high dynamic range imaging · taking photos for hdri works best with a tripod take multiple photos...

High Dynamic Range Imaging

Kent Messamore

8/13/2009

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What is High Dynamic Range Imaging?

Normal Cameras can capture a dynamic range of 6-9 stops

By merging multiple exposures for highlights, midtones, and shadows using HDR software, dynamic ranges of 10-15 stops can be captured in 32 bit images

HDR images however, cannot yet be viewed as Monitors and Printers cannot display this dynamic range and 32 bit images

Tone mapping is used to compress the dynamic range into viewable form

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Example from my porch

If exposed for outside the window, inside is too dark

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Example from my porch

If exposed for inside the porch, outside is too light

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Example from my porch

HDR Image allows for correct exposure for both

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Taking Photos for HDRIWorks best with a tripod

Take multiple photos

Focus should be same (manual focus)

ISO and F/stop should be same

Vary either speed or aperture to change exposure between shots

Limit as much as possible anything moving between shots as this will create ghosts in the final image.

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Without a tripodIt is possible to do HDRI without a tripod

Use Auto Exposure Bracketing along with continuous shooting mode, i.e. three shots in one second, all with different exposures

Brace yourself as much as possible or rest your camera on something.

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3 Exposures, Tripod, AEB

f/5.6 1/2000 ISO 320

f/5.6 1/8000 ISO 320

f/5.6 1/500 ISO 320

+&- 2 Stops

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From Bridge to PhotoshopTools -> Photoshop -> Merge to HDR

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From Lightroom to PhotoshopRight Click -> Edit In ->Merge to HDR

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Can adjust white point. Click OK

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Processing in PhotoshopSwitch to 8 or 16 bits

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Four different ways to process.See if you like one or the other.

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Local adjustment with curves

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There are better ways to Tone Map than Photoshop. Save 32 bit file as Radiance.HDR

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HDRI ApplicationsPhotomatic (most popular)

Photomatic Pro ($99)- Includes HDR Generation and Tone Mapping. Includes Lightroom Plug in. Free Trial

Photomatic Pro Plus – Includes Photoshop Plug in

Dynamic HDR - Generation & Tone Map - $55

FDRTools - $61- Generation & Tone Map

HDRShop - $400 – Kitchen sink

Picturenaut – Free (Doesn’t Support RAW Files)

PhotoAcute – HDR Generation only (handles ghosts well)

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Photomatic Pro (using Photoshop HDR image)

Tone Map

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Photomatic Pro Adjustments for Tone Mapping

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Basic Adjustments

Strength - Start High. At end, lower to taste

Color Saturation - Much overused. Use restraint

Luminosity - Controls how bright shadows are

Light Smoothing - Smoothes transitions between tonal areas. High is more like a photograph; low more like a drawing (posterized)

Microcontrast – affects contrast in small detail

White Point – Sets white upper limit

Black Point – Sets Black lower limit

Gamma – Sets image overall brightness

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Color & Detail AdjustmentsTemperature – makes warmer or cooler

Saturation Highlights – increases saturation

Saturation Highlights – increases saturation

Micro-smoothing – Smoothes transition between tonal zones. Set high more like a photograph; Low more like a drawing.

Highlight Smoothing – affects highlights

Shadows Smoothing – affects shadows

Shadow Clipping – clips blacks

Presets – Can save preset settings

Initiate Tone Mapping process

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Other HDR Images

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HDRI

End