• Members 509 posts
    April 20, 2023, 12:53 p.m.

    I understand. Sometimes circumstances force us to work a certain way and that's fine. But it is funny that what seems like hundreds of posts have been written about this and that, and it turns out that for most purposes, either approach is fine and worrying about the effect of the ISO knob on image quality is pointless. It works pretty much the same, either approach!

  • Members 509 posts
    April 20, 2023, 12:57 p.m.

    Adjusting the ISO for the optimum for your particular camera can improve the SNR if that is how it is designed. But the shot noise increases in lockstep with the signal, so raising ISO does nothing to improve this. It only works on read noise. And read noise is much lower these days. You might even think of it as negligible. Jim Kasson reckons you can squeeze a little more out of an A7riii by setting the optimal ISO, but it's such a small improvement, the more casual among us might consider it not worth the effort of thinking about it. But if you are a good craftsman you can eek out a tiny bit more SNR.

    I'm such a bad craftsman, I set my expectations lower. If I shoot to within about a stop of optimum, I'm delighted.

  • Members 2288 posts
    April 20, 2023, 1 p.m.

    pretty much from tonight's studio test shots.

  • Members 509 posts
    April 20, 2023, 1:06 p.m.

    The downside of raising ISO is it increases the risk of clipping. Although I'm not sure what the practical circumstances would be where it is a real issue. If I'm struggling for light, it's unlikely I'll overexpose. I can see why it is a bad idea to do what my wife did, shooting her safari at ISO 4000 in bright light. A combination of underexposure and risk of clipping is not good.

  • Members 3347 posts
    April 20, 2023, 1:07 p.m.

    To be honest, in good light you could just about train a monkey to take a nice looking shot with any modern camera in Auto mode. It's in low light situations where I find ETTR and maximising the exposure* within artistic constraints is most beneficial for minimising visible noise. In good light, if i'm 1/2 to 1 stop under optimal exposure** I find it generally has little affect on the final image quality after processing the raw data. With raw data I find I can be a little lazy sometimes when fine tuning exposure*.

    * exposure - amount of light that struck the sensor per unit area while the shutter was open
    ** optimal exposure - the maximum exposure* within dof and motion blur requirements without clipping important highlights.
    *** under exposed - more exposure* could have been added with the DOF and blur constraints still being met without clipping important highlights.

  • Members 2288 posts
    April 20, 2023, 1:11 p.m.

    not so fast. someone with more knowledge could answer this
    Screenshot 2023-04-20 231041.jpg

    Screenshot 2023-04-20 231041.jpg

    JPG, 1.9 MB, uploaded by DonaldB on April 20, 2023.

  • Members 3347 posts
    April 20, 2023, 1:17 p.m.

    I can't verify what processing/editing might have been done to those images. Post links to the raw files.

  • Members 509 posts
    April 20, 2023, 1:35 p.m.

    The ISO 100 one looks brighter. Is that what you mean? If so, just reduce the settings in your raw editor until it looks the same. You can set the brightness in post to anything you want.

  • Members 976 posts
    April 20, 2023, 1:35 p.m.

    Getting rid of the specular highlights may help exposing still life better ;)

  • Members 280 posts
    April 20, 2023, 6:25 p.m.

    If you are using the camera in A or S modes, changing the ISO setting will apply a bias to the metering system. So you will get a different exposure.

    Don

  • Removed user
    April 20, 2023, 9:49 p.m.

    Don't know which version I used. It was a couple of years after Adobe moved over to a subscription model.

  • Members 2288 posts
    April 20, 2023, 9:57 p.m.

    isnt that weird. last night i could see different noise patterns in the black background between the 2 images ,but this morning it is not visible due to ambient light hitting my monitor.

  • Members 3347 posts
    April 20, 2023, 10:44 p.m.

    And that is exactly why you shouldn't calibrate monitors using your eyes as you said you did in another thread.

  • Members 369 posts
    April 21, 2023, 4:32 a.m.

    I'm a longtime Adobe products user. I started with Photoshop Elements about 15 years ago and migrated to Lightroom some ten years ago. I've been with Lightroom ever since. The Creative Cloud subscription has really stabilized things and improved the quality of the products. The newest release of Lightroom Classic (v12.3) includes an AI Denoise tool that is simply amazing. One could argue that Adobe was well and truly late to the party with denoising tools but, my goodness, was it worth the wait! I'm looking forward to seeing what Adobe packages with AI Denoise in the updates they'll deliver over the next 12 months. I would not be surprised to see them package an AI sharpening tool with Denoise. The Creative Cloud subscription is easily among the top-5 best values in photography.

  • Members 861 posts
    April 21, 2023, 4:55 a.m.

    Thanks to all of you keeping my Adobe stock's price high.

  • Members 202 posts
    April 22, 2023, 5:10 p.m.

    So the D850 is essentially ISO invariant above ISO 400. What about between its lowest ISO and ISO 400?

  • Members 1737 posts
    April 22, 2023, 5:24 p.m.

    That's not how CMOS sensors work. They use source followers, column amps and muxes. And you'll never find 15 volts applied to a CMOS sensor.

  • Members 1737 posts
    April 22, 2023, 6:05 p.m.

    Not if the read noise is a fair amount less than the photon noise. The two add as the square root of the sum of the squares, so the higher component dominates.