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07-10-2012, 06:30 PM   #16
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I'm in the 1/2 stop mode with manual aperture lenses because they are indexed in either full stops and half stop increments, with auto aperture lenses I use the finer adjustment of the infinitely variable aperture and 1/3 stop indexing on the body for finer contorl

07-10-2012, 06:43 PM   #17
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I use 1/3 settings. After 35+ of using film with ISO/ASA settings in 1/3 stops it's just easier for me.
07-10-2012, 06:52 PM   #18
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QuoteOriginally posted by DAZ Quote
From the point of ISO it is probably better to stay in whole stops that way you are not mixing analog amplifiers and digital gain.
Can you say anything more about what you mean or how this works? Maybe you could point to some reference. It sounds complicated to me but I'd like to find out know more to understand it.
07-10-2012, 07:08 PM   #19
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QuoteOriginally posted by TomTextura Quote
Can you say anything more about what you mean or how this works? Maybe you could point to some reference. It sounds complicated to me but I'd like to find out know more to understand it.
As you change and increase ISO setting from base of the sensor you using an analog amplifiers like you do when you turn up the radio. For each step, 100 to 200 for example you use a different set of amplifiers in discreet steps. Each step also adds some noise and decrease DR. This works up to the maximum gain for a sensor (1600 for the K5) past this the signal goes to the A/D (analogy to digital) converter. Then to get more this digital information is just multiplied to give higher ISO numbers. This also multiplies the noise and deceases DR. When you use ISO steps between the full stops (like 300) you are using the ISO 200 amplifier then A/D converting, then doing a multiplication on the data. All the math parts can be better accomplished PP.


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07-10-2012, 07:34 PM   #20
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@DAZ Thanks for answering my question. I more or less knew about the digital multiplication past the max ISO of a sensor to get the expanded sensitivity range. What I wasn't aware of was that intermediate steps rely on amplification. This is the first I've heard of it. So, ISO steps between whole stops can impact IQ negatively then?
07-10-2012, 07:43 PM   #21
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QuoteOriginally posted by TomTextura Quote
@DAZ Thanks for answering my question. I more or less knew about the digital multiplication past the max ISO of a sensor to get the expanded sensitivity range. What I wasn't aware of was that intermediate steps rely on amplification. This is the first I've heard of it. So, ISO steps between whole stops can impact IQ negatively then?
Yes but to a much smaller degree then above the max of the sensor. At the lower ISO numbers it is mostly a matter of convenience. If you shoot only RAW like I do it is just better to deal with small steps in PP that way the change is not baked in and you can still change it.


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07-11-2012, 03:00 AM   #22
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QuoteOriginally posted by DAZ Quote
As you change and increase ISO setting from base of the sensor you using an analog amplifiers like you do when you turn up the radio. For each step, 100 to 200 for example you use a different set of amplifiers in discreet steps. Each step also adds some noise and decrease DR. This works up to the maximum gain for a sensor (1600 for the K5) past this the signal goes to the A/D (analogy to digital) converter. Then to get more this digital information is just multiplied to give higher ISO numbers. This also multiplies the noise and deceases DR. When you use ISO steps between the full stops (like 300) you are using the ISO 200 amplifier then A/D converting, then doing a multiplication on the data. All the math parts can be better accomplished PP.
Something like that, but not quite. Watch out or you'll start another Internet myth
07-11-2012, 04:27 AM   #23
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QuoteOriginally posted by kh1234567890 Quote
Something like that, but not quite. Watch out or you'll start another Internet myth
Can you help clarify what it's actually like? I'm really interested in this between whole ISO stops matter.

07-11-2012, 04:50 AM   #24
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Why do we need stops at all in todays dslrs where everything is electronic and infinitely variable?
07-11-2012, 06:17 AM   #25
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QuoteOriginally posted by TomTextura Quote
Can you help clarify what it's actually like? I'm really interested in this between whole ISO stops matter.
There are many good write-ups on the net (ranging from oversimplified to overcomplicated). Some, such as this one, are actually correct and readable . Another good one relating to base ISO etc is here.
07-11-2012, 07:35 AM   #26
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QuoteOriginally posted by kh1234567890 Quote
There are many good write-ups on the net (ranging from oversimplified to overcomplicated). Some, such as this one, are actually correct and readable . Another good one relating to base ISO etc is here.
Thanks! I'll be giving these a look at.
07-11-2012, 08:09 AM   #27
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*All* amplication - analog or digital - increase nosie. If it didn't, it wouldn't be much of an amplifier.

So if you are at ISO 400 and then go to ISO 800, you get approximaely twice as much noise. If you go to ISO 560, you get approximately 1.4 times as much noise. Whether the amplification from 400 to 560 is done via analog or digital means is beside the point. OK, maybe - tpand this is a big maube - the analog amplification will result on 1.4002 times as much noise and the digital amplification would results in 1.4003 times as mich noise, but even if so, so what? It's stoll less noise than ISO 800. And really, without knowing the specific camera in question and doong reallly detailed measurements, there is no way to say for certain if that 1.4002 to 1.4003 advantage is really in favor of analog or digital - it's going to totally depend on the specifics. And realisically, the camera only offers one choice anyhow, so what's the poont of worrying about it?

Unkess you are somehow thinking that the digital amplification performed by your camera is somehow so flawed that it will managed to make ISO 560 more than twiice as bad as ISO 400 instead of only around 1.4 times as bad, in which case you might be believing that ISO 560 would actually end up being worse than ISO 800. You can put that notion to rest. No digital device could possibly be so bad at basic arthemtic that it can do simle multiplficiation with a high degree of reliability. If the camera werw that bad at arithmetic, you couldn't get an image out of it.
07-11-2012, 08:55 AM   #28
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QuoteOriginally posted by Marc Sabatella Quote
*All* amplication - analog or digital - increase nosie. If it didn't, it wouldn't be much of an amplifier.
So if you are at ISO 400 and then go to ISO 800, you get approximaely twice as much noise

<snip>

If the camera werw that bad at arithmetic, you couldn't get an image out of it.
What are you on about ?

It is the signal to noise ratio that matters. If anyone following this thread wishes to educate themselves then the Wikipedia article on image noise is actually quite well written and sensible.
07-12-2012, 10:42 PM   #29
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QuoteOriginally posted by kh1234567890 Quote
What are you on about ?
I don't know what you mean - which part of my post did you have trouble understanding? I realize there typos; sorry about that. Not a big fan of the iPad keyboard.

QuoteQuote:
It is the signal to noise ratio that matters.
True in a sense, but I don't see how that fact that relates to anything I wrote.
07-12-2012, 11:46 PM   #30
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Anyway....

I use 1/3 stops because it integrates with flash better. My Yongnuo increments in 1/3s, (I gues most flash does) and I get confused if I'm trying to manually match 1/2s and 1/3s. I would rather use 1/2 for simplicity, but I also think it's good to learn the more complex way.
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