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10-25-2010, 01:37 PM - 1 Like   #1
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K-5 low iso comparison opinions please

Hi,

I'd be interested to know what other folks with K-5 think about the lower iso output of the k-5 in comparison to other models such as K-7 and so on.
I have jumped from k100d to k-5 so only have that as a reference. One of the reasons I waited so long to upgrade was because I like the 'feel' of the K100d pictures and the prints I get. Possibly a function of low pixel count and always using decent lenses.
Very pleased so far with the K-5 low iso output but like to know what others are experiencing.

Allan

10-25-2010, 01:41 PM   #2
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Very good point!! IQ is not just about high ISO performance!!!

Andras
10-25-2010, 02:42 PM   #3
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QuoteOriginally posted by planedriver Quote
Very good point!! IQ is not just about high ISO performance!!!

Andras
While it's not just about high ISO performance, that was the major difference improvement of the K5 over the K7 (next to improved AF). So it's certainly understandable why there is no much (initial) interest in the high ISO performance of the K5.
10-25-2010, 02:46 PM   #4
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I've found the K-5's low-ISO performance superior to the K-7's (less grain, especially in blue skies), but it's not nearly as big a difference as at high-ISO. I guess you'd expect that.

The K-5 also has slightly "cooler" colors by default.

10-25-2010, 03:45 PM   #5
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This is going to be anecdotal and only comparing the K-5 to the K-7, but...

At low ISOs I have noticed that the K-5 renders fine detail, like hair for example, a bit better than the K-7. The K-5 also really seems to reward nice lenses when they are stopped down with some extra resolution boost. I also think the K-5 has a weaker anti aliasing filter than the K-7, which makes for sharper looking photos before post processing.

All this said, when I shot a wedding with the K-7 and K-5 this weekend I had trouble telling the two cameras apart when I was looking through my shots that I took in good light. In fact, the difference was more apparent based on what lens each camera was using, a K-7 with the DA* 200 looked like a K-5 with a DA*200, while the two cameras using different lenses looked very different. When I did the same thing with high ISO photos, it was very clear even from small resolution previews that the K-5 was and is the better performer, especially at ISO1600+.
10-25-2010, 04:21 PM   #6
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I have a question related to metering. Is the K-5 more tolerant of underexposure than the K-7 in terms of generating noise if underexposed?
10-25-2010, 11:46 PM   #7
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QuoteOriginally posted by Clarkey Quote
I have a question related to metering. Is the K-5 more tolerant of underexposure than the K-7 in terms of generating noise if underexposed?
The K-5 is said to have close to 14 stops of DR @ ISO 80, which is 3.5 stops better than the K-7 @ ISO100. The deep shadows on the K-5 at low ISO have been described as being "smooth as silk".

Given that the deep shadows are cleaner, the K-5 should be more forgiving of underexposure. Especially at low ISOs.
10-26-2010, 12:38 AM   #8
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it is definetly 2 or 3 stops better than k-x.

10-26-2010, 12:46 AM - 1 Like   #9
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Very interesting question. I'm particularily interested in seeing the difference between ISO80 on the K-5, ISO100 on the K-5 and ISO100 on the K-7. Esp in terms of DR.

ISO80 being an extended mode, and ISO100 being the sensor's native sensitivity, makes me wonder whether ISO80 will have better DR or not. I would guess not. Overexposing by 1/2 stop compared to ISO100 would mean that full pixel capacity would be reached 1/2 sooner at ISO80, reducing highlight DR by 1/2 stop, no? Unless Pentax/Sony pulled a trick to artificially increase pixel capacity in ISO80?

For me ISO80 is about longer exposures for land/cityscapes, which generally have large DR and more specifically often feature highlights (the white of the foam in a waterfall, the headlights of cars in a nightly cityscape, ...). Having 1/2 stop less DR would make ISO80 less interesting for this than ISO100...

Looking forward to finding out...

Wim
10-26-2010, 12:54 AM   #10
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QuoteOriginally posted by Ishpuini Quote
Very interesting question. I'm particularily interested in seeing the difference between ISO80 on the K-5, ISO100 on the K-5 and ISO100 on the K-7. Esp in terms of DR.

ISO80 being an extended mode, and ISO100 being the sensor's native sensitivity, makes me wonder whether ISO80 will have better DR or not. I would guess not. Overexposing by 1/2 stop compared to ISO100 would mean that full pixel capacity would be reached 1/2 sooner at ISO80, reducing highlight DR by 1/2 stop, no? Unless Pentax/Sony pulled a trick to artificially increase pixel capacity in ISO80?

For me ISO80 is about longer exposures for land/cityscapes, which generally have large DR and more specifically often feature highlights (the white of the foam in a waterfall, the headlights of cars in a nightly cityscape, ...). Having 1/2 stop less DR would make ISO80 less interesting for this than ISO100...

Looking forward to finding out...
Actually, according to GordonBGood, ISO80 is closer to the base/native sensitivity of the Sony Exmor HD APS-C sensor used in the K-5, and explains the better IQ at ISO80 vs. ISO100.

Since there seems to be quite a bit of interest in this topic, here is the conversation from the other forum (my apologies if linking like this is frowned upon):

Re: Stunning k-5...: Pentax SLR Talk Forum: Digital Photography Review

Reading further into Gordon's comments, the DR of the K-5 at ISO800 beats the K-7/K20D at ISO100 (this has been confirmed by him in a different thread).
10-26-2010, 01:53 AM   #11
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QuoteOriginally posted by photogerald Quote
Actually, according to GordonBGood, ISO80 is closer to the base/native sensitivity of the Sony Exmor HD APS-C sensor used in the K-5, and explains the better IQ at ISO80 vs. ISO100.

Since there seems to be quite a bit of interest in this topic, here is the conversation from the other forum (my apologies if linking like this is frowned upon):

Re: Stunning k-5...: Pentax SLR Talk Forum: Digital Photography Review

Reading further into Gordon's comments, the DR of the K-5 at ISO800 beats the K-7/K20D at ISO100 (this has been confirmed by him in a different thread).
Tx!! I had missed those posts.

If this is the case (and I doubt not) it seems strange Pentax put ISO80 in the extended ISO range instead of in the standard range.

Might be shooting in ISO80 all the time then... To think I was actually considering not activating extended ISO in the K-5 (contrary to all my previous Pentax DSLRs) because the standard range high ISO limit seemed enough for me...

Wim

Last edited by Ishpuini; 10-26-2010 at 02:05 AM.
10-26-2010, 06:09 AM   #12
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Thanks for the link. That was an interesting thread. I does indeed look like underexposed shots hold up better. To my eye, the unprocessed shots look at least two stops better than the equivalent K-7 shots where exposed in a low light environment.

Now, what to get, Topaz, or a K-5?
10-26-2010, 08:15 AM   #13
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QuoteOriginally posted by photogerald Quote
Actually, according to GordonBGood, ISO80 is closer to the base/native sensitivity of the Sony Exmor HD APS-C sensor used in the K-5, and explains the better IQ at ISO80 vs. ISO100.

Since there seems to be quite a bit of interest in this topic, here is the conversation from the other forum (my apologies if linking like this is frowned upon):

Re: Stunning k-5...: Pentax SLR Talk Forum: Digital Photography Review

Reading further into Gordon's comments, the DR of the K-5 at ISO800 beats the K-7/K20D at ISO100 (this has been confirmed by him in a different thread).
In all honesty, this has me more excited about the K-5 than does the high ISO noise level. Being able to retain detail in highlights and shadows in contrasty scenes will be of benefit to almost all shooters, not just those who shoot in low light. 14 stops of DR from an APS-C sensor places it in the range of MF sensors. That is truly mind boggling!

Rob
10-26-2010, 02:52 PM   #14
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QuoteOriginally posted by robgo2 Quote
In all honesty, this has me more excited about the K-5 than does the high ISO noise level.
I agree. Does anyone know where I can buy the fri#### thing?
10-26-2010, 07:13 PM   #15
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If the suggested DR is for real, the K-5 is gem.
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