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Old Aug 29, 2007, 10:30 AM   #1
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I took some pictures that some asked about, so I was looking at the exif data for it and had a question. The photo I took was at full optical zoom, which with my camera is 12x or 432mm (right?). But in the exif data, it says that the focal length was 70mm. I'm confused.... please help clarify this for me. THANK YOU!!
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Old Aug 29, 2007, 10:47 AM   #2
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amy129 wrote:
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I took some pictures that some asked about, so I was looking at the exif data for it and had a question. The photo I took was at full optical zoom, which with my camera is 12x or 432mm (right?). But in the exif data, it says that the focal length was 70mm. I'm confused.... please help clarify this for me. THANK YOU!!
I guess, 70mm is the actual physical focal length for the 1/1.8" CCD, but the 432mm means "normalized" to Full-Frame 35mm film scale i.e. a crop-factor of roughly 6X

You may read the EXIF more carefully and maybe the 432mm figure is hidden somewhere,


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Old Aug 29, 2007, 11:27 AM   #3
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Amy and Big Potato-

Can I offer a bit of help. The focal length of 36mm to 432mm is the focal length of the Z-712 camera expressed in 35mm terms. Please remember that the size of the 35mm image is 24mm X 36mm, or roughly an inch by one and one half inches. Because the size of the imager used on the Z-712 is many times smaller than that 35mm image, every thing can be reduced in size. Thus, the camera is smaller, a much smaller lens can be used, and still produce equal results, etc.

The exif date is expressing the focal length of your particular lens for that particular photo. It is not expressing the focal length of that lens in equivalent 35mm terms.

if the Z-712 camera were built to 35mm sizes, it would be roughly 4 times larger in physical size and of course it would also weigh 4 time more than it does.

Sarah Joyce


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Old Aug 29, 2007, 3:27 PM   #4
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Thank you... that makes sense with the difference with 35mm.

So when someone asks how far I was zoomed out for a particular shot, what do I say? All the way with my 12x zoom or 70mm or what?




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Old Aug 29, 2007, 3:29 PM   #5
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Thank you... I couldn't find it, but that doesn't mean it's not there and I'm just looking in the wrong place. :-) I just want to know if I'm able to tell other's how far I was zoomed out for a photo. No biggie really... I'd just like to be able to know that.
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Old Aug 29, 2007, 4:16 PM   #6
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big_potato is right. In all the EXIF data I've seen both the actual (70mm) and effective (432mm) info has been there. In each case the effective info has been further down.

That said, there are different programs to display EXIF data and some give more complete info than others.
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Old Aug 29, 2007, 6:13 PM   #7
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IrfanView gives both the actual and the equivalent focal lengths when viewing the EXIF data for my Z612 so Kodak does include both in the EXIF. Different EXIF viewers may pick up different data elements. I think most of us with P&S cameras (including superzooms) use the 35mm equivalent focal lengths as frame of reference while DSLR users tend to use actual focal lengths and assume the reader knows the multipication factor for that particular camera.
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Old Aug 29, 2007, 8:15 PM   #8
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I've been using ACDSee since day-1 I knew about EXIF,

and has been seeing 2 vers of focal lengths all the time.

So I knew what Amy meant.
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Old Aug 29, 2007, 8:34 PM   #9
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I use Irfanview but didn't know the exif info was available through that. THANK YOU!!! Very helpful.
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