Pentax KP and sigma 18-35mm

pixelvandal · 04-09-2020, 01:20 AM

Hey guys.
I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc.
I've had the best luck with that lens on the k5 and my friends k5iis.

My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha.

Thank you

Adam · 04-09-2020, 01:53 AM

Originally posted by pixelvandal

Hey guys.
I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc.
I've had the best luck with that lens on the k5 and my friends k5iis.

My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha.

Thank you

More of a general comment- AF calibration issues will often be specific to each individual camera/lens combo, rather than a specific type of camera. I'd recommend using the Sigma dock to apply AF adjustments if they are needed on other bodies.

cport · 04-09-2020, 07:14 AM

Originally posted by pixelvandal

Hey guys.
I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc.
I've had the best luck with that lens on the k5 and my friends k5iis.

My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha.

Thank you

I do not use Sigma lenses. But a friend of mine always let his lens adapt at local Sigma service to his body.

CarlJF · 04-09-2020, 07:56 AM

Originally posted by pixelvandal

Hey guys.
I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc.
I've had the best luck with that lens on the k5 and my friends k5iis.

My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha.

Thank you

Looking at the full review on PF, random focus seems a "feature" of this lens. They tested no less than seven copies on many different bodies and all had issues. So, I would not hold my breath when testing on the KP! Even if it works under the test condition, it wouldn't mean the lens is fine. What they observed in the review was unpredictable back and front focus varying with focal length and focus distance (and maybe even with aperture)... So, even if you could calibrate the lens to work fine under some specific sets of conditions with the dock, the issue will appear again as soon as you use other conditions. It seems the only "fix" is to work in liveview... BTW, this issue isn't specific to Pentax, it's also reported by Canikon users...

Last edited by CarlJF; 04-09-2020 at 08:23 AM.

04-09-2020, 01:20 AM	#1
pixelvandal Senior Member Join Date: Dec 2012 Location: Gold Coast Posts: 209	Pentax KP and sigma 18-35mm Hey guys. I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc. I've had the best luck with that lens on the k5 and my friends k5iis. My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha. Thank you

04-09-2020, 01:53 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,164	Originally posted by pixelvandal Hey guys. I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc. I've had the best luck with that lens on the k5 and my friends k5iis. My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha. Thank you More of a general comment- AF calibration issues will often be specific to each individual camera/lens combo, rather than a specific type of camera. I'd recommend using the Sigma dock to apply AF adjustments if they are needed on other bodies. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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04-09-2020, 07:14 AM	#3
cport Pentaxian Join Date: Jan 2013 Posts: 418	Originally posted by pixelvandal Hey guys. I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc. I've had the best luck with that lens on the k5 and my friends k5iis. My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha. Thank you I do not use Sigma lenses. But a friend of mine always let his lens adapt at local Sigma service to his body.

04-09-2020, 07:56 AM	#4
CarlJF Veteran Member Join Date: Sep 2014 Location: Quebec City Posts: 1,184	Originally posted by pixelvandal Hey guys. I'm shooting the sigma 18-35mm with the k5, with far better focus accuracy than the k3 I tried it on. Lots of reports of bad focusing on the k3 and k3ii. As well as the k30,50,70 etc. I've had the best luck with that lens on the k5 and my friends k5iis. My question is, is anyone shooting the lens on the KP? Does anyone have any hands on experience? I love the lens but it drove me nuts on the k3. Hoping it's slightly better with the KP, but not holding my breath..... Haha. Thank you Looking at the full review on PF, random focus seems a "feature" of this lens. They tested no less than seven copies on many different bodies and all had issues. So, I would not hold my breath when testing on the KP! Even if it works under the test condition, it wouldn't mean the lens is fine. What they observed in the review was unpredictable back and front focus varying with focal length and focus distance (and maybe even with aperture)... So, even if you could calibrate the lens to work fine under some specific sets of conditions with the dock, the issue will appear again as soon as you use other conditions. It seems the only "fix" is to work in liveview... BTW, this issue isn't specific to Pentax, it's also reported by Canikon users... Last edited by CarlJF; 04-09-2020 at 08:23 AM.

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