K5 - ISO 80

Which is better 80 or 100. And if 80 is better why is it not the default setting.

80 is an expanded as 28600 is

It depends what you mean by better, because sometimes the lower ISO levels are reached via electronic wizardry and the camera sensor may still be shooting at ISO200, the "native" level.

Also, low ISO may in theory offer low noise, but that won't help if we end up with camera shake because the shutter speed is too low. For this reason I mainly shoot at ISO200 or ISO400 and the K-5 has no problem with that.

but what is expanded in relation to quality. Would I be better sticking to 100 most of the time.

I think the only way to be sure you are getting what you need is to try it out. Shoot an image with a high dynamic range at all the ISO values that you are likely to use and see what the end result is.

That test will tell you what benefit you will gain by shooting at various ISO values.

That is what I was meaning John, if it is due to electronic manipulation should I stick to 100. Or are you hinting that 200 is the base default.

Sorry John both typing at the same time.

I'm pretty sure that ISO200 is the "Native" ISO of the K-5, along with most if not all of the others. However, with different sensors there could be exceptions, so that's not a definitive answer.

The K-5 is so good at controlling noise that I wouldn't worry too much. You could always check with the JPS technical people to see what they say. They are the official Pentax repair house and you'll find their contact details by downloading the forum for repairs. Being a PU PLus members you're entitled to 20% discount on servicing, so the form can be downloaded from this site. Shop>Exclusive Discounts.

All ISO settings are arrived at by electronic manipulation. the K-5s ISO range adjusted in the analogue domain ( pre convertors ) is I think contended. but I would imagine that ISO 80 is arrived at by digitally reducing gain

I realised as I was typing that all ISO had to be electronic manipulation but assumed that if you had to expand it, it would produce a poorer image

Expanded just means a setting outside a chosen default limit by Pentax. I suppose they put in the Limit to allow some users to stick within a certain range. I turned on the expanded range soon as I opened the box

This made me smile! I took my K-5 out of the box before I started playing with any settings!

Cheers
David

Not a measurebater I'd far rather just take piccies but even given DXO's flaws,I'll offer this as a graphical representation, my own in the field findings would tend to support this too...
Look under dynamic range and you'll see it's best at ISO 80,
Amongsst other stuff...

http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Pentax/K5

P.S. Don't shoot the messenger for mentioning DXO.

I think you can mention DXO. it's not a threat to Pentax Sycophancy

I read this bit on the dynamic range from DPreview link and set 'Highlight Correction' (pg214) and 'Expanded Sensitivity' (pg91) to give me a lowest ISO of 160.