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01-05-2008, 08:36 AM   #1
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wierd stuff

So this past week, i finally got to use the K10d again (along w/ 2 new lenses 10-17 fish, and 50-135DA*) all was hunky dory, great shots on both lenses (plus the sigma 28 f/1.8) . I'll post some shots once i get them sorted. anyway, when i was emptying out my card to my laptop after day 1, i noticed my file name changed from "IMGPxxxx" to "_IGPxxxx" (x=shot number)

i didnt change anything on the settings or what not.

also, yesterday I was playing around w/ a sigma lens i just got for cheap (NIB too) and the min aperture is f/22, but when i was setting it on the camera, it was going all the way down to f/32. I Mounted another sigma lens, same thing...f/32, then i mounted on the "kit" f/27

the times i did go out, it was out on really cold weather (teens) and frequent lens changing...

my shots are still coming ok, no big IQ issues (unless I fudge it up)

thoughts?...

01-05-2008, 08:58 AM   #2
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I think - and I'm not sure, it's been a long time since I shot JPEG - IMGP is used for RAW file captures, and _IGP is for JPEG file captures.

Try flicking between the two and checking this.
01-05-2008, 09:08 AM   #3
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_IGP is for the AdobeRGB, _IMPG is for sRGB.
01-05-2008, 09:38 AM   #4
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On the min. aperture issue: For many zoom lenses, the min. aperture changes with the focal length. Perhaps that's what you observed.

01-05-2008, 03:28 PM   #5
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QuoteOriginally posted by Jodokast96 Quote
_IGP is for the AdobeRGB, _IMPG is for sRGB.
YES! thanks. I did go from sRGB to Adobe RGB...
01-05-2008, 03:29 PM   #6
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QuoteOriginally posted by Ole Quote
On the min. aperture issue: For many zoom lenses, the min. aperture changes with the focal length. Perhaps that's what you observed.

that be max opening...which is f/3.5 on the short end, and f/5.6 on the long end.
and no.......the aperture ring on the 2 sigma lenses go up to f/22, but again...in Av and M mode, i can set it up to way past that
01-05-2008, 03:44 PM   #7
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it's the color space in the camera that does this...

QuoteOriginally posted by Jodokast96 Quote
_IGP is for the AdobeRGB, _IMPG is for sRGB.
His post is correct, nothing else to add...
01-06-2008, 03:44 AM   #8
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The min and max aperture of a zoom lens changes with it's focal length; except for constant aperture zooms.

Take my Sigma 17-70mm F2.8-4.5 lens for example. The minimum specified aperture is F22, but this listed min aperture is for the wide end only.

So,
At 17mm, the max aperture is F2.8, and the min is F22 (as specified)
At 70mm, the max aperture is F4.5 but the min goes all the way to F40

i.e. at the long end, it loses 1 1/3 stops

01-06-2008, 08:38 AM   #9
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QuoteOriginally posted by pop4 Quote
The min and max aperture of a zoom lens changes with it's focal length; except for constant aperture zooms.

Take my Sigma 17-70mm F2.8-4.5 lens for example. The minimum specified aperture is F22, but this listed min aperture is for the wide end only.

So,
At 17mm, the max aperture is F2.8, and the min is F22 (as specified)
At 70mm, the max aperture is F4.5 but the min goes all the way to F40

i.e. at the long end, it loses 1 1/3 stops

yes yes I see it now. I thought it only worked on the short end, and not the long end. it's been a while since i really used zooms, and even longer since i've stopped down to all the way to that low
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