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05-14-2016, 11:37 AM   #1
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Sigma 1.4x APO EX vs Sigma 1.4x APO EX DG teleconverters - quality image comparison?

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)

05-14-2016, 12:00 PM   #2
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As far as I know, your first explanation is (probably) the correct one because the same is true for the early generations of the Sigma 70-200 F2.8
05-14-2016, 12:27 PM   #3
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I have had both and have not seen any differences in performance. Sorry if this is not technical enough for you but it's all I can offer because now I only have one of them.
05-14-2016, 12:42 PM   #4
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Further to my first comment, the "DG" and "DC" suffices were introduced to allow the lenses for FF ("DG") and APS-C only ("DC") lenses to be easily distinguished from each other.

05-14-2016, 12:42 PM   #5
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QuoteOriginally posted by h_r_nobre Quote
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.

You will not help if [...]
You will not help if [...]
You will not help if [...]
You will not help if [...]
You will not help if [...]
You will not help if [...]


Thanks in advance for the careful reading about what is the question here (just to remember: ONLY image quality comparison between [...]
IS THIS FOR REAL ??? You know, new member, I have about zero interest in going through all your hoops to help you...

Last edited by fwcetus; 05-14-2016 at 12:48 PM.
05-14-2016, 01:06 PM   #6
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fwcetus

IMHO, that is a grossly unfair thing to say to anyone - especially a newbie! - who is asking a perfectly reasonable question about something of which he does not know very much.

If you have "zero interest" then why comment AT ALL?
05-14-2016, 01:36 PM   #7
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QuoteOriginally posted by jeallen01 Quote
fwcetus

IMHO, that is a grossly unfair thing to say to anyone - especially a newbie! - who is asking a perfectly reasonable question about something of which he does not know very much.

If you have "zero interest" then why comment AT ALL?
Did you find OP's "you will not help if..." gibberish acceptable as a start to a normal conversation? The OP comes across like some crown prosecutor, not at all like someone looking for advise. With so many demanding exceptions in his/her question, the OP should bloody well get the two TCs in question and compare them himself/herself!
05-14-2016, 02:21 PM   #8
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It has to be said that, on reflection, excanonfd does have a point about the OP's original post - but also that one of the basic points is that the OP's question was quite valid, and some of us gave our honest views.

OTOH, the OP should learn not be as "specific" (!) in future about the replies that he/she would like to see posted - we have all made errors ( I certainly have !) but that he/she (whatever) needs to understand that people on this forum give their best advice that they can (fwcetus excepted!).

05-14-2016, 02:39 PM   #9
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Why all the specifications and test on these two TC,s, they are not a great TC going by the reviews on the forum, it would be no advantage it seems or is there some reasoning behind this. I have the DG convertor, if the OP wants to send me the other TC, I will do a comparison/test.

Last edited by gmans; 05-14-2016 at 02:44 PM.
05-14-2016, 02:52 PM   #10
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gmans

In my experience, the 1.4x DG is actually quite a good TC - I have been using one for quite a few years with the 70-200 f2.8 "non" DG and the 100-300 f.4.0 DG on a K-5 and K-3, i.e. I have used and commented on it with experience, not on the basis of " the reviews on the forum" - but maybe you have a poor copy (or poor copies of the lenses with which you used it - they do vary, as I have found before, and after, my 100-300 f4.0 was serviced and fixed)?.

Therefore, unless the Overwhelming forum view is that something is "not good", then I suggest that you refrain from using "third party evidence" as one of the things on which to base "subjective" comments.

BTW: the 1.4x DG is OK but the 2.0X DG is another matter - that's why I got rid of mine.

Finally, virtually all TC's are compromises between increased focal length and degraded IQ - some are good but many are poor, but I don't put the 1.4X DG in the latter category.

Last edited by jeallen01; 05-14-2016 at 03:00 PM.
05-14-2016, 03:05 PM   #11
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QuoteOriginally posted by jeallen01 Quote
gmans

In my experience, the 1.4x DG is actually quite a good TC

BTW: the 1.4x DG is OK but the 2.0X DG is another matter - that's why I got rid of mine.
yes and yes
05-14-2016, 03:07 PM   #12
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QuoteOriginally posted by jeallen01 Quote
gmans

In my experience, the 1.4x DG is actually quite a good TC - I have been using one for quite a few years with the 70-200 f2.8 "non" DG and the 100-300 f.4.0 DG on a K-5 and K-3, i.e. I have used and commented on it with experience, not on the basis of " the reviews on the forum" - but maybe you have a poor copy (or poor copies of the lenses with which you used it - they do vary, as I have found before, and after, my 100-300 f4.0 was serviced and fixed)?.

Therefore, unless the Overwhelming forum view is that something is "not good", then I suggest that you refrain from using "third party evidence" as one of the things on which to base "subjective" comments.

BTW: the 1.4x DG is OK but the 2.0X DG is another matter - that's why I got rid of mine.

Finally, virtually all TC's are compromises between increased focal length and degraded IQ - some are good but many are poor, but I don't put the 1.4X DG in the latter category.
No worries mate, I said going by the reviews (there is better TC,s so it's not a grate TC) and i am quite happy with mine excepting it does not have a connection to my 70-200. By the way read my signature footnote and refrain from telling me what I can and can't do.
05-14-2016, 03:56 PM   #13
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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.
05-14-2016, 04:05 PM   #14
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QuoteOriginally posted by h_r_nobre Quote
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.
Fair enough mate, the specifications of your question was a bit tough to meet that is all, the DG is not to bad and I use it on the FA300 4.5 with a little degradation to the lens/image. But that is only my opinion and experience with its use. Any way hope this helps some what and welcome to the forum.
05-16-2016, 04:15 AM   #15
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QuoteOriginally posted by h_r_nobre Quote
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.
I think the problem with your post is that it is unlikely that any one has both TCs it might have been better to see if there are local to you members and arrange a get together to do the shots.

The other thing is that the sigma TCs are specific. To a few lenses, not intended for general use. The front element protrudes out about 10-12 mm into the rear of the lens, it is only recommended for long and fast sigmas (and due to legacy some older long and fast Pentax lenses)

I think you will find that optically there is no difference between the eX and EX DG products except the possibility of a coating on th rear element. It has never been a issue for me, as I have used the 1.4x for 13 years on 4 different Pentax DSLRs

My 2x TC is the EX DG version, but that is simply a matter of purchasing it long after I got my 70-200/2.8EX (no DG on lens either)

Both the 1.4 and 2 X give excellent results with my lens especially at the long end wher they get used the most.
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