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07-21-2016, 09:06 PM   #1
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Does DR affect Aperture?

That's my question.

07-21-2016, 09:17 PM   #2
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QuoteOriginally posted by rlatjsrud Quote
That's my question.
DR as in dynamic range or dust removal?

Neither has much to do with the aperture.

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07-21-2016, 10:20 PM   #3
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QuoteOriginally posted by rlatjsrud Quote
That's my question.
You could ask the question the other way around for something a bit more interesting.

Does aperture affect Dynamic Range?

It is actually a very good question and something that I have experimented with some.

I would recommend trying an experiment though. Get a tripod and find a scene that has controlled Dynamic Range (IE lighting).

Open your lens all the way and take shots at ISO 100 at whatever shutter speeds are needed. Then bump it up to ISO 200 and repeat. then 400 and repeat. At 800 you can stop.

Then close down a stop or two and repeat. And then close down a stop or two again and repeat again.

It wouldn't be hard you just have to be consistent and maybe take notes of what you are doing.

Finding that 'right' ISO/shutter speed/aperture combo isn't always as easy as it looks.
07-22-2016, 12:03 AM   #4
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QuoteOriginally posted by rlatjsrud Quote
That's my question.
Flip that question on its head - how could aperture possibly affect dynamic range?

07-22-2016, 02:27 AM - 1 Like   #5
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Aperture does not affect dynamic range, except in as much as it affects your ability to shoot at lower iso. The lower the iso you pick, the more dynamic range you will have. If the only way you can get to iso 200, say, is by opening your aperture up to f2, then if you set your aperture to f4 and iso 800, you will have less dynamic range.

If you are on a tripod and can use iso 100 with impunity, regardless of your shutter speed, then aperture will not affect dynamic range at all.
07-22-2016, 04:20 AM   #6
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OP: You did not by any chance miss-type and mean "HDR?" SFAIK, HDR changes only shutter speed.
07-22-2016, 07:56 AM - 1 Like   #7
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QuoteOriginally posted by Digitalis Quote
Flip that question on its head - how could aperture possibly affect dynamic range?
Aperture won't change the sensor's DR capabilities but it can affect the DR of the scene by modulating the amount of diffuse light that pollutes pixels that should be dark.

1. Aperture will affect the amount of diffuse light reflected from lens element edges on to the sensor in the dark parts of the scene. If you hold your lens up to strong light with the aperture fully open, you can see various parts of the structure of the lens reflecting light especially the edges of glass elements and sometimes the metal, too (matte black is never really black). Close down the aperture and many of sources of spurious light will be less visible.

2. Similarly, aperture will interact with any finger prints, dirt, or haze in the lens which can also diffuse light from the bright parts of scene onto the dark parts of the scene.
07-23-2016, 02:51 AM   #8
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DR is a property of the sensor. It closely correlates with pixel size.



07-23-2016, 05:23 AM   #9
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QuoteOriginally posted by clackers Quote
DR is a property of the sensor. It closely correlates with pixel size.
Indeed! The sensor does play a major role. Yet a fogged, non-multicoated lens can limit the dynamic range of what reaches the sensor just as an 8-bit file format might limit the DR despite the quality of the lens and sensor.

DR is a holistic property of the entire image formation system (lens, sensor, processing pipeline, file format, etc.) any of which can degrade the DR.
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