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Forum: Pentax SLR Lens Discussion
05-14-2016, 03:56 PM
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I thank all you about your posts. I suppose this is a free virtual place in a free country where I can express myself within the law and civility respecting the PentaxForums rules. Just to clarify, all that limitations were to avoid the posts discuss irrelevants things about the original question trying thus a line as direct as possible to an eventual answer, what would be good to all with interest on the original question.
A special thanks to jeallen01.
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Forum: Pentax SLR Lens Discussion
05-14-2016, 11:37 AM
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Hi !
I'm looking for image quality comparisons (sharpness, distortion, chromatic aberration etc) between Sigma 1.4x APO EX vs Sigma 1.4x APO EX DG.
The comparison must have the same camera, the same lens(es), the same apertures, the same ISO, the same subject in the same position, the same crop factor, the same day or night, the same hour of the day or of the night, the same place, the same tripod (if anyone) etc. It should be pretty obvious but I have seen one or another image quality comparison of apples to oranges here at PentaxForums, so I prefer to reinforce these points. In other words, everything must be the same except the teleconverters.
Please, pay attention: ONLY Sigma 1.4x APO EX vs Sigma 1.4x APO EX DG image quality comparisons.
It's acceptable if these teleconverters are together in a comparison with more teleconverters.
You will not help if you give your opinion about just one of them (comparison means two or more),
You will not help if you say about photographic technique with one of them or with both (remember: image quality comparison, not how to use).
You will not help if you say about another teleconverter and only one of them (they must be present together in any comparison).
You will not help if you say that one is better than the other without technical basis (sorry, no subjective opinions).
You will not help if you say that one of them is better with a certain lens than with another lens (the comparison must be between the teleconverters, not between the lenses)
You will not help if you say that teleconverters increase the flaws of the lens in addition to include their owns (I know that).
I did the homework and I found these on PentaxForums:
SIGMA APO 1.4x EX Teleconverter Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database
"Similar in construction and physical parameters to the APO 1.4x EX DG but released prior to optimized coatings for digital cameras."
Sigma 1.4x DG EX APO Teleconverter Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database
"SIGMA EX APO DG Tele Converter. The DG means optimised for digital, but it is very similar to it's predecessor the Sigma EX APO 1.4x."
Someone else had the same curiosity five years ago, but the point was lost among several others irrelevant things discussed:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/164050-help...f-x1-4-tc.html
(Moderators: please change the place of this question if you better judge to join this one with that from 2011, above).
Thanks in advance for the careful reading about what is the question here (just to remember: ONLY image quality comparison between Sigma 1.4x APO EX vs Sigma 1.4x APO EX DG)
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Forum: Sold Items
05-12-2016, 11:01 AM
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Hi !
DPreview says:
"Conclusion - Cons: Needs detailed AF microadjustment for best results";
"Inconsistent autofocus in difficult conditions even after microadjustment."
"...we've only used the Canon mount version of the lens - it's possible other versions may work better."
Have you ever experienced the same or similar AF problems with your copy in Pentax-mount?
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Forum: Sold Items
05-08-2016, 09:14 AM
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Near to that lens my Sigma AF 400mm f/5.6 APO Tele Macro is just little and weak as a newborn. If I could I would buy that 400mm f/2.8, but I could only pay in easy installments.. :-)
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Forum: Sold Items
05-08-2016, 06:14 AM
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Forum: Sold Items
05-04-2016, 08:48 PM
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PM sent
---------- Post added 05-05-16 at 12:32 PM ----------
Just checking: is this the Pentax-mount version?
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Forum: Sold Items
05-04-2016, 08:15 PM
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Forum: Sold Items
05-04-2016, 04:37 PM
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Forum: Sold Items
05-04-2016, 04:16 PM
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Forum: Pentax K-1 & K-1 II
05-04-2016, 04:55 AM
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Thank you all for the information and suggestions.
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Forum: Pentax K-1 & K-1 II
05-03-2016, 08:01 PM
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Do you know the size limit for card capacity and write speed in K3? I didn't find it in the manual.
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Forum: Sold Items
05-01-2016, 10:24 PM
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 | For Sale - Sold: AF Lenses, F, FA, FAJ, DA, No Primes Currently, 12 Zooms, 16mm-300mm, Sigma, Tamron
Posted By
h_r_nobre |
Replies: 92
Views: 33,483
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Forum: Sold Items
04-30-2016, 02:47 PM
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Forum: Sold Items
04-30-2016, 01:47 PM
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I sent you a private message.
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Forum: Sold Items
03-24-2012, 06:38 AM
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Hi !
Is the current price US550,00 or lower?
How much the costs to send it to Brazil by international mail?
Thanks.
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Forum: Sold Items
03-24-2012, 05:22 AM
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Hi !
The lens was sold? I'm in Brazil.
I would like to buy the lens if you can send it to Brazil.
Thank you.
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Forum: Welcomes and Introductions
10-15-2009, 03:45 AM
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Hi alsterling !
Interesting story. I already went to Brasilia, Goiania and Uberlandia many years ago. If you need something from Belo Horizonte, tell me.
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Forum: Pentax SLR Lens Discussion
10-14-2009, 07:04 PM
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Private message sent on the Pentax 2X-L rear converter-a.
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Forum: Welcomes and Introductions
10-04-2009, 08:25 AM
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Just a few words. I'm a biologist from Belo Horizonte, MG, Brazil. I'm new here. I'm glad to have found this forum. Let's share our experiences and help each other. Thanks in advance.
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