Wednesday, August 28, 2013

HDR Photography-The Amazing and Treacherous World of High Dynamic Range Photography



The advent of digital photography has brought revolution after revolution. As I’ve said before, generally, in the days of film what you got in the negative or slide was pretty much what you were stuck with. One problem with photography then and now, but especially in the days of film, is  the limited dynamic range, also referred to as exposure latitude. When we view a scene with our amazing eyes, we can see detail in the darkest shadows and the brightest highlights virtually in the same instant. We can discern a dynamic range on the order of 25:1. Our eyes adjust so rapidly that we don’t even notice this amazing ability. In photography, the range we can capture is greatly reduced. With film it was on the order of 9:1, or 9 f stops. When making a print, this range is reduced even farther to somewhere on the order of only 4 f stops.  The great photographic master, Ansel Adams, based his entire method on maximizing the dynamic range he could capture on film and in print. He did this by over or under exposing the film in combination with applying specialized developing techniques using various chemical developers and developing times. He would then manipulate his prints by dodging and burning areas and again, in combination with developing techniques and chemicals, to extend the apparent dynamic range of a photograph. These were complicated techniques. All, to create a photograph that matched his imagination and hold detail in the blackest blacks and the whitest whites. This was the holy grail in the hey day of black and white photography.
 
Enter the world of digital photography. Now, my sensor has a greater latitude than film somewhere on the order of eleven f stops. But still, it doesn’t come close to the capability of the human eye. And you also have the problem of the lesser latitude of photographic paper.HDR to the rescue: high dynamic range photography. Now we can capture three, five, seven or nine, or even 21 different exposures from very dark to extremely bright and merge them all in HDR software. This creates an image that combines all the details of the blackest blacks and whitest whites in a single frame.


So what are the steps to creating an HDR photo?


First, it’s imperative that you use a tripod. I’ve tried to do it hand-held, but shooting a series of bracketed exposures even shooting at five frames a second will inevitably have movement between each frame.


Next, you need your series of bracketed exposures. This means that you have to shoot the high contrast scene you’ve chosen with those three, five or seven different exposure settings ranging from very under-exposed to very over-exposed. 


These are the five brackets I used to create the photo at the top of this post:

-2 stops


-1 stop


Normal


+1 Stop


+ 2 Stops




       Many cameras have the capability to automatically bracket exposures. This makes things much easier. Without auto-bracketing, you have to manually adjust your exposure between each photo.

Some consumer cameras, especially point and shoot cameras, can now create HDR photos automatically in the camera.


I usually set my camera to do five brackets with a one f stop difference between brackets. This five f stop range from under-exposure, to capture detail in the brightest highlights, to overexposure, to capture the details of the darkest shadows, is usually sufficient.


I said above that you can do even more brackets. You can get crazy with them shooting fifteen brackets at intervals of 1/3 of a stop, but I haven’t found much advantage to that.


You first have to establish you median exposure. You do this by using your histogram as in this blog post:


http://dreamcatcherimaging.blogspot.com/2013/07/understanding-camera-histograms-in.html


After that, set your auto-bracketing and make your exposures. You can use your fingers like in the Panorama post 
to mark the beginning and end of your brackets: 


http://dreamcatcherimaging.blogspot.com/2013/07/panorama-photography-photographing-and.html


      But after importing the photos, it’s usually pretty obvious what photos you’ve shot for HDR.

And another thing, I always shoot my exposures from under-exposed to over-exposed, from - to +. With auto-bracketing, it’s a setting on the camera. It makes it easier and more obvious which photos I will use to create the high dynamic range photograph.


Once you’ve imported the photos, you need an HDR program to process them. Photoshop has HDR capability, but I prefer either Photomatix or Nik’s HDR Efex Pro. Photomatix and HDR Efex are plugins for programs like Lightroom and Aperture as well as Photoshop and the latest versions of Photoshop Elements. You can export from these program directly into the plugin.


I won’t get into the process of working with the software here, I just want to introduce you to the basic steps. Suffice it to say, there are a lot of things you can do while manipulating your images in the HDR software. Both Photomatix and HDR Efex have presets, kind of like recipes. By clicking on each preset, you’ll get very different looks. These can be fine-tuned with the controls in the software. And as always, just play and have fun. You can’t screw up.


As I said in the title, you’ll be amazed with what you can create. But...there is a treacherous side as well. It’s very easy to become enamored with the saturation, detail and bizarre looks you can achieve with HDR photography.

  The internet is full of clumsy, why-to-obvious, and ridiculously over-saturated HDR photos. The challenge is to use HDR subtlety and to create photographs that mirror the reality or convey the feelings you had when you were inspired to photograph the scene in the first place.

      I shot the exposures for this HDR photograph during a Vail Nature Center Photography Workshop on Shrine Pass. Clouds frequently present a problem because their brightest highlights get blasted out especially when there are some deeper shadows to deal with. I made five exposures but I only used these three brackets to create the HDR photo.





Here is the final image:



And just to compare the capability of today's cameras and processing software, here is the middle bracket processed in Lightroom 5 only:




You can see that the clouds show much greater texture and the shadow somewhat lower contrast. Which do you like? Well, it's a matter of taste.

Copyright 2013 Dennis Jones/Dreamcatcher Imaging



Check out my travel blogs on my extensive world travels at:

http://www.dreamcatcherimaging.com/blog/

Wednesday, August 21, 2013

JPEG vs TIFF vs RAW Which Photo File Format to Choose?




These are the three main image file formats. Different uses require different file formats. The web, for example, requires a JPEG. If you have a point and shoot, likely, your only choice is JPEG.
Jpeg is a compressed image file. The camera decides which pixels are important in an image and compresses the image to a smaller size file as it’s being processed.
In other words, the camera processes the image, making it look as good as it can, and throws away lots of pixels it doesn’t need. It does a great job in figuring out what’s important but it does throw away information forever. 
Another disadvantage of jpegs is that if you work on a jpeg and make changes to it, say brightening it or giving it more contrast of saturation or putting it through a filter, each time you save it, more pixels are thrown away. An advantage, is that pretty much any imaging software can work with jpegs and they don’t take up much storage space.
TIFF is an uncompressed format. It’s a great format to use when making changes to an image after processing because all the information is saved. You can also set many cameras to capture in TIFF. Again, most software can work with TIFFs.
RAW is the most flexible format to capture in. Every bit of the information is contained in a RAW file. All professional cameras and most prosumer cameras can shoot in RAW. To complicate things, every manufacturer has their own propriatory RAW format; .nef for Nikon, .crd for Canon, .ref for Fuji, etc.. The camera doesn’t process the RAW image at all. You’ve gotta process it yourself. You do this in one of the many cataloging programs out there, either a manufactorer’s propriatary program like Nikon’s Capture NX or something like Apple’s Aperture, Adobe Lightroom or Adobe Camera Raw.
If you’re serious about your photography, then you’ll shoot in RAW, period! It’s got every pixel of information you can use in the image file. Why would I shoot in JPEG and let the camera decide what’s important when I can shoot in RAW? And, I’ve  got to process the image no matter which format I use.
Plus, a RAW file has much more exposure latitude than the severly limited JPEG. 
In other words, you can increase or decrease the exposure, (lighten or darken the image), during processing to a far greater extent with a RAW file without stretching the pixels beyond their breaking point. Yes, it’s possible to break pixels, especially if they’ve been thrown away and aren’t even there!
Another thing, you don’t actually make changes to the RAW file. Through what’s called Metadata, you tell the software how to manipulate the file so it looks the way you want it to look. This is called non-destructive processing. If your artistic tastes change later, you can always go back and make more changes to the original file without a single pixel being damaged in the process.
And, you can save different versions of the photograph, say a really saturated version or a black and white version. These, you would save as a tiff for maximum quality. When I use some of my software plugin filters, I save the result as a TIFF. 
I can convert both RAW and TIFF files easily into JPEGs for use on the web or for emailing or to send to a lab that requires JPEGs for printing without effecting the original file. I also export files as JPEGs for slide shows, video or Powerpoint presentations because the high resolution and size of RAW and TIFF files is pointless in these relatively low rez products and can gum up the works.
So, what format should you use?
If all you're doing is posting online, emailing your photos to friends, sharing them with family, or making small prints for albums, jpegs will do just fine. But...if you’re serious about your photography, shoot only RAW.



Copyright 2013 Dennis Jones/Dreamcatcher Imaging

www.dreamcatcherimaging.com

Check out my travel blogs on my extensive world travels at:

www.dreamcatcherimaging.com/blog





Thursday, August 15, 2013

Establish an Easy Method for Cataloging Your Photos





Nothing is more important when dealing with photographs than developing an easy system for cataloging your photos. It’s very frustrating, not to mention time consuming, trying to find a photo you want to share or have printed when you have a haphazard filing system. Worse yet, with no system at all. And, it is a very simple thing to set up.

By default, when you download photos from your camera or memory card, they are inevitably and automatically put into a folder with a date. To me, this is the worst kind of catalog. I have no idea what I was doing on say, September 29, 2011, let alone what photos are in the folder.

If this is your filing system, you’ve got to open every folder from around the time you think the photographs were taken to find what you’re looking for. What a pain.

No matter what software you are using to catalog your images or how you are storing them on your computer, it is an easy matter to import your photos into a folder with a name that is associated with your subject as you download them.

For example, all my pictures go into one main folder, My Pictures, and no where else. Within My Pictures, I have a folder called Friends. These are friends we’ve visited or have visited us and all the photos I’ve taken of friends go into this folder. But it doesn’t stop there. I have sub-folders of the Friends folder to hold the photos of each set of friends. You can also make sub-folders of these that relate to specific events, places visits or even dates or years.

If I’m looking for a photo of say, Jim and Ginny Jinks that I shot while visiting them in Florida, it takes a couple of clicks and there it is.

The same method works great with our families. First, I have a folder named Family. Underneath that are sub-folders named for the families and family members. Events like Christmas and Thanksgiving are in their sub-folders listed by the year.

Yolanda’s grand-daughters have been in several plays, so in the sub-folder of Family named Skylar and Sage, I have sub-folders for each play.

It’s so easy. But you have to be consistent.

We travel a lot. So, I have a Travel folder. (Not to mention my travel blog, Light Traveler, www.dreamcatcherimaging.com/blog.) In my Travel folder are sub-folders of the countries. Under that, sub-folders of the cities or regions. If I’ve been somewhere more than once, there’s a folder for the year and then the city.

Of course, if you’re like me, you’ll have several different places or things on your CF or SD card that don’t fit neatly into one category. Plus, after I download them, I have to edit through them and delete the photos I don’t want. For that, I have a folder under my main photo folder named Newest Downloads. All the mixed up stuff goes in there until I have time to edit through and process it. Then, it only takes a few minutes to either drag them to the appropriate folder or create a new folder and drag them there.

I don’t care what software you use or where you have them stored on your computer, it’s a simple matter to set up an easy to use filing system. If you haven’t already set one up, then it’ll take some time to organize it. But once set up, it only takes a few seconds to put things where you’ll be able to find them.

If you don’t have the time or patience to organize the photographs you already have, then at least set up a filing system for the new photos you take and use it from now on. It’s so easy.
But if you’re one of those who keep hundreds or thousands of shots on a card until it fills up, store it and buy a new card. Heaven help you.


Here’s a screen capture of part of my Travel folder:



Copyright 2013 Dennis Jones/Dreamcatcher Imaging
Check out my travel blogs on my extensive world travels at:


Friday, July 26, 2013

Understanding Camera Histograms in Photography







It took me a while after switching to digital photography, to fully understand the histogram. Now, for me, it’s an essential tool in determining proper exposure in my photography.

Most all cameras today can display a histogram. From the least expensive and simplest point and shoot to the most sophisticated professional camera, they all have the capability to display a histogram after you’ve taken the picture. Some cameras with electronic viewfinders will display the histogram live, even before you press the shutter.

Professional cameras will even display a histogram showing the three color channels, red, green and blue, (RGB), in addition to the luminance histogram showing the brightness of all the color channels together.

So what is the value of viewing a histogram? To me, it is everything. It is how I determine the proper exposure of every picture I take. But I’m a serious professional photographer.

Most serious amateurs, if they understand it, will take advantage of their histogram. But do those of you who simply want to have fun taking pictures of their friends, families and vacations need to consult the histogram? Not really. Modern-day point and shoot cameras and consumer level digital single lens reflex cameras, DSLR’s, do a great job producing good exposures and beautiful photos. But it never hurts to have a little understanding of such a deceptively simple yet potentially confusing camera function.

As I said above, it took me a while to understand the thing. There was nothing even remotely resembling it on film cameras and it was not something that anybody taught. My switch to digital would have gone much smoother had I understood it from the beginning.

So here it is, in all it’s simplicity.

Essentially, the histogram is my light meter. Because of it, a lightmeter is one piece of equipment I don’t no longer have to carry. Now that is heresy to some, but so be it. My life is simpler without having to take a lightmeter reading of every photograph I’m about to take.

Here is an example of what a good histogram looks like:



Here is an underexposed histogram:



And here an overexposed histogram:



That’s it, that’s all you need to know.

But then, of course, there’s more to it. Fundamentally, you don’t want your histogram to be climbing the walls. That is to say, the left side of a histogram shows the blacks and shadows in the scene. The right side show the whites and highlights.

If your histogram is climbing the left wall as in the underexposed histogram above, then you’re blocking up your shadows, i.e. there will be no detail in your shadows. If it’s climbing the right wall like the overexposed example, your blasting out your highlights. Again, no detail. And with jpegs, no possibility of getting the details back.

Here are photographs to go with the above histogram examples.

Good exposure:



Underexposed:



Overexposed:




And what are all those peaks in the histogram? They simply say that at that particular brightness level, the camera sensor is picking up more pixels. In other words, the scene you’re shooting is made up more of a particular shadow or brightness or mid-tone than other brightness’s. 

But that’s confusing the issue. All you need to know is whether you have a fairly even distribution across the histogram without blocking up the shadows and/or blasting out the highlights.



Copyright 2013 Dennis Jones/Dreamcatcher Imaging
Check out my travel blogs on my extensive world travels at:

Sunday, July 21, 2013

Panorama Photography-Photographing and Merging Panoramic Photos

Gore Range Panorama, Vail Colorado


Time was when you had perhaps three choices for creating a panoramic photo: 

1) You could print only a narrow strip of the film or slide. This was okay if you were using a 4x5 or larger camera but 35mm or smaller, forget about it. Make anything larger than perhaps a 10” print and the loss of detail was very apparent. Older film point and shoot cameras gave you a panorama option but all it did was crop the 35mm frame just like above, and show a crop in the viewfinder accordingly.

2) You could also painstakingly merge several exposures in the darkroom. Very difficult. 

3) Or, you could use a specialized panoramic camera.

That was then, this is now. 

Lots of cameras now will even do it for you. Simply put it in panorama mode, take a few pictures while panning across the scene that capture what you want and the camera will stitch them together. Even the iPhone has a wonderful pano feature; put it in panorama mode and slowly pan across the scene. All the stitching is done automatically. Pretty amazing.

But for high quality panoramas, there’s a bit more involved. And really, it is only a bit but you do have to own some stitching software, some are free, some not. 
Here’s a link to Ken Rockwell’s site. He is an excellent on line resource for many things photographic. This is his article on stitching software which explains the software better than I.


I don’t know when it was written, but Photoshop’s Merge to Panorama has definitely improved with the past few iterations of PS and it is what I use.
Ideally, you should use a tripod. But it’s not necessary except at night or in dim light. What is most important is that you take your shots from left to right, (the software is designed to work this way), that you overlap each shot by about a third, and that you keep the horizon or you subject level and even across all your exposures.
This is easiest on a tripod where you can level both the tripod and the camera. You can even use a bubble level to level the camera between shots. Vello makes one for $15 that fits in the camera’s flash hot shoe. Now though, some high-end cameras come with a Virtual Horizon function.
Using the Manual exposure setting, adjust your aperture and shutter speed, take a shot of the scene and make sure you have a good exposure by checking your histogram. (More on that in another post.) Once you’re satisfied with the histogram. Take an Auto-focus reading and then turn auto-focus off. You don’t want your camera to focus on something in the foreground in one of your shots and then something in the distance in another.
That being said, there’s no reason you can’t do it on full auto, both exposure and focus. You just have to be aware of the potential auto-focus problems and that your camera’s exposure metering system might see each shot slightly differently giving you varying exposures.
Line up your first, left-hand shot and then practice how you’re going to overlap each shot and keep the subject level in the viewfinder.
Once you’re got it, line up the first shot again and stick one finger in front of the lens and take a picture. This will tell you later that this is the beginning of a pano. Now, take your shots. After the last capture, stick two fingers in front of the lens and take another picture to mark the end of the pano. When you download everything, maybe days or weeks later, you’ll know that the frames between your fingers are for a panorama.
Open these in your stitching software, click Merge or whatever you’re supposed to click and ouila’, a beautiful panoramic photograph.
        Here are the four photographs I used to create the Gore Range Panorama Photo plus the photos with my fingers to mark the images to be used. The finished Pano is below as well as at the top of this post.











Copyright 2013 Dennis Jones/Dreamcatcher Imaging
Check out my travel blogs on my extensive world travels at:

Thursday, July 18, 2013

Focus Stacking in Photography-Creating Infinite Depth of Field





One of the biggest challenges in photography has always been maintaining sharp focus from the foreground to the background in an image. In the past, this required either using the smallest aperture possible like f22 on SLR’s or getting out the big 4x5 camera. 

With macro photography, the problem is multiplied because even at the smallest apertures, the plane of focus is so very narrow. The closer you get, the narrow it becomes, often just millimeters.

A 4x5’s ability to change the perspective by using swings, tilts and shifts of the front and rear standard in conjunction with f32, 45 or even f64, allowed photographers to keep everything in focus from a subject inches from the lens to mountains in the distance.

Once again, I say an emphatic Hallelujah! for digital photography. Lugging around a heavy 4x5 camera, the film holders and a big heavy tripod, not to mention the other accouterments, like light meter, dark cloth, loupe, lenses etc. was always a major ordeal. Sure the quality from a 4x5 inch piece of film was incredible, but hiking miles into the best spot was at best, a labor of love.

Ansel Adams, the great master, did it as did so many other great artists even up until today. They even started a movement called Group f64. 

You’ve seen the caricature of someone behind a big camera looking through the ground glass beneath a black cloth. Well, what you didn’t see is the person beneath the cloth first composing the faint upside down and backwards image on the rear ground glass and then using a magnifying loupe to carefully inspect the focus. Then of course, they had to make their shifts and tilts, re-compose, check the focus, etc. ad nauseum.

Been there, done that. And I can’t laud enough praise on today’s cameras that give me far greater ease of use along with extremely high quality. Not to mention weighing significantly less.

But still, the problem of keeping things in focus from front to back is still there. Sure, you can use the smallest apertures, but the sharpness gets degraded as you close down. Plus, every lens has a sweet spot where it’s sharpest. My 28-300 Nikon is sharpest between f9 and f11.

So what if I could use my sharpest aperture while keeping everything from front to back in focus? What if you can do that on the tiniest of subjects, in this case, the center of an iris.

Enter Focus Stacking. It has to be done on a tripod and using manual focus. Whether you’re shooting a landscape with a close foreground and distant mountains or a flower, simply take a series of exposures with varying planes of focus. First focus on what’s closest to the camera, then focus on something a little further back, focus farther still and finally take a shot of the most distant part of the composition. This can take two to however many shots, but usually 3-5 will suffice.

Make sure all the photos are shot at the same aperture otherwise things will get really screwed up. And of course, make sure the exposures are all the same, the camera and zoom don’t move and the wind isn’t blowing

After downloading the images. Open them in PhotoAcute, Helicon Focus, Picolay or Zerene. These programs do a reasonable job and prices vary from free to $149.

Photoshop also does a good job. With PS, which is what I used here, select the photos in Bridge and go to Tools/Photoshop/Load files into Photoshop layers. Photoshop opens the photos as layers. Select all the layers. Align the layers under Edit/Auto-align layers/Projection Auto. Then use Edit/Auto-blend layers/Stack images. Flatten the layers when photoshop is finished and prepare to be amazed.

Here are the four shots I used. You can see how narrow the planes of focus are in each. The finished shot is both at the top of the blog and below the others.










Copyright 2013 Dennis Jones/ Dreamcatcher Imaging


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