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09-04-2008, 09:12 PM   #121
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That's a nice tool,
thank you gavinhw

09-04-2008, 09:19 PM   #122
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QuoteOriginally posted by kojuo Quote
That's a nice tool,
thank you gavinhw

Thanks, but whatever you do, don't pick/look at the Canon 70-200L F4 IS lens, because if you pick a camera based on its lenses...
09-05-2008, 12:37 AM   #123
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so we got 2 buyers of this lens? and I assume both happy with there purchase...anymore? hoping to get it in 2 wks...
09-05-2008, 03:02 AM   #124
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QuoteOriginally posted by gavinhw Quote
For a comparison of the Sigma and Tamron 70-200mm's, check out this page.
Wow..... It's day and night in favor of Tamron

09-05-2008, 05:21 AM   #125
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QuoteOriginally posted by gkopeliadis Quote
Wow..... It's day and night in favor of Tamron
But not if you actualy compare the shipping HSMII against the Tamron rather than an out of production Sigma .

Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Review

And the same camera ;-))

Last edited by awaldram; 09-05-2008 at 05:30 AM.
09-05-2008, 06:22 AM   #126
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QuoteOriginally posted by awaldram Quote
But not if you actualy compare the shipping HSMII against the Tamron rather than an out of production Sigma .

Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Review

And the same camera ;-))
Still, in resolution Tamron outperforms hands down the Sigma on all focal lengths except 135mm.
On the CA field the wow stands in favor of the Tamron on all focal lengths.

...OR DO I MISINTERPRET THINGS?
09-05-2008, 06:39 AM   #127
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QuoteOriginally posted by gkopeliadis Quote
Still, in resolution Tamron outperforms hands down the Sigma on all focal lengths except 135mm.
On the CA field the wow stands in favor of the Tamron on all focal lengths.
My short summary:
- Tamron is sharper *when it's in focus* (random BF/FF issues w/ built-in motor that may or may not be in the Pentax version)
- possible bad copy at 135mm
- Tamron has better bokeh
- Sigma is faster and quieter because of HSM

If Tamron ever figures out how to do HSM and fixes that BF/FF problem, it'll be a no brainer...
09-05-2008, 06:45 AM   #128
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QuoteOriginally posted by kenyee Quote
... - possible bad copy at 135mm...
This 135mm issue is reported by every test.

09-05-2008, 10:11 AM   #129
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QuoteOriginally posted by gkopeliadis Quote
This 135mm issue is reported by every test.
What I have found strange in the above site tests is the Tamron at 135 F2.8 showed almost no CA while at F16 it was bad. The contrast is quite different from lenses to lenses and some selections made absolutly not sense while looking at the results. Some lenses are almost perfect at F2.8 but not acceptable at F10, what up with that. I would not trust these images. Either they were not properly loaded to the site or are linked to the wrong lenses. Play around with the settings and see for yourself.

CA is normal caused by curvature of the glass which required correction. By going from 2.8 to 10, one only changes the aperture blades taking the light from the center of the glass at slow F ration. Slow F ratio, ie F10, should always increase sharpness and reduce CA compared with F2.8. In the tests on this site the reverse is often seen. It does not make any sense therefore not to be trusted.
Am I wrong in my understanding?
09-06-2008, 08:40 AM   #130
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Its like a 200mm prime, that zooms.

The fact that Tamron has obviously sacrificed the middle end to make a superb long end pleases me greatly, I almost always use my zoom lenses at the extreme ends. And for a telephoto it is almost always at the long end.

At 200mm it is basically prime quality; her is a comparison to the Canon 200mm 2.8. Tamron 70-200mm f/2.8 Di LD (IF) Macro Lens Review

So I look at this lens at a 200mm prime that happens to have a shot end.
09-08-2008, 01:56 AM   #131
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QuoteOriginally posted by Denis Quote
...CA is normal caused by curvature of the glass which required correction. ...
CA is coused by the "glass" of the lens. Transparent meterials have different refraction index for different wavelengths. So a lens focuses different colors at diferent points.
See Wikipedia
09-08-2008, 02:06 AM   #132
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QuoteOriginally posted by gkopeliadis Quote
CA is coused by the "glass" of the lens. Transparent meterials have different refraction index for different wavelengths. So a lens focuses different colors at diferent points.
See Wikipedia
Isn't it also influenced by the camera itself? (I'm talking about modern DSLR cameras; not film SLRs)
09-08-2008, 02:21 AM   #133
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QuoteOriginally posted by ftpaddict Quote
Isn't it also influenced by the camera itself? (I'm talking about modern DSLR cameras; not film SLRs)
It influences all cameras, telescopes, microscopes etc.
DSLR cameras additionaly suffer from a kind of CA called Purple Frginging (here refered as PF)
09-08-2008, 02:10 PM   #134
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QuoteOriginally posted by blwnhr Quote
Shot with the new (Series 2) Sigma Macro (not Pentax mount, obviously). Focus is on the alloy between the 2 blue plates.

Full res shot is sharp as a tack. Reduced size image doesn't do it justice.

1/250, f/4, ISO-200, 82mm.

It's a nice pic, but nothing about it would address what I saw when trying to make up my mind by looking at samples on other mounts. I really wish I could find the page again with the comparisons as It was just some walk aorund the neighborhood and take some pics of the same things at the same settings. The DOF in your pic would hide most of the corner softness that bugged me.

It's not like either is awful, but there were enough pluses on the tamron side i didn't expect, and enough minuses on the sigma side i didn't expect, that I fugred I couldn't beat the $699 price and the in stock indicator and pulled the trigger.

For the record, the 135mm softness is there in my copy too, probably the biggest issue with it real world would be doing "macro" shots at that focal length.
09-09-2008, 08:14 AM   #135
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QuoteOriginally posted by blwnhr Quote
Shot with the new (Series 2) Sigma Macro (not Pentax mount, obviously). Focus is on the alloy between the 2 blue plates.
Full res shot is sharp as a tack. Reduced size image doesn't do it justice.
1/250, f/4, ISO-200, 82mm.
I can't draw any conclusions about border sharpness with this photograph.
One issue is that by the subject the borders are out of focus plane.
The other issue is that in order to judge you should have 1:1 crops of the borders.
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