Ask Tim Grey

Today’s Question: Why use HDR [high dynamic range] when you can adjust shadows and highlights in Lightroom or Camera Raw?

Tim’s Quick Answer: High dynamic range (HDR) techniques enable you to retain full tonal detail in a photo, even when the contrast in the scene is too great to be contained within a single capture. If highlight and/or shadow detail is completely lost in a single photo, the Highlights and Shadows adjustments will not be able to recover that information.

More Detail: Many software tools for optimizing digital photos include controls that enable you to focus adjustments on just the brightest or darkest areas of a photo, including darkening bright areas and brightening dark areas. However, these adjustments will not provide a solution if all information was lost in the brightest or darkest areas of a photo.

In other words, HDR photography is not first and foremost about how you adjust the final image, but rather how you retain detail in the image is retained in the first place.

If a scene you are photographing exhibits significant dynamic range, such as having the sun in the frame but also having foreground subjects backlit, a single photo will not be able to contain the full range of tonal values. If you expose for the sun, the dark shadows will be completely blocked up. If you expose for the shadows the sun will be completely blown out.

In this type of situation, you can bracket the exposure and then blend those bracketed exposures into an HDR result. That HDR image can then be adjusted to determine how you interpret the final result, such as by adding a little contrast so the image doesn’t exhibit a strong “HDR look”.

Many HDR software applications are also capable of applying similar adjustments to single captures rather than only HDR images created from bracketed exposures. But the key is that if the scene exhibits greater contrast than can be contained within a single photo, you’ll need to use HDR techniques to retain full tonal range in the final image.

Today’s Question: Can you cover how to shoot a snow scene to avoid blown highlights?

Tim’s Quick Answer: Other than checking the histogram to confirm you haven’t lost highlight detail due to over-exposure, when photographing a scene with snow it can be helpful to meter directly off the snow and increase that exposure reading by about two stops for snow in full sun and by about one stop for snow in shade or under a full overcast sky.

More Detail: The meter in your camera can be thought of as trying to make whatever you meter off of have a brightness value of 50% gray. If you meter off of a gray card, that works pretty well. When metering off a general scene that can be a little tricky, and it can be especially challenging when there is snow in the scene.

In general, you would not want the snow in a scene to appear with a luminance value of middle gray. But there is also a risk of snow being blown out in a scene, especially if the snow represents a relatively small portion of the frame. For example, if the scene is mostly dark trees with small areas of snow, the camera will likely brighten the exposure based on the dark trees, possibly losing detail in the areas of bright snow.

You can obviously check your exposure after the capture by using the histogram display, for example. However, you can likely get more consistent and accurate exposures in this type of situation by metering off the snow in the first place and compensating for the exposure accordingly.

If the area of snow is relatively small in the frame you may need to switch to the Spot metering mode for your camera. You can then meter off the snow, which would result in an exposure where the snow appears quite dark. To compensate for the fact that the snow should be much closer to white than to middle gray, you need to increase the exposure based on the metering.

For snow in full sun, you will generally get a good exposure by increasing the exposure by two stops compared to the metered value. If the snow is in full shade or the sky condition is full overcast, increasing the exposure by one stop will probably suffice. You may need to fine-tune to get the best exposure, but this approach will work quite well most of the time.

Today’s Question: Can you rename and sequence photos in batch mode after import [into Lightroom Classic] for which you forgot to do during initial import?

Tim’s Quick Answer: Yes, you can rename photos in a batch process within Lightroom Classic even after importing photos into the catalog. The process is very similar to configuring the renaming during import.

More Detail: It can be helpful to rename photos if for no other reason than to simply have more meaningful filenames. You can rename photos right at the time of importing the images into Lightroom Classic, but some photographers prefer to wait until later in their workflow. For example, if you delete outtakes after renaming, you would have gaps in the numbering for your filenames if you used a sequence number as part of the filename structure.

To rename after photos have already been imported into your Lightroom Classic catalog, first navigate in the Library module to the folder or collection containing the photos you want to rename. Make sure there aren’t any filters set that would cause only a portion of the images to be displayed (unless you only want to rename photos based on specific filter criteria). Select the photos you want to rename, such as by choosing Edit > Select All from the menu if you want to rename all photos that are currently displayed based on the folder or collection and the established filter criteria. Then choose Library > Rename Photos from the menu to bring up the Rename Photos dialog.

In the Rename Photos dialog you can then specify the template you want to use for renaming the images using the File Naming popup. If an existing template doesn’t fit your preference for the filename structure, you can choose the template that best matches your preference, and then choose Edit from the File Naming popup.

In the Filename Template Editor dialog, you can then define a structure for the way you want to rename your photos, both by typing in specific text you want to include in the filename for each photo and choosing among the available variables with the popups and Insert buttons below. After defining an updated template, you can save it by choosing “Save Current Settings as New Template” from the Preset popup, entering a name, and clicking the Create button. Then click Done to close the Filename Template Editor dialog.

At this point you can update the values for the Custom Text and Start Number fields if those are included in the filename structure template you’ve selected. Then click OK and the selected photos will be renamed based on the settings you established.

Today’s Question: Are HEIF/HEIC raw file types?

Tim’s Quick Answer: No, the HEIF/HEIF file type is not a raw capture format. It can be best described (at the risk of over-simplifying) as an improvement over the existing JPEG file type.

More Detail: Many photographers first came across the HEIC/HEIF image type with an update to the iOS operating systems for iPhones, which added support for this file format. You can opt to capture in JPEG for greater compatibility, or in HEIC for higher efficiency.

In this context, the primary advantage of HEIC/HEIF is that the file size will be about half that of a JPEG file with comparable image quality. The HEIC captures still employ lossy compression, meaning there is a degradation in image quality.

As with many other file formats, the particulars depend upon the specific implementation. For example, the HEIC/HEIF file type is capable of supporting 16-bit per channel bit depth, whereas the JPEG format only supports 8-bits per channel. However, on the iPhone the result will still be an 8-bit per channel image (at least with current models).

More to the point in terms of comparing to a raw capture, an HEIC/HEIF capture contains full pixel data for each pixel. In other words, the data gathered by the image sensor is processed in-camera to provide full pixel data. With a raw capture the actual information captured by the image sensor is recorded without processing (or with minimal processing), which can provide greater flexibility later in your workflow.

So, HEIC/HEIF is a great alternative to JPEG, and is increasingly supported by imaging software. However, there are still advantages to a raw capture when that option is available, in terms of potentially greater bit depth, greater dynamic range, and no image compression applied.

Today’s Question: How many photos do you recommend capturing when bracketing for HDR [high dynamic range]? And how many stops should each photo be separated by?

Tim’s Quick Answer: How many frames you’ll need in a bracketed sequence will vary by the specific photographic situation. I recommend bracketing in two-stop increments and making sure that you have enough photos in that sequence to cover the full tonal range of the scene. That can require around five (or more) captures in extreme cases, such as when including the sun in the frame.

More Detail: There’s no need to bracket exposures for HDR by less than two stops between each exposure, so I recommend starting there.

If you’re going to use a manual process for bracketing by just adjusting the shutter speed for each exposure, for example, you can start with an exposure that is dark enough to retain the brightest highlight detail, and capture exposures in two-stop increments until you’ve brightened to the point that full shadow detail is revealed.

If you’re using automatic exposure bracketing, you need to make sure you’re bracketing enough to cover the full range of tonality in the scene. Some cameras only offer three exposures for automatic bracketing, so in some cases you may need to use a manual approach. But many cameras offer five, seven, or even nine frames for automatic bracketing.

Obviously, you could test to determine how many bracketed exposures you need, but especially if time is of the essence, you may find it is easier to just bracket at the maximum number of exposures available for automatic bracketing on your camera, and then delete any unnecessary frames later.

Today’s Question: If you are visiting multiple locations as part of one trip do you label the folder with multiple names: London and Paris 2009, or create individual folders for London 2009 and Paris 2009?

Tim’s Quick Answer: To me the answer here depends on how you think about the trip, which in turn will determine what assumptions you’re going to make later about where the photos are stored.

More Detail: My approach to defining a folder structure is to create folders based on the way I think about a group of photos. In other words, if I’m looking for a particular photo, what is the context I’ll think about for that photo, and therefore what might be a logical name for the folder in which I will find the photo.

For me personally, the context for my photos tends to be location. But for other photographers there may be other considerations, such as the date of capture, the people who appear in the photos, or other possibilities.

You then need to consider how many folders would be appropriate for a given set of photos. The example cited in today’s question is a great example, in that it gets to the core of the way I recommend thinking about folder structure.

For example, I had a trip that included stops in Iceland, Paris, and Prague. While it was one big trip, to me it felt like individual photo adventures. So, I have individual folders for each of those locations.

On another trip I spent time with a good friend traveling around Spain, including time crisscrossing the Pyrenees Mountains between France and Spain. While a good number of my photos were captured in France, to me that trip was focused on Spain. So, all of the photos from the trip are in a “Spain Road Trip” folder, rather than individual folders for Spain and France.

These are just a couple of examples, of course, but the point is that I recommend grouping photos into folders based on your sense of how (or whether) those photos belong together. The folders can then be named based on how you think of the images, so that when you’re looking for a particular photo, you’ll already have a sense of what the name of the appropriate folder might be. That, in turn, will help you locate photos more easily in the context of navigating to a particular folder.

Today’s Question: Is original filename preserved anywhere when renaming is used [in Lightroom Classic], especially when exporting?

Tim’s Quick Answer: If you rename photos within Lightroom Classic, the original filename is preserved in metadata so you can review that filename or revert the filename as needed. However, when you rename upon export that “new” filename is not preserved along with the original photo in your catalog.

More Detail: You can, of course, rename photos from within Lightroom Classic. For example, you can simply change the File Name field in the Metadata section of the right panel in the Library module. You can also batch-rename multiple selected photos using the Library > Rename Photos command on the menu.

When you rename photos in Lightroom Classic, the original filename is preserved in the “Original Filename” field that will then appear in the Metadata section of the right panel in the Library module. You can obviously review that original filename there, or use the original filename within the batch renaming feature to revert photos to their original filenames.

However, when you rename photos during export, the original filename is not preserved as part of that process. That is because you’re not actually renaming the photo being managed in your Lightroom Classic catalog, but rather are creating a new file with a new name.

Today’s Question: When performing image cleanup work in Photoshop why do you use an empty image layer instead of a duplicate layer?

Tim’s Quick Answer: The primary benefits of performing image cleanup work on a new empty image layer rather than a copy of the Background image layer are reduced file size and a more streamlined workflow.

More Detail: In Adobe Photoshop the primary reason to use layers is to provide a non-destructive workflow. For example, by performing image cleanup on a separate layer you are not altering the underlying Background image layer directly. This makes it very easy to then correct or eliminate any changes that ended up not working out well.

When it comes to image cleanup, you can either create a copy of a complete image layer (such as the Background image layer) or create a new empty image layer. The option for working with an empty image layer for this purpose is possible because most of the image-cleanup tools in Photoshop enable you to work across multiple image layers. For example, you can cleanup blemishes that exist on the Background image layer by painting on a new empty image layer, and the Background image layer can be used as the basis of the pixels created on the cleanup layer.

If you duplicate the Background image layer, you are effectively doubling the base file size. So, one of the key benefits of using an empty image layer for image cleanup is that the file size won’t increase significantly at all.

In addition, working with a separate image layer provides more flexibility in your workflow. You can easily erase pixels on the image cleanup layer if some of the cleanup steps didn’t work out as well as you would have liked, for example.

In general, I don’t recommend creating a copy of the full Background image layer unless the task you’re performing requires that step. This might be the case for certain filters or creative effects, for example. However, it is not necessary to duplicate the Background image layer for most image-cleanup tasks.

Today’s Question: I have my [Lightroom Classic] catalog and images on an external hard drive. I think there are advantages to have the catalog on the internal hard drive. Can I move it without causing problems?

Tim’s Quick Answer: Yes, you can indeed move your Lightroom Classic catalog to a different storage location. Having the catalog on an internal hard drive will often provide improved performance compared to using an external hard drive. You just need to be sure to quit Lightroom Classic first, and then transfer the entire folder containing the catalog file to the new storage location.

More Detail: Lightroom Classic revolves around a catalog that contains the information about the photos you have imported into Lightroom Classic. Performance can be improved by having the catalog on the fastest hard drive available, which often means an internal hard drive rather than an external hard drive.

Of course, some photographers prefer to have their catalog on an external hard drive along with their photos so that they can move the drive between more than one computer, and work with their catalog and photos on different computers.

Moving the catalog is relatively straightforward. First, you’ll want to know where the catalog is actually stored. You can get this information in the Catalog Settings dialog, which can be accessed from the Edit menu on Windows or the Lightroom Classic menu on Macintosh. On the General tab of the Catalog Settings dialog you can click the Show button to open a window in your operating system showing the folder that contains your catalog, with the folder selected.

Before moving that folder, you need to quit Lightroom Classic. You can then drag-and-drop the folder to the preferred storage location. As a precautionary step, it is a good idea to back up the catalog before moving it. In addition, I recommend copying the folder that contains your catalog files, rather than moving it. You can then rename the original folder to indicate it is a backup copy, so you don’t accidentally use that version of the catalog moving forward.

Once you’ve copied the catalog files to the new location, you can open the catalog in Lightroom Classic by double-clicking on the catalog file with the “lrcat” (as in Lightroom Catalog) filename extension. That will launch Lightroom Classic and open the catalog in the new location, and everything within Lightroom Classic will be just as it was before you moved the catalog.

Today’s Question: If you were going to project images on a TV mounted to a wall, what kind of resolution would you suggest?

Tim’s Quick Answer: For photos you’ll project on a TV (or digital projector or computer monitor) I recommend resizing the images based on the actual pixel dimensions of the display.

More Detail: When sharing photos digitally, they can be resized to pixel dimensions that match the pixel dimensions of the display or projector that will be used to present the images. The pixel-per-inch (ppi) resolution is not a factor in this context.

Before you can resize the images, you need to know the pixel dimensions of the display. Keep in mind that in most cases it is possible to set a number of different resolution settings for the display, so you’ll want to confirm which setting will actually be set on the display.

Some displays may use a relatively low resolution, at least by today’s standards. For example, you may find some displays use 720p HD resolution, which translates to 1280×720 pixels. Other displays might make use of 1080p HD resolution, which has pixel dimensions of 1920×1080.

Newer television displays often have higher resolutions, such as 4K or even 8K. A display with 4K resolution will generally have pixel dimensions of somewhere in the vicinity of 4,000 pixels on the long side. That might be something like 4096×2160 pixels, for example. Displays with 8K resolution will offer pixel dimensions of around 8,000 pixels on the long side. For many photographers, these large pixel dimensions may actually represent a higher resolution than their camera captures in the first place.

And again, keep in mind that the resolution promoted for a given display is not the only resolution the display will be capable of projecting in most cases. So be sure to prepare your images based on the display resolution setting that will actually be used.