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Thread: a900 ISO: 100 vs 320

  1. #51
    Super Duper
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by Quentin_Bargate View Post
    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.

    Quentin
    I actually agree, and even wish there was ISO 25 available for some situations. I don't see this camera as a high ISO solution, so I don't use it that way (800 is about all I really need for a majority of my work, with 1000 as a reserve when needed.) Conversely, I'm not a fan of the lower ISOs on the Nikon D3/D700 ... but from about ISO 500 and above I love it.

    This is why I'd like to see Sony bring out a D700 competitor ... although it's been explained to me why that probably won't happen.

    I also think the noise issue at 320 is exaggerated. In 100% computer screen blow-ups it is far more apparent than in a print, even a large print. What is apparent in the ISO 320 print is the gain in micro detail which adds to the over-all dimensional feel a bit more.

    Personally, I don't want the camera to lessen the micro contrast qualities that some of the Zeiss lenses bring to the party ... at the very least I want the camera to stay out of the way of those charcteristics.

  2. #52
    Workshop Member kuau's Avatar
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by hardloaf View Post
    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
    So based on this test, is 320 superior even if the test was done properly exposed?

    Steven
    Steven Kornreich
    www.kuau.com

  3. #53
    hardloaf
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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by kuau View Post
    So based on this test, is 320 superior even if the test was done properly exposed?

    Steven
    That's subjective - you'll have to decide for yourself depending on what and how you shoot. There is less noise with 200, but shadows will be clipped. More noise and better shadows with 320. If shadows will need to be pushed with tone curve or exposure correction I'd definitely stay with 320.
    Personally I always stay at 320 because I don't even consider its noise level to be something to worry about. I tested 320 up to 30 sec. without any in-camera NR and it's definitely non-issue for me, but it's much safer for future post-processing.

  4. #54
    jmvdigital
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    Re: a900 ISO: 100 vs 320

    Just curious what you guys think of Michael's weigh in of the issue on LL:

    The camera's base ISO is 200, with ISO 100 being an extended speed. On most cameras the use of lower than native ISO is usually not a worthwhile exercise since it simply crushes dynamic range and contrast. But that's not the case with the A900. What the use of ISO 100 appears to do is reduce headroom at the top end of the exposure scale, but opens it up about a half stop in the shadows. It also lowers the noise (which is already very low at 200) from a Noise Ninja reading of 11 down to 9. According to DxOMark the noise reduction is almost 1db, from a SNR of 35.2 at ISO 200 to 36.3 at ISO 100, corroborating what is seen in Noise Ninja.

    Based on an extensive series of tests, I am now shooting with the A900 at ISO 100 when I can, which means when working on a tripod and when shadows are more important than highlights.

    BUT: But, be aware that by reducing the ISO below the camera's native 200 you are sacrificing one of the A900's great image quality assets, and that's its very broad highlight "shoulder". To my eye this gives the camera a very distinctive advantage in that highlights seem more film-like, with less of a tendency to clip, and to show more nuanced tonal and colour separation in lighter tones. For many current and prospective users, especially those with a sophisticated appreciation for the nuances of image quality, this highlight latitude may provide the camera's biggest appeal, so only switch to ISO 100 in situations where slightly lower noise and more shadow range are what's desired.
    http://luminous-landscape.com/review...ne-month.shtml

  5. #55
    hardloaf
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    Re: a900 ISO: 100 vs 320

    Hello Justin.
    Quote Originally Posted by jmvdigital View Post
    Just curious what you guys think of Michael's weigh in of the issue on LL:



    http://luminous-landscape.com/review...ne-month.shtml
    Nothing have changed for me and I still don't use any ISO below 320. MR did the right thing though - he tested everything with his workflow and made his conclusions. I always encourage everybody to do the same - you may love one converter or another, but most of people don't realize that their converters and the whole workflow may severely limit their cameras and lenses abilities and you must adapt your shooting style, reflexes and habits to squeeze more out of your equipment. This is certainly the case for pretty much all converters, noise filters, lens corrections and so on.
    RPP is designed to minimize those limitations and you can actually get pretty much everything out of your camera and lens, but there are consequences. Everybody who tried RPP knows what I mean

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    Senior Member douglasf13's Avatar
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    Re: a900 ISO: 100 vs 320

    I gotta say, Andrey, I finally moved back to an all Mac computer arrangement, and I started using RPP. Wow, what a revelation. Sure, LR3 beta has come along way over LR2, and the ease of workflow is nice, but your converter is so good that I'm willing to add the extra step in there...regardless of a bit of waiting time. I'm sending my RPP made tiffs to PS/LR, and that seems like a wonderful compromise. The film sims are great, btw. Donated earlier this week!

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    Re: a900 ISO: 100 vs 320

    Quote Originally Posted by fotografz View Post
    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)
    You're assuming that the modeling lights are voltage regulated and therefore constant ?

    Or you metered for each shot ?

    I've been shooting with Profoto for over a decade and I have seen the modeling lights dim with line voltage fluctuations.

  8. #58
    hardloaf
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    Re: a900 ISO: 100 vs 320

    What can I say - welcome back to the Mac world and I'm glad that you find RPP useful

    Quote Originally Posted by douglasf13 View Post
    I gotta say, Andrey, I finally moved back to an all Mac computer arrangement, and I started using RPP. Wow, what a revelation. Sure, LR3 beta has come along way over LR2, and the ease of workflow is nice, but your converter is so good that I'm willing to add the extra step in there...regardless of a bit of waiting time. I'm sending my RPP made tiffs to PS/LR, and that seems like a wonderful compromise. The film sims are great, btw. Donated earlier this week!
    Andrey

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