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Old Jun 22, 2010, 6:38 AM   #11
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Why are you comparing it to a film camera? The TZ5 is not a film camera.

I understand what you mean about the 'X' values, and I don't care about them. 140mm is so-and-so away from me and 280mm is twice as far. So basically, I just care about the actual distance, not the zoom amount.
Why the argumentative tone in your responses to me? I tried to be civil with my responses. This will be my last post to you ever so not to worry.

From your response you don't have a clue as to what crop factor, focal lengths and zoom values are. Your ZS5's 280mm at max zoom is NOT twice as far as the GH1's 140mm at max zoom is as you put it. Both are 280mm at max zoom in 35mm film terms (which means a film camera). I won't try to explain it further.

Good luck with your T2i and sorry I tried to help out,
Sky

Last edited by skylark; Jun 22, 2010 at 7:03 AM.
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Old Jun 22, 2010, 11:24 PM   #12
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Why the argumentative tone in your responses to me? I tried to be civil with my responses. This will be my last post to you ever so not to worry.

From your response you don't have a clue as to what crop factor, focal lengths and zoom values are. Your ZS5's 280mm at max zoom is NOT twice as far as the GH1's 140mm at max zoom is as you put it. Both are 280mm at max zoom in 35mm film terms (which means a film camera). I won't try to explain it further.

Good luck with your T2i and sorry I tried to help out,
Sky
Sorry, I'm just upset about getting so few replies. I feel jinxed.

I'd really appreciate it if you could explain how 140mm=280mm.
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Old Jun 23, 2010, 5:14 AM   #13
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Sorry, I'm just upset about getting so few replies. I feel jinxed.

I'd really appreciate it if you could explain how 140mm=280mm.
Track,

Guess we both had bad days. I’m sorry as well. Lets forget our misunderstanding and go on from here.

Why 140mm can be equivalent to 280mm? Basically it’s because of the inconsistent ways manufacturers refer to their lens’ focal lengths.

For your TZ5, the zoom is listed as 28-280mm. Those focal lengths are the 35mm film equivalent focal lengths. This is common for cameras with non removable lenses. The camera manufacturer does the “35mm film equivalent” conversion so the public doesn’t have to.

The GH1 on the other hand, usually has it’s supplied zoom lens listed as 14-140mm. This is common for removable lenses. When that lens is installed on a GH1, a phenomena known as “crop factor” comes into play. The GH1 has a crop factor of 2 so the 14-140mm lens is equivalent to 28-280mm in 35mm film equivalent focal lengths. --- Note that “if” this lens could be installed on a different camera with a different crop factor, then it would have different 35mm equivalent focal lengths. That’s why the lens is not listed as a 28-280mm lens. It all depends on which camera it’s mounted on.

The end result is that the zoom focal lengths on a GH1 are the same as on your TZ5. With both mounted on the same tripod in turn, both would capture the same size images at wide and at full zoom for practical purposes.

To understand what crop factor is, one needs to understand what “focal length” is. Here’s a link to a wikipedia explanation of focal length. Scroll down to the “In Photography” section.

http://en.wikipedia.org/wiki/Focal_length


Once you have a handle on focal lengths, read what “crop factor” means. Here’s two links to crop factor:

http://en.wikipedia.org/wiki/Crop_factor


This second link to crop factor might be easier to understand: (Not sure why the clickable link won't work so copy and paste the following url and replace the " dot " com with a period.)

http://www.digitalcamerareview dot com/default.asp?newsID=3611



Note that your TZ5 also has a crop factor and it’s larger than the GH1’s crop factor since the TZ5 has a smaller sensor. It’s just that Panasonic lists the 35mm equivalent focal lengths since the lens is not removable so it saves us from having to do the conversion. Also note that the GH1 lens is usually listed as 14-140mm with (35mm film equivalent: 28-280mm) in parenthesis as in this bhphotovideo listing: (click on the specification tab and scroll down to “Optics”.)

http://www.bhphotovideo.com/c/produc...ra.html#Optics


If you have any questions, please post them and I’m sure someone will be glad to answer.

Best regards,
Sky

Last edited by skylark; Jun 23, 2010 at 5:58 AM.
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