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11-11-2018, 08:23 PM   #1
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K5 Extended ISO

I just purchased a used K5 and I am trying to find my way around in it.

I know that the "native" ISO range is 100-12,800 and it can be extended to have a range of 80-51,200. I read through the manual and found the menu setting to enable the extended range.

My question is: is there any drawback to leaving the extended range enabled? I will probably shoot mostly with a fixed ISO setting (its the old school in me) and if I do use auto-ISO, I would probably have the range limited to say 100-3200.

I think I understand that the extended range is achieved by playing software games with the image, after it is captured, rather than setting the sensitivity of the sensor.

Even with today's better sensors and better noise reduction software, the noise at extremely high ISO's is probably noticeable, so I would not use that unless I had to. But, if extended sensitivity is enabled, do exposures made in the "native" range suffer, compared to shooting with extended sensitivity enabled?

If there is no drawback, it seems a little like the "Allow aperture ring setting". No one has ever come up with a good reason not to enable that. After all, it only applies if you're using a lens with an aperture ring and you move it off the "A" setting.


Just for background, I'm coming from a K10d, which only allowed ISO settings from 100-1600, and anything above 400 was iffy, if not downright unusable, so these extended ISO ranges are hard to get my head around.

11-11-2018, 08:42 PM - 2 Likes   #2
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Welcome to the K-5 family. I've had mine for 4 years, and when I went through the manual I saw the extended ISO, and set it to the 80-..., and never looked back.

For the most part, I'll be in the 400-1600 range with birds, and HS band competitions, but have gone up to 3200 for faster shutter speeds, and I'm always surprised by the K-5's ability to handle noise.

But I like the 80 option when shooting at f1.4.
11-11-2018, 09:02 PM   #3
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I have been using a K-5 for years. I haven't found any drawbacks to extended iso range. I personally find the images useable up to iso 5000 so go ahead and try it. Most likely you will never turn off extended iso. I use iso 80 more frequently than the highest values but the top iso settings are useful for adjusting composition when doing night time photography.
11-11-2018, 09:24 PM   #4
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I discovered extended range a couple of years into my K5 ownership. Since then it's been in extended range mode. I haven't noticed any negative impact

11-11-2018, 09:39 PM - 2 Likes   #5
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Another vote to turn it on and leave it on. And be sure to play around with shooting at high ISO, practicing with shots that don't matter.

The reason for that is that working with high ISO isn't as straightforward as many rules of thumb might suggest. People often say things like a K-5 has good image quality up to ISO XXX. But you don't have much idea what their idea of image quality might be, so you need to find your own threshold. And that threshold may vary depending on the situation.

High ISO image quality depends a lot on proper exposure. If you can nail the exposure you're more likely to get a cleaner image. That means that you can have images shot at 1600 that are noisier than images shot at 5000.

Finally, it took me some time to realize that dialing up the ISO is a good idea with long lens photography when it allows you to get a good shutter speed. A blurry, noiseless photo at ISO 100 looks quite a bit worse than a sharp, noisy one at 3200.

Have fun sorting this all out!
11-12-2018, 02:02 AM   #6
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QuoteOriginally posted by bkpix Quote
.....High ISO image quality depends a lot on proper exposure.....
It might also be relevant here to mention here that using the lowest ISO value loses the ability to implement the D-Range Highlight Correction option.

The experts here will correct me if this is wrong but, If I have understood it correctly, D-R HC smooths the transition from brightness into blown highlights and works for both JPEG and raw files. So, if it is not set, more exposure care is needed when considering the right hand side of the histogram, as the scope for highlight detail recovery in PP might be quite restricted.

Philip
11-12-2018, 05:02 AM   #7
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QuoteOriginally posted by MrB1 Quote
It might also be relevant here to mention here that using the lowest ISO value loses the ability to implement the D-Range Highlight Correction option.

The experts here will correct me if this is wrong but, If I have understood it correctly, D-R HC smooths the transition from brightness into blown highlights and works for both JPEG and raw files. So, if it is not set, more exposure care is needed when considering the right hand side of the histogram, as the scope for highlight detail recovery in PP might be quite restricted.

Philip
If enabling that (highlight correction), while extended ISO is enabled, it will automatically make the lowest possible iso to select 160, in order to use the last stop for the correction. If extended isn't enabled, the lowest ISO that can be used (with highlight correction enabled) will be 200.

Note that the K5 sensors actual base is 80, so I'd say it's unwise to NOT enable extended iso...you do get increased dynamic range and lower noise compared to iso 100 (although 100 is still very good so mostly just measurable differences, not always visible).
11-12-2018, 06:17 PM   #8
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The only disadvantage to enabling the extended ISO range is is you actually use it!

Actually, try the extended ISOs out, just so you can get a feel for what they are like. Try them also in B&W mode, I find them more usable that way.

11-13-2018, 09:59 AM - 1 Like   #9
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I don't think there's any disadvantage to enabling extended mode. I wouldn't let auto ISO go beyond 6400, though, unless you frequently photograph low light action.

ISO 80 opens up some new possibilities at the low end. It's even less noisy than ISO 100 if you have to really push the shadows in a high contrast photo. You can also use ISO 80 to get longer exposures for extra water and cloud movement blur, if you don't have a dark enough ND filter available.

On my K-5 I rarely went higher than ISO 3200 because of noise. If 3200 wasn't enough I would put the camera on a tripod and use longer exposures. If trying to photograph a moving subject in very low light, though, noise is better than motion blur.
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