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Thread: Focal Length Comparison

  1. #1
    rpcrowe's Avatar
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    Focal Length Comparison

    Several members, like Liz, appear to be trying to decide what focal length lens or lenses would be best for their needs. Here is a neat focal length comparison site in which you can play with various focal lengths on full-frame and crop cameras.

    http://tamron-usa.com/lenses/learnin...comparison.php

    We always need to remember that the selection of photo equipment is ALWAYS a series of choices and compromises. However, IMO, the lens is the most important parameter that decides ultimate image quality. Virtually any DSLR camera, full frame or crop, new or used, will be capable of producing very good to excellent quality images if paired with very good to excellent lenses.

  2. #2
    Dizzy's Avatar
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    Re: Focal Length Comparison

    Thanks Richard! That looks like a great tool to show just what the view will be like
    from a given lens (even if we can't afford any more..lol).

    Mike
    Last edited by Dizzy; 10th September 2011 at 05:15 PM.

  3. #3
    alexis88's Avatar
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    Re: Focal Length Comparison

    Richard thanks a lot! That's really useful!!

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    Re: Focal Length Comparison

    One here from Canon too.

  5. #5
    Moderator Dave Humphries's Avatar
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    Re: Focal Length Comparison

    I appreciate these were provided in good faith to help, but the subject of focal lengths is fraught with confusion, caused mainly by different sensor sizes.

    I suspect many people will be using these to get an idea of what lenses will look like on a camera they probably don't own yet, that may well be a different format from what they are used to; e.g. a P&S/compact/bridge camera, and this is where they can easily draw the wrong conclusion.

    Canon wins on simplicity, but;
    it is designed for "EF lenses" so I have to assume that will be on a FF body.
    These figures and views shown are only directly comparable for a P&S/compact/bridge camera user migrating to FF (which is very unlikely).
    If anyone using a P&S/compact/bridge camera now is investigating what lenses will look like on the common APS-C/DX crop factor cameras, they must remember to multiply the advertised lens focal length by the crop factor, then use this tool. These factors are 1.5x for Nikon, 1.6x for most Canons and 2x for 4/3 and micro 4/3.

    e.g. a lens described as "70-300mm" will, on a DX/APS-C body, be equivalent to approx 105-450mm (Nikon DX) or 112-480 (Canon APS-C), unfortunately, the Canon tool only works at specific steps of focal lengths, so isn't much help to most people in being able to see the range they'll get in this example.


    The Tamron one is a tad more complicated to use, but also far more useful.

    Assuming you are considering a crop body camera, ensure the "Digital" icon (below large picture) is lit orange.
    Don't select any of the Tamron lenses on the right unless the focal length range matches what you're after.
    Just drag the slider on the scale to the focal lengths you want to see demonstrated.
    If you're looking at wide angles, the third sample picture (instead of first) is more useful.

    If you are thinking of going to Full Frame, click the "35mm Film" icon (below large picture) to light that orange, which removes the 'compensation' for crop factor.
    Beware; this tool isn't much help for people considering 4/3 format; cameras by Olympus, Panasonic, Leica, Sigma, etc. unless you use the "35mm Film" option and double the focal lengths;
    e.g. an Olympus 14mm = 28mm on this tool with "35mm Film" lit orange.

    Hope that helps,
    Last edited by Dave Humphries; 11th September 2011 at 08:57 AM.

  6. #6
    Steaphany's Avatar
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    Re: Focal Length Comparison

    Quote Originally Posted by Dave Humphries View Post
    the subject of focal lengths is fraught with confusion, caused mainly by different sensor sizes.
    May I then suggest that the admins & coders here at CiC create a brand independent focal length to field of view comparison tool. Both the Tamron and Canon tools are there to encourage sales of the manufacturer's products. A CiC tool which allows selecting how any lens would work on any sensor/camera, with out manufacturer bias, would clear up most of the potential confusion, especially if the tool presented two images side by side to compare lens and sensor/camera models, or display the short and long views of a Zoom.

  7. #7
    Moderator Dave Humphries's Avatar
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    Re: Focal Length Comparison

    Quote Originally Posted by Steaphany View Post
    May I then suggest that the admins & coders here at CiC create a brand independent focal length to field of view comparison tool. Both the Tamron and Canon tools are there to encourage sales of the manufacturer's products. A CiC tool which allows selecting how any lens would work on any sensor/camera, with out manufacturer bias, would clear up most of the potential confusion, especially if the tool presented two images side by side to compare lens and sensor/camera models, or display the short and long views of a Zoom.
    Sounds like a great idea, but it is way beyond my skills.
    I do like your two views on different formats idea.

    I did some googling;

    I found this page; http://www.ophrysphotography.co.uk/p...ocallength.htm, which is better than the alternatives that give non overlaid example images.

    The there is also this one; http://lens-reviews.com/Technical-Ta...tion-tool.html, which does cope with different crop factors. Unfortunately the camera model list is way out of date and the range starts at 17mm and runs to 300mm on a bizarrely chosen image (for the prupose).

    For completeness, here's the Nikon version (10 - 600mm); http://imaging.nikon.com/lineup/lens/simulator/, it only deals with their DX and FX format combinations and is very slow to load (you'll see why when you use it and zoom into 600mm - lots of images are used). I actually find this one quite nice to use (after the wait).

    Cheers,

  8. #8
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    Re: Focal Length Comparison

    What I think is strange is that 1 70-200 F2.8 is 8 inches long, and another one is 10 inches long. Just seems funny to me. Although I am only a beginner and some of the explanations are a bit over my head.

    By the way...those links all help. COmpared to my 10 which is about 22mm...anything seems closer.
    Last edited by lizzy310; 13th September 2011 at 08:22 PM.

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