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12-26-2010, 12:39 PM   #1
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Teleconvertor use on K5

Hi, buddies. One question:

Anybody ever tried this match on K5: PENTAX SMC 1.7X AF ADAPTER with Sigma APO 150-500mm f/5-6.3 DG OS HSM ? If so, how about the performance?

It's so hard to get the clear info about this in my city. Many thx.

12-26-2010, 08:17 PM   #2
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Azure, I liked your city a lot when I was there. Nice spot.

For the TC. I don't know the image quality of this combo. But I guess AF would not work anymore because the effective aperture (f/8.5 -f/11) is too small.
12-27-2010, 01:45 AM   #3
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QuoteOriginally posted by azure_sun Quote
Hi, buddies. One question:

Anybody ever tried this match on K5: PENTAX SMC 1.7X AF ADAPTER with Sigma APO 150-500mm f/5-6.3 DG OS HSM ? If so, how about the performance?

It's so hard to get the clear info about this in my city. Many thx.
I dont think the camera model matters a lot but with your sigma and the Pentax adapter the only way you will be getting joy out of your picture taking is to manually focus. The adapter reduces the f stop by 1.5 and you are then getting into a range where the adapter's autofocus capability is compromised. Otherwise the Pentax adapter is of high quality and the IQ is outstanding.

I have posted some pictures on this matter in another thread.
Look here.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/126389-telecon...ml#post1310531

Greetings
12-27-2010, 02:00 AM   #4
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QuoteOriginally posted by falconeye Quote
Azure, I liked your city a lot when I was there. Nice spot.

For the TC. I don't know the image quality of this combo. But I guess AF would not work anymore because the effective aperture (f/8.5 -f/11) is too small.
You've been to Hangzhou? Sounds nice.

AS to manual focus, I suppose it 's OK for me. Thx for your info.

12-27-2010, 02:18 AM   #5
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I have tried the Sigma 1.4x, 2x and Pentax 1.7x on my 50-500mm/K-5 and have to say I was so underwhelmed with the picture quality I never bothered again.
12-27-2010, 02:19 AM   #6
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QuoteOriginally posted by Schraubstock Quote
I dont think the camera model matters a lot but with your sigma and the Pentax adapter the only way you will be getting joy out of your picture taking is to manually focus. The adapter reduces the f stop by 1.5 and you are then getting into a range where the adapter's autofocus capability is compromised. Otherwise the Pentax adapter is of high quality and the IQ is outstanding.

I have posted some pictures on this matter in another thread.
Look here.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/126389-telecon...ml#post1310531

Greetings
Wow, that's what I want to find. Many thx, mate
12-27-2010, 02:34 AM   #7
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Hi azure-sun
Here is another pic of the crop with light sharpening applied. That's all of the PP I did, nothing else.

Greetings

Last edited by Schraubstock; 07-24-2011 at 03:09 AM.
12-27-2010, 02:52 AM   #8
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QuoteOriginally posted by Mike.P Quote
I have tried the Sigma 1.4x, 2x and Pentax 1.7x on my 50-500mm/K-5 and have to say I was so underwhelmed with the picture quality I never bothered again.
From ur experience, I roughly think at least Pentax 1.7x can be used with Sigma APO 50-500mm. An encouraging news

12-27-2010, 03:09 AM   #9
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QuoteOriginally posted by Schraubstock Quote
Hi azure-sun
Here is another pic of the crop with light sharpening applied. That's all of the PP I did, nothing else.

Greetings
Truly not bad. one problem is it is so hard to land one of pentax 1.7x on the local market here.

Just can't wait to give it a try
12-27-2010, 01:31 PM   #10
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QuoteOriginally posted by azure_sun Quote
You've been to Hangzhou? Sounds nice.
Yes. After having visited it, I must say famous for a reason. I took the train from Hangzhou to Ningbo where I have a business partner.

Downtown Hangzhou is magical. As are the hills west of the lake (I took the bike -- nice experience too -- for some reason all Chinese ride their bike much slower than us ).
01-01-2011, 08:21 AM   #11
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An interesting trick I haven't had an opportunity to try yet - In good light, live view AF might work even at those very small apertures where normal AF fails.
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