Category: Ask Tim Grey

Today’s Question: Can you explain how posterization can occur in the first place for a preview image versus a “real” image, as you explained in a recent Ask Tim Grey email?

Tim’s Quick Answer: Posterization is generally caused by applying very strong adjustments to a photo, which reduces the range of tonal and color values available and reduces the smoothness of gradations in a photo. Posterization is most common with images that have a low bit depth, which is why JPEG images are more susceptible to posterization than high-bit RAW captures.

More Detail: Posterization is the loss of smooth gradations of tone or colors in a photo, so in some respects you could say that posterization is the result of adjustments that reduce the total number of tonal or color values.

For example, if you increase contrast in an extreme way, you are compressing the range of tonal values, leaving fewer shades available. A simple example would involve a black and white image of a relatively clear sky. That sky would likely transition from a moderately dark shade of gray to a relatively light shade of gray, for example. Increasing contrast significantly would reduce the number of shades of gray that could be used within that sky, so that the gradation would no longer be smooth.

In some cases a strong adjustment might not be necessary to produce posterization in an image. For example, with some extreme situations simply converting from a high-bit image (such as a RAW capture) to an 8-bit image (such as a JPEG) could result in some posterization.

In particular, if you save a JPEG image (which is always only 8-bits per channel) at a relatively low Quality setting, there is a higher risk of posterization. In the context of Lightroom, for example, if you use a low Quality setting for the previews (this setting can be found in the Catalog Settings dialog) there is a higher risk of posterization in your JPEG previews displayed in the Library module. But chances are it is only the preview that is affected, and the Develop module will show you the actual quality of the image.

Today’s Question: I have an image that shows posterization [the loss of smooth gradations of tone and color in an image] in the Library module [in Lightroom] but when I go to the Develop module it does not show up.  I have seen it 3 or 4 times and was wondering if you could explain this.

Tim’s Quick Answer: The short answer here is that the Develop module presents a more accurate preview, and that the Library module presents a JPEG preview of your photo. Therefore, the preview quality in the Library module will not always reflect the true quality of the underlying photo.

More Detail: There are several factors that affect the preview you see in the Library module in Lightroom. To begin with, that preview is a JPEG version of your original capture, which by definition will not reflect the full quality of the original capture in many cases.

In addition, you can actually adjust the resolution and quality of the preview that is rendered for the Library module. To do so, first bring up the Catalog Settings dialog by choosing Catalog Settings from the Lightroom menu in the Macintosh version of Lightroom or from the Edit menu on the Windows version. On the File Handling tab you can adjust settings for the size of the preview image to be generated as well as the overall quality of that preview. This latter setting relates to the Quality setting when saving a JPEG image.

The aim of the Library module is really to enable you to quickly browse and manage your photos, and so the JPEG preview approach makes sense. But of course in some cases you need to evaluate the true quality with the most accurate view of your photo as possible. In those cases I highly recommend using the Develop module within Lightroom. There might be a slight delay in updating the previews for your photos in the Develop module, but in some cases it is worth accepting that delay in return for a more accurate view of your photos.

As a general rule, I recommend using the Library module when you are organizing and performing a basic review of your photos. When you need to evaluate the true quality of your photos, use the Develop module to browse the images. And when you need to evaluate sharpness I recommend using the 1:1 zoom setting within the Develop module.

Today’s Question: Why not just put all the images into one folder? If I’m very diligent about populating all pertinent metadata fields and adding keywords, won’t that be the means to locate most desired subsets of images using search?

Tim’s Quick Answer: While the metadata included with your photos can be invaluable for locating your photos, personally I still prefer to use folders to organize photos. My general aim in this regard is to provide an additional layer of organization, and to provide a workflow that is somewhat independent of whatever software I might be using (such as Adobe Lightroom) to view and sort photos based on metadata.

More Detail: In many respects this is something of a philosophical question. After all, the folders we create on our hard drives aren’t really physical objects. In fact, you could think of the folders you create on your hard drive as being just another type of metadata applied to your photos. Just as you can add photos to collections in Lightroom, so too can you add them to folders on your hard drive, and then filter the images based on which folder (or collection) you added them to.

However, the folder structure on your hard drive can be thought of as being more “durable” than some of the other metadata you might apply, since those folders are created and managed at the operating system level, rather than potentially being managed at the application level. That is a particular concern with metadata that is specific to an application rather than to an established metadata standard.

For example, in Lightroom the pick and reject flags, membership in collections, and virtual copies are all Lightroom-specific features that would no longer be available if you suddenly stopped using Lightroom to manage your photos.

So, my preference is to add the layer of organization that a folder structure can provide, and to ensure that at least some of my overall organizational workflow will still be available even if the software I am otherwise using to manage my photos were to suddenly become unavailable for any reason.

Having said all that, I don’t personally recommend going to a lot of trouble to create a folder structure and then sort photos into individual photos. For example, I generally recommend against the practice of creating folders for individual subjects (or categories of subjects) and then moving every single image into the appropriate subject-based folders.

In general I keep my photos from a single photographic trip, outing, or photography session within a single folder, and try to use a name for that folder that will be helpful when it comes to locating those folders later.

With software such as Lightroom, of course, you can always bypass your folder structure to search for photos from your entire catalog based on other metadata values. But personally I prefer to maintain a meaningful folder structure for my photos.

Of course, my preferred approach isn’t the right solution for all photographers, so I encourage you to step back and think about what might make the most sense for you both in terms of the amount of effort required to implement your workflow along with what approach will help ensure you’re always able to find the specific photos you need when you need them.

Today’s Question: How do I add a new folder [in Lightroom] at the highest level above all my existing folder names?

Tim’s Quick Answer: There are a couple of approaches you could take here, but the simplest (I think) is to use the “Add Folder” command to create a top-level folder, and then if desired drag-and-drop existing folders into that new folder.

More Detail: By default Lightroom doesn’t reveal the top-level folder (or hard drive) in a way that makes that storage location accessible. However, you can still create new folders in any available storage location.

First off, if you’d like to be able to see the top-level folder (or hard drive) within the Folders list, you can most certainly do that. Simply right-click on any of the existing folders on the desired hard drive and choose the “Show Parent Folder” option from the popup menu. This will reveal the folder (or hard drive) that is the direct parent of the folder you right-clicked on. When you no longer want to see that parent storage location you can right-click on the parent location and choose “Hide This Parent” from the popup menu.

In addition, you can very easily create a new folder in any available storage location. To do so, click on the “plus” (+) symbol to the right of the Folders header on the left panel in the Library module and choose “Add Folder” from the popup menu that appears. Navigate to the desired storage location (such as the hard drive you use as the primary storage location for your photos) and click the New Folder button to create a new folder. You can specify a name for that folder and click the Create button in the New Folder dialog. Then click the Choose button to close the navigation dialog.

At this point the new folder you created will appear on the Folders list on the left panel in the Library module. You can then drag-and-drop other folders into this new folder if you’d like. For example, if your intent was to create a new parent folder to contain all of the folders containing your folders, you could drag-and-drop all of the existing folders into the new folder you created. To make that process even faster, you can click on the top folder on the list and then hold the Shift key on the keyboard to click on the last folder on the list, selecting all of the folders in between in the process.

If you want to toggle the selection of any folders on the list you can hold the Ctrl key on Windows or the Command key on Macintosh while clicking on a folder to toggle the selection of that folder on or off.

You can then position your mouse over any of the selected folders and drag-and-drop all of the selected folders to the new parent folder you created. In this way you can, for example, create categorized parent folders to contain specific groups of folders containing your actual photos.

Today’s Question: Two points you have made in your emails have me questioning my workflow. The first is being non-destructive to my original image by using layers in Photoshop for changes such as spot healing. The second is not creating duplicate images in Lightroom in order to down the clutter. With the workflow I am using this doesn’t work out so well. I will begin editing in Lightroom but at some point I will want to move the file to Photoshop to clean it up, resize, or do some procedure that can’t be done in Lightroom. After finishing the Photoshop work on the file it gets saved as an EDIT copy and I end up with two files in my catalog. Is there a means of avoiding this two-file problem and allowing the changes in Photoshop to be a part of the original Lightroom file without destroying the original?

Tim’s Quick Answer: Working in Photoshop with a photo that is being managed by Lightroom requires that an additional copy of that image file be created. However, while it is not possible to apply Photoshop adjustments directly within Lightroom, it is possible to streamline your organizational workflow to avoid additional “clutter” in Lightroom.

More Detail: Within Lightroom the adjustments you apply in the Develop module are applied in a non-destructive way. What that means is that you are storing the information about your adjustments within the Lightroom catalog, and the source image file on your hard drive remains unaltered.

While it is possible to work non-destructively in Photoshop through the use of adjustment layers and image layers, those features require that you open an actual image file within Photoshop. In the context of a Lightroom-based workflow, that means you must create a copy of your original image as part of that process.

So, for example, if you send a RAW capture from Lightroom to Photoshop, a new TIFF or PSD file is created from that original file, with the file type depending on the setting established within the Preferences dialog. By default, however, that new copy of your image is added into a stack with the original. You can then collapse the stack so that you will have less clutter when browsing your photos in Lightroom.

To collapse (or expand) the stack of photos, you can click on the text banner that indicates the number of images in the stack on the thumbnail for the photos that are included in that stack. You can also expand or collapse the stack by right-clicking on any of the images in the stack, choosing “Stacking” from the popup menu, and then selecting the applicable option from the Stacking submenu.

When a stack is expanded, you can also right-click on an image within the stack and choose the “Move to Top of Stack” option from the Stacking submenu to cause the image you right-clicked on to be at the top of the stack. That, in turn, means that the selected image will be the thumbnail representation of the stack when the stack is collapsed.

By stacking images together and keeping the “final” version of the photo at the top of the stack, you can display a single thumbnail for two or more copies of an image, helping to reduce clutter in your Lightroom catalog.

Today’s Question: Do you recommend buying a dedicated underwater camera, or using an underwater case for a camera or smartphone?

Tim’s Quick Answer: The answer here depends in large part on your personal preference and how serious you are about underwater photography. For casual underwater photography I recommend a dedicated “rugged” camera that is waterproof. For more serious photography I recommend employing an underwater housing for a digital SLR.

More Detail: Photography has a (well-earned) reputation for being a relatively expensive pursuit, and taking your photography underwater can certainly increase the cost when it comes to equipment. An underwater housing for a digital SLR, along with strobes and other accessories, can easily cost several thousand dollars. Especially for photographers who are just looking for a casual way to include underwater subjects in their photography, that can be an option that is considered too expensive to pursue.

I’ve used a variety of underwater cases for different cameras. As a good “in between” option I’ve made use of a relatively inexpensive underwater bag for a digital SLR, with very good results. I used a bag from Ewa-Marine, an example of which you can find here:

http://timgrey.me/ewa-marine

I’ve also used several different cases for a smartphone, which I’ve had mixed results with. My current favorite is a bag that has proven to work quite well overall, an example of which you can find here:

http://timgrey.me/dicaphone

In general I’ve found that when I want to achieve the best quality possible for my photos, I prefer to use an underwater housing (such as the bag from Ewa-Marine noted above) for a digital SLR or mirrorless camera. For more casual underwater (or near the water) photography, I’ll protect my smartphone with an underwater case or bag.

However, every time I go underwater with my iPhone, I realize that it probably isn’t worth the risk of damaging my phone in pursuit of casual underwater photos. Therefore, I think a dedicated point-and-shoot camera that is waterproof and rugged in general makes the most sense for more casual photography in or near the water.

For example, this CoolPix model from Nikon provides a rugged point-and-shoot photography option that is also waterproof to depths of up to 100 feet:

http://timgrey.me/nikwater

Today’s Question: In a recent column, you dealt with the problem of CDs or DVDs deteriorating and losing the photos stored on them. I immediately went to my “back-up” DVDs to make certain they were still useable. I have about 100 DVDs going back to the early 2000s when that was the preferred means of backing up photos from a hard drive. My plan is to transfer all photos from the DVDs to one or more external hard drives (3 or 4 TB) to avoid the possibility of losing photos due to break down of the DVDs. Do you agree?

Tim’s Quick Answer: Yes, absolutely! I highly recommend transferring photos from any “at risk” storage media to something you can feel more confident about, and of course ensuring you have at least one good backup (and preferably more) of that data.

More Detail: In this case the specific question relates to optical media (CDs and DVDs). But the same concept here relates to many other outdated storage devices. Years ago I had photos stored on floppy disks, Zip disks, and a variety of other storage devices that are now obsolete to the point it is very difficult to find a drive that can read the media.

Optical media is heading in the direction of obsolescence, with many (if not most) computers no longer including an optical drive. Thus, it won’t be too long before it is very difficult to find a drive that can read a CD or DVD. Therefore, I would most certainly recommend copying any photos stored on optical media to something that is more “current”, such as a hard drive.

Over time you may also find that other storage devices become obsolete. For example, a FireWire connection (IEEE 1394) is not as common on a computer as it used to be, and so if you had an external hard drive that only had a FireWire data connection you may want to transfer any photos or other data from that drive to another drive.

The key is to perform some degree of ongoing maintenance when it comes to your overall storage for your photos and other data. I recommend periodically taking an inventory of your overall storage situation, and updating any storage that is at risk of becoming obsolete. And, of course, always make sure you have a reliable backup copy (or multiple copies) of your photos, ideally stored on different storage devices that you keep in separate physical locations.

Today’s Question: [Monday’s question] brings up something I have been curious about. You recommend copying the metadata from Lightroom into the source files (sidecar in the case of RAW). When I create a virtual copy and then make modifications to it, do those changes ever get written to the source file, even when my preferences are set to do so?

Tim’s Quick Answer: No. When you save metadata to your photos from within Lightroom, that information is only saved for the original (master) photo, not for your virtual copies.

More Detail: When you create a virtual copy within Lightroom, that virtual copy and the metadata updates (or adjustments) you apply only exist within the Lightroom catalog. The option to save metadata directly to the source files on your hard drive is not available for virtual copies within Lightroom. In addition, if you enable the option to automatically write metadata updates to the source files in the Catalog Settings dialog, that setting will not apply for virtual copies.

There is something of an exception here, however. If you export a virtual copy from Lightroom, a new copy of the image file will be created, and that new copy will contain the metadata updates you applied to the virtual copy as long as you choose to include the applicable metadata as part of the image file(s) within the Export dialog. For example, it is possible to export both the original (master) version of a photo as well as a virtual copy for that photo, and end up with two copies of the original RAW capture with an XMP sidecar file for each of those images.

When it comes to writing metadata updates directly to your source image files from within Lightroom, however, only the original (master) image is updated. Virtual copy metadata updates are only saved within the Lightroom catalog, or as part of new copies of photos created during the export process.

Today’s Question: A very basic question I know, but a friend and I cannot agree. She maintains that in Lightroom CC before you start any processing on an image in the Develop Module you should make a [virtual] copy and work on the copy so that the original is always there. I have never done that, believing that if I work on an image then if I want the original I can take a virtual copy and reset. In fact in my mind I still end up at the same point that she does. Which is the best way to go? And to settle a point please!

Tim’s Quick Answer: There is certainly no need to create a Virtual Copy for every photo you work on in the Develop module. To me, taking this approach simply creates unnecessary clutter, and doesn’t provide a significant advantage considering Lightroom’s non-destructive approach to photo editing.

More Detail: A Virtual Copy in Lightroom simply represents an additional set of adjustments for a given source photo. Those adjustments are always kept separate from the underlying source photo, which is why we describe Lightroom as providing a non-destructive workflow when editing images.

Creating a Virtual Copy before working on a photo would obviously provide you with the potential to have the source image represent the “before” version of the photo, while the Virtual Copy represents the “after” version of the photo. But you could also use the Before/After views in the Develop module to see what the image looked like before versus after applying all of your adjustments.

As noted in the question, it is also quite possible to create a Virtual Copy after you’ve applied adjustments to the source photo in Lightroom. You could then click the Reset button at the bottom of the right panel in the Develop module for either the source image or the Virtual Copy, so you would have the same net effect as though you had created a Virtual Copy before you got started.

Since you can create the same Virtual Copy after applying adjustments in the Develop module, my personal preference would certainly be to not create a Virtual Copy for every photo I work on in the Develop module. Instead, I would only create a Virtual Copy when I feel that I actually need one for any reason, avoiding the unnecessary visual duplication for the photos I work on in most cases.

Today’s Question: I understand that stopping down the lens aperture all the way will maximize depth of field, and opening up the aperture all the way will minimize depth of field. But how do I figure out what aperture to use for depth of field somewhere in between the extremes?

Tim’s Quick Answer: In theory you could calculate the depth of field for a given situation based on the specific conditions. In general, however, I find the depth of field preview feature to be a much better approach, especially in conjunction with the Live View display available on many cameras.

More Detail: The depth of field achieved for a scene depends on a variety of factors, including the lens aperture and the distance to the subject. Once you have configured the overall shot, the lens aperture is often your “final” way of controlling the depth of field.

There are a variety of tools available for calculating depth of field, including apps for smartphones that can be very helpful. However, if your camera includes a depth of field preview feature, that feature can provide a fast and easy way to evaluate the effect of different lens aperture settings.

By enabling the depth of field preview (often with a button near the lens mount) the lens aperture will stop down so you can see the impact on depth of field through the viewfinder.

Of course, because stopping down the lens will cause the scene through the viewfinder to be darkened, it can be a little challenging to actually evaluate the result. However, if you have a Live View feature with exposure simulation on your camera, you can easily evaluate the result using the LCD display on the camera. Simply enable the Live View display, ensure the exposure simulation feature is also enabled, and activate the depth of field preview.

With this approach you can simply adjust the lens aperture while in Aperture Priority mode to see the impact on depth of field. Based on this evaluation, you can then determine the specific aperture setting that will provide the look you prefer for the scene.