Chromatic Aberration Trouble


Today’s Question: In Adobe Camera Raw under Lens Corrections and Remove Chromatic Aberration it’s limited to only 2 colors, purple and green. Nothing seems to work at all, no matter how I adjust the dials! What is going on here?!

Tim’s Quick Answer: If you’re not seeing an effect with the controls for removing chromatic aberrations, it is most likely an indication that you’re not using settings appropriate to the image you’re working on. I recommend increasing the Amount value for both purple and green to the maximum, and spreading the Hue control handles to the extreme ends of the scale. You should then see a rather significant loss of color along contrast edges in the photo, and you can then fine-tune the controls as needed for the photo.

More Detail: The controls you’re referring to are the Defringe controls, and they operate independently from the “Remove Chromatic Aberration” checkbox. In other words, you don’t need to turn on the “Remove Chromatic Aberration” checkbox in order to employ the Defringe controls.

In general I find that turning on the “Remove Chromatic Aberration” checkbox adequately resolves color fringing in about half of the photos that exhibit such fringing. For the other half of images that require this adjustment, the Amount and Hue sliders for purple and/or green must be used to produce a good result in the photo.

The Amount sliders (for purple and green) determine the degree to which the colors present in chromatic aberrations will be reduced in saturation. The two slider handles for the Hue sliders (for purple and green) determine the specific color range to be affected.

By maximizing the hue spread and the Amount setting for purple, you’ll be reducing saturation for colors ranging from cyan to red, including purple and magenta in between. In other words, colors within that range will turn gray.

Similarly, maximizing the hue range and the strength of the adjustment for the green sliders will cause colors ranging from orange through cyan (including green) to be reduced in saturation.

With this approach, you should see a relatively large gray area along contrast edges within the photo. Obviously you don’t want to actually remove so much color that you end up with a gray band along contrast edges in the photo. So you can then refine the settings as needed.

My general approach when it comes to using the sliders is to start with a high value for Amount, and then expand the Hue range until I can see gray fringing along contrast edges in the photo. I’ll then reduce the Hue range until only the problematic colors are being affected. I then reduce the value for Amount to establish a value that is just enough to remove the chromatic aberrations without causing new problems for the photo.

Text Readability


Today’s Question: Many of our friends prefer Adobe Bridge to Lightroom because the controls are easier to see (black on white) and also larger. The gray on black interface of Lightroom is harder to see and just doesn’t seem to communicate like Bridge. Or can those colors be changed?

Tim’s Quick Answer: Unfortunately you aren’t able to change the overall interface color in Lightroom in a way that will improve the readability of text and other controls. You can enlarge the font size, but you can’t change the colors for the text or controls.

More Detail: There is an option for changing the Background color in the Preferences for Lightroom. However, that option relates to the background behind the image, not to the overall interface.

You can change the Font Size option on the Interface tab in Preferences. There are options for “Small” and “Large”. I recommend the “Large” option to make the text easier to read. Note that when you change this setting you need to restart Lightroom for the change to take effect.

I agree that it would be very nice to be able to change the overall interface appearance within Lightroom. If you would like to let Adobe know you would like to see this update (or another feature or improvement) in a future version of Lightroom, I encourage you to submit the feature request form here:

Search by Size


Today’s Question: Can I search in Lightroom for images based on size or pixel dimensions?

Tim’s Quick Answer: Yes, you can search for images based on pixel dimensions in Lightroom, though not by the normal method of using filters. Instead you would need to create a Smart Collection for this purpose.

More Detail: Lightroom includes a variety of criteria to choose from when using the Library Filter to locate specific photos. However, pixel dimensions or other options related to the size of the image are not included. Smart Collections, however, can employ pixel dimensions as part of their criteria, providing a solution here.

Start by creating a new Smart Collection. To do so, click the plus (+) symbol to the right of the Collections header on the left panel in the Library module. Then choose “Create Smart Collection” from the popup menu to bring up the Create Smart Collection dialog.

You can define a variety of criteria as a filter for the Smart Collection, which will in effect become a saved search result that is updated automatically in real time. Enter a meaningful name for the Smart Collection, and then define your criteria below. In this case, for example, you could click the popup under the criteria listing and choose Size > Long Edge to define a size based on the longer side of the image.

The next popup allows you to specify how to evaluate the criteria. In this case, for example, perhaps you want to use the “is less than or equal to” option to find images with relatively short pixel dimensions. Enter the specific value in the text box to the right.

When you’re finished defining the criteria for the Smart Collection, click the Create button at the bottom-right of the Create Smart Collection dialog. You can then click on the name for this new Smart Collection in the Collections section of the left panel in the Library module to view all of the images that meet the specific criteria you defined.

Archiving Photos


Today’s Question: I am running out of disk space and would like to know the best way to archive photos that are part of my Lightroom catalog without loosing the ability to restore them if needed.

Tim’s Quick Answer: There are a couple of options you might consider. First, you could simply move some of your photos to a different storage location, without removing them from your Lightroom catalog. Second, you could export some of your photos to a separate catalog, and then remove them from your master catalog.

More Detail: My personal preference in this situation would be to obtain a larger hard drive and then transition all photos to that new hard drive. This approach enables you to retain all of your photos within your Lightroom catalog, with the ability to gain access to greater storage capacity.

If you don’t want to transition to a larger hard drive, you could certainly archive a portion of your catalog to a different drive. The first approach would be to simply move some of your folders to a different drive, doing so within Lightroom.

For example, you could create an archival storage location on a different drive. Start by clicking the plus (+) icon to the right of the Folders header on the left panel in the Library module in Lightroom, choosing Add Folder from the popup menu that appears. Navigate to a location that has adequate storage, and click the New Folder button. Create a new folder named something like “PHOTO ARCHIVE” and click the Choose button to add that folder to Lightroom.

Make sure you have a good backup of your photos before actually moving images. You could then drag individual folders from the existing storage location to the new “PHOTO ARCHIVE” folder you created on a different storage device. This will free up space on your primary storage device, while still enabling you to access those photos within your Lightroom catalog.

If you prefer to move the photos and remove them from your Lightroom catalog, I recommend creating a new “archive” catalog. You can select all of the photos you want to archive, and then use a two-step process to copy them to another catalog and remove them from the current catalog.

The first step here would be to use the Export as Catalog command found on the File menu to create a new catalog with the selected images. Be sure to turn on the “Export negative files” checkbox so that the actual image files are copied as part of this process. Once you’ve confirmed the photos have been copied successfully and that you have a full backup of all of your photos, you can use the Photo > Remove Photo command to remove the selected photos from your Lightroom catalog, using the option to delete the photos from the disk as part of that process.

It is important to use caution with either of these approaches in order to safeguard your images and avoid problems in your catalog.

TIFF Compression


Today’s Question: How would using ZIP compression rather than “None” [in the External Editing settings for Preferences in Lightroom] affect opening the resulting photo once it is sent back to Lightroom or Photoshop?

Tim’s Quick Answer: TIFF image files with ZIP compression are supported by a variety of software applications, including Photoshop and Lightroom. As a result, there is not a significant issue with using the ZIP compression option for images you are managing in a workflow that includes Lightroom and Photoshop. The only potential issue would be the risk of other software applications not supporting TIFF images with ZIP compression. In general you won’t find this to be a problem.

More Detail: In the External Editing section of the Preferences dialog in Lightroom you can specify the file type and other settings to be used when sending a photo to another application, such as Photoshop or various plug-ins.

In the past there had been issues with a lack of support for TIFF images with compression applied, especially with the LZW compression option. These issues have largely been resolved, with most imaging applications supporting both ZIP and LZW compression for TIFF images.

As a result, I generally don’t hesitate to apply compression to TIFF images. I typically employ the LZW option rather than ZIP, but both of these options provide lossless compression and are widely supported. In other words, either option will typically be perfectly fine, and will result in smaller file sizes compared to the “None” option.

Frankly, the bigger issue here relates to the potential to create layered images in Photoshop. When you create layers in Photoshop the resulting image cannot be opened with layers intact using other software applications, because the features in question are specific to Photoshop. But again, in the context of a workflow employing Lightroom and Photoshop, this isn’t a significant concern.

Metadata Mismatch


Today’s Question: I have 98,000 photos in my Lightroom catalog. When I select all and use the Save Metadata command I get a message that some photos have been changed in an external application. Should I choose Cancel or Overwrite?

Tim’s Quick Answer: If you are confident that the Lightroom catalog reflects all of the metadata for your photos, you can choose the Overwrite option. If you’re not sure, you could review the metadata for photos individually, and then resolve the mismatch for each image.

More Detail: The message you’re receiving indicates that there is metadata in the actual photos on your hard drive that is not reflected within your Lightroom catalog. As you can probably appreciate, using the Overwrite option will replace the metadata in the photo on your hard drive using the metadata in the Lightroom catalog for each photo.

When there is a metadata mismatch it means there was an update to the metadata for an image outside of Lightroom. So, for example, you might have opened a RAW capture directly in Photoshop (without using Lightroom), causing Adobe Camera Raw settings to be updated in metadata. Or you might have added some metadata in Adobe Bridge, for example.

If you’re confident that you haven’t performed any metadata updates outside of Lightroom, it is probably safe to simply overwrite the existing metadata for the photos themselves. But you’ll want to be sure that you are truly confident that Lightroom contains all of the correct metadata for the photos.

You can review specific images to try to determine the nature of the metadata mismatch. For example, you can go to the Metadata option on the Library Filter Bar (View > Show Filter Bar from the menu in the Library module). Set a column to Metadata Status, and choose the option to display images with a mismatch, making sure that all other filter columns are set to “All”.

You can then review individual images, examining the metadata in Lightroom as well as with a browser such as Adobe Bridge to confirm there aren’t any metadata values shown in Adobe Bridge that are not reflected in Lightroom.

Once you’re confident that Lightroom reflects all of the metadata you are concerned about for your photos, you can overwrite the metadata for the image files on your hard drive.

Autofocus Performance


Today’s Question: Is it more difficult for autofocus systems to grab focus at wider (lower numerical) f-stops? Specifically, does the camera spend more time hunting at f/4 than at f/11 due to factors such as narrower depth of field?

Tim’s Quick Answer: Actually, you could say that the opposite is true. There are actually two considerations here. First, under normal circumstances your aperture setting on the camera doesn’t impact autofocus, because the camera essentially ignores your aperture setting when it is establishing autofocus. However, the maximum aperture size for a given lens does impact autofocus, with a larger aperture size (smaller f-number) providing an advantage.

More Detail: You may have noticed that it can be much more difficult for your camera’s autofocus to achieve focus when photographing a scene at night. The camera might search back and forth attempting to achieve focus, and it might fail to establish focus altogether. This is due to the lack of available light in the scene.

Similarly, the maximum aperture size (smallest f-number) available for the lens impacts the amount of light that will be available. When you reduce the size of the lens aperture by stopping down the lens to a larger f-number, you are restricting the amount of light that enters the lens. Less light makes it more difficult to achieve autofocus, as noted above.

However, most cameras today ignore the aperture setting you have established when attempting to focus. The aperture is left wide-open until you actually take a photo, at which point the aperture closes down based on the setting you have established, the mirror moves out of the way if you are using a digital SLR camera, and the image is captured.

So your camera is establishing autofocus based on a wide-open aperture. But different lenses offer different maximum aperture sizes. For example, there are a variety of 70-200mm lenses available, and in many cases a given manufacturer will offer an f/2.8 version as well as an f/4 version of the lens. With the f/2.8 version of the lens you can obviously achieve narrower depth of field. But you may also be able to achieve autofocus faster with the f/2.8 depending on the specific circumstances, because more light is being let into the lens when the camera is focusing.

The bottom line is that in general the aperture setting on the camera (for most cameras and lenses) has no impact on autofocus performance. However, the maximum aperture size of the lens being used will have an impact on autofocus performance as well, with a larger maximum aperture size providing an advantage.

ISO versus Exposure


Today’s Question: I am going to be going on an African safari where we will be photographing in early morning and early evening light. I will be using a Panasonic FZ300 bridge camera, which tends to have some noise. I have the camera set so that it won’t go beyond an ISO of 400, because the noise gets pretty bad beyond that, but I usually shoot at ISO 100. It occurred to me that I might be better off setting my exposure compensation to the plus side rather than increase the ISO. My question is: Are they pretty much the same or would one be better than the other?

Tim’s Quick Answer: No, exposure compensation is not the same as ISO, and you can’t interchange the two. When it comes to photographing in low light conditions, you’ll need to keep a careful eye on the ISO setting, shutter speed, and lens aperture, to make sure you are creating the best image based on the necessary compromises.

More Detail: When we are photographing under relatively strong lighting conditions, we are often able to make our decisions about exposure settings without too much compromise. When photographing under low light conditions, there is going to be some compromise involved.

I recommend that you start off by evaluating the current conditions and determining a basic set of appropriate exposure settings. For example, you may very well be able to use a wide-open lens aperture (smallest f-number) if you are focusing from a relatively large distance and you aren’t worried about minimal depth of field.

Next, you’ll need to consider how fast a shutter speed you need based on movement within the scene and your ability to hold the camera steady if you won’t be using a tripod. As a general rule, you want to use a shutter speed that “matches” or exceeds the lens focal length. In other words, if you are using a 500mm lens you want a 1/500th of a second shutter speed (or faster), while with a 100mm lens you can probably use a 1/100th of a second shutter speed. You’ll also want to take into account motion within the scene, beyond your ability to hold the camera steady.

So, for example, you might be shooting with an aperture of f/4 and a shutter speed of 1/500th of a second when using a long lens. Now the question is how high do you need to set the ISO in order to achieve a proper exposure for the lighting conditions. In early morning light, before the sun is above the horizon, you might need to increase the ISO setting up to around 1600 in order to achieve a proper exposure.

Appropriate exposure settings will vary based on the specific conditions, of course, but the point is to evaluate the available light based on the settings you need to establish. In this specific scenario you can probably shoot with the lens aperture wide-open. Then consider a shutter speed that will be appropriate based on the degree of motion in the scene, and choose an ISO setting based on that.

Regardless, you want to achieve a proper exposure. Exposure compensation should be used to compensate for situations where the camera’s meter is “tricked” by the current lighting conditions. Exposure compensation does not, however, take the place of an appropriate ISO setting for the exposure.

In the type of situation you describe, noise will likely be unavoidable. Fortunately, through the use of noise-reduction software you can produce acceptable results even when there is noise in the original capture. But a bit of noise is better than a shot blurred by a shutter speed that is too slow, for example.

RAW Interpretation


Today’s Question: As you know, Adobe Standard is the default camera calibration option applied to images in Lightroom and Adobe Camera Raw. I read a recent article discussing high contrast images where the application of Adobe Standard could increase the risk of clipping because of its default contrast enhancement, necessitating the use of exposure, shadow, highlight controls to remedy.

I would much prefer to start with what may appear to be a flatter image and then make my own judgments and adjustments concerning contrast. Secondly, I certainly don’t want the calibration standard to increase the risk of default clipping in my RAW images. So my own conclusion is that Adobe Standard should be abandoned and the use of a “flat” or “neutral” camera calibration should be applied to all imported images.

What are your thoughts?

Tim’s Quick Answer: This isn’t an issue I would worry too much about. In some respects, you can think of this as a situation where regardless of which Profile option you choose for Camera Calibration, you’re going to need to fine-tune your overall adjustments for the image.

More Detail: Processing RAW captures in general involves interpreting the information gathered by the image sensor to create the initial file. This is why each software application for processing RAW captures will produce a slightly (or sometimes significantly) different interpretation of the image.

The Camera Calibration controls in Lightroom and Adobe Camera Raw are primarily aimed at compensating for the behavior of the camera. For example, you can essentially change the definition of the primary colors (generally Red, Green, and Blue) used to create the final image.

The Profile popup within the Camera Calibration adjustments can be thought of in some ways as an overall preset that determines the basic interpretation of the photo. There are certainly differences in overall tonality and contrast based on the preset you select, but the various adjustments can also be compensated for relatively easily.

If the profile you select (such as the default “Adobe Standard” option) results in too much contrast, you can compensate by reducing the value for Whites and increasing the value for Blacks. If the profile you’ve selected results in a flat appearance you could instead increase the value for Whites and decrease the value for Blacks.

But again, the adjustments based on the Profile setting will not be so extreme that you’re not able to compensate with other adjustments. If you find that you’re happier with the initial interpretation of your images based on a Profile option other than “Adobe Standard”, there is no reason not to switch to that Profile option, perhaps even changing the default settings in Lightroom or Adobe Camera Raw based on your preferred Profile.

Mask Inversion


Today’s Question: Sometimes I don’t realize that I forgot to invert my selection [in Photoshop] until after I’ve added an adjustment layer, causing the layer mask to be the opposite of what I meant. Is there an easier way to fix that instead of using the Undo command to take a few steps back so I can invert the selection and then add the adjustment layer again?

Tim’s Quick Answer: Yes! You can simply invert the layer mask to reverse the area of the image being affected by an adjustment layer.

More Detail: I actually prefer to perform most of my work on a layer mask rather than a selection, in large part because this approach enables you to evaluate your work based on the actual effect in the image. Therefore, I often invert a layer mask for an adjustment layer rather than inverting the selection originally created as the basis of that layer mask.

A layer mask is really just a pixel-based image used in a different way compared to “normal” pixels in a photographic image. As such, you can use all of the various tools within Photoshop to alter a layer mask just as you would an image. In this case, for example, you can simply invert the layer mask to reverse the area being affected by a targeted adjustment.

The first step is to make sure that the layer mask is active, which you can do by clicking the mouse on the thumbnail for the layer mask on the Layers panel. Then simply use the Invert command to invert that layer mask. You can, for example, choose Image > Adjustments > Invert from the menu. You can also press Ctrl+I on Windows or Command+I on Macintosh as a keyboard shortcut to invert the currently active layer mask.