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Thread: a900 ISO: 100 vs 320

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    a900 ISO: 100 vs 320

    Lately there's been some talk on this forum that 320 ISO would be an interesting ISO setting for the a900. Kind of a 'sweet spot' for the right exposure and noise. I compared 100 to 320 ISO and here are some screenshots of in-camera jpgs. It looks like 100 ISO shows more detail, saturation, better contrast and also less noise.

    There's some purple fringe in the 320's that not visible in 100. Probably makes sense with the higher sensitivity, but it may be one more reason to stick with 100 ISO.

    What are your thoughts? Why use 320 ISO?

    320 is on the left, 100 right.

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    Re: a900 ISO: 100 vs 320

    Been wondering about the same reports. Good thread
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    Re: a900 ISO: 100 vs 320

    I think the comparison needs to be done in raw though. ISO 100 does look sharper.
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    Re: a900 ISO: 100 vs 320

    Hmm - okay, but what about ISO 200 - which Sony reckons is the correct base ISO?

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by carstenw View Post
    I think the comparison needs to be done in raw though. ISO 100 does look sharper.
    Hi Carsten, I agree, raw must compared too. Interesting thing here: in RD standard settings things look different... Now 320 seems to look better. 320 is still noisier though.

    again, 320 on the left, 100 on the right.

    (will do more testing/developing tomorrow, bedtime in Amsterdam )

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    Re: a900 ISO: 100 vs 320

    Why use ISO 320?

    Subject motion?

    The question is why test anything in jpg?

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    Re: a900 ISO: 100 vs 320

    ISO 100 is a +1 EV exposure comp of ISO 200, and there is no gain difference between the two. You essentially exposed the ISO 100 one more stop than the ISO 320 shot. Try this again in raw with ISO 200. Also, the reason for ISO 320 is that doesn't clip and blob out shadow detail. This may or may not make things appear very slightly more noisy overall than ISO 200, but it's worth it in most situations, IMO. ISO 200 destroys shadow detail, which is easily checkable with Rawanalyze.

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    Re: a900 ISO: 100 vs 320

    Okay, this made me curious. So I just ran a controlled test in studio.

    Available but constant light (Profoto modeling lights in soft boxes, no variable)

    A900, 24-70 @ 70/5.6 on a tripod to keep it a constant. RAW.

    Walked through all ISOs from 100 through 3200.

    Batch sync processed in CS4 Bridge-ACR.

    Opened as 16 bit tiffs in CS4, viewed at 100% on screen.

    ISO 320 clearly shows more micro detail than 100 which seems to suppress it, (see the crop where a finger print is more clearly visable in the 320 shot).

    320 shows a bit more noise than 100 but not a lot more, and in most practical applications would be a non issue. Color looked a bit better at ISO 320.

    No surprise, ISO 200 records more nano detail than 100 but not quite as well as the 320, while exhibiting the noise level very close to the 100.

    In all but the most huge enlargements I'd agree that 320 is the optimal balance between recording detail with acceptable noise levels when working at the lower ISO end.

    The question is how much sharpening with 100 works, and how much selective noise control for 320 works, and in the end which is better? I suspect that if you sharpen 100 to gain back the detail the noise will be enhanced, so you may as well have shot 200 or 320 in the first place.

    I would only resort to 100 if trying to control shallow DOF in extraordinarily bright conditions, or to produce a slow shutter speed, but not for IQ.

    HIGH ISOs

    I detected very little applied difference between ISO 1250 and 1600. There is some, but the noise structure is very similar.

    But when compared to ISO 1000 it was clear that 1000 was the best high ISO because it did not exhibit a salt 'n pepper type grain structure apparent in 1250 and 1600.

    Plus, ISOs 1250 and above (but not much in 1250) increasingly showed blue blotches in the solid black areas. ISO 1000 showed no signs of this at all.

    My working conclusion would be that 1000 is highly usable on this camera if exposed with the usual care needed for any high ISO application. 800 is better, and 640 even better ... with 640 being the optimal balance between detail and noise in mid range ISOs. But 800 is no slouch.

    -Marc

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    Re: a900 ISO: 100 vs 320

    Marc,
    Will this test now change your basic setting to 320? Based on the long thread this weekend and an email from Jono that is where I set it.

    terry

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    Re: a900 ISO: 100 vs 320

    Very interesting indeed. Marc, are there visible differences between let's say iso 320 and 400 or 250?
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    Re: a900 ISO: 100 vs 320

    Each sensor model in digital cameras has one sensitivity and this is a basic physical property of the sensor. All in-camera ISO adjustments cannot change it - they work through internal analog/digital processing when information is extracted from the sensor after image is captured, kind of internal push/pull in film terms. So whatever it captures is going to be the same as long as shutter and aperture are same, ISO doesn't matter at this stage.

    When you compare two shots at ISO 100 and 320 you essentially gave sensor 1 2/3 stops more light in case of ISO 100, so no wonder it's less noisy.

    Regarding ISO 320 - just make a shot at ISO 200 and 320 with good colored shadow details and process them identically in IDC f.e. Shadows will be different and at ISO below 320 they can get weird tint like greenish or purplish and also they'll get clipped. It's easier to see if both shots are equally underexposed.

    Even Sony warns about limited DR for ISOs below 200 and they are not kidding. I'd never recommend anybody to use those actually

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by hardloaf View Post
    Each sensor model in digital cameras has one sensitivity and this is a basic physical property of the sensor. All in-camera ISO adjustments cannot change it - they work through internal analog/digital processing when information is extracted from the sensor after image is captured, kind of internal push/pull in film terms. So whatever it captures is going to be the same as long as shutter and aperture are same, ISO doesn't matter at this stage.

    When you compare two shots at ISO 100 and 320 you essentially gave sensor 1 2/3 stops more light in case of ISO 100, so no wonder it's less noisy.

    Regarding ISO 320 - just make a shot at ISO 200 and 320 with good colored shadow details and process them identically in IDC f.e. Shadows will be different and at ISO below 320 they can get weird tint like greenish or purplish and also they'll get clipped. It's easier to see if both shots are equally underexposed.

    Even Sony warns about limited DR for ISOs below 200 and they are not kidding. I'd never recommend anybody to use those actually
    So, If you are in a bright situation and you max out on shutter speed you are better off with an ND filter than going lower on ISO?

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    Re: a900 ISO: 100 vs 320

    Now that is a PITA to deal with. Must be a way to draw out a better base 100. Not so sure I am seeing the contrast lower in the ISO 100 shots. Can we not add some clarity to the 100 shots to draw out more detail. Seems to me this maybe a higher DR that is flattening out the file at 100 and the 320 shots we are seeing the contrast higher because it is shortening the DR. Has anyone actually measured the DR difference between these two ISO's. I have a tough time going with a base 320 on any cam. 200 is more reasonable
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    Re: a900 ISO: 100 vs 320

    Guy,
    I'm not saying I would always do this but just following the thought all the way through to see what the "best" answer is vs. making a decision about the practical answer.

    terry

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    Re: a900 ISO: 100 vs 320

    I realize that but I am seeing some DR difference here and it is affecting the micro contrast by lowering the contrast on the ISO 100 shots. Some small adjustments in the raw conversion like clarity can bring that right back in line with micro contrast.
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by TEBnewyork View Post
    So, If you are in a bright situation and you max out on shutter speed you are better off with an ND filter than going lower on ISO?
    If you want to stay wide good ND will be the best option quality wise, but usually I just prefer to step down.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Guy Mancuso View Post
    I realize that but I am seeing some DR difference here and it is affecting the micro contrast by lowering the contrast on the ISO 100 shots. Some small adjustments in the raw conversion like clarity can bring that right back in line with micro contrast.
    Guy is right, the 100 ISO crop clearly shows greater dynamic range. Notice ISO 100 has MORE shadow detail in the dark tones top left just below the gray patch, and overall tonality is smoother (compare the orangish color patch, in the ISO 320 crop it's going blotchy).

    Last month I spent 5 weeks on a road trip in the West shooting the A900, much of the time at 100 ISO, and the files processed in Raw Developer are simply superb, with way more DR and shadow detail than my 4x5 Velvia chromes and a very natural filmlike look. In my landscape work the reported clipped shadows at less than ISO 320 is simply not showing itself. If someone has measured such with their camera sample, cool, but for me the result in 20x30 prints is all I care about and there is zero visible issue for me. Before I left on the trip I carefully ran an indoor test comparing every ISO in 1/3rd steps from 100 to 800, and 100 definitely shows the lowest noise on my A900.

    Cheers,
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    Re: a900 ISO: 100 vs 320

    Hi There
    Well, I think this is all extremely interesting, however, personally, after 6 months shooting at ISO 200 (which Sony say is native) I've found no problems with shadow areas, and I also find it convenient for most circumstances. (which, of course, is not to say that it is the best, just that it is okay).

    Marc - I found your comparison between ISO 1000 and 1250 really useful

    The nice thing about this is that I no longer have any qualms about using ISO 320, if I really couldn't shoot wide enough open with ISO200 I would use ISO100 without any worries either - using an ND filter adds all sorts of other variables into the mix anyway.

    I know we all want the best out of our kit, but sometimes this gets dangerously close to angels dancing on the heads of pins - I'll settle for the lovely files out of the A900, and I'll use whatever ISO seems appropriate at the time (in the knowledge that the cameras only obvious compromise is that it's not a high ISO machine).

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by fotografz View Post
    The question is how much sharpening with 100 works, and how much selective noise control for 320 works, and in the end which is better? I suspect that if you sharpen 100 to gain back the detail the noise will be enhanced, so you may as well have shot 200 or 320 in the first place
    -Marc
    I agree, this is THE question. I'd like to know the answer and get on taking pictures with this wonderful camera. I plan to work with this system for two years and don't want to end up with a large archive full with 100 ISO shots regretting I didn't shoot 320, or vice versa.

    The results so far seem to suggest that the difference between 100 and 320 is not such big deal, but than again every bit of more detail and less noise is a nice bonus to the already very pleasing results we get from this camera.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Guy Mancuso View Post
    I realize that but I am seeing some DR difference here and it is affecting the micro contrast by lowering the contrast on the ISO 100 shots. Some small adjustments in the raw conversion like clarity can bring that right back in line with micro contrast.
    Guy, I was thinking along those lines too, so I brought the 100 ISO shot into RD again and took down exposure 0,59 and added contrast + 0,20 to match the 320 ISO that was developed with standard settings.

    Now there doesn't seem to be much difference, really. Obviously 320 is still noisier though.

    BTW What do you guys think about the color fringe on the letterbox in the 320 shot?

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    Re: a900 ISO: 100 vs 320

    I totally agree with Ross and Jono. I have been shooting since I got the A900 at ISO 100 with excellent results. I only go higher when it is absolutely required. I have no convincing reason yet to do otherwise.
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    Re: a900 ISO: 100 vs 320

    Peter, the simple fact that you had to bring down the ISO 100 shot makes your test faulty, as it is more exposed to the right to begin with, which results in less noise.

    Edward shooting ISO 100 is fine, but it is exactly the same as shooting ISO 200 with +1 EV comp.

    We are all free to shoot with whatever settings we choose, but I think if everyone shoots a bunch of similar shots at ISO 200 and 320, and then looks at them in Rawanalyze, they will see that 200 shadow clipping is rather obvious. It is so noticeable that some a believe that the A900 uses NR at lowISO (I disagree.)

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by TEBnewyork View Post
    Marc,
    Will this test now change your basic setting to 320? Based on the long thread this weekend and an email from Jono that is where I set it.

    terry
    Yes Terry, I think so. Based on this exploration, I see no practical real world advantage in using ISOs below 320 unless it is to control DOF or to decrease shutter speed for creative reasons.

    BUT, I'll know better once I actually apply the notion in my real world work.


    Perhaps what was more important to see was what ISOs in the mid range and high end to apply if possible. In most of my shooting situations ISO 1000 seems very workable. So ISO 320, 640 and 1000 appear to be a good working base in terms of IQ.

    Here are those three ISOs I would gravitate to as a working base. All three were sharpened for web (click on them individually to see better renditions), and I left the dust on the subjects to see any effects on nano resolution. I also applied Nik Define 2 to the ISO 1000 file to see how it would stand up to the 640 file ... not bad.

    I used Auto Color in PS/CS4 to keep consistent ... and found it gratifying to see a pretty consistent color rendition across such a wide range of ISOs.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Guy Mancuso View Post
    Now that is a PITA to deal with. Must be a way to draw out a better base 100. Not so sure I am seeing the contrast lower in the ISO 100 shots. Can we not add some clarity to the 100 shots to draw out more detail. Seems to me this maybe a higher DR that is flattening out the file at 100 and the 320 shots we are seeing the contrast higher because it is shortening the DR. Has anyone actually measured the DR difference between these two ISO's. I have a tough time going with a base 320 on any cam. 200 is more reasonable
    Guy, from what I am seeing with full res screen shots, ISO 100 is a waste of time for my applications. Attempts to restore the micro detail that the Zeiss lenses deliver just increases the noise.

    However, ISO 200 is a different matter. It does retain enough micro detail to make it far less traumatic when sharpening. I'd say that for your applications the base would be 200 ... which I believe is the native resolution of this camera if I'm not mistaken.

    Now, what hasn't been explored is really huge enlargements, and what happens with ISO 100, 125, and 160 shots using a really good sharpening program.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by jonoslack View Post
    Hi There
    Well, I think this is all extremely interesting, however, personally, after 6 months shooting at ISO 200 (which Sony say is native) I've found no problems with shadow areas, and I also find it convenient for most circumstances. (which, of course, is not to say that it is the best, just that it is okay).

    Marc - I found your comparison between ISO 1000 and 1250 really useful

    The nice thing about this is that I no longer have any qualms about using ISO 320, if I really couldn't shoot wide enough open with ISO200 I would use ISO100 without any worries either - using an ND filter adds all sorts of other variables into the mix anyway.

    I know we all want the best out of our kit, but sometimes this gets dangerously close to angels dancing on the heads of pins - I'll settle for the lovely files out of the A900, and I'll use whatever ISO seems appropriate at the time (in the knowledge that the cameras only obvious compromise is that it's not a high ISO machine).
    I tend to agree. I'm working in such hectic, hell-bent-for-leather environments that I need everything at my disposal. That said, this was useful in that it gave me a base range to gravitate to when possible. Prior to this I set 400 as a shooting base for most the work I do, knowing 320 may provide a touch better IQ makes it the base I will start at. And ISO 1000 becomes the top target unless absolutely necessary. Above that I'd probably opt for the D700.

    -Marc

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by fotografz View Post
    Guy, from what I am seeing with full res screen shots, ISO 100 is a waste of time for my applications. Attempts to restore the micro detail that the Zeiss lenses deliver just increases the noise.

    However, ISO 200 is a different matter. It does retain enough micro detail to make it far less traumatic when sharpening. I'd say that for your applications the base would be 200 ... which I believe is the native resolution of this camera if I'm not mistaken.

    Now, what hasn't been explored is really huge enlargements, and what happens with ISO 100, 125, and 160 shots using a really good sharpening program.
    Thanks Marc you know I come from the old school still and we always want the lowest ISO to gain the most out of the film or sensor. I feel more comfortable at the ISO 200 mark than I do at the ISO320 mark. Obviously this maybe a mental thing and if I owned one which I hope to do someday i would just feel better at ISO 200. I know somewhat stupid but can't change my spots. LOL

    Also I like wide open a lot to even in the bright AZ sun so I tend to like the ISO numbers to be as low as I can go. This is all very interesting though I have to say and excellent tests too that show it's range. I pretty much thought the top is ISO 1200 with maybe a little help. What I would like to try and I will do this in a couple weeks at the workshop when 2 of these A900 are there is process the files in C1 which has always been very good at noise control and maybe we can see cleaner high ISO's. Also like to run a test against my P30+ and actually a Nikon D3x will be on board as well. So I may try a couple things but from all that I have seen of this Sony i am impressed and i am really hard to impress on the gear front. Have too many gold T shirts.
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by fotografz View Post
    I tend to agree. I'm working in such hectic, hell-bent-for-leather environments that I need everything at my disposal. That said, this was useful in that it gave me a base range to gravitate to when possible. Prior to this I set 400 as a shooting base for most the work I do, knowing 320 may provide a touch better IQ makes it the base I will start at. And ISO 1000 becomes the top target unless absolutely necessary. Above that I'd probably opt for the D700.

    -Marc
    I know for your pro use you wouldn't go over 1000. I need to play around above ISO 1000 and see how high I can go for printing at smaller sizes (5x7 or at most 8x10). There were some real practical reasons for owning the D700 but to have this many pixels I should be able to get small things looking OK.

    Also, just to reiterate on the ND question I posed, as I said to Guy, I like understanding the theory but I'm generally both practical and lazy.

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    Re: a900 ISO: 100 vs 320

    Shooting at ISO 320 vs 200 sounded counter intuitive to me since the purported base ISO is 200 on the A900 and things logically would only go downhill from there. This seems to be backed up by DXO.

    I was curious what the differences might be so I pulled a couple of RAW file examples from imaging resource and processed them with Raw Developer by pushing up the shadows. Below are crops from 400 and 200 ISO examples. Don't have ISO 320 examples so maybe that is significantly different (I doubt it but willing to be proven wrong).

    These examples show pretty much what you would expect. You are giving up dynamic range (i.e. we are losing detail in the shadows) by bumping the ISO...

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by jonoslack View Post
    Hi There
    Well, I think this is all extremely interesting, however, personally, after 6 months shooting at ISO 200 (which Sony say is native) I've found no problems with shadow areas, and I also find it convenient for most circumstances. (which, of course, is not to say that it is the best, just that it is okay).

    Marc - I found your comparison between ISO 1000 and 1250 really useful

    The nice thing about this is that I no longer have any qualms about using ISO 320, if I really couldn't shoot wide enough open with ISO200 I would use ISO100 without any worries either - using an ND filter adds all sorts of other variables into the mix anyway.

    I know we all want the best out of our kit, but sometimes this gets dangerously close to angels dancing on the heads of pins - I'll settle for the lovely files out of the A900, and I'll use whatever ISO seems appropriate at the time (in the knowledge that the cameras only obvious compromise is that it's not a high ISO machine).
    Yeah, the higher ISO comparisons were of more value to me since the instances I get to use ISO 100 are almost nonexistent.

    When I know I will be shooting in that kind of "fat light" I use the H3D-II/39 which walks away from A900 at a brisk pace

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by fotografz View Post
    Yeah, the higher ISO comparisons were of more value to me since the instances I get to use ISO 100 are almost nonexistent.

    When I know I will be shooting in that kind of "fat light" I use the H3D-II/39 which walks away from A900 at a brisk pace
    HI Marc
    well, I'm not sure we ever get light quite that fat this far north!

    An interesting point - I took some shots last night, almost literally in the dark, really just to see what's what. I'd set the camera at 1250 ISO with the 135 at f1.8, but I had to under-expose by 2 stops to get a minimum shutter speed of 1/125th (the chickens were moving). The results are okay (you can see them on the fun pictures thread if you're interested).

    The question is - is it better to under-expose at a lower ISO, or to expose properly at a higher one?

    I think Douglas reckons that you should never go above 400 ISO, simply underexpose progressively and bring it back in post processing.

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  31. #31
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    Re: a900 ISO: 100 vs 320

    Folks, you just need to realize that shooting digital is like having a film body with only one film available and obviously it has only one ISO. There is no choice here - it's mounted there permanently. The ISO number itself is kind of irrelevant - in digital it's different for all cameras and not comparable to other cameras when shooting Raw, so don't get stuck with "lower is better" and so on. You can push/pull process of course, it's easy in digital, but it's not harmless and has it's pitfalls. All I can say - do your testing like Marc did. All these things are highly dependant on your converter and overall workflow, especially in defining the top limit. The basic rules are still the same and for digital the most important one is - expose properly. When you shift your ISO in camera you are playing with overexposure, underexposure, push and pull - exactly as it would be on film and probably it's better for you to know what you are actually doing.

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    Re: a900 ISO: 100 vs 320

    Yes and no you still can't get past the 1/8000 shutter and that can cause problems with trying to shoot with a wide open aperture. Also it can relate to flash fill in getting to high in ISO will push the shutter beyond what it can sync at as well. Most camera's are 1/250 sync in bright sun that is F11 by our sunny rule at ISO 100 . Now just One stop at F16 ISO 200 we need to get a crap load of more juice out of a fill flash unit and a portable unit will not cut it. So besides the base we have a issue in two sectors that become extremely important and for a wedding shooter outdoors and fill flash a nightmare if the true base is 320. I have been up against this wall more times than I can count and pulling out a Ranger at 1200 watts of juice is not always a option. We still have to have a low ISO or fill flash we will stop running out of F stops with a high ISO
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  33. #33
    hardloaf
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Guy Mancuso View Post
    Yes and no you still can't get past the 1/8000 shutter and that can cause problems with trying to shoot with a wide open aperture. Also it can relate to flash fill in getting to high in ISO will push the shutter beyond what it can sync at as well. Most camera's are 1/250 sync in bright sun that is F11 by our sunny rule at ISO 100 . Now just One stop at F16 ISO 200 we need to get a crap load of more juice out of a fill flash unit and a portable unit will not cut it. So besides the base we have a issue in two sectors that become extremely important and for a wedding shooter outdoors and fill flash a nightmare if the true base is 320. I have been up against this wall more times than I can count and pulling out a Ranger at 1200 watts of juice is not always a option. We still have to have a low ISO or fill flash we will stop running out of F stops with a high ISO
    Well tell me about this - I live in California and know what sun is and I was also frustrated when discovered that 320 thing, but this is the digital reality and it's the same story for all kinds of digital cameras. Your scenario actually is rather interesting and it's a good subject for testing - somebody needs to check what actually works better with fill flash, plain ISO 100 or overexposed higher ISOs.

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    Senior Member Braeside's Avatar
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    Re: a900 ISO: 100 vs 320

    Guy, does High Speed Sync with the Sony flashes help in this scenario?
    For those that are not familiar - with HSS you can use flash at higher than the max shutter sync speed. I appreciate that the flash has to run a burst of small flashes as the shutter slit traverses the frame to do this and it will take more juice to do that.
    David Anderson

  35. #35
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Greg Seitz View Post
    Shooting at ISO 320 vs 200 sounded counter intuitive to me since the purported base ISO is 200 on the A900 and things logically would only go downhill from there. This seems to be backed up by DXO.

    I was curious what the differences might be so I pulled a couple of RAW file examples from imaging resource and processed them with Raw Developer by pushing up the shadows. Below are crops from 400 and 200 ISO examples. Don't have ISO 320 examples so maybe that is significantly different (I doubt it but willing to be proven wrong).

    These examples show pretty much what you would expect. You are giving up dynamic range (i.e. we are losing detail in the shadows) by bumping the ISO...
    There are many problems one on top of another with this test. Most obvious to me f.e. - RD is not doing good job with pushing shadows and makes noise worse than it actually is and those Raw files are compressed ARWs (lossy),
    which is not harmless if you want to push. In any case all this is not that relevant. Higher ISOs are more noisy just because sensor gets less and less light from camera light meter while ISO grows, so more noise. What's important here is that we have case when picture has more details and more noise and ISO 320 resolves maximum amount of details and still remains rather clean.

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Braeside View Post
    Guy, does High Speed Sync with the Sony flashes help in this scenario?
    For those that are not familiar - with HSS you can use flash at higher than the max shutter sync speed. I appreciate that the flash has to run a burst of small flashes as the shutter slit traverses the frame to do this and it will take more juice to do that.
    Not sure Sony has this feature , can someone let us know but even so with other systems there is very little power output to do this for like a group at 15 ft or so
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    Senior Member Braeside's Avatar
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    Re: a900 ISO: 100 vs 320

    It does have that feature Guy - HSS - but the question you rightly ask is there enough juice to do this. I only have the small 3600HS-D Minolta flash, not the bigger Sony 58-AM so cannot really test this in a sunny situation - not that I have this problem here just now !
    David Anderson

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Guy Mancuso View Post
    Not sure Sony has this feature , can someone let us know but even so with other systems there is very little power output to do this for like a group at 15 ft or so
    Yes, it has HSS. Same limitations as any HSS... more or less depending on the power of the unit.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by hardloaf View Post
    Well tell me about this - I live in California and know what sun is and I was also frustrated when discovered that 320 thing, but this is the digital reality and it's the same story for all kinds of digital cameras. Your scenario actually is rather interesting and it's a good subject for testing - somebody needs to check what actually works better with fill flash, plain ISO 100 or overexposed higher ISOs.
    When I've run into that so far, I just use ISO 100 so I can use the flash at or below normal sync speeds. Use the 85/1.4 like that a lot. It's not like 100 sucks or anything. I carry a polarizer with me in case I run out of options ... I've used it like that exactly zero times.

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    Re: a900 ISO: 100 vs 320

    Thanks Marc you know me i look at all the curve balls being thrown. Like all Pro's are jobs are to solve problems and create workarounds. Every system and every setup has something that you need to work and just good to know what some of these things are. I been working around low sync speeds all my career and just have to work at it some.
    Photography is all about experimentation and without it you will never learn art.

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    Re: a900 ISO: 100 vs 320

    Since ISO values are a bit abitrary in all cameras anyway, maybe Sony just needs a firmware release that adjusts ISO 200 to ISO 320, so that people get over the mental hurdle of using 320? BTW, this isn't unique to the A900. There are other cameras that exhibit similar behavior. If I remeber correctly, the original 5D was one of them.

    Andrey, as far as ISO 100, are you finding it to be more than just ISO 200 with +1 ev comp? Your posts seem to be implying something different, which is news to me.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Guy Mancuso View Post
    Thanks Marc you know me i look at all the curve balls being thrown. Like all Pro's are jobs are to solve problems and create workarounds. Every system and every setup has something that you need to work and just good to know what some of these things are. I been working around low sync speeds all my career and just have to work at it some.
    Guy, when I know I have a big group to shoot or something like that I've just tossed the Metz Potato masher in a Boda bag and strap it to the roller ... I picked up a Sony module for it ... then I'm carrying my own bag of sunlight with me

    BTW, I picked up the Metz from a forum member for less than my smaller Sony flash cost me.

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by hardloaf View Post
    There are many problems one on top of another with this test. Most obvious to me f.e. - RD is not doing good job with pushing shadows and makes noise worse than it actually is and those Raw files are compressed ARWs (lossy),
    which is not harmless if you want to push. In any case all this is not that relevant. Higher ISOs are more noisy just because sensor gets less and less light from camera light meter while ISO grows, so more noise. What's important here is that we have case when picture has more details and more noise and ISO 320 resolves maximum amount of details and still remains rather clean.
    Of course higher ISO is noisier, that's my point, it kills shadow detail thus reducing the dynamic range.

    I'm surprised you see more detail with 320 as that is clearly not the case here - look closely at the details in the bark of the tree, there are details in the 200 shot that have vanished in the 400 shot. Some of the noise is probably from sharpening with RD but the same amount was used on both files.

    It would be great to have you show some examples of 320 vs 200 where the 320 files look better overall since I don't see it with these 400 vs 200 files - providing raw files would be great.

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    Re: a900 ISO: 100 vs 320

    I'm glad I started this thread, there seems to be a lot of interest for this topic. I'm very happy with all the dicussion and feedback, thanks everyone.

    Andrey, I think it would be very helpful indeed if you could produce some examples of your workflow in RPP with the a900 files. And also a straightforward list of the camera settings you'd advise would be much appreciated. Now I know Douglas has kindly provided us with a lot of exposure and UniWB advise, but it would be nice to have it all in one thread and coming straight from you.

    Meanwhile I developed one of the testshots I did in RPP. I really think RPP deserves it's own thread on this forum. First of all, it's amazing how much detail can be pulled out of the a900 files with RPP! But these files look noisier. Now Andrey and Douglas and Mr. Borg will say that's because you didn't use the 'right' settings and underexposed. I'd like to find that out for myself, so please post examples and your settings.

    Anyway, back to 100 vs 320:

    Again there's more detail in the 320. But the 320 shots are certainly a lot more noisy.
    320 on the left, 100 on the right.

    Screenshot to show detail, screenshot to show noise difference and full shot. BTW, all my shots were f3.2 with the CZ 85.

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    Re: a900 ISO: 100 vs 320

    Peter,

    Have you had a chance to compare 200 vs 320?

    Thanks,

    Greg

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    Re: a900 ISO: 100 vs 320

    ISO 100 is useful where you need slower shutter speeds or a reasonable aperture. In fact I wish Sony did ISO50. Of course one can use ND filters but camera makers generally seem more intersted in blathering on about their cameras high ISO capability, which for many is not a priority.

    Its good to see ISO 320 produces decent results, but at the cost of more noise and reduced dynamic range. I'd only use it if I needed a faster shutter speed. I take most shots on ISO 100 or 200.

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  47. #47
    hardloaf
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by douglasf13 View Post
    Andrey, as far as ISO 100, are you finding it to be more than just ISO 200 with +1 ev comp? Your posts seem to be implying something different, which is news to me.
    Ok, probably I have to explain why I don't like those below-200s. I checked Raw data for ISO100 and 200 and to my surprise found that actually there is only 1/3 EV of a difference between them in midpoint. This means that when camera set to 100 gain is actually set to 160. Camera meter though exposes it like 100. Now guys enable your long forgotten film reflexes and answer what's going to happen if we expose ISO 160 film as 100?

    I find this all way too weird and complex to use when shooting. They essentially overexpose 160 for 2/3 EV and plus those clipped shadows in R and B channels make everything highly unpredictable. Thanks Sony, but no.

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    Re: a900 ISO: 100 vs 320

    Hi Greg, not yet, but would like to do that in the coming week.

  49. #49
    hardloaf
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by peterv View Post
    Andrey, I think it would be very helpful indeed if you could produce some examples of your workflow in RPP with the a900 files. And also a straightforward list of the camera settings you'd advise would be much appreciated. Now I know Douglas has kindly provided us with a lot of exposure and UniWB advise, but it would be nice to have it all in one thread and coming straight from you.
    I'll do this in a separate thread - this one is already too long.

    Meanwhile I developed one of the testshots I did in RPP. I really think RPP deserves it's own thread on this forum. First of all, it's amazing how much detail can be pulled out of the a900 files with RPP! But these files look noisier. Now Andrey and Douglas and Mr. Borg will say that's because you didn't use the 'right' settings and underexposed. I'd like to find that out for myself, so please post examples and your settings.
    I'd say if you see objectionable noise in RPP which shows in final prints or down-sampled web images you need to start with decreasing sharpness slider in RPP and do selective sharpening in Photoshop or something like this. RPP doesn't do any noise filtering, so whatever you see is pretty much what your camera produces. This all is intentional and indeed is a topic for another talk.

    Anyway, back to 100 vs 320:

    Again there's more detail in the 320. But the 320 shots are certainly a lot more noisy.
    320 on the left, 100 on the right.

    Screenshot to show detail, screenshot to show noise difference and full shot. BTW, all my shots were f3.2 with the CZ 85.
    I wouldn't call it 'a lot more noisy' for most of practical uses. I'll try to produce some samples, but let's first settle with few things.

    1. Properly exposed shot on ISO 320 will have more noise than on ISO 200. No doubts in that. ISO 200 should also produce higher DR, if not that R/B channels shadow clipping. So it actually doesn't - all that advantage is eaten by clipping and non-linearity in R/B channels.

    2. 320 is good because that's first ISO which doesn't clip shadows. Please stop repeating that you don't see it in all your hundreds of ISO200 shots - just shoot something with colored shadows at 200 and 320, process identically and compare ignoring noise. If you don't see the problem then you have nothing to worry about - your perception is in balance with Sony and go get some life
    Last edited by hardloaf; 28th May 2009 at 14:52.

  50. #50
    hardloaf
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    Re: a900 ISO: 100 vs 320

    Here is first example.
    Same exposure (shutter and aperture), different ISOs.
    200 left, ISO 320 right.
    Shots were underexposed, so 320 was compensated for 3 stops and 200 for 3 2/3 in converter. Also only WB and tone curve were applied without any kinds of filtering, sharpening and so on. In theory 200 should be cleaner, but actually 320 shows disproportionally better result with exactly the same amount of light reaching the sensor. 200 has purple shadows and on 100% view you can see that it's really troubled.

    Attachment 16969

    Attachment 16970

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