question for a camera pro...

Discussion in 'Beyond the Basics' started by cypilk, Apr 22, 2004.

  1. cypilk

    cypilk TPF Noob!

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    what do all the numbers mean in lenses?.. i mean.. zoom mm and aperature numbers.

    well, here are some of my questions.. what is?!

    1. filter size
    2. f-stop range
    3. maximum focus distance
    4. magnification
    5. angle of view
    6. groups / elements
    7. maximum reproduction ratio?
    8. whats a teleconverter?

    what are some of the units the numbers are in?


    yeah..some of these questions are kind of newbie :D :D :D
     
  2. Big Mike

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

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    I'm not a camera pro but...

    1. Filter size is the diameter (in millimetres) of the threads on the front of the lens...where you would screw on a filter.

    2. F-stop range is the minimum to maximum aperture that the lens can be adjusted to, with respect to the focal length. The lower number is how big the aperture can open (ie: F1.8) and the high number is the smallest the aperture can close down to (ie: F22)

    3. Maximum focus distance? Do you mean minimum distance? If so, it's the minimum distance that you have to be from the subject for the lens to be able to focus clearly. (ie: with most lenses, you can't focus if you are less than a foot or two away...

    4. Magnification is the magnification factor of the lens. A longer focal length will have a bigger magnification. (ie: a 100mm lens has greater magnification than a 50mm lens)

    5. Angle of view is the angle that the lens sees. A longer lens has less angle of view but has more magnification. A wide angle lens captures a wider view but does not magnify very much.

    6. Groups \ elements is referring to the number of pieces of glass used in the lens.

    7. maximum reproduction ratio, I'm not too sure...but I think it refers to the lens's macro ability. If the lens can focus very close to an object, then it has greater reproduction ratio. It would be the ratio of the size of the object vs the size of the image on the negative.

    8. A converter is an attachment that you put between the lens and the camera to increase the effective focal length. The common ones are 1.4x and 2x. The 2x for example will effectively double the magnification of a lens...turning a 50mm into a 100mm.
     
  3. cypilk

    cypilk TPF Noob!

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    woah..so teleconverters could save me a lot of money. .i was planning on buying a whole new zoom lens..cause mine is only 24-120 ..well its a 24-120mm f/3.5-5.6D AF Zoom-Nikkor..i wanted at least a 200 or 300...

    and aperature for lenses... my camera can go way past what my lens is.. but i'm sure its not limited to what my lens says...

    what are the pros and cons of getting a teleconverter instead of a whole new lens?
     
  4. Galaxy_Stranger

    Galaxy_Stranger TPF Noob!

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    1.Filter Size: This likely refers to the thread of the filter. This should match the thread of the lense you're putting it on. So, if your lense has a 55mm thread you use a filter that also has a 55mm thread.

    2.F-Stop Range: It probably refers to Tonal or Contrast range. F-Stop refers to the size of the aperture. Tones in relation to F-stop.

    3.Maximum Focus Distance: I'm not sure about this one. Regular lenses can be set to infinity, so as long as the subject/background is at least at the focal point it'll be in focus. This term may refer to Macro lenses/filters, since when shooting small objects they can be out of focus by being too far away - "minimum focus distance". http://photonotes.org/cgi-bin/search.pl?input=Focus distance&which=d

    4.Magnification: "The process of enlarging the size of something, as an optical image." You'll see this like 4X or 5X on point and shoots. This means the lense magnifies the image 4 or 5 times what would be considered a "normal" size.

    5.Angle of View: Depends on the context. Mostly, it means your Field of Vision - which is dependent on the lense you're using. But, I always use it when talking about the subject :p , which nobody else does. I guess it comes from trying to explain everything to customers... http://photonotes.org/cgi-bin/search.pl?input=Angle of View&which=d

    6.Groups/Elements: Yeah, I need a little context here. Is it Elements in terms of Lenses, or Groups in terms of composition?

    7.Maximum Reproduction Ratio: Aspect Ratio, maybe? This probably has to do with the scale of the negative to the size of the final print.

    8.Teleconverter: This is a nifty doohickey that looks kinda like a lense. It is placed in between the camera body and your normal lense. Teleconverters can increase your focal length - turning a 200mm lense into 400mm. The drawback to this is that is kills the light getting to your film, so your lense aperture has to be larger than the converter's. I wanna say it's about 4 full stops difference.
     
  5. markc

    markc TPF Noob!

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    The lens determines the aperture range you are working with. On some cameras, you can set it on the body, but it's only passing that info to the lens itself. Manual cameras often have a dial right on the lens.

    info on teleconverters
     
  6. Big Mike

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

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    Ya I should have mentioned that teleconverters steal light. A 2x will cost two stops of light. With your 3.5-5.6 lens, a teleconverter will probably cost the use of auto focus if your camera has it. Most AF cameras need at least F5.6 to use AF.

    Also, a good TC will cost as much as a lens. So you might be better getting a long prime (non-zoom) lens.
     
  7. cypilk

    cypilk TPF Noob!

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    so...about the lens construction...say 16...elements in 13 groups (2 aspheric) ..what does that mean?.. yeah..its sort of a real technical question.....

    oh yeah..whats d- type lens?
     
  8. markc

    markc TPF Noob!

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    There is a PDF here: http://www.zeiss.de/C12567A8003B8B6F/EmbedTitelIntern/Lens_Production/$File/Lens_Production.pdf
     
  9. danalec99

    danalec99 TPF Noob!

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    cypilk, Are you seriously considering photography as a career?
     

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