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jeantree · 10-07-2014, 08:57 AM

My Kx normally has ISO capabilities from 200 to 6400. If I can use the expanded ISO to go down to 100 (the only end I care about, now at least) why don't they just put it on there in the first place? Do I loose something when I set to expanded ISO? If so, what, and how much?

Bcrary3 · 10-07-2014, 09:02 AM

That is a really good question, I am curious to see if anyone has any ideas, I have the same thing on my K5.

RonHendriks1966 · 10-07-2014, 09:06 AM

I don't think so, the iso100 is the best performing setting.

http://www.dxomark.com/Cameras/Pentax/Kx

bobpur · 10-07-2014, 09:15 AM

Gives excellent results. Go out and take pictures, try different settings nothing is going to break.
I don't have any Dxomark charts on my walls just great pics from my Kx !

jeantree · 10-07-2014, 09:37 AM

Originally posted by RonHendriks1966

I don't think so, the iso100 is the best performing setting.

http://www.dxomark.com/Cameras/Pentax/Kx

So again, the question, why don't they just put it with the other settings? Why do I have to go enable expanded ISO?

climit · 10-07-2014, 10:01 AM

just guessing that iso100 and iso12800 are not native iso? but the product of processing? so they slow down the camera? (slower frame rate or lesser max number of frames for the buffer?), I haven't tried though, I rarely shoot in bursts.

**THoog** · 10-07-2014, 11:09 AM

Short answer: You may lose some "highlight headroom". The K-x is designed around a base ISO of 200, so to get ISO 100, it actually overexposes, then adjusts. Apparently, the sensor actually does best at ISO 125 - see this (headache-inducing) discussion on that other site:

What's the deal with the Pentax K-X base ISO setting (ISO-200 vs "Extendable"-100)?: Pentax SLR Talk Forum: Digital Photography Review

Last edited by THoog; 10-07-2014 at 12:14 PM. Reason: Over, not under exposes.

Bcrary3 · 10-07-2014, 11:10 AM

Is there one for the K5?

climit · 10-07-2014, 11:40 AM

Originally posted by THoog

Short answer: You may lose some "highlight headroom". The K-x is designed around a base ISO of 200, so to get ISO 100, it actually underexposes, then adjusts up. Apparently, the sensor actually does best at ISO 125 - see this (headache-inducing) discussion on that other site:

What's the deal with the Pentax K-X base ISO setting (ISO-200 vs "Extendable"-100)?: Pentax SLR Talk Forum: Digital Photography Review

not under you mean overexposes at 100.
this makes for the better iq

---------- Post added 7th Oct 2014 at 21:45 ----------

I read in some leica discussions of the trend to overexpose 1 stop to get the maximum of detail because that way they get the most information possible because the information in digital is not analog as in film. The best is to overexpose as much as not to burn any highlight. And then correct in pp.

Adam · 10-07-2014, 12:06 PM

Originally posted by jeantree

So again, the question, why don't they just put it with the other settings? Why do I have to go enable expanded ISO?

They "resolved" the issue on future bodies- current-gen Pentax cameras don't have ISO expansion.

**THoog** · 10-07-2014, 12:14 PM

Originally posted by climit

not under you mean overexposes at 100.

Yep. Edited. Thanks.

climit · 10-07-2014, 01:57 PM

Originally posted by Adam

They "resolved" the issue on future bodies- current-gen Pentax cameras don't have ISO expansion.

Adam, it is not an issue.

10-07-2014, 08:57 AM	#1
jeantree Senior Member Join Date: Jan 2011 Location: Missouri Photos: Gallery Posts: 221	expanded ISO on my Kx My Kx normally has ISO capabilities from 200 to 6400. If I can use the expanded ISO to go down to 100 (the only end I care about, now at least) why don't they just put it on there in the first place? Do I loose something when I set to expanded ISO? If so, what, and how much?

10-07-2014, 12:06 PM	#10
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Originally posted by jeantree So again, the question, why don't they just put it with the other settings? Why do I have to go enable expanded ISO? They "resolved" the issue on future bodies- current-gen Pentax cameras don't have ISO expansion. 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 purchasing one of our Pentax eBooks. 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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10-07-2014, 09:02 AM	#2
Bcrary3 Veteran Member Join Date: Feb 2013 Location: Wisconsin Photos: Gallery Posts: 391	That is a really good question, I am curious to see if anyone has any ideas, I have the same thing on my K5.

10-07-2014, 09:06 AM	#3
RonHendriks1966 Banned Join Date: Jan 2009 Photos: Gallery Posts: 9,675	I don't think so, the iso100 is the best performing setting. http://www.dxomark.com/Cameras/Pentax/Kx

10-07-2014, 09:15 AM	#4
bobpur Inactive Account Join Date: Jul 2010 Photos: Gallery Posts: 328	Gives excellent results. Go out and take pictures, try different settings nothing is going to break. I don't have any Dxomark charts on my walls just great pics from my Kx !

10-07-2014, 09:37 AM	#5
jeantree Senior Member Join Date: Jan 2011 Location: Missouri Photos: Gallery Posts: 221 Original Poster	Originally posted by RonHendriks1966 I don't think so, the iso100 is the best performing setting. http://www.dxomark.com/Cameras/Pentax/Kx So again, the question, why don't they just put it with the other settings? Why do I have to go enable expanded ISO?

10-07-2014, 10:01 AM	#6
climit Senior Member Join Date: Aug 2010 Location: Kalamata Posts: 224	just guessing that iso100 and iso12800 are not native iso? but the product of processing? so they slow down the camera? (slower frame rate or lesser max number of frames for the buffer?), I haven't tried though, I rarely shoot in bursts.

10-07-2014, 11:09 AM	#7
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Short answer: You may lose some "highlight headroom". The K-x is designed around a base ISO of 200, so to get ISO 100, it actually overexposes, then adjusts. Apparently, the sensor actually does best at ISO 125 - see this (headache-inducing) discussion on that other site: What's the deal with the Pentax K-X base ISO setting (ISO-200 vs "Extendable"-100)?: Pentax SLR Talk Forum: Digital Photography Review Last edited by THoog; 10-07-2014 at 12:14 PM. Reason: Over, not under exposes.

10-07-2014, 11:10 AM	#8
Bcrary3 Veteran Member Join Date: Feb 2013 Location: Wisconsin Photos: Gallery Posts: 391	Is there one for the K5?

10-07-2014, 11:40 AM	#9
climit Senior Member Join Date: Aug 2010 Location: Kalamata Posts: 224	Originally posted by THoog Short answer: You may lose some "highlight headroom". The K-x is designed around a base ISO of 200, so to get ISO 100, it actually underexposes, then adjusts up. Apparently, the sensor actually does best at ISO 125 - see this (headache-inducing) discussion on that other site: What's the deal with the Pentax K-X base ISO setting (ISO-200 vs "Extendable"-100)?: Pentax SLR Talk Forum: Digital Photography Review not under you mean overexposes at 100. this makes for the better iq ---------- Post added 7th Oct 2014 at 21:45 ---------- I read in some leica discussions of the trend to overexpose 1 stop to get the maximum of detail because that way they get the most information possible because the information in digital is not analog as in film. The best is to overexpose as much as not to burn any highlight. And then correct in pp.

10-07-2014, 12:14 PM	#11
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Originally posted by climit not under you mean overexposes at 100. Yep. Edited. Thanks.

10-07-2014, 01:57 PM	#12
climit Senior Member Join Date: Aug 2010 Location: Kalamata Posts: 224	Originally posted by Adam They "resolved" the issue on future bodies- current-gen Pentax cameras don't have ISO expansion. Adam, it is not an issue.

expanded ISO on my Kx

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