Posts Tagged photography
Correct Exposure — Getting the Most From Your Bits
Posted by admin in photography on February 3, 2012
There has been a lot written about “Exposing to the Right” (ETTR). Most notable among the proponents of this approach to exposure is Luminous Landscape. Without knocking the approach taken in other blog articles about this technique, I believe they get bogged down in the science of it and don’t really concentrate on the technique itself.
Some Basic Facts
The deal is this: When we shot transparency film, there was (essentially) no post-processing we could do. So many of us got in the habit of underexposing by a small amount to increase perceived saturation. Chuck that out the window.
Fact 1: Digitally captured images, and particularly RAW images, retain a good deal of information that is not visible on your screen and in fact in the histogram your image editing software shows you. Some will quarrel with this statement, but it works out to be true in practice and the theory is boring.
Fact 2: It’s easier to deepen overexposed shadows than to open (recover) underexposed ones. Why does this matter? Because underexposed shadows are where most of the really nasty noise in your images will come from.
Fact 3: Your camera’s histogram will tell you what the sensor sees and therefore what is recorded in the RAW image. This will always be different from what your image processing software shows you. This matters a lot, and I’m about to explain why.
Now That We Know That, What to Do?
Most people perceive a pleasing image as one that is saturated. In landscape type images this is especially true. That typically translates to an underexposed image. It is also just what we used to do with transparency film. Big surprise, right? But what happens is that if we pathologically underexpose, it shackles us when we get to post-processing because we have discarded a lot of information about the shadows (the notion being that blown highlights are somehow worse than blocked up or noisy shadows).
The first really, really important thing is to shoot all your images in RAW. Without that, this technique is of far lesser value.
What to do when you are shooting is keep the histogram on your camera showing, or at least examine it regularly. Your camera’s meter will quite often optimize to create an image with values distributed around the mid-tone, but not really bumping up against the highlights — images that will look pleasing right on the back of the camera. To take advantage of the “expose to the right” Zen, you need to shoot test shots, opening your exposure (you can use exposure compensation or do it manually — your choice) until you start to blow the highlights out. Often, I find that is up to a full stop overexposed as compared to the meter’s normal reading.
Tip: Some people find that turning the camera’s feature to blink blown out highlights helps them find the correct exposure point.
So here is an image right out of camera that was exposed to the right:
And here is the histogram:
As you can see, the distribution of luminosity values (the lower histogram) is not a bell curve distributed around the middle. Rather, it is concentrated more toward the right side of the histogram, so most of the image information in mid-tone and highlight.
But, you say, the image is blah! I don’t want blah images. To which I would answer: Precisely, so let’s move a few sliders, to restore the blacks, add a little contrast back in, and presto, we get this:
This is about 15 seconds of post processing to achieve a result with structured, detailed highlights, great mid tone detail, and beautiful rich blacks with no noise. Notice how much more detail there is in the clouds and the water?
For the record, here is the histogram after the tweaks:
Wrap-Up
Exposing to the right is a great way to improve some of your image making. I should note that it will almost certainly slow you down as you work to get the rightmost good exposure. I also find this technique of little use in studio settings where I have absolute control of the lighting. But for walk-around shooting it can make for some very flexible images that will survive post-processing in spectacular form.
Note: This example image was made with a Canon 1Ds Mark III and the processing I’ve shown was done in Capture One. Results would be similar with pretty much any DSLR and also with Lightroom, Aperture, or Adobe Camera RAW.
Even in Digital Photography, Glass Filters Still Matter
Posted by admin in photography on January 24, 2012
I recently returned from a trip to the Caribbean and packed very few glass filters. Many of the effects and color correction filters simply don’t matter anymore because they can be done in post-processing. But there are still a few that matter very much.
Filters I Still Carry
Skylight or UV
I use these to protect the lens and for no other reason. I’d rather scratch a filter than the lens glass. I cannot honestly say that either skylight or UV makes any apparent difference to my images. But every one of my lenses that isn’t a macro has one or the other on it.
Circular Polarizer
I always try to carry one of these filters. It’s not always necessary — in fact, it’s often unnecessary — but I’d rather have it and not use it than the other way around.
This image (no correction, right out of camera) was shot with a circular polarizing filter. As you can see, the coral sea bottom is clearly visible. One of the effects of a circular polarizer when shooting water scenes is to reduce polarized glare, allowing for a clearer view of details below the surface. Nik Software has a wonderful polarizing tool in their Color Efex software. It’s important to note that this is an emulation of what might happen if you had used the glass filter to begin with. In the case of the image I’ve shown, the image information below the surface would have been lost in the glare, so the software emulation would not have reproduced the effect — it would have deepened the blues and slightly enhanced the contrast in the clouds, but that’s it.
Scratch and Star Filters
At night, these filters can lend some sparkle to an image. Again, the effect can be reconstructed in Photoshop, but many of us have better things to do with our time. And… there’s something special about a purely analog effect.
Gradient Neutral Density Filters
For those shooting RAW you might be thinking you’re off the hook with this one. What a gradient ND filter does is apply a neutral density (darkening) across one half of the frame. The filter can be rotated to match your horizon line. You use these when, for example, the sky is very bright as compared to the foreground. And why would the RAW shooters think they’re off the hook? Because you can fix it in Lightroom or Adobe Camera RAW. But again, the better your image is made, the more you will be able to do with it later. Getting it “right” in camera is the best first step you can take.
Neutral Density Filters
Regular ND filters darken everything. These tend not to be particularly useful in a travel or landscape setting, as you can normally drop the ISO to 100 or so and crank up the shutter speed. So unless you are looking for motion blur and shallow depth of field, they aren’t a carry-around filter. But… for small-studio work, you might find your lights are too bright to shoot portraits at flattering apertures (say, f/5.6 or so). An ND filter can really help out here by giving you back a stop.
Filters I No Longer Carry
- Color Correction: I just can’t justify carrying any color-correction filters because I shoot everything in RAW and the chances are I will get a more accurate color rendering in post-processing than if I had guessed and used a filter in the field.
- Color Effects: Similarly, for effect filters like the coffee or blue/yellow filters that were so cool on film, there is more flexibility shooting it neutrally in RAW and deciding on this kind of effect in post.
- Soft-focus: Sadly, the soft-focus filter has found its way out of my gear bag. There are so many Photoshop techniques and add-on filters to get dreamy effects or flattering skin treatment that soft-focus in the world of still digital photography is (in my opinion) better left to post.
- Warming, Landscape, etc.: Same as color correction. This can be handled with the tweak of a slider, be it color temperature, clarity…
And the Wrapup Is…
I still use glass filters, but sparingly. I typically get thin filters, as I have no need to stack them; it’s either the skylight or the polarizing filter — never both. Each time I get a new lens that has yet a different barrel size, I curse the lens manufacturer over the change and re-evaluate what kind of glass filter is absolutely necessary.
But with that said, now that digital is not a shiny new toy, I find myself thinking, “I’ll fix it in Photoshop later” a lot less. When you’re faced with thousands of images to process, the ones that get bypassed are the ones you have to “fix.” If there’s a way to get it right in camera, the original idea of the image might make it to the select pile of images (if there’s such a thing as a digital “pile”).
I’ve used a boatload of Photoshop tools and add-ons. By far the most useful are:
- Adobe Camera RAW color balancing. This cannot be overstated. This is where your color correction filtering comes into your digital workflow. I’ll say it again: Get your color balanced how you want it using your RAW converter; anything after that is destroying perfectly good pixels.
- Nik Color Efex Pro. These are about the coolest tools available for changing the color and applying effects way beyond what you can do in Camera RAW. You can download a demo copy and see how they work for you but be forewarned: They are addictive!
At the end of it all, I find that less is more in terms of applying filtration. If the image was captured correctly, then it should be a snap to post process it.
Digital Infrared Photography
Posted by admin in photography on July 13, 2011
Some things go in cycles, and infrared photography is one of those things. It’s kind of a quirky way of recording an image — you record only the infrared part of the spectrum reflected from your subject.
A bit of history: Once upon a time we all shot film. Infrared film came in a number of different varieties. The primary distinction was color or black & white and if you see IR images now, you are probably looking mostly at black & white. The black & white infrared film had the eerie characteristic of haloing or blooming around the highlights, making the image look not only somewhat negative but also gauzy or even ghostly.
Fast forward to digital. The way people started out doing digital infrared was to use something like an R72 or an 87 filter — a deep red that cut all the light except the infrared. It has an immense filter factor, so exposures have to be extremely long.
Infrared Sensor Filters
At this point, enter a company called LifePixel. They are based in Washington State (USA) and will convert your digital camera to shoot only infrared. I mean only infrared. They do this by replacing the highpass filter that normally goes over the sensor with one that only allows the infrared part of the spectrum to pass. Sound familiar? But the beauty of this solution is that exposures are of normal duration — i.e., if you were shooting f/8 at 125th of a second with your normal DSLR, then it would be pretty much the same with the converted one. This reduces the need for extraordinarily long exposures.
Color Infrared
Here is an example of an image shot in raw on a converted Canon 20D with no post-processing:
You may notice somewhat brown skies along with the signature white trees and ghostly look associated with infrared. The image is pretty much monochromatic. However, the cut filter does allow the sensor to detect a bit of color and since it is recording in RGB, it doesn’t look quite like a black & white infrared. There are two directions to go with this. The first is to do some smart juggling in Photoshop:
For this image, I did a bit of levels adjustment to bring up the whites and darken the blacks, added an S-curve to enhance contrast, then the important part: Used the Channel Mixer to mix red to 100% blue and blue to 100% red. Green is left alone. This makes the sky blue and gives the appearance of a color infrared. You can read a bit more here.
Black & White Infrared
I’m not crazy about the weird color infrared look, preferring, instead, the stark black & white look. Here’s the same image done as a black & white.
For this image, I simply took the image from the first version, popped it into Nik Silver Efex Pro, made a few adjustments, and voila!
Conditions for Infrared
Infrared light does not reflect off everything, so don’t think you’re going to make all kinds of keen night shots and so on… You have to test and try and feel out what looks best in infrared. One thing you will see right away is that foliage is wicked cool in infrared. It’s so easy, you’ll find yourself developing a magnetic attraction to all things green even if you are allergic to plants. Other subjects that are absolutely amazing in infrared are structured cloudy skies. That is, thunderstorm style clouds where there are darker and lighter areas of cloud. Just plain overcast won’t be as much fun.
Finally, cityscapes can be eerie in the best possible way in infrared, but as with many infrared subjects, your mileage may vary. These are particularly sensitive to the direction of the light so some experimentation is necessary to get some usable shots.
Summary
Infrared is a really fun technique and one that really cannot be duplicated in post-processing. It’s the result of a particular part of the spectrum falling on the sensor — this part of the spectrum is absent once a digital image is captured on a normal camera.
However, converting a camera to infrared means you are sacrificing a camera. One use only, which is why I mentioned that these images were made on a 20D — obviously, this was an older camera and one that could be sacrificed at the altar of infrared.
One additional change that should be made is that of focus. This is important to understand. Different bandwidths of light are focused by the lens at different locations. Because infrared has a wavelength longer than that of visible light, lenses are not optimized to focus it at exactly the sensor plane. As a result, you either need to modify your lens to focus appropriately, or you need to take this into account yourself by refocusing manually. Because you cannot perceive infrared light with your eyes, you absolutely cannot focus for infrared by eye. LifePixel performs this modification to lenses, which makes it an obvious choice as opposed to using an IR filter.
Everybody’s a Photographer
Posted by admin in photography on July 12, 2011
Well, I said I was moving my blog to a different server and it happened. Now that that’s over, it’s back to some photography posts.
The camera industry has done an all-around good job of making photography accessible to nearly everyone. Two cheers to them. Three cheers to the mobile phone industry. They are the ones who have really made everybody a photographer. Not every cell-phone image is art, but many are images that would never have been made if the photographer had relied on having his or her camera on hand.
If you are a serious photographer, you may be wondering why cell-phone images matter. I can’t answer that for everyone, but for me they matter because they are taken of pretty much anything and everything in the human experience. By devices that fit in a pocket or purse. By your phone! The rules are a bit changed but the game is the same. With a big expensive camera or with a cell phone the things that matter most are where you point it and when you push the button.
So, if you are tempted to dismiss cell-phone photography as “just fooling around,” give it another thought.
Two Simple But Effective Lightroom Tricks
Posted by admin in photography on October 31, 2010
One thing Apple got really right in Aperture was to make a zoom center wherever you clicked. So, if you click on a model’s eye, you see a zoomed version of that eye. Lightroom, by defaut, zooms to center, so if you click on that eye, you might get the bellybutton.
Tip #1: Zoom Clicked Point to Center
Choose the Preferences item from the Lightroom menu (this is different in Windows, I know… you’ll find it).
In the dialog box that comes up, in the “tweaks” section, tick the “Zoom clicked point to center” checkbox.
Dismiss the dialog and just like that, zooming happens to the point you choose!
Tip #2: Use Stacking Wisely
Aperture and Lightroom have a concept called stacking. If you are unfamiliar with it, imagine your images are a deck of cards, and they are arranged by suit. The top card is what shows and there are four stacks — one for each suit.
That’s kind of what happens when you stack your pictures. They take up a ton less space on the screen, and allow you to group them visually. So here’s an example: When shooting this model, we chose a them, took a number of shots, waited a minute or two to discuss the next theme, then moved into those shots.
Autostacking
There is a very cool feature called autostacking that takes advantage of the fact that photographers often shoot “in bursts”, as I described. Just go to Photo > Stacking > Auto-Stack by Capture Time. You can adjust the sensitivity slider to account for how long or short your pauses were, but the best guess of a minute is normally good.
Now that you have only a fraction of the images on the screen you had before, the question how to open up (expand) one of the stacks. The trick is to recognize a stack. Here is what one looks like:
See the little number 17 in the upper left corner of the image? That means there are 17 images in the stack including the one chosen to represent the stack. To open it up, the first thing many people do is unstack the photos. Not a good choice. What you want to do is “expand” the stack. To do this, click on the image representing the stack and press the S key.
As you can see, the highlighted image on the left is the top of the stack, and the dimmer frames are all the images contained in the stack. You can now edit or do whatever you like with these images. And you can press S on any one of them to collapse the entire stack neatly into place when you’re done.
There are many more stacking options including arranging the images within the stack and choosing the stack image. Just shop around the menus or check out the Adobe help for more tips on how to do this.
Fun With iPhone Photography
Posted by photodiva in photography on December 3, 2009
I’ve had an iPhone for a while and the camera, while not incredibly great, is incredibly fun. The great thing about taking photographs with a cell phone is it’s not serious. I mean, reaaalllly, does anyone expect cell phone pictures to be any good?
Lightroom for Stock Photography
Posted by photodiva in photography on November 29, 2009
Lightroom is a bit of a hybrid between digital asset manager and photo processor. It’s not Photoshop and it’s not Extensis Portfolio. In version 2.0 and later of Lightroom, the retouching tools are sufficient to give you good results for many images without getting into Photoshop. The filing and filtering tools are good enough to keep pretty organized.
A Suggested Workflow
After noodling around with this for a bit, I’ve settled on the following philosophy: “Do what makes sense in Lightroom’s Develop Module. If there is any remaining work, edit in Photoshop.” So, here’s what I do as I go over a photo shoot:
- Edit. Use whatever flagging you like — color coding, stars, whatever. When you have decided on an image…
- Crop/straighten if necessary.
- Color correct if necessary.
- Exposure correct and watch the edges so highlights and shadows are not clipped.
- Look at edges for chromatic aberration — this applies primarily to high-resolution digital cameras like the Canon 5D Mark II or 1Ds Mark III. Correct if necessary.
- Use the keen spot-removal tool at 100% to make sure there is no sensor dust in the image.
- Move on to the next image. It’s that simple and quick!
There are a number of other adjustments you can make in Lightroom, and your image might benefit from them. Here’s the catch. If there is a stray object that borders on an important object, the spot-removal tool may not produce good results. This is the primary reason I ever take an image into Photoshop anymore. Precise cloning and healing. To do this, simply use Lightroom’s Edit In Photoshop command.
Once you’re done partying on the image in Photoshop, just save and close. Switch back to Lightroom and there, right beside the original, is your new copy.
Finally, export the JPEG to a location you can remember so you can upload the image.
Summary
Switching tools is time consuming. Do it as infrequently as possible. Stay in Lightroom when possible, but bail into Photoshop where it is obvious.
The Elusive White Background
Posted by photodiva in photography on May 13, 2009
Photos shot on a white background are easy for buyers to use. White provides a consistent color (or non-color, if you will). So, as a result many of us spend time perfecting setups that will allow for people or objects to be isolated on these pure white backgrounds — “floating in space.” Built in camera meters are, unfortunately, not designed to help you achieve that look. Nobody, however well intentioned, can give you a “secret formula” for creating this white background look, but here are some guidelines:
- Your camera will try to make a scene’s exposure average out to 18% gray. That means a scene that is mostly white will wind up looking gray because the in-camera meter is working at cross purposes to your intent.
- To be white (and that means 255, 255, 255 in RGB), the background must be 1.5 to 2 stops brighter than the main subject.
- Lights tend to produce “hot” spots that could be 2 stops brighter at the center, but falling off at the edges.
These effects look, to read many of the blog posts on the net, easy to achieve by taping a couple of little strobes in strategic positions. This turns out not to be the case for reliable results. Besides the +2 exposure for the background, there are a couple of other questions:
- How do you get a background that bright?
- And how do you make sure that light doesn’t pollute your subject?
How to Get a Really Bright Background
There is only one way to do this, with a few variants: Shine a really bright light at it. The variants are that you can shine a light off a white background, shine several lights off that background to reduce falloff at the edges of the frame, or shine bright lights through a translucent background. So that’s at least one light in addition to your keylight.
How Not to Get Light Pollution on the Subject
The short answer to this is distance. The further from the background the more distinct the separation between the subject an the background and the less background light will spill around the edges of the subject. The longer answer is that whatever light you have pointing at the background needs to be modified so all of its output is toward the background and none up off the ceiling, or back at the subject. Barn doors, black cards, cereal boxes, anything that doesn’t let light shine through is fine.
The Other Option: Photoshop
The words I hate to hear in conjunction with a planned photograph is “and we can Photoshop this later.” If you know about the problem beforehand, it’s always easier to solve the problem with cropping and lighting. Ok, say that doesn’t work. No way do you get your 255, 255, 255 background that you so dearly desire. The temptation is to grab the eraser tool and start hacking. And everything is fine until you get near the object you wanted isolated, at which point, everything begins to look quite artificial.
Canon 5D Mark II: Lots of Pixels!
Posted by photodiva in photography on April 19, 2009
- The 5D is amazingly quiet. So quiet, if fact, that it doesn’t seem you’ve made your exposure. Spooky… but cool in a way.
- Canon implemented a feature called “Live View” on the 40D and later 1-Series DSLRs. This sounds kind of dumb initially. After all, who uses an LCD plate on a DSLR? It turns out to be incredibly useful for no-shake, deliberately composed studio shots. The 5D also has this feature, but it is tangled up in the video features of the camera, so it is easier to make mistakes and clunkier to use than the same feature on the 1Ds. Clunky because if you’re a dyed-in-the-wool Canon user, you will come to expect the SET button (you know, the one in the middle of that big wheel you turn with your thumb) to control important functions. The SET button turns Live View on and off on the 40D and 1Ds Mark III, but there is a separate button on the 5D that is overloaded to both control Live View and control the HD video capability. I’m sure that, over time, I would get used to this, but my first encounter with this particular control was not a positive one.
- As one might expect, the resolution from the 5D is amazing. The RAW images come out to about 22MB, so buy more hard disks. A subjective opinion: The images from the 5D are way better than the 40D just because of the density. The images from the 1Ds Mark III seem “creamier,” if that’s a good way to characterize image quality.
- Flash. Prosumer cameras from Canon – and I categorize the 5D at the top of that basket – have always had built in flashes. They weren’t great, but in an absolute emergency, the could provide some fill. The 1-series never has had built-in flashes, on the assumption that carrying heavy gear makes you a good photographer (I made that part up). Anyhow, if you decide on a 5D, set aside a few dollars for one of the 580EX speedlights.
- Feel. I’ve been shooting with the 1D and 1Ds bodies for the last several years and every time I pick up a camera without a vertical-release grip, I feel like someone cut a hand off. It’s just plain weird. If you have gotten used to a vertical release grip, then you might want to consider the add-on accessory for the 5D.
- Weather hardening. This is a major point Canon makes in their sales. The 1-series bodies have more weather-resistant seals at all their coupling points – lens mount, electronics attachment points, etc. But if you use your camera with some care and don’t drop it in water, then saving a few thousand dollars can go a long way toward making you feel better.
- Sensor cleaning and mapping. The new Canon cameras have these features. They are better than nothing, but you will still need to clean your sensor. Period. I don’t care what the sales pitch is, sensors attract junk and not all that junk can be shaken off. Caveat photographer when you use your sensor cleaning gizmo-du-jour. Sensor filters can be scratched and damaged easily. Now, to mapping, this seems like a non-feature to me. You have to use the Canon software to take advantage of it. Basically, the idea is that the software identifies and remembers repeated “bad spots” caused by hot pixels or persistent dust. It then edits these spots out using some kind of nearest-neighbor algorithm. This works pretty well on the large sensors because there is just so much data, but I have to come back to the fact that you have to use the Canon software. Using Adobe Camera RAW is so infinitely superior that it renders any advantage from this sensor mapping irrelevant when compared to all the ACR utility you would have to give up if you used the Canon software.
- Lens performance. Here is the bad news: The old lenses that were performing quite nicely, thank you very much, won’t anymore. Two reasons: 1) The sensor has far greater resolution; and 2) Full-frame sensors bring out chromatic aberration near the edges of images, especially an minimum or maximum apertures. This is not a new problem, nor is it a problem unique to the 5D. It just is. The CA adjustment in Adobe Camera RAW will clean up all but the worst offenders. I am able to get acceptable performance out of my 15mm fisheye and 17-35mm wide zoom. The chromatic aberration is there at f/2.8 and sometimes at f/22, but f/5.6 through f/11 are just fine.
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