*Ist DS vs K10D actual sensitivity

Matjazz · 07-09-2007, 05:56 AM

Hi,
I'm considering a used K10D. I've asked the seller to send me raw files from K10D and he sent them along with DS raw files of the same scene. As I expected the K10D has more noise than DS, but the thing that stroke me most was that K10D images were significantly darker at the same exposure settings. I had to use +2/3 ev in raw developer to compensate.
Anybody else noticed this? Could this indicate problems with that K10D? Am I being paranoid

SupremeMoFo · 07-09-2007, 06:51 AM

Well, I'll double check, are all of shutter speed, aperture, and sensitivity the same? Are you comparing exactly the same scene? The K10D does have a slight preference for underexposing.

RiceHigh · 07-09-2007, 06:53 AM

Originally posted by Matjazz

Hi,
I'm considering a used K10D. I've asked the seller to send me raw files from K10D and he sent them along with DS raw files of the same scene. As I expected the K10D has more noise than DS, but the thing that stroke me most was that K10D images were significantly darker at the same exposure settings. I had to use +2/3 ev in raw developer to compensate.
Anybody else noticed this? Could this indicate problems with that K10D? Am I being paranoid

The ISO speed rating and the actual ISO speed rating are matching and accurate for all Pentax DSLRs I have used, these include the *ist D, DS, K100D and K10D. As you say, when I used an external meter, then I know the actual ISOs were accurate. At least Phil Askey found the same:

Pentax K10D Review: 14. Photographic tests: Digital Photography Review

Pentax K100D Review: 14. Photographic tests: Digital Photography Review

So, if you asked me if it indicates problems with your K10D or just the K10D, I am afraid that the answer is Yes. It is just an underexposure problem for your case described.

RiceHigh · 07-09-2007, 06:56 AM

Originally posted by SupremeMoFo

Well, I'll double check, are all of shutter speed, aperture, and sensitivity the same? Are you comparing exactly the same scene? The K10D does have a slight preference for underexposing.

Amazing and wonderful creative new term "preference for underexposing"! Next time we can say about for "preference for out-focusing" if someone reports such a problem or etc.! LOL..

SupremeMoFo · 07-09-2007, 07:01 AM

As we all know, better slightly underexposed than overexposed, and it looks far better.

davek · 07-09-2007, 01:29 PM

Originally posted by SupremeMoFo

As we all know, better slightly underexposed than overexposed, and it looks far better.

Is that right? I always thought that it was best to expose to the right (of the histogram), to minimize noise in the dark areas. Generally, I expose for the highlights.

Matjazz · 07-09-2007, 01:36 PM

The settings and the scene were exactly the same, lit by natural light from windows. A simple cloud over the sun could make all the difference and that is the most likely scenario.
I just wanted to make sure and RiceHigh answered just what I was asking.

07-09-2007, 05:56 AM	#1
Matjazz Veteran Member Join Date: Sep 2006 Location: EU/Slovenia Photos: Gallery Posts: 774	*Ist DS vs K10D actual sensitivity Hi, I'm considering a used K10D. I've asked the seller to send me raw files from K10D and he sent them along with DS raw files of the same scene. As I expected the K10D has more noise than DS, but the thing that stroke me most was that K10D images were significantly darker at the same exposure settings. I had to use +2/3 ev in raw developer to compensate. Anybody else noticed this? Could this indicate problems with that K10D? Am I being paranoid

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07-09-2007, 06:51 AM	#2
SupremeMoFo Veteran Member Join Date: Mar 2007 Location: Queensland, Australia Posts: 668	Well, I'll double check, are all of shutter speed, aperture, and sensitivity the same? Are you comparing exactly the same scene? The K10D does have a slight preference for underexposing.

07-09-2007, 06:53 AM	#3
RiceHigh Veteran Member Join Date: Nov 2006 Location: Hong Kong Posts: 1,934	Originally posted by Matjazz Hi, I'm considering a used K10D. I've asked the seller to send me raw files from K10D and he sent them along with DS raw files of the same scene. As I expected the K10D has more noise than DS, but the thing that stroke me most was that K10D images were significantly darker at the same exposure settings. I had to use +2/3 ev in raw developer to compensate. Anybody else noticed this? Could this indicate problems with that K10D? Am I being paranoid The ISO speed rating and the actual ISO speed rating are matching and accurate for all Pentax DSLRs I have used, these include the *ist D, DS, K100D and K10D. As you say, when I used an external meter, then I know the actual ISOs were accurate. At least Phil Askey found the same: Pentax K10D Review: 14. Photographic tests: Digital Photography Review Pentax K100D Review: 14. Photographic tests: Digital Photography Review So, if you asked me if it indicates problems with your K10D or just the K10D, I am afraid that the answer is Yes. It is just an underexposure problem for your case described.

07-09-2007, 06:56 AM	#4
RiceHigh Veteran Member Join Date: Nov 2006 Location: Hong Kong Posts: 1,934	Originally posted by SupremeMoFo Well, I'll double check, are all of shutter speed, aperture, and sensitivity the same? Are you comparing exactly the same scene? The K10D does have a slight preference for underexposing. Amazing and wonderful creative new term "preference for underexposing"! Next time we can say about for "preference for out-focusing" if someone reports such a problem or etc.! LOL..

07-09-2007, 07:01 AM	#5
SupremeMoFo Veteran Member Join Date: Mar 2007 Location: Queensland, Australia Posts: 668	As we all know, better slightly underexposed than overexposed, and it looks far better.

07-09-2007, 01:29 PM	#6
davek Veteran Member Join Date: Sep 2006 Location: Elmira, On, Canada Posts: 461	Originally posted by SupremeMoFo As we all know, better slightly underexposed than overexposed, and it looks far better. Is that right? I always thought that it was best to expose to the right (of the histogram), to minimize noise in the dark areas. Generally, I expose for the highlights.

07-09-2007, 01:36 PM	#7
Matjazz Veteran Member Join Date: Sep 2006 Location: EU/Slovenia Photos: Gallery Posts: 774 Original Poster	The settings and the scene were exactly the same, lit by natural light from windows. A simple cloud over the sun could make all the difference and that is the most likely scenario. I just wanted to make sure and RiceHigh answered just what I was asking.