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Thread: Boosting exposure in LR

  1. #1

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    Boosting exposure in LR

    My Ds3 has a limit, by my standards, of ISO 400>if I take an underexposed image, which was set at ISO 100, and must apply a +1.00 in LR to bring it up to proper exposure, the amount of noise is equal to what I would see from a ISO 400 image without LR exposure adjustment.

    Are newer camera bodies that can shoot at higher ISO values handle badly missed exposures more capably than the older bodies...can you boost exposure in LR by +1.00, assuming an initial setting of ISO 100, without adding visible noise to that image?

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    Brownbear's Avatar
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    Re: Boosting exposure in LR

    Hi Chauncey,

    I have a Nikon D7100 and I can boost exposure in a raw photo (no other adjustments) by 1 in LR with the exposure slider and see no visible noise at 100%. I also tried it with a photo from a Sony 200 and a Nikon D80 at iso 100 and saw no noise at 100%.

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    Shadowman's Avatar
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    Re: Boosting exposure in LR

    Quote Originally Posted by chauncey View Post
    My Ds3 has a limit, by my standards, of ISO 400>if I take an underexposed image, which was set at ISO 100, and must apply a +1.00 in LR to bring it up to proper exposure, the amount of noise is equal to what I would see from a ISO 400 image without LR exposure adjustment.

    Are newer camera bodies that can shoot at higher ISO values handle badly missed exposures more capably than the older bodies...can you boost exposure in LR by +1.00, assuming an initial setting of ISO 100, without adding visible noise to that image?
    Doesn't the D3s have an ISO range of 12.800 or do you mean noise is noticeable at ISO 400? Is there an in-camera noise reduction function on your model?

    As Christina states, you can adjust exposure in LR as long as the noise isn't too visible.

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    dje's Avatar
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    Re: Boosting exposure in LR

    Hi chauncy

    I have found similar behavior with my Canonn 600D. ie you get more noise if you increase exposure in pp than you do if you increase the ISO by an equivalent amount. At least this applies for the lower range of ISO value.

    From what I've read, it depends where the noise is generated. Noise generated before the ISO amp in the sensor chip will be increased as the ISO setting is increased whereas noise generated after the amp, mainly in the A/D converter will not. With many cameras, the post ISO amp noise is dominant at the lower values of ISO. So as the ISO is increased from say 100 to 400, the noise doesn't increase much. On the other hand, increasing exposure will amplify all noise coming from the sensor.

    Once you get to a certain ISO value, the noise generated before the amp starts to dominate. At this point, there is probably not much difference between increasing ISO and increasing exposure in pp.

    The following curve from DXOMark shows dynamic range for three cameras. If you assume the maximum output doesn't vary much with ISO, then the dynamic range is an indication of how much the noise increases with ISO in an inverse way. ie a reducing dynamic range equates to increasing noise.

    Boosting exposure in LR

    You can see from this curve that for the Canon 5D and the Nikon D3s, the sort of behavior I mentioned above applies. ie the noise doesn't really start to increase much until the ISO gets to around 400. On the other hand, the curve for the Nikon D7000 is pretty much linear all the way. My guess is that Nikon are getting better noise performance out of their A/D converters in their latest sensors. Whatever the reason, for this camera, it probably wont make much difference whether you increase ISO or compensate for it in pp. But I'm not is a position to vouch for that.

    Dave

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    jprzybyla's Avatar
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    Re: Boosting exposure in LR

    Hello Chauncey, normally the range without problems to recover the exposure in Lightroom is +/- 2 stops. Recovering a underexposed image will show the noise from the image being underexposed.

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    Re: Boosting exposure in LR

    Okay, another question...can a camera's ISO performance degrade over time? It does seem to get worse.

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    Re: Boosting exposure in LR

    No I do not think so, I think it maybe another problem, when you take a shot, how are you exposing it, over or expose to the right or are you under exposing the image. What is you histogram showing, right, or left exposure, better to my thinking to expose to the right to gain more detail in the shadows. Maybe you can tell use from the raw image you took or from a screen shot so we can see the original histogram of the image.

    Cheers:

    Allan

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    Moderator Dave Humphries's Avatar
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    Re: Boosting exposure in LR

    Quote Originally Posted by chauncey View Post
    Okay, another question...can a camera's ISO performance degrade over time? It does seem to get worse.
    It may; for example, if you are shooting a lot in succession or using Live View, the sensor (being almost continuously on) warms up considerably, it will then produce more noise, give it a break to let it cool down (but don't leave it in direct sunshine!)

    But I guess you probably meant with age of camera - pass - if you fancy a new camera and can afford it ...

    HTH,

  9. #9

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    Re: Boosting exposure in LR

    New camera...yeah I want one, but with the exception of the ISO difficulties, the newer ones aren't offering anything that I need.

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