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Wednesday, July 25, 2012

Boosting your ISO without boosting it.

    An exposure trick I learned approximately 4 years ago when I shot with a Pentax K10D was to boost the ISO beyond the 1600 ISO limit of my DSLR in low light situations by setting the camera to underexpose the image by 1 or 2EV thereby doubling or quadrupling the shutter speed. I did this only when my aperture setting was set at its maximum of f2.8 but still could not muster the shutter speed needed to freeze the action or reduce the motion blur significantly due to the camera's 1600 ISO limit; it is the reason why I stated in this post that ISO is the least important, in my opinion, of the three components needed to get the "right" exposure. I would then overexpose the resulting images by 1 or 2 EV respectively during post work in Adobe Lightroom or Photoshop by utilizing the exposure tool in these applications: this gave the effect of shooting at 3200 or 6400 ISO respectively. The images did contain the sensor noise that normally comes with shooting at high ISOs in low light. This was fixed by utilizing noise reduction software like Noise Ninja which was very popular at the time.
    Obviously, shooting this way results in more post work and cleaning images with noise reduction software does have its drawbacks. The resulting images appeared "smudged" and not sharp with detail loss. Detail loss is somewhat minimized by shooting in camera RAW. I would sharpen the image by using a tool in Photoshop called the unsharp mask but one can only sharpen the detail captured :-(
    Believe it or not, this is one of the "tricks" employed by camera makers that boast of making cameras with the ability to shoot at 3200, 6400 or even, in my opinion, a ridiculous 12800 ISO. Your DSLR is like a computer with applications built in to perform certain tasks. In this case, there are applications built into the firmware of the camera to boost the ISO and then employ built in noise reduction software to produce "cleaner" images in low light shooting conditions. Take a look at the following image on my website; it was shot with my D7000 at 3200 ISO at f3.5. What do you think? I could have opened the aperture a bit more but I was having enough problems with focusing due to the narrow DOF at that aperture setting, and I wanted to minimize the loss of DOF as much as possible.
    Some cameras handle noise reduction better than others while some brands don't even bother with it and leave the image with all the details including sensor noise to the photographer to deal with. Full frame or 35mm cameras tend to handle low light shooting better due to the larger sensor installed in them. Getting the newer DSLRs in the market does help a lot especially for photographers like me who dislike post work and prefer to get the images right during the shoot and not in post.

2 comments:

  1. Thanks for your blog, it's very interesting to read it. I'm using macphun.com/noiseless filter for improving my pictures. It removes noise perfectly, try it.

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  2. Pixlr is a functional editor, which spoils the pictures ... very functional program, but unfortunately it spoils pictures. After processing this program acquire pictures uneven gradient and abrupt transitions from one tone to another, and much to lose as the color. I can do better with https://photolemur.com or even freeware GIMP...All this forces me to abandon using Pixlr

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