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03-16-2018, 02:36 PM   #61
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QuoteOriginally posted by Kombivan Quote
so lets hope the adding of a pentax x converter doesn't mess with the exposures of images like some of the others on the market do.
I've got both Tamron 1.4 and Pentax 1.4 TCs, neither do anything to my exposures.





03-16-2018, 05:02 PM   #62
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QuoteOriginally posted by clackers Quote
I've got both Tamron 1.4 and Pentax 1.4 TCs, neither do anything to my exposures.
I wouldn't use the phrase 'messing with the exposure'. All any TC's do, in relation to exposure, is steal some light, of course. But it's a constant.

I have 4 TC's (Pentax DA AF REAR CONVERTER 1.4X AW, Kenko P-AF 1.4X TELEPLUS MC4 DG, Kenko Pz-AF 1.5X TELEPLUS SHQ, Pentax REAR CONVERTER-A 2X-S). All have their quirks.

If any new Pentax FF TC is able to match or exceed the quality of the DA 1.4, it will be a very good TC.
03-16-2018, 09:51 PM   #63
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You can laugh and have your comments but the thing is you'll remember my post's when it's your turn to cop it from a af converter. Mine was a sigma 1.4x don't see any sigma's above. it may have also happened buy going from one converter to another. Not only that the 107v firmware upgrade is for problems with x converters.
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03-16-2018, 10:00 PM   #64
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Hopefully a 1.7x. But in the end what ever it is I'll be getting one.

03-17-2018, 01:38 AM - 3 Likes   #65
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QuoteOriginally posted by Kombivan Quote
You can laugh and have your comments but the thing is you'll remember my post's when it's your turn to cop it from a af converter. Mine was a sigma 1.4x don't see any sigma's above. it may have also happened buy going from one converter to another. Not only that the 107v firmware upgrade is for problems with x converters.
Why would you even think that a Pentax converter might do anything of the kind? Compatibility problems are not unheard of with Sigma products.
03-17-2018, 02:50 AM - 1 Like   #66
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QuoteOriginally posted by Kombivan Quote
You can laugh and have your comments but the thing is you'll remember my post's when it's your turn to cop it from a af converter. Mine was a sigma 1.4x don't see any sigma's above. it may have also happened buy going from one converter to another. Not only that the 107v firmware upgrade is for problems with x converters.
I don't think anyone is laughing. With respect, though, it's highly unusual to have exposure problems caused by a TC - in fact, it's the first time I've come across this personally, and if it was a general problem with that converter and body combo, we'd have heard about it long before now given how long both items of equipment have been around.

If you've proven the TC is causing the problem through repeatable, controlled-environment A/B testing using the same settings both with and without the TC, and you've absolutely ruled out user error by your test method, then there must be some kind of fault with that particular copy of the Sigma converter. It could be as simple as contacts that need cleaning, or it could be a hardware or firmware issue.

The K-5 v1.07 firmware update from 2014 was specifically in relation to the HD DA 1.4x AW rear converter, which was released that year. The update didn't have anything to do with exposure problems so far as I know, and wasn't relevant to other tele-converters.

Last edited by BigMackCam; 03-17-2018 at 03:07 AM.
03-17-2018, 03:02 AM   #67
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QuoteOriginally posted by BigMackCam Quote
I don't think anyone is laughing. With respect, though, it's very unusual to have exposure problems caused by a TC - in fact, it's the first time I've come across this personally, and if it was a general problem with that converter and body combo, we'd have heard about it long before now given how long both items of equipment have been around.

If you've proven the TC is causing the problem through repeatable, controlled environment A/B testing in (M)anual mode using the same settings both with and without the TC, and you've absolutely ruled out user error by your test method, then there must be some kind of fault with that particular unit. It could be as simple as contacts that need cleaning, or it could be a hardware or firmware issue.

The K-5 v1.07 firmware update from 2014 was specifically in relation to the HD DA 1.4x AW rear converter, which was released that year. The update didn't have anything to do with exposure problems so far as I know, and wasn't relevant to other tele-converters.
I use a 1.4x TC on another brand. It’s no thicker than a pack of playing cards, works seamlessly and has only a very small impact on IQ with a one stop penalty. No exposure issues. Considering how small these converters are but how much extra focal length is achieved, they strike me as a excellent buy. But quality is the key, I think. I imagine a cheapo third-party one might be beer glasses all round. A new quality one from Ricoh in the near future would surely be a pop move.
03-17-2018, 03:28 AM   #68
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Also, as with all teleconverters, there are restrictions on which lenses can and can't be used with any particular make and model.
Not all lenses are compatible with being used with a TC..

03-17-2018, 04:20 AM   #69
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QuoteOriginally posted by Kombivan Quote
sigma 1.4x
Which one?....theres a few.
03-17-2018, 05:32 AM   #70
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FF TC would be nice in general, but it would be nice to see dedicated lenses being presented with the TC. Currently DA 200/300, D-Fa 70-200 and maybe the 2.8/100 macro will provide useful results with 1.4x TC, 2x TC is possible, but image quality will suffer and DA 300 will have an effecteiv f/8 - not something your AF system really appreciates. Recently some nice tele lens TC combos were released by PanaLeica and Olympus. Pentax had dedicated TCs for long A* glass before. Although I don't see remakes of of tele glass from Pentax, it would be nice in combination with new TC(s).
All the discussion on Tamron and Sigma TCs is only based on the lack of decent Pentax TCs for the longest time.
03-17-2018, 06:21 AM - 1 Like   #71
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There's a page somewhere, where Sigma tells you which converters work with which lenses. I researched it briefly hoping for a converter for my 70-300. They don't make one for it, and given the IQ, that's a good thing.

I use converters fro two reason, to extend long lenses and to increase the enlargement ratio of my macro lenses. I'm not actually in favour of uses like sticking one on 50 1.7 to make it a 70. Much of the negative opinions of TCs come from people who use them in away they were't really designed to be used.

With my limited knowledge of optics, I would assume that it's much harder to design a TC to cover a wide field of view, than the much more arrow field of view of a telephoto.

SO, unless you've read the Sigma site and your lens has been certified by Sigma as being acceptable for the lens you use it on, you probably just have in incomparable lens.

Last edited by normhead; 03-17-2018 at 07:19 AM.
03-17-2018, 06:29 AM - 1 Like   #72
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QuoteOriginally posted by normhead Quote
There's a page somewhere, where Sigma tells you which converters work with which lenses.
That page is here: Lenses | Sigma Corporation of America

Scroll down to the section titled "APO 1.4X EX DG TELECONVERTER/ APO 2.0X EX DG TELECONVERTER". The first table shows compatibility with current lenses, the second with discontinued lenses
03-17-2018, 12:29 PM   #73
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In the lens review section theres reports on many TCs...That Sigma chart only shows the most recent two,there are older AF TCs that are fine with all K mounts.
03-17-2018, 12:55 PM   #74
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QuoteOriginally posted by surfar Quote
In the lens review section theres reports on many TCs...That Sigma chart only shows the most recent two,there are older AF TCs that are fine with all K mounts.
The first table on that page is for the latest ("NEW") 1.4x and 2x TCs... the second table that I referred to is for the two older equivalent models. I guess there are other even older Sigma TCs not listed here, but the important thing here - I think - is the lenses that are shown to be compatible for the previous generation 1.4x and 2x TCs.
03-17-2018, 02:31 PM   #75
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QuoteOriginally posted by Paul the Sunman Quote
Given the dearth of modern extreme telephoto options available for K-mount, a FF TC would be extremely welcome to pair with the DFA 150-450. Indeed, I'd say it's a necessity to value-add to the current DFA lineup, and I'm surprised it wasn't a priority.

Like others, I don't imagine that a FF TC would be technically the most challenging task on Pentax's plate, but I don't know that for sure. Let's hope we see it sooner rather than later.
I was sort of tauht in the old school---to keep your TC's away from zooms on the theory that the zooming had already pushed the optics to the limits but I have a really nice FA 300 f 2.8 and an FA 600 that would
appreciate the FA feature added I have the older manual ones.
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