking about focal length of a camera lens. To summarize what he said, dont use anything less than 100mm for coins. Some camera have a smaller frame (image sensor) than traditional 35mm film, so they have something called a crop-factor, so on MOST consumer level DSLR you need to multiply the listed focal length on the lens by 1.5. For example, the best lens for coins IMHO is the 105mm Nikkor Micro, this is really (105 x 1.5= 157.5mm equivalent lens) @dougsmit (I think) is saying 150mm is just about perfect, so my example is about perfect. However, since some people with big $$ have "full-frame" cameras, this 105mm lens would only be 105mm, and he is saying this may not be good enough. On a full-frame camera, you would want to buy a macro lens that said 150mm or more to get great coin photos.

    Perhaps see my thread here. CLICK ME

    The problem with 150mm and above, you need to get WAY back from very large coins. On USA coins, it's not a problem. But if some ancient coins are really plate sized, this will be an issue. I don't know much about ancient coins, are they really that big?

    [​IMG]
     
    Last edited: Jul 18, 2014
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  3. dougsmit

    dougsmit Member

    The majority of macro lenses focus to life size 1:1 reproduction ratio which means that the image on the sensor can be as large as the coin itself. Using a 'crop' camera That means you can fill the frame with a coin no smaller than about 13mm across. With a full frame camera that jumps to 24mm. To shoot smaller coins, you either add accessories (extension tubes) or just crop (the easy way).

    geekpryde is right about large coins. If you mainly collect silver dollars, you will not want even a 100mm lens. I have half a dozen ancient coins as large as a silver dollar so that is not a problem to me. The 100 to 150 mm range works well for people with a collection like mine (mostly 5 to 25mm).
     
    geekpryde likes this.
  4. TJC

    TJC Well-Known Member

    Great Hero coin!
     
  5. Goulash

    Goulash New Member

    Great coin ancient Joe, how do you get the pic like that when the coin appears suspended.
     
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