Be Thankful For Olympus Gear

Started Apr 23, 2013 | Discussions thread
Great Bustard
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Re: The "ISO-less camera" argument
In reply to John King, Apr 28, 2013

John King wrote:

boggis the cat wrote:

Have you noticed that there is a bit of a push to argue that 'ISO' is no longer a valid concept?

That was one of Newman's favourite fight starters ...
I agree with Bryan Peterson's continued use of the "Exposure triangle" - ISO (sensitivity of the recording medium), Aperture (the hole in the diaphragm in the lens) and Shutter speed (how long the recording medium is exposed to the light source). Seems so self-evident, and has been used by photographers ever since photography began. No less valid today than it was 150 years ago ... . All other decisions are aesthetic decisions, and just as important in their own right. They are just not exposure parameters, per se. They are determined by the meber of the exposure set chosen. Peterson stresses this constantly.

There was a thread in the Open Talk forum where this was being discussed.  I jumped in here:

http://www.dpreview.com/forums/post/51328732

but did not get a reply to my argument for ISO in that thread.

Am I missing something obvious?  I don't see how a sensor can have limitless 'sensitivity', so therefore we have to always consider that third element (even if we have an ever increasing latitude).

I agree. So does every photographer and author on the subject I have ever had anything to do with. Even auto ISO is still applying a value to the sensitivity of the recording medium. It's just blather to suggest otherwise, IMNSHO.

The sensitivity of a digital sensor is fixed, except inasmuch as read noise is less at higher ISOs for non-ISOless sensors.  In other words, f/2.8 1/100 ISO 400 and f/2.8 1/100 ISO 1600 have the same exposure for a given scene, but not the same brightness.

The advantage to the ISO 1600 photo is that it will be less noisy than the ISO 400 photo pushed to the same brightness if the sensor was not ISOless.  The disadvantage to the ISO 1600 photo is that more of it may be blown (due to the limited bit depth of the image file), regardless of whether the sensor is ISOless or not.

Recently, an excellent article on exposure was written by gollywop:

http://www.dpreview.com/articles/8148042898/exposure-vs-brightening

As a side, he's also written an excellent article on colors management:

http://www.dpreview.com/articles/7270088913/color-management-a-walkthrough

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