Tag: photography

High Dynamic Range #2 (HDR)

How the limitations of the camara sensor create HDR problems.

In the first posting we discussed how colors are translated into three numbers in a digital camera, one for each of the three primary colors – Red, Green and Blue (RBG for short).  After all, digital cameras are computers complete with processors, memory and software.  We described the 8 bit color mode in which the numbers range from 0 to 255 and are used to measure and store the brightness of each color.  Zero is darkest dark possible and 255 is the brightest bright possible.  When all three colors are combined in equal proportions you end up with gray.  If all three colors are zeros (0,0,0) you have pure black; if they are all 255s (255,255,255) you have pure white.

Camera Sensor Dynamic Range

The next step in this journey of understanding it to realize how the pixels in the camera sensor work.  Recall that each pixel is really three pixels – one for each of the primary colors.  While the following is an oversimplification, suffice it to say that the sensor has a built in dynamic range that can be measured in stops.  That is to say, the range from the darkest darks to the brightest brights that the sensor is capable of capturing can be measured in stops.  This is also true of all films.  For example, the dynamic range may be as little as five stops (generally most color positive films) and as much as ten stops or more (generally the most advanced digital cameras). For the remainder of this discussion we can assume our camera has a dynamic range of 7 stops.  It can be illustrated in this way….

 Sensor Dynamic Range

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High Dynamic Range #1 (HDR)

How digital convert the world into numbers.

This is the first in a series of articles that address the fascinating topic of High Dynamic Range or HDR.  HDR not only refers to situations you face when photographing in the field but also the digital darkroom techniques for processing HDR images.  This first article will lay the groundwork necessary for understanding HDR.

How often do you look at your photographs and are dissatisfied because the images appear washed out, or at least parts of then.  Maybe you took an outdoor family shot at a gathering or picnic.  The people may look great but the sky is washed out.  Or perhaps you were on vacation and something similar happened – part of the image was washed out.  The opposite could also happen.  The image could be too dark.

Normally modern digital cameras have very sophisticated built in light meters that give you excellent exposures.  But often the conditions of the scene you are shooting are simply beyond the capability of camera to capture, regardless of whether you’re shooting digital or film.

If you’re collecting pictures for the family album these defects may not be a problem at all.  It’s the memories that the photograph conjure that are important, not the technical merit of the image.  These are photographic records of important events in our lives.

But if you’re intention is to create a work of art, a washed out image is one sure way to frustrate your efforts.  If you’re shooting RAW you have some ability to recover washed out highlights or black shadows.  However, once you’ve completely lost your highlights and/or shadows there’s nothing you can do to recover them.

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Canon 1Ds Mark III Upcoming Shoot

Well, no shooting with the new toy yesterday or today.  As I haven’t given up my day job yet it’s necessary to get some consulting hours in to bring home the bacon.  Besides, the client is happier when I pay some attention to them.  However, the RRS L bracket came today.  So I’ll be able to attach the camera to the tripod without having to use the long lens – always a good thing to be able to do.

But this weekend is going to be very exciting.  First of all, it’s the 1st Annual Joshua Tree Gathering, open to anyone who owns a camera and isn’t afraid to use it.  See the post.  But I’m going to attempt a series of sunrise shots from first light to the sun fully up.  The thing that makes this interesting is I’m going to attempt to do this as  360 degree panorama.  I hope I don’t have to add HDR to the mix.  Arg!

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2008 Joshua Tree Gathering

The first annual Joshua Tree Gathering is scheduled for January 18th through January 20th in Joshua Tree National Park.  We welcome photographers of all levels of ability.  If you’re interested, leave me a comment to this post.

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Welcome Roger Nordstrom

My brother, Roger, just launched his own blog yesterday.  I added his site to the Glogroll and will be adding an RSS feed.  I encourage you to check it out at RogerNordstromPhoto.blogspot.com.  He also has a very nice website with some of his amazing work.  You’ll want to check that out also at RogerNordstromPhoto.com.  You’ll love his work.

 Welcome Roger.

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Wandering in the Fog

I worked on two photographs tonight that have been giving me trouble for the last week or so.  Both were shot in Zion NP.  The one I’ve been working the longest on was what I finished up on tonight.  Hopefully I have it.  We’ll know tomorrow morning.

My point in this post is I often get the feeling I’m wandering in the fog.  You can’t see where you’re going very well and you just stumble around.  You take a step, look around and decide where to go from there.  It’s a slow process.  I make a print.  It takes several minutes for it to come off the printer.  Then I look at it.  Often times it’s very disappointing, especially tonight.  Think about what’s wrong with it for a while, make the changes in PS and make another print.  It’s disappointing so think some more, fiddle in PS some more and make another print.  Hours go by.

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Photoshop Discoveries 2

Use of Spot Healing Brush

I have an image that is a shot of the Eastern Sierra at sunrise.  There are gorgeous clouds hanging over the peaks.  The early morning sun lit them on fire along with the mountains.  It was amazing!

My exposure was pretty close to being right on.  And yet, there was one part of the clouds that technically wasn’t clipped but was very close.  The RGB numbers were not 100% but were in the high 80% to low 90%.  The thing was there wasn’t much detail and it really stood out.

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Welcome Jack Graham

In photography one of the most powerful means of growing is through interactions with the other photographers we meet, be they in workshops or in the field.  Not only do you learn from artists who create amazing photographs but you also build friendships.

One such chance meeting of an outstanding photographer and friend is Jack Graham.  We met on the banks of Mono Lake in October of 2006.  I was there by myself; he was leading a workshop.  We were shooting the South Tufa at sunrise under the harvest moon setting in the west above the imposing Sierra Nevada range.

I added the address to Jack’s blog in the blogroll.  You can also click here.

You’ll also want to be sure to check out his work.  You can click here.

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DxO Impressions 1

I mentioned in an earlier post that I was using DxO now.  I was introduced to the product in November at the Digital Summit workshop in Zion National Park.  It looked pretty interesting and besides I got a deal I couldn’t refuse.  I waited for the release of DxO Optics Pro 5 before jumping in.  There were a lot of improvements made to version 5 that corrected some of the more serious shortcomings of version 4.

First of all, DxO works with RAW images.  And given the sorts of corrections it applies, it makes sense to use DxO before any other RAW converter like LR, ACR or Capture One.  So that’s where it comes in my workflow.  Actually, I generally import RAW images into LR first, review and rank them in LR.  When I determine the images I want to work on I then bring them into DxO and work on them there before returning to LR.

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