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"Sweet Spot" for ISO best sensor performance


ECohen

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That actually isn't what I meant ...By "sweet spot" I meant that was my starting point that I would like to use.... only if it makes sense. Like choosing Plus X/FP4 or choosing Portra 160, because I like the balance of grain to color/tone.....I would only choose Tri X or push to 1600 as a last resort ....or for an effect. I treat digital 3200 and 6400 the same as a last resort or for an effect.

 
I look at digital and  the sweet spot being 200 the same way ....if it that works for my exposure combination, great if not I adjust, being concerned when inside at around 1600, past that the quality is not to my liking.
 
I would never intentionally under expose just to use ISO200 and fix in photoshop because that adds new undesirable variables....more undesirable (to me ) than using the camera between 200 to 800 ...1600 is OK but I prefer the look of lower ISO. 
 
 I was wondering how you all decide where to start as far as ISO.  How do you think of ISO on the M as it factors into the creative process of making your exposure choices.
 
Thanks to all for your replies it is truly helping me grow as a digital photographer learning to see digitally 
 
And as an aside:
How do you all see ISO 100 ? 

 

 

I think that the idea that's emerging from this thread is that the base ISO is "the" place to shoot with your shutter speed and aperture varied as necessary for stopping motion and DOF.   ISO as we knew it in film is quickly becoming a dated concept.  In film, the emulsion was varied to allow for shooting in less light...  with, of course, longer processing times and larger grain.  Digital is recorded electronically, much like audio recording.  Just as audio recordings get "hiss," digital signal-to-noise ratio generates "noise" in our images with less signal.  Dialing up the ISO results in less "signal" being captured and subsequently more "noise;  a completely different process that is "sold" to former film photographers as "ISO."

 

So, when you dial up the ISO, you ARE intentionally under-exposing, and the camera's processor fills in the blanks to the best of its ability.  The point here is that, within reason, you can in fact underexpose by several stops, and still get a better image in PP than if you dialed up the ISO to 1600 or higher.

 

Don't use ISO 100 unless there's no other choice.  There's really not much point to that either. 

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"So, when you dial up the ISO, you ARE intentionally under-exposing, and the camera's processor fills in the blanks to the best of its ability.  The point here is that, within reason, you can in fact underexpose by several stops, and still get a better image in PP than if you dialed up the ISO to 1600 or higher."

 

No kidding....now theres a project for testing tomorrow .... Thank You ....I never would have thought to work that way.

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The point here is that, within reason, you can in fact underexpose by several stops, and still get a better image in PP than if you dialed up the ISO to 1600 or higher. 

 

 

Perhaps.  I checked that hypothesis on my Q.  I compared images shot at 1600 with one shot at 800 but under exposed by one stop then pushed in lightroom.   Another comparison was with an image shot at 400 and pushed two stops.   The noise patterns were different, but I could not say any one was better or worse than another.  However, I was not trying to bring out the darkest darks, either.

 

I have not tried that test on my M 262, yet.  I should do that soon.   And perhaps I should compare all to ISO 200.

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The noise patterns were different, but I could not say any one was better or worse than another.  However, I was not trying to bring out the darkest darks, either.

 

As ever, lots of variables; sensor, software, scene contrast, degree of underexposure, colour temperature and so on. I've found my preferred ways of working - just clip highlights on the camera display (effectively showing the camera's interpretation jpeg) and then afterwards process to control highlights and their tonality and pull up the shadows as required (avoiding banding). Works for me using Photoshop's RAW converter and then post processing in Photoshop, but it will vary from each of us. Of course if you don't want to spend time post processing then 'accurate' in camera exposure using ISO settings is a 'better' solution, but for me, well I haven't shot jpegs for years nor can I remember adjusting ISO from base.

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Perhaps.  I checked that hypothesis on my Q.  I compared images shot at 1600 with one shot at 800 but under exposed by one stop then pushed in lightroom.   Another comparison was with an image shot at 400 and pushed two stops.   The noise patterns were different, but I could not say any one was better or worse than another.  However, I was not trying to bring out the darkest darks, either.

 

I have not tried that test on my M 262, yet.  I should do that soon.   And perhaps I should compare all to ISO 200.

 

Yes, you should be comparing your dialed-up ISO shots to the pushed, base ISO shots.  Comparing 400, 800, and 1600 ISO shots are just comparing how the camera handles the increasing  noise to signal ratio.

 

Now, all that said, I still dial up the ISO on my M9P occasionally if I'm in really low light because I still think that way...  but generally speaking I still shoot it like I shot film, and leave it on the base ISO of 160 for probably 99% of what I shoot, and dial in the highlights and shadows in Lightroom from the .dng file.

 

here's an example...  the OOC .jpg and the way I wanted it post processed.  Notice both the highlight and shadow recovery in the PP version. 

 

25081216920_76de5dcbf6_c.jpg20160224-L1000259 (Medium) by Roger H, on Flickr

 

25251694276_634ee70b60_c.jpg20160224-L1000259 by Roger H, on Flickr

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[...] You guys are far more scientific and well as art people. What conclusions have you come up with? 

How do you think about your ISO in relation best quality file on the M240? [...]

 

Being neither a scientist nor an artist i suspect my point of view will interest nobody else than a couple auto iso shooters here but besides Foveon based ones, all digital cameras look more or less similar to me so i'm just interested in their lower and higher acceptable isos regardless of push/pull tweakings. 

In this respect, i would rate the M240 (100-3200) as an average camera, much better than my old R-D1 (200-800) and M8.2 (160-640), close to my Panasonic LX100 (100-1600) and Fuji X-E2 (100-3200) but outperformed by my Sony A7s (100-12800) which has less pixels though. 
I would welcome a 100-6400 range in the next M body. No bragging 50-50000 a la SL601 please, a clean 100-6400 (or 50-6400) would be enough.
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Lets talk real world for a minute.

 
It is preferred that we shoot at  ISO 200.... Done.... perfect exposure PP till you get what you want
 
Say you cant arrive at the exposure you want at base (200) with the tools available. You up the ISO and we all agree 400 800 and 1600. Depending on your end result they will work "almost" as well as ISO 200. noise contrast  and color are more than acceptable....to me?
 
I see your point but I don't think it makes sense to LOCK your camera on ISO 200 and bring out/back in Post for every shot......then tweak for you desired result.  To me that seems like theory not real world...and too much work
 
do think of this like film, right or wrong it seems to me that's how this camera was designed to be used? ISO200 is your "sweet spot" then as needed you have additional choices available 200 to 1600 ISO, then you are free to adjust out the specific quarks that are inherent when you leave the base and add your particular feeling /quality at the end. 
 
Same holds true for 2000 through 6400 in this range you have a real challenge to use or try to adjust the file so you can obtain an acceptable amount of evils.....a difficult task at 6400 but depending how bad you want the shot , 2000 to 3200 could be made acceptable ...again depending on your expectations......Remember how we lowered our expectations when we had to shoot Trix  at 1600 developing it in Accufine ? The M240 shot 6400 looks better than that. We accepted  those giant balls of grain for the sake of getting the shot.
 
When I asked the question of how you all deal with the "sweet spot "in ISO I never expected the conversation to go the direction of ISO 200 is the best  with "I under expose and fix it later, because the result of a 200 ISO shot 2 or 3stops underexposed yields a better result then using 400 800 or 1600."
 
Did I read your posts correctly? I rarely make giant prints and I'm pretty good in Photoshop but I dont think locking my camera at ISO200 and adjusting for every shots exposure for best result first  is a method of shooting I can adopt? I will make more tests as you all given me something too think about.
It's the 2 or 3 stops under exposed thing that doesn't make sense when I have the tools 400 to 1600 available to me?  Currently I do fix exposure first in Post but never the extreme of 2 or 3 stops ...those, I throw away.
 
Anybody else have to think twice when typing ISO?....I always want to write ASA and there is the reason I think the way I do
 
Hep I like your Silo...you live in an very interesting part of the country ...neat stuff sand I do always appreciate you help and advice 
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Lets talk real world for a minute.

 
I see your point but I don't think it makes sense to LOCK your camera on ISO 200 and bring out/back in Post for every shot......then tweak for you desired result.  To me that seems like theory not real world...and too much work
 
do think of this like film, right or wrong it seems to me that's how this camera was designed to be used?
 
When I asked the question of how you all deal with the "sweet spot "in ISO I never expected the conversation to go the direction of ISO 200 is the best  with "I under expose and fix it later, because the result of a 200 ISO shot 2 or 3stops underexposed yields a better result then using 400 800 or 1600."
 
Did I read your posts correctly? I rarely make giant prints and I'm pretty good in Photoshop but I dont think locking my camera at ISO200 and adjusting for every shots exposure for best result first  is a method of shooting I can adopt? I will make more tests as you all given me something too think about.
It's the 2 or 3 stops under exposed thing that doesn't make sense when I have the tools 400 to 1600 available to me?  Currently I do fix exposure first in Post but never the extreme of 2 or 3 stops ...those, I throw away.
 
Anybody else have to think twice when typing ISO?....I always want to write ASA and there is the reason I think the way I do
 
Hep I like your Silo...you live in an very interesting part of the country ...neat stuff sand I do always appreciate you help and advice 

 

 

Hey thanks, Evan.   And yes, I've never fully tumbled to ISO either...  ASA is still where it's at in my head.

 

That said, "right or wrong" all you're doing when you dial up the ISO on your Leica is fooling the meter into thinking that there's more light than there is.  There may be some electronic wizardry going on in the processor, but the sensor records at ISO 200 regardless of what you set the ISO at... unlike film whose sensitivity actually varied with the emulsion formulation.

 

So, you can blithely twirl the ISO dial all you want... and let the electronics figure out what to do with the signal, or you can mentally calculate how many stops you're off, and make the exposure.

 

Twiddling the ISO will make the .jpg look properly exposed, and it'll be pleasing on the LCD and make you smile, but it won't give you a .dng image with the least amount of noise possible.

 

And don't worry... I've known about this since the dawn of digital sensors and I still have a tough time wrapping my head around it when I'm actually taking an exposure.  And frankly, in most cases I'm not sure that there's enough difference between what's recorded at ISO 200 and ISO 800 to worry about it...  

 

My point, though, is still that ISO is a dated film concept that has no valid application on a sensor past its base sensitivity.  Everything else is done by a processor and signal-to-noise amplifier.   ISO is merely a device for fooling a light meter and letting old guys like us think in terms we're used to.  If digital cameras didn't have a variable ISO setting when they were introduced,  no one would have bought them because we'd all have thought we were locked into whatever the base sensitivity of the sensor is.  Well, we are...  but the manufacturers let us think we aren't, and let us use our meters and all three exposure settings anyway as if we weren't.  

 

The Lytro camera is another thing I just can't get my head around...  changing perspective and focus in an image that's already captured?   There are concepts coming down the pike that just don't fit the ideas that we older guys have about imaging...  I recently bought a Mamiya AFDii outfit...  I've had it a couple of weeks, and I'm going to resell it because I just bought a Mamiya 645 pro outfit that still has the manual dials I'm used to.  I used to like to play with the new stuff...  and I don't any more.  It's not because I can't figure it out, I just don't want to.  I'd rather make images the way I'm already comfortable with rather than have to learn a new process before I can make the same images. 

 

The evolution of technology is a two-edged sword.  There's cool new stuff... but rather than learning it, I'd rather spend my time doing making images instead of figuring out how to use new the technology.  Perhaps that's the tempering that comes with maturing?

Edited by hepcat
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eCohen & hepCat:

 

We're all, apparently, from the same photographic era, as it were: we all shot film until we were proficient [sic], and are now shooting digital as a second language. Which means we all think in ASA/ISO as we did with film, but are just learning that the idea was kept around but doesn't really actually mean anything, except that it allows us to continue making images that we can chimp, rather than drown everything out in darkness. ISO variations then do two things: keep us from blowing out highlights, and allow us to chimp effectively (focus, dof, composition, etc.), as long as we stay within the range of the CMOS, which is much greater than we think.

 

How many stops is that sensor actually capturing then? What units could I be more efficiently using/thinking in than ISO/fStop/ShutterSpeed? Lumens? So then a whole new way - for me - of looking at capturing light: what combination of aperture and shutter speed will allow the appropriate range of lumens access to the CMOS.

 

One of the Holy Triad of exposure adjustments appears to have been taken from us, but that's short-sighted, because what we're learning is that the CMOS effectively has a much wider range of stops than film: from, let's say, three stops below ISO200 (native sensitivity), to perhaps as many as seven stops above (ISO3200+three stops). So as long as my exposure is within those eleven stops, I should have data to manipulate - RAW files assumed - trusting that the RAW file isn't automatically discarding highs and lows just because the meter said so based on ISO/fStop/ShutterSpeed inputs (but my experience of Christmas Eve, shooting after dark, was that the meter gave up ("I can't see nothin!"), while the sensor kept gathering light ("Oo: pretty!").

 

Which is to say, I might help myself through the transition by shooting the M240 like an M4: no internal light-meter, because that just tricks me into old patterns: use the Lumu in my iPhone as a spotmeter dialed up to whatever ISO I like (say... max of 3200 on the M240), choose the aperture/shutterspeed combo I like, leave the M240 set on 200, and bang away.... So: ISO200, any shutter speed and aperture combo that won't blow out highlights and would capture blacks at (theoretical) ISOs up to 3200, and bob's your uncle in post-processing.

 

What we need, really, is the metering revolution, not evolution: kill the ISO inputs, give us a meter that shows what the CMOS is capable of registering and how many stops we're exploiting with our current f/speed combo, retain the chimping capability despite exposure (a sort of temporary auto-gain for the camera display), and post-processing that acknowledges the new methods.

 

Whoa.

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eCohen & hepCat:

 

 

Whoa.

 

Yep.   Whoa.  And it's only going to improve.  

 

Set the ISO at 200 and shoot away 'cause you're gonna have image.  And dial it up the way you want it to look in PP.

 

Shutter speed is for stopping action, and aperture is for controlling DOF...  and that, as they say, is pretty much...  that. 

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I sense you guys must be kidding ?  You cant possibly work this way....can you?

 
So forget the LCD and expose however you want ....with your camera set to ISO 200 ?
What if I want to check focus , my LCD is 3 stops dark....or perhaps a client wants to take a look at the LCD?
 
Fixing in Post of course is doable (to a point).... but with all the variables not Batch able. So what your saying is a lot of post work. Its not just a couple of PS sliders then batch the rest of the days shoot.
 
Why are you ignoring 400 800 and 1600 for all that post work ?  Not to mention the LCD for checking stuff.... all kinds of stuff. I would rather use what Leica gave me and tweak 400~1600  and "zero" out their quarks.
 
You really work this way? I'm feeling that this group is pulling my leg...for the sake of explaining why ISO doesn't matter in digital.
I get that....... but to ignore 400~1600 because 200 is the base ....dare I say thats a silly way to work.
 
How do you really work.......? Hep your still shooting professionally thats what you do? Under expose and fix everything in post? ......When do you have time for anything else  ;)  
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I think some here are talking the ISO equivalent of pixel peeping.   In most instances it makes little difference if I let the camera do its magic to bring out the image by dialing in more gain or if I take the low gain image and try to boost it out of camera.   The end results are quite similar, especially if the picture is going to wind up on a web page at 1024x768 resolution :)

 

There are likely times when it makes a difference. For me those times are rare. I'll mostly let the camera do the job because it's easier.   If I spent most of my time shooting start at night I might feel different.

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There are likely times when it makes a difference.

 

 

The very few cases where it makes a difference pushing in post, it means that the camera firmware is badly implemented.

A DNG file can also store push values, which the camera could use if it "thinks" it makes more sense to push in post.

Edited by CheshireCat
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Agree that is is the easy option, but surely the processing power of a modern computer (either flavour) with Lightroom or Capture one or whatever has to be better than an in-camera processor doing the same job?

 

 

Usually, in-camera processors are hardware accelerated and tuned specifically for that particular camera.

For specific tasks, they can be faster than a powerful generic multi-core CPU.

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So we might push on this (as RED already has: thanks for that link): ask Leica to delete the ISO jerry-rig, give us a menu option that would show Lumens/CMOS range readout, and have revised Chimp options: one that flattens or stretches the image data so that we can proof focus/dof/motion/composition (essentially what it does now), perhaps an overlay with a full-CMOS-range histogram - including stop values/lumens - and another with pointers indicating highest and lowest values in the file and whether or not they fall within the range of the CMOS (blowouts and burieds) with lumen values... thinking of light like this feels like the difference between metric and Imperial units (although, thankfully, both f-stop & shutter-speed are simple mathematical ratios, so not quite, although the numbers used for aperture, although traditional and logical, are still a little on the obtuse side).

 

Who's willing to hack their M240 software in the name of progress & science?

 

And do I dare introduce the question of ETTR/ETTL?

 

 

 

eCohen starts the best* threads

*for hijacking

Edited by icqcq
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I sense you guys must be kidding ?  You cant possibly work this way....can you?

 
So forget the LCD and expose however you want ....with your camera set to ISO 200 ?
What if I want to check focus , my LCD is 3 stops dark....or perhaps a client wants to take a look at the LCD?
 
Fixing in Post of course is doable (to a point).... but with all the variables not Batch able. So what your saying is a lot of post work. Its not just a couple of PS sliders then batch the rest of the days shoot.
 
Why are you ignoring 400 800 and 1600 for all that post work ?  Not to mention the LCD for checking stuff.... all kinds of stuff. I would rather use what Leica gave me and tweak 400~1600  and "zero" out their quarks.
 
You really work this way? I'm feeling that this group is pulling my leg...for the sake of explaining why ISO doesn't matter in digital.
I get that....... but to ignore 400~1600 because 200 is the base ....dare I say thats a silly way to work.
 
How do you really work.......? Hep your still shooting professionally thats what you do? Under expose and fix everything in post? ......When do you have time for anything else  ;)  

 

 

I'm not pulling your leg...  I'm just explaining why the ISO settings on digital cameras are essentially irrelevant.    WE were taught in the film days that it makes a difference in the sensitivity of the medium.  That's just not a valid concern any longer. The medium's sensitivity doesn't change with the ISO setting.... it's just the way the camera processes the signal that changes.   The ISO settings are truly just there to make us feel like we're getting our money's worth, and to make it feel like a film camera for us old guys.  If you look at the very latest cameras like the GoPros and Lytro...  there are no settings.  Anywhere.  They just don't need them.

 

There ARE times when it's useful to dial it up... such as checking focus or for pixel peeping on the LCD...  and that's really only necessary if you don't have live-view and are pixel peeping a .jpg.  If you have live-view, it'll show you a properly exposed image no matter how you set the camera for focusing (unless you turn that feature off.  Honestly, as long as you've got a shutter speed you can hand-hold, and the exposure isn't more than four or five stops under-exposed, you'll have the same (or potentially better) image than if you'd dialed up the ISO.  It's magic I tell ya.

 

For the sake of being able to be lazy and use my meter in really low light conditions, I let the ISO "float" as high as 1000 ISO on my M9P as there isn't much discernible difference up to ISO 1000 for what I shoot.  That covers pretty much everything I ever do.  But honestly, I could just as easily leave the ISO on 200 and not worry about it.  Using flash, or in normal sunny-16-ish conditions, I set it at 160 and leave it.

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So we might push on this (as RED already has: thanks for that link): ask Leica to delete the ISO jerry-rig, give us a menu option that would show Lumens/CMOS range readout, and have revised Chimp options: one that flattens or stretches the image data so that we can proof focus/dof/motion/composition (essentially what it does now), perhaps an overlay with a full-CMOS-range histogram - including stop values/lumens - and another with pointers indicating highest and lowest values in the file and whether or not they fall within the range of the CMOS (blowouts and burieds) with lumen values... thinking of light like this feels like the difference between metric and Imperial units (although, thankfully, both f-stop & shutter-speed are simple mathematical ratios, so not quite, although the numbers used for aperture, although traditional and logical, are still a little on the obtuse side).

 

 

 

I suspect that in the next year or two, that will be the revolutionary new exposure system introduced by just about everybody.  It'll take a few years for current thinking to completely obsolete for the newer system, but yes, that's where we're heading.  RED is leading the charge.  I expect something from all of the major players to use that system in the next couple of years...  and then the change-over will begin.  The old analog light measuring systems will no longer have any relevance to the digital imaging world. 

Edited by hepcat
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[...] You really work this way? I'm feeling that this group is pulling my leg...for the sake of explaining why ISO doesn't matter in digital.

I get that....... but to ignore 400~1600 because 200 is the base ....dare I say thats a silly way to work.
How do you really work.......? Hep your still shooting professionally thats what you do? Under expose and fix everything in post? ......When do you have time for anything else  ;)  [...]

 

Reminds me of those threads about the way of "composing" in PP. See what i mean, we just need a 100 MP camera, shoot and crop in PP. Seems like there are two ways of being a photographer thanks to digital: in the field and in the armchair :D. Just kidding folks B)

Edited by lct
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