Shooting RAW, DXOMark, what settings for Auto-ISO.

Started Dec 2, 2011 | Discussions
gava Senior Member • Posts: 1,032
Shooting RAW, DXOMark, what settings for Auto-ISO.

So lately I have been shooting RAW again with the X100.

And I think Auto-ISO is great. I can set my minimum shutter speed at 1/60 and then go into A-priority and let the camera take care of exposure.

Read this page...

http://www.dxomark.com/index.php/Publications/DxOMark-Reviews/Fujifilm-X100-DxOMark-Review/The-ISO-Sensitivity-Graph-Explained

What I first took away from that is that when shooting RAW one might as well set the maximum ISO=1600 (measured ISO=1000), because it's never going to go higher than that anyway.

But then it occurred to me that by setting it higher you can underexpose and push and still get the camera to choose a shutter speed appropriate to the situation and avoid motion blur and take the hit on the noise. Just push in LR as appropriate.

Which is better?

ISO1600 1/15 f2 use max ISO and take a chance on motion blur.
ISO3200 1/30 f2 push it a stop in post and avoid motion blur.
ISO3200 1/60 f2 push it 2 stops in post and avoid motion blur.

All lead to loss of resolution.

http://www.imx.nl/photo/technique/technique/page40.html

I honestly don't know what the right thing to do here is. Some experimentation is in order perhaps. I do know that I was shooting with my 5D2 last weekend and I was absolutely shocked at how quickly an ISO800 file fell apart in the shadows compared to the X100.

I'm not sure what to think, but I have just gone into my camera and turned my minimum shutter speed down from 1/60 to 1/40.

Thoughts?

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Northgrove Junior Member • Posts: 29
Re: Shooting RAW, DXOMark, what settings for Auto-ISO.

Given these choices, I think 1/15 sec may be too slow for consistent lack of motion blur. 1/30 should usually work with this focal length as far as this amateur imagines, and sounds like a sweet spot for post-processing. May blur the occasional shot, but only for pretty few exceptions in this case? Pushing two stops for 1/60 sounds risky for the shadows in my opinion, but then again, I haven't had time to do much RAW processing with my X100 yet and only speaking from experience with my D90.

OP gava Senior Member • Posts: 1,032
Re: Shooting RAW, DXOMark, what settings for Auto-ISO.

Haha, just wait until you see the files.

D90? Fergeddaboudit.

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FastAndLight Junior Member • Posts: 25
Re: Shooting RAW, DXOMark, what settings for Auto-ISO.

I use the exact same shooting method of Aperture priority and auto ISO, except I keep my auto ISO set to max out at ISO1600 and 1/60 min shutter speed.

I had trouble reducing motion blur both from my hand holding and the subject's motion if I went much below 1/60. However, if you are taking a shot of something that isn't moving and can rest or brace the camera, you can obviously go much lower.

However, it is a tough call and all personal preference. It also has a lot to do with what you are shooting and what you are trying to go for. If I am out with my friends, I will turn the max ISO to 3200, but keep the shutter speed min, because usually getting the sharper shot is more important than final noise levels.

Play around with it some and you will get a feel for it.

Also, when dealing with really pushed, ISO3200 files, I like to use RPP. It is worth the extra effort with the improved quality of the final image compared to Lightroom or Aperture.

Jeff Charles Veteran Member • Posts: 7,514
Re: Shooting RAW, DXOMark, what settings for Auto-ISO.

gava wrote:

http://www.dxomark.com/index.php/Publications/DxOMark-Reviews/Fujifilm-X100-DxOMark-Review/The-ISO-Sensitivity-Graph-Explained

What I first took away from that is that when shooting RAW one might as well set the maximum ISO=1600 (measured ISO=1000), because it's never going to go higher than that anyway.

DXOMark measures the ISO gain that is applied to the raw file. The actual ISO is that plus the gain that is applied by the JPEG engine in the camera, or by the raw processing software on the computer. DXOMark explains this here: http://www.dxomark.com/index.php/Publications/DxOMark-Reviews/Fujifilm-X100-DxOMark-Review/The-ISO-Sensitivity-Graph-Explained

So, even though DXOMark measured a max raw ISO of 1000 for the X100, if you set ISO in the camera to 3200, for example, the amount of gain applied to X100 files after processing is about the same as other cameras at 3200.

Which is better?

ISO1600 1/15 f2 use max ISO and take a chance on motion blur.
ISO3200 1/30 f2 push it a stop in post and avoid motion blur.
ISO3200 1/60 f2 push it 2 stops in post and avoid motion blur.

You need enough shutter speed to prevent motion blur (if that is your intent), and a small enough aperture to get the DOF (or the lens sweet spot) that you want. ISO is a byproduct of those two decisions and of the scene illumination. For still subjects, especially if you can brace against something, 1/15 may do. For moving people, obviously you need a faster shutter speed.

I set auto ISO max to 3200, use aperture priority, and set minimum shutter speed higher or lower, depending on the situation.
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Jeff

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