Low ISO

Interesting that the forced extended range to 80 is considered the best. All about how much voltage applied to the sensor gives the best results.

whereabouts on that page are we clicking ? can't seem to see where you are looking

Select the "Measurements" TAB

It's a TAB that says "Measurements"

Not the TAB that says "Specs"

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gotcha Ta for that.

my it drops (dynamic range) quite quickly as you crank up the ISO

other than longer shutter speed spotentialy being needed are there any downsides to going to 80 ISO ?

I can't think of any downsides as long as the exposure is
correct. You would of course need good light and it would
work well with flash.

It does effect the highlight/shadow protection, but I think
you are restricted to ISO 200 with that anyway.

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Very interesting. I always thought that the best dynamic range was achieved using the hightlight/shadow protection, but as Algi says, that restricts us to ISO 200 and above.

Does that mean that the dynamic range (without protection) is better at ISO 80 compared to when protection is turned on i.e. at ISO 200?

Regards
Nigel

If you're shooting in RAW it's best to leave the highlight and shadow settings switched off. There is no point in them for RAW shooters.

Regards
David

Are you sure about that? They definitely wouldn't be any
use for JPG's

The Nuthatch in my portfolio was rescued from a black DNG
file. I've still got the JPG as well I might see how much
I can rescue from that.

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I can't quite follow your logic here Algi and you do seem to be contradicting yourself in this thread. You said earlier "The best Dynamic and Tonal Range for the K-5 is at ISO 80 which is actually ISO 70".

If this is true, then the dynamic range at ISO 80 without the Highlight / Shadow correction turned on is greater than the Dynamic Range at ISO 200 (minimum available) with it turned on. Am I not correct? If I am wrong, then your previous assertion is also wrong.

Given that it is much easier to recover details at the extremes of the dynamic range in RAW than it is in JPEG (and retain better quality whilst doing so), I fully stand by my previous point that if shooting in RAW, what's the point in having Highlight and Shadow correction turned on? If the data is there in the file, then RAW processing can surely recover it? With jpeg the camera has already processed it and makes its own decisions so it may not have done as good a job as a person would with decent RAW processing software.

Having said this, I see no logic or relevance in your other statement as to the Shadow and Highlight correction "not being any use for jpegs". Surely the camera uses the sensor information as its starting point for processing a jpeg and if Pentax thought that using the Dynamic Range settings at ISO 200 was not providing a benefit why would they offer this setting? I would bet you a pound to a penny that a jpeg shot with these turned on would look different to a jpeg shot with them turned off.

Going back to my first point, I usually shoot RAW and ISO 100 maximum, unless taking shots of action subjects or things like birds in low light. I think I am getting the best dynamic range from my K-5 by shooting this way.

Regards
David

The K-5 Manual doesn't explain this in detail. I'll have
to have a look around tomorrow to see why they restrict
the minimum speed to ISO 160-200 and if it applies to
JPG and RAW. If it's not needed in RAW why is it there?

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As far as I can tell it actually compresses the dynamic range and does not increase it. It stands to reason, also if the manual is read carefully it states that it 'reduces the occurrence of overexposed and underexposed areas'. To me, that means compression, not expansion. The manual also does not differentiate between RAW and Jpeg when shooting with the dynamic range options turned on which implies it affects both.

The accepted wisdom of most knowledgeable K-5 users (judging by what I've read and what people have said to me) is that the best dynamic range is achieved by leaving these settings turned off, lowering the ISO as far as possible and shooting / processing RAW files. My experience of using the K-5 also leads me to the same conclusion.

Regards
David

I'll have to check if I have these switched on and go to iso 80 then as I mostly shoot on a tripod anyway and oft in scenes with a huge dynamic range.

thanks for this

I fully concur with that.

On the K-5 the best dynamic range is at ISO 80

Yup you can roughly lose a stop ( 6dB ) of dynamic range for every doubling of the ISO

Nope.