Ask Tim Grey

Today’s Question: Why don’t today’s cameras have the ability to know by themselves what Time Zone they’re in via GPS? I guess that, currently, to take care of Time Zones it’s either (a) manually as you describe or (b) through a synchronization with an external GPS device. Am I correct?

Tim’s Quick Answer: I’m sure there must be some cameras that will set the time zone automatically based on GPS. However, inexplicably, the cameras I’m familiar with can update the time based on the GPS signal, but do not set the time zone for you automatically. This is simply a matter of the camera manufacturer not including such a feature on their cameras, which seems like a bit of a glaring oversight to me.

More Detail: Quite a few digital cameras include a built-in GPS receiver, or support an accessory GPS receiver. One of the features of having a GPS signal is the ability to set the correct time based on the information contained in the GPS signal. However, with the cameras I’m familiar with, this option does not adjust the time zone based on your GPS location, so you’ll still need to remember to set the time zone manually.

At the moment my primary camera, for example, is the Canon EOS 7D Mark II (https://timgrey.me/canon7d2). One of the reasons I originally opted for this camera is that it includes a built-in GPS receiver. This enables my photos to be automatically tagged with location information in metadata. Later, I can view my photos directly on the map in Lightroom Classic, for example, which I find very helpful.

Within the menu system for my camera you’ll find that you can choose to have the time on the camera automatically updated based on the GPS signal. However, when you select this option you are only updating the reference time. You can think of this as the camera updating the current Universal Coordinated Time (UCT). However, this automatic update does not include an update to the current time zone setting for the camera.

Let’s assume, for example, that I have my camera set to the Chicago time zone, but I am currently in Italy. When I choose the option to have my camera’s time updated based on GPS, the time on my camera will very accurately reflect the current time in Chicago, but my photos will be tagged with the wrong time for my current location (Italy).

I can’t imagine why it isn’t possible to have my camera automatically update the time zone setting based on my current GPS location, so that the time shown in metadata for all of my photos can be consistently accurate, provided I have a good GPS signal. After all, in general I don’t mind if the time in metadata for my photos is off by a few seconds, but I don’t want it to be off by a few hours. And since I’ve forgotten to update the time zone for my camera more times than I’d like to admit, I really wish my camera could set the time zone automatically, in addition to updating the actual time based on GPS.

Today’s Question: I have a follow-up question to your October 28 email about deleting previews. With regard to deleting previews in Lightroom Classic, wouldn’t it also be possible to delete previews from within Lightroom? I see that I can delete Previews by going to the menu and choosing Library > Previews > Discard 1:1 Previews. And, I can do this on a folder basis. This seems like a good option after I have finished processing photos within a folder that I will not likely need to revisit again.

Tim’s Quick Answer: The 1:1 previews in Lightroom Classic are a subset of the overall previews referenced in my answer about deleting the previews file. By default 1:1 previews are discarded automatically after 30 days, but you could also discard them manually (or change the frequency). But this would generally not free up as much space as deleting the full previews file.

More Detail: I generally recommend generating Standard previews when you import your photos into Lightroom Classic. In addition, you can generate 1:1 (or full-resolution) previews if you prefer. The 1:1 previews will also be generated automatically anytime you zoom in on an image in the Library module.

The Standard previews are not full resolution, and therefore the 1:1 previews will be larger than Standard previews. Thus, it can be helpful to discard 1:1 previews if you won’t likely need them in the future. For example, after reviewing and optimizing photos from a given photo trip, you likely would not need the 1:1 previews for those images. And, of course, if you zoom in on one of those images, the 1:1 preview will be generated again automatically.

You can adjust the settings for automatically discarding 1:1 previews in the Catalog Settings dialog. On the File Handling tab you’ll find the “Automatically Discard 1:1 Previews” popup. From that popup you can choose to have 1:1 previews discarded if they have not been used in thirty days, one week, or one day. There is also an option to never discard 1:1 previews if you prefer.

I recommend selecting an option for automatically discarding the 1:1 previews based on how frequently you tend to go back to your images. If you need to free up hard drive space, you could also discard previews manually for some (or all) of your photos by selecting those photos and choosing Library > Previews > Discard 1:1 Previews from the menu.

Today’s Question: My Nikon D810, good as it is, does not automatically determine the white balance correctly, much less taking care of the color profile. Gray Cards are nice for manually determining the white balance, but they cannot calibrate the color profile. I’ve been using [the X-Rite] ColorChecker for a while, and it has made a significant improvement in my photos: color-wise, they “snap into life.” How do you personally take care of these technical issues in your own photography?

Tim’s Quick Answer: I actually don’t tend to use any special tools for calibrating or adjusting color at the time of capture, since the vast majority of my photography employs natural light. I also know that I’ll always want to fine-tune the color in my photos to taste, so I’m not too worried about having the color absolutely “perfect” from the start.

More Detail: Naturally, in general we want accurate color in our photographs. However, in most cases I’m also trying to preserve the impact of the actual color of the light (such as at golden hour), not trying to make the photo appear that the light source was pure white.

For example, if you use a gray card to establish a more accurate white balance setting for the camera, you are essentially removing the color element of the light illuminating the scene. Suddenly a photo captured at golden hour would look more like it was captured in the middle of the day.

Therefore, solutions such as using a gray card or ColorChecker (https://timgrey.me/colorchecker) generally aren’t ideal for me, since I’m using available light and typically want to preserve the color of that light.

While selecting a specific White Balance preset in the camera can be helpful, I generally leave the White Balance setting at “Auto”. That’s because I’m always shooting in the raw capture mode, and so I can refine the White Balance adjustment in post-processing without any degradation in image quality.

To be sure, for something like product photography, using something like the ColorChecker Passport (https://timgrey.me/colorchecker) can be invaluable, as it will not only compensate for the general color of the light, but also specifically correct individual color ranges. For my personal needs, this isn’t something that generally applies. So for me, “Auto” White Balance combined with some post-capture adjustments work great. For many photographers though, more involved solutions can certainly be helpful.

Today’s Question: I’ve noticed in my Lightroom [Classic] Plug-in Manager that I have several plug-ins I never use. All indicate “Installed and running”. If I remove the plug-ins, is there any benefit to be gained? Any risk in degrading Lightroom performance if I remove them?

Tim’s Quick Answer: Removing plug-ins from Lightroom Classic won’t have a dramatic impact on performance. However, I do think it makes sense to remove unused plug-ins, in part to simply remove clutter, to possibly improve performance in some cases, and to reduce the risk of compatibility issues.

More Detail: Some of the plug-ins you’ll find in the Plug-in Manager in Lightroom Classic (File > Plug-in Manager from the menu) are installed automatically by Lightroom. Others may have been installed by the user. If there are plug-ins you don’t use, you can certainly remove them. Note that in the case of plug-ins included with Lightroom, plug-ins you remove may get installed again with a future update to Lightroom.

While there is a Remove button in the Plug-in Manager dialog, this option often won’t be available. Instead, you’ll need to remove plug-ins directly from the folder where they are installed. You can select a plug-in from the list within the Plug-in Manager dialog, and then click the “Show in Finder” (Macintosh) or “Show in Explorer” (Windows) button in the Status section to the right. This will bring up a window in your operating system, where you can delete the applicable plug-in file. I then recommend restarting Lightroom.

Of course, whatever features are provided by the plug-ins you delete will no longer be available once you’ve deleted the plug-in. But there may be some minor benefits in some cases if you remove plug-ins you definitely don’t plan to use.

Today’s Question: The question about the Previews file [in Lightroom Classic] brings up another: Is there any reason to keep a growing Previews file? Can you periodically delete it and start fresh?

Tim’s Quick Answer: The primary reason to keep the Previews file for Lightroom Classic is to optimize performance when browsing your photos in the Library module. If you want to recover space, or suspect the Previews file is causing other problems, it can be safely deleted and Lightroom will re-build previews as needed. Just be sure to only delete the Previews file, and not the actual catalog file.

More Detail: The Previews file for Lightroom Classic contains what are essentially JPEG image previews of your original captures being managed in your Lightroom catalog. In other words, that Previews file represents a cache for your images, enabling a faster browsing experience as well as providing the ability to view your images even when the original source files are unavailable. For example, if you store your original captures on an external hard drive, even with that drive disconnected you can still browse your photos based on the Previews that have been generated.

While the Previews file certainly provides benefits in terms of performance and offline browsing, there is no permanent harm caused by deleting the Previews file. If your hard drive is getting close to full, deleting the Preview file can provide a quick way to recover a considerable amount of free space. In addition, at times I’ve seen situations where some Previews get corrupted, leading to problems browsing images. Deleting the Previews file can resolve this type of issue.

The first step is to navigate to the folder that contains your Lightroom Classic catalog files. You can quickly get to that folder by clicking the “Show” button in the Information section of the General tab of the Catalog Settings dialog in Lightroom Classic. Within the folder that is revealed when you click this button, you can see the Lightroom catalog, which has a filename extension of “.lrcat”. That is the most important file in the folder containing your catalog files, as it is the actual catalog being used to manage your photo library. In addition to the lrcat file, you’ll see a variety of other files associated with the catalog. One of those will be the Previews file.

The Previews file will have the same base filename as your Lightroom Catalog, with “Previews” appended to that filename. The filename extension will be “.lrdata”. This file can be deleted, though I recommend first quitting Lightroom. After deleting the Previews file and launching Lightroom again, a new Previews file will be created automatically. Note that initially you won’t see any previews for your photos, but they will be generated as you browse your photos. That means the new Previews file will be considerably smaller than the file you deleted, but will gradually grow over time as you browse additional folders containing photos, and new previews are generated for the photos in those folders.

Today’s Question: Both Adobe Color Themes and blend modes for the brush tool [in Adobe Photoshop] seem to really only be of use for graphics such as in InDesign or Illustrator. Have you found any use in editing photographs for either one?

Tim’s Quick Answer: I would agree that the Color Themes feature in Adobe Photoshop is really more aimed toward graphic designers rather than photographers. However, blend modes can be helpful for photographers in a variety of situations.

More Detail: The Color Themes feature in Photoshop enables you to select and define groups of colors. For example, you could have a group of colors that go well together, such as complementary colors. This type of feature is mostly helpful when you are using color a bit more directly, such as with graphic design. However, there are certainly ways you could employ Color Themes with a photographic image, such as using a theme as the basis of a Gradient Map adjustment to assign color tints based on tonal values in a photo.

Blend modes are also not something I would consider one of the more important Photoshop features for the typical photographer, but there are a variety of ways blend modes can be helpful for photographic images.

In a broader sense, for example, you could use the Multiply or Screen blend modes to create composite images with a multiple exposure effect. This would involve stacking multiple layers, and then selecting a blend mode for one or more layers using the popup on the Layers panel.

Blend modes can also be helpful in the context of the Brush tool. For example, you could use the Overlay blend mode to apply a dodging and burning effect, painting with black and white at a very low Opacity setting. I recommend performing this task on a separate layer, so that the blend mode would actually be applied to the layer rather than with the brush.

To be sure, these features are not among the most commonly used features for photographic images. But as with so many features in Photoshop, there are a variety of ways you can employ the features for creative effects or a streamlined workflow to achieve a particular look for a photo.

Today’s Question: Can you help clear up my confusion about file sizes? When I download a JPEG image from my iPhone, Lightroom shows it as having a file size of around 7.24MB. (The sizes vary from image to image, from about 2.0MB to 7.5MB.) If I send that JPEG to Photoshop I get a PSD image showing a file size of 69.8MB. This size of 69.8MB seems to be constant, no matter what the size of the original iPhone JPEG file is. If I then export the PSD image as a JPEG file I get a JPEG with a file size ranging from about 6MB to about 13.5MB. What’s happening here? Is there a benefit to getting the larger JPEG files by first producing a PSD?

Tim’s Quick Answer: In this case the primary source of confusion relates to differences in compression being applied to the JPEG images. Compression at different quality levels along with variations in the pixel data in the source image can lead to considerable differences from one JPEG file to the next.

More Detail: There are three key factors that affect file size in this context. The first is the total number of pixels contained in the image, meaning the pixel dimensions or number of megapixels. The second is the bit-depth of the image, with JPEG images only supporting 8-bit per channel mode. The third factor is compression, which is a significant variable for JPEG image file size.

With JPEG compression there is a Quality setting, which effectively controls how strong the compression should be applied. Stronger compression yields smaller file sizes, but also lower image quality. That’s not to say the image at a lower Quality setting will always have an obviously degraded image quality, but there is a difference at the pixel level. In addition, the contents of the image affect compression effectiveness. A very simple image will compress to a smaller file size than a complicated image, all other things being equal.

In this particular example one JPEG is being created by the camera (an iPhone), and the other JPEG is being created based on a derivative PSD image. While the latter JPEG may have a larger file size, there has also been an addition application of compression applied, which will have at least a small adverse effect on the quality of the image. So I would still start from the source JPEG capture, even though the file size is smaller.

Note, by the way, that the PSD file has its own set of factors affecting the file size. For example, the PSD created through Lightroom can have a bit depth of either 8-bits per channel or 16-bit per channel, with the latter causing the base file size to be twice as big. In addition a PSD file can contain layers, saved selections, layer masks, and other elements that can increase total file size. As for compression, Photoshop will use lossless compression with PSD files, which can help produce a file smaller than an uncompressed TIFF image, but still considerably larger than a JPEG image.

File size variations can be confusing, to be sure. Just keep in mind that in general it is best to start with your original source capture when optimizing a photo. When creating a derivative image it is generally best to use a file with no compression (or lossless compression) such as a PSD or TIFF image if quality is of primary concern. For other forms of sharing, a JPEG image will often provide a good solution.

Today’s Question: Isn’t it true that preview files [for Lightroom Classic] need to be on the same drive as the catalog? This brings into play the same issue of available storage space you mentioned regarding an internal SSD drive. Preview files can really eat up a lot of drive space resulting in primary drive filling up. For this reason I have just last week moved my catalog and preview files to an external SSD connected to computer via USB-C. The catalog and previews are now removed from my primary internal drive (SSD). If previews can in fact be in a different location than catalog, would it be preferable to return the catalog to the internal SSD C drive but leave previews on external?

Tim’s Quick Answer: Yes, the preview files for your Lightroom Classic catalog must be stored in the same location as the catalog itself. Therefore, the only way to avoid having your previews consume space on your internal hard drive is to move the Lightroom catalog (and thus the previews) to another drive. Keep in mind, however, that this solution can also cause a degradation in overall performance in Lightroom.

More Detail: There’s no question that the previews file for Lightroom Classic will consume considerably more storage space than the Lightroom catalog. That can have a significant impact on the available space on your internal hard drive, especially if your primary internal hard drive is an SSD drive, which will typically provide less total storage capacity than a conventional hard drive.

Just to provide some context, consider my Lightroom Classic catalog, which contains more than 400,000 photos. The actual catalog file that Lightroom uses to manage the information about my photos is less than 4GB in size. The previews file, on the other hand, is almost 90GB in size.

If you want to move your previews file for Lightroom Classic to a different drive, you’ll actually need to move the entire folder that contains the catalog and related files. That can obviously free up considerable space on the internal hard drive on your computer. However, there may be a performance penalty involved with this approach.

Quite often, an external hard drive will offer slower performance than an internal hard drive. The specific performance you can achieve depends on the speed of the storage media itself, as well as the interface used to connect the storage device. In many cases an internal hard drive will have a faster interface than would be available with an external hard drive. So, if you’re going to use an external hard drive to store your Lightroom Classic catalog and related files, it can be critically important to make sure that external hard drive offers optimal performance. Otherwise, relatively slow performance for your Lightroom catalog can result in a frustrating experience within Lightroom.

Today’s Question: I’m trying to figure out a way to import iPhone “Camera Roll” [or other smartphone] photos into Lightroom Classic at full resolution. How can I do this?

Tim’s Quick Answer: You can actually import photos into Lightroom Classic directly from your smartphone through the normal Import feature. You could also download photos using other software, and then import into Lightroom as a separate process.

More Detail: One of the challenges of importing smartphone captures into Lightroom Classic is that Lightroom doesn’t provide a way to delete photos from the source you are downloading from. That means you would need to delete the photos from your smartphone manually after importing into Lightroom, assuming you didn’t want “extra” copies of those photos on your device.

Because of this issue, my preference is to download photos from my smartphone to my computer, using software that includes an option to delete the photos once they are downloaded. I then import those photos into Lightroom separately.

You could use Adobe Bridge to download photos to your hard drive, for example. In the Photo Downloader dialog within Adobe Bridge there is a “Delete Original Files” checkbox. However, if you turn this option on, photos will be deleted from your smartphone as soon as Adobe Bridge finishes downloading them.

My preference is to not delete the photos from my smartphone until I have imported those photos into Lightroom Classic and made an additional backup copy of the photos. Therefore, Adobe Bridge isn’t my preferred solution. I happen to use the Image Capture application included with the Macintosh operating system. With this software I can download the photos from my smartphone, import them into Lightroom Classic, and back up my photos hard drive. I will then delete all of the downloaded photos using the Image Capture software, which I keep running in the background while performing the other tasks.

But again, if you don’t mind manually deleting the photos from your smartphone, you can simply use the import feature in Lightroom Classic to download the source images (including HEIC captures with newer iPhone updates) directly from your smartphone.

Today’s Question: Following up on your discussion of correcting capture time based on different time zones, why don’t you just leave your camera always set to Universal Coordinated Time (UCT)?

Tim’s Quick Answer: While using Universal Coordinated Time (UCT) as a permanent time setting for the camera can be convenient, it can also lead to confusion about what the local time was when a given photo was captured.

More Detail: It can certainly be a minor hassle to need to update the time (and possibly date) on your camera when you travel across time zones. This is one of the reasons many photographers simply leave their camera permanently set to Universal Coordinated Time (UCT). However, this introduces additional challenges if you actually want to know what the correct local time was for the capture of a given photo.

To calculate local time based on UCT, you obviously need to know your location (or at least which time zone you’re in). You also need to know if there are any additional adjustments, such as for Daylight Saving Time in the United States or Summer Time in Europe. These are obviously not insurmountable problems, but they can be especially challenging if you’re trying to locate photos based on capture time long after they were actually captured. If you don’t recall the specific location where a given photo was captured, determining the local time based on the capture time in metadata could be challenging.

My preference is to try to always have the accurate local time reflected as the time of capture in the metadata for my photos. Admittedly, at least with today’s software, that information isn’t always especially helpful. If I’m looking for photos captured around sunset, for example, the accurate timing information can be helpful. But more often than not the capture time is interesting but not critical (and sometimes it isn’t even all that interesting).

While I don’t make extensive use of the actual capture time for my photos all that often, I do prefer to have the information in metadata be as accurate as possible. So I prefer to try to remember to accurately set the time zone for my camera, rather than leaving the camera permanently set to a single time zone such as UCT.