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02-18-2017, 07:56 AM   #1
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Anyone tried the Sigma 10-20mm f/4.5-5.6 + HD 1.4x Converter on K-1?

I've seen a couple test shots on a Canon 5dII with a Kenko 1.4x converter and this lens (they dubbed the Wigma -- Wide Sigma. As opposed to the 50-500 Bigma haha).

It looked decent enough with no discernible vignetting. But I'm wondering, specifically, how the HD 1.4x converter with this lens on the 36MP K-1 handles?

The Wigma essentially becomes a 14-28 if it fares well. Anyone willing to post a few test shots? I'm especially interested in edge (sharpness) and vignetting performance

02-18-2017, 08:19 AM   #2
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Forgive me if I'm a bit dense but what exactly is the point of making a wide angle lens less wide angle with a tc?
02-18-2017, 09:15 AM   #3
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QuoteOriginally posted by marcusBMG Quote
Forgive me if I'm a bit dense but what exactly is the point of making a wide angle lens less wide angle with a tc?
No, you're not dense - unless you have had good reason to do such a thing it certainly doesn't sound like a smart thing to do!

Regarding the 10-20 zoom, I have not tried the Sigma/K1 combo. But, I do regularly use a 1.4x rear converter A with my DA 10-17 and my z70 film body. With the obvious exception of losing AF, it works fabulously to give me a full-frame 14-24 fisheye with full control of the aperture. I don't know if all FF TCs will work in such a manner, but it would be useful with a number of crop-sensor lenses.
02-18-2017, 09:32 AM   #4
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QuoteOriginally posted by marcusBMG Quote
Forgive me if I'm a bit dense but what exactly is the point of making a wide angle lens less wide angle with a tc?
It takes a crop lens and removes the vignetting on full frame mostly. Makes for a cheap mans ff ultrawide.

Now back to the topic.. does anyone have any shots on K-1 with this setup?

02-18-2017, 11:13 AM   #5
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Search out posts by Kengoh in the K1 images thread. He regularly uses a Sigma 10-20 on his K1 in FF mode.
02-18-2017, 11:17 AM   #6
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Anyone tried this technique with the DA15?
02-18-2017, 11:42 AM   #7
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I rented the 1.4TC last week and used it on the K1 and it vignettes a lot, it's not full frame. I'm not sure how it would turn a apsc lens to a cheap man's ff lens.

I have the Sigma lens also to bad you didn't post this question last week I would've tried it out. I never thought of putting a TC on a wide lens.

02-18-2017, 11:57 AM   #8
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QuoteOriginally posted by WPRESTO Quote
Search out posts by Kengoh in the K1 images thread. He regularly uses a Sigma 10-20 on his K1 in FF mode.
He doesn't use the teleconverter with it. Instead he crops the vignetting out, resulting in around a 24MP file. That's nice (and I might end up doing this) but its different from what I'm asking.

---------- Post added 02-18-17 at 12:59 PM ----------

QuoteOriginally posted by KiloHotelphoto Quote
I rented the 1.4TC last week and used it on the K1 and it vignettes a lot, it's not full frame. I'm not sure how it would turn a apsc lens to a cheap man's ff lens.

I have the Sigma lens also to bad you didn't post this question last week I would've tried it out. I never thought of putting a TC on a wide lens.
It works with the crop 50-135mm on K-1 in this way. There are several sample shots on the forums.


But can we please stay on topic. I don't want this thread turning into 'this is impossible/dont know how it would work/ havent tried it' versus 'here are the results' and letting us decide individually.
02-26-2017, 04:57 PM   #9
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*bump*

Someone has this camera, lens, and converter combination and is willing to try?
02-27-2017, 12:47 AM   #10
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QuoteOriginally posted by mee Quote
I've seen a couple test shots on a Canon 5dII with a Kenko 1.4x converter and this lens (they dubbed the Wigma -- Wide Sigma. As opposed to the 50-500 Bigma haha).

It looked decent enough with no discernible vignetting. But I'm wondering, specifically, how the HD 1.4x converter with this lens on the 36MP K-1 handles?

The Wigma essentially becomes a 14-28 if it fares well. Anyone willing to post a few test shots? I'm especially interested in edge (sharpness) and vignetting performance
Although... not the exact configuration. My 'poor mans 15-30' is my Kenko(Tamron) 1.5x Pz-AF and my 10-20 F4-5.6EX.

Just put it on my K-1. Works fine FF. Corners ok/no dark corners. Haven't really made testshots to qualify yet.
02-27-2017, 04:05 PM   #11
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QuoteOriginally posted by photocles Quote
But, I do regularly use a 1.4x rear converter A with my DA 10-17 and my z70 film body. With the obvious exception of losing AF, it works fabulously to give me a full-frame 14-24 fisheye with full control of the aperture.

I also use the DA10-17 on FF but without a TC. The angle of view at 10mm on APS-C is the same as 15mm on FF, except at 15mm it covers the whole sensor. (You can actually get a bit more than 10mm on APS-C at around 14.5mm on FF.) So for me it's a 15-17mm FE zoom with AF, and if I want 17-25 I can crop. It all depends what you want out of the lens of course.
02-27-2017, 04:07 PM   #12
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I have Sigma 10-20 3.5 and Pentax DA HD 1.4x. When I get home I'll try it and post pictures. Don't expect too good a result as I can confirm both DA*200 and DFA 150-450 both vignette severely with the 1.4 TC. However, the wide-angle may have a better ray angle through the TC and get less vignetting. Proof is in the photo! TBC...

Below is Sigma 10-20 F3.5 at 16mm without any TC, no corrections - straight export to jpg from raw in Lightroom:
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02-28-2017, 06:56 AM   #13
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I hope we see a 1.5x converter from Pentax/Ricoh in the near future; WR included��������
02-28-2017, 08:29 AM   #14
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I have the Sigma 10-20 but not that teleconverter. I do have an old film Tamron 2x teleconverter somewhere. Might be an interesting test to play with.
02-28-2017, 07:49 PM   #15
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QuoteOriginally posted by phoebus Quote
I have Sigma 10-20 3.5 and Pentax DA HD 1.4x. When I get home I'll try it and post pictures. Don't expect too good a result as I can confirm both DA*200 and DFA 150-450 both vignette severely with the 1.4 TC. However, the wide-angle may have a better ray angle through the TC and get less vignetting. Proof is in the photo! TBC...

Below is Sigma 10-20 F3.5 at 16mm without any TC, no corrections - straight export to jpg from raw in Lightroom:
That's interesting.. thanks for that. It looks like the corners are really poor... the vignetting I can handle (as it isn't really that bad to me) but the softness is something I cannot handle. That's too bad.


I appreciate the example!!

---------- Post added 02-28-17 at 08:53 PM ----------

QuoteOriginally posted by Sweets Quote
I hope we see a 1.5x converter from Pentax/Ricoh in the near future; WR included��������
A 1.4/1.5x AW converter would be nice for Full Frame to use on K-1. I can only imagine the price it would cost considering the outrageous markup on the DA 1.4x for crop.

Considering how constrained Ricoh Imaging seems to be (likely as a result of Ricoh corporate), I suspect if they do launch one it wont be for another couple of years.

The issue with converters is people buy them to extend the range (and life) of their current (already paid for) lenses. And Pentax is in the situation of wanting (needing?) to sell us brand new lenses.
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