Ask Tim Grey

Today’s Question: You mentioned that it was possible to have Lightroom Classic batch generate previews for all photos at once. How do you go about doing so?

Tim’s Quick Answer: You can rebuild previews for selected photos in Lightroom Classic by going to the menu in the Library module and choosing Library > Previews > Build Standard-Sized Previews. This includes being able to select all images in the All Photographs collection so you can build previews for your entire catalog.

More Detail: If you have some images without any previews or with previews that seem to have become corrupted and aren’t updating, you can build previews for selected photos, or even for your entire catalog. Note, however, that if you simply build previews that won’t replace existing previews. So if some previews seem to be corrupted you’ll need to discard the previews first.

You can discard previews for selected photos in the Library module by choosing Library > Previews > Discard Standard and 1:1 Previews. If you want to build previews for selected photos you can choose Library > Previews > Build Standard-Sized Previews.

If you want to ensure that previews are built for all photos in your catalog, start by going to the All Photographs collection in the Catalog section of the left panel in the Library module. Then be sure that the Library Filter bar above the grid view display is set to “None”, so that all photos will be visible without any filter. Then choose Edit > Select All from the menu to select all the photos. At that point you can discard previews if you want to replace all existing previews. If you just want to build previews for any photos that don’t have them, choose the Build Standard-Sized Previews command at this point. Lightroom Classic will then process all images, building previews for any that don’t already have previews.

Note that the process of building previews for a large number of photographs can take considerable time. This can range from several hours up to potentially several days, depending on how many photos need to have the previews built.

Today’s Question: With a recent update Lightroom Classic said “What’s new December 2024”, which included “Discard Standard Previews – You can discard the standard previews to manage your disk space better by selecting Library > Previews > Discard Standard and 1:1 Previews.” I didn’t do this. Should I?

Tim’s Quick Answer: No, you shouldn’t discard standard previews in Lightroom Classic unless some of your previews are corrupted or you are in urgent need of free hard drive space.

More Detail: A recent update to Lightroom Classic includes a new feature enabling you to discard the standard-sized previews from within Lightroom Classic. This includes the ability to discard previews for selected photos, such as only the photos in a single folder. Before the addition of this feature, the only way to discard previews would be to discard the previews file associated with the catalog file, which would cause all previews to be lost. That, in turn, would require that Lightroom Classic build previews for your photos all over again as they are browsed, or in batch if you choose to do so.

If you are in urgent need of free hard drive space, you could discard the previews file to quickly recover some space. If you have built 1:1 previews you could also discard the previews file for that, which could potentially be even larger than the file for the standard previews.

However, you can also discard selected previews, such as if some of the previews aren’t updating properly. To do so, select the photos you want to discard previews for, such as by selecting all the photos in a given folder. Then from the menu while in the Library module choose Library > Previews > Discard Standard and 1:1 Previews. Note that there is not an option to discard the standard previews (approximately your display dimensions) without discarding the 1:1 previews (full-resolution previews).

Under normal circumstances you shouldn’t need to discard standard previews. In general, this should only be necessary if the previews are updated for some photos. If that should occur, you can use this new command to discard only the previews that are causing a problem, rather than having to rebuild previews for your entire catalog.

Today’s Question: I was sorting images in the library module of Lightroom Classic when suddenly a funny screen popped up and said something about face recognition. The next thing I know the center screen says “No photos found”. I do not want facial recognition. How can I disable it?

Tim’s Quick Answer: You can pause face detection in Lightroom Classic by clicking the identity plate and clicking the pause button to the right of the Face Detection label. There will then be an indication that face detection is paused.

More Detail: While you can disable face detection in Lightroom Classic, doing so won’t prevent you from switching to the people view by either clicking the button for people view on the toolbar below the preview area or by pressing the letter “O” on the keyboard. It also won’t remove the face regions and keywords for faces that had already been detected in photos.

If you make sure that the Face Detection feature is paused, no new faces will be identified in your photos. If you had associated a name with a photo where a face region was defined based on Face Detection, you can remove that identifier by right-clicking on the thumbnail for a person in the people view and choosing “Remove Face Region” from the popup menu.

In this case the indication of “No Photos Found” means that there aren’t any photos where people were detected. As long as you keep the Face Detection feature paused, there won’t be any face regions added to photos, and therefore no photos will appear in the people view. With Face Detection paused, and therefore disabled, you may notice slightly after performance as well, since Lightroom Classic won’t be busy in the background trying to determine which photos have faces in them.

Note, by the way, that the Face Detection feature can be incredibly helpful in terms of streamlining your workflow for adding keywords that identify the people who appear in your photos. Therefore, if you have photos of people you want to identify, such as family members, you may want to keep Face Detection enabled and be sure to add the names for people who have been detected in Lightroom Classic.

Today’s Question: I had been told to focus one-third of the way into a scene to achieve maximum depth of field, and this seemed to work well. But I recently saw a video suggesting that this was a myth in photography. Can you confirm whether this really is a myth?

Tim’s Quick Answer: The “rule” of focusing one-third of the way into the scene you are photographing relates to the hyperfocal distance, and I would say that it isn’t exactly a myth, but it is often a bit misunderstood.

More Detail: The hyperfocal distance is the closest distance you can set your focus while still having the depth of field extend all the way to infinity. Making sure you are focusing at or beyond the hyperfocal distance can therefore help ensure maximum depth of field, which is a popular goal in landscape photography, for example.

When you do set your focus at or beyond the hyperfocal distance, your depth of field will extend from approximately half the distance between you and the focus point all the way to infinity. Because of this, many photographers have employed the rule of thumb to focus a third of the way into the scene. The idea is that doing so will generally cause the entire scene to be in focus, because the depth of field will extend from about halfway between you and the focus point and infinity.

However, this only actually works if your focus point is at or beyond the hyperfocal distance. In landscape photography this rule of thumb often works out well, because of the distances and camera gear involved. However, it won’t work for all scenes. Depending on your configuration, focusing one-third of the way into the scene won’t necessarily result in depth of field that extends all the way to infinity, for example.

As a more extreme example, let’s assume the scene you’re photographing is a small detail with a macro lens, where you’re focusing a few inches away from the subject. No matter where you set your focus, you will not achieve depth of field for the entire scene, and more than likely the depth of field will only be a fraction of an inch. Focusing one-third of the way into the scene won’t increase depth of field and will likely mean that what little depth of field you do have isn’t in the area of the scene you are most interested in having in focus.

I recommend the PhotoPills app for calculating depth of field and hyperfocal distance. My video training course can help you learn to make the most of this powerful app for iOS and Android smartphones and tablets, and is available on the GreyLearning website here:

https://www.greylearning.com/courses/photopills

Today’s Question: My primary computer is a laptop, and so I tend to have it plugged in most of the time. I’ve heard that it is bad for the battery, but is this really a problem?

Tim’s Quick Answer: The issue with leaving your laptop plugged in most of the time is that the battery will never have a chance to discharge, which can cause the battery to degrade more quickly.

More Detail: Battery health is maintained longer when you allow the battery to go through regular discharge cycles. In the context of a laptop computer that means it is ideal to not leave the battery plugged in at all times, but rather to run on battery power and only plug the laptop in when the battery needs to be recharged.

This habit will help extend the life of your battery. If you leave the laptop plugged in most of the time, the battery health will gradually degrade, to the point that the battery won’t hold as much of a charge. For example, a healthy battery can be charged to 100%. An unhealthy battery might only have the equivalent of about a 50% charge, for example, even when you’ve completely charged it, and the battery shows that it is 100% charged. Eventually, a battery that is not healthy will get to the point that even when fully charged it doesn’t provide enough power to be useful.

I can tell you from personal experience that this battery health issue is very real. I have poor laptop battery habits, in that I keep my laptop plugged in most of the time. My wife has excellent habits in this regard, only plugging her laptop in when the battery level is low, and it needs to be recharged. On several occasions we have both gotten new laptops at the same time. After months of use, it starts to become very clear that the battery health on her laptop is considerably better than mine.

For Macintosh users, by the way, there is an easy way to check the current health of your laptop’s battery. In System Settings go to Battery, and click the info icon (the letter “I” in a circle) to the right of the Battery Health status. In the dialog that appears you’ll see an indication of your battery’s health, expressed as a percentage. This is the percentage of power the battery actually has when it shows as being fully charged.

Modern batteries perform considerably better in this regard than older batteries, but this battery health issue is still a factor and is worth considering when it comes to your habits about charging your laptop battery. And, of course, the same concept applies with other batteries, such as those for your camera.

Today’s Question: I recently ordered a mousepad featuring one of my photos, and was surprised when it arrived that the photo was cropped around all edges. How can I make sure that the entire photo is shown when printed like this?

Tim’s Quick Answer: When printing a photo where the image goes all the way to the edge of the media (such as a mousepad or paper print) there will always be a small degree of cropping for the image to make the borderless print possible. The only other cropping that would occur is if the image didn’t match the aspect ratio of the print.

More Detail: A borderless print involves an image that goes all the way to the edge of the media, whether that’s a print on photo paper or some other media, such as a photo mousepad. However, it is basically impossible to perfectly print a photo right to the edge of the media without losing at least a small portion of the image. Either the photo would be printed partially off the edge (such as with a borderless photo inkjet print) or the borderless effect would be created by cutting after printing (causing a small portion of the image to be lost in the process).

In effect, when printing a borderless image, you need to allow for the outer perimeter to be cropped out of the final print. The area that is designated as possibly being cropped out is referred to as the “bleed area”, where the image bleeds out into the area of the print that will be cut out. The standard bleed area for borderless printing is 1/8th of an inch (0.125 inches). However, the bleed area can vary for different types of printing and different media types.

In addition to the image getting cropped based on the bleed area for a borderless print, there is also the potential for an image needing to be cropped based on the aspect ratio of the output. For example, a common print size is 8″x10″, but most digital cameras have a sensor with an aspect ratio that would result in an 8″x12″ print rather than an 8″x10″ print, requiring that two inches be cropped from the longer side to match the aspect ratio of the print.

Today’s Question: I ordered the Canon Rebel T7. What arrived today was the Canon 2000D. Is the Canon 2000D the same camera as the T7? I assume it is, because online and elsewhere it’s referred to the Cannon 2000D/Rebel T7.

Tim’s Quick Answer: This appears to be an example of a “gray market” product, meaning a product intended for an international market being sold in the US. In many cases gray market products are not covered under the manufacturer’s warranty, among other potential limitations.

More Detail: It will probably come as no surprise that there are two sides to the issue of gray market products. While there are certain risks or limitations involved with purchasing gray market products, many photographers actually seek out gray market cameras to get the advantage of a lower price.

In the case of the specific example from today’s question, the Canon EOS 2000D is the European version of what is the Canon EOS Rebel T7 (https://bhpho.to/4gK2opX) in the Americas. These cameras have the same basic features, but there are some localized differences, such as chargers for different power outlets for their respective regions.

If you purchase the 2000D in the US, it means it was not sold by an authorized reseller. In other words, in effect you’re buying a used camera (even if the box was never opened) from a private individual (even if a company is selling you the product). Of course, if you had purchased a 2000D in Europe, you could obviously travel to the US and have a perfectly good camera. So the overall business issue here is that the authorized reseller is being bypassed.

For the consumer, as long as the product is legitimate and hasn’t been modified (such as by adapting the battery charger from a European to a US outlet type) there isn’t any inherent problem with buying a gray market product. And in most cases you’ll find that gray market products are less expensive than the markets intended for your market. For this reason, many photographers seek out gray market products to save money on their gear. In this situation you just need to make sure you’re buying from a reputable seller and that the product is legitimate.

However, you may not be able to get warranty coverage, technical support, or rebates if you buy a gray market product. Canon, for example, calls out that they won’t provide these benefits to those who purchase gray market products, as outlined on their website here:

https://www.usa.canon.com/support/gray-market

Many photographers purchase gray market products on a regular basis and are very happy with their purchases. I’ve even heard from photographers who were able to get warranty coverage (even from Canon) for gray market products. However, if you’re going to purchase a gray market product, you should be aware that there are some risks. And if you unknowingly purchased a gray market product, you may want to consider returning it for a refund or contacting the manufacturer to see if they’ll be able to cover the warranty and provide technical support.

Today’s Question: For some reason the backup drive of my external drive where I keep all my photos is included in my Lightroom Catalog, so I have duplicates of pretty much all images in the catalog. It seems to me that this is unnecessary and doubles the size of my catalog. Should I just remove the backup drive from the Lightroom Classic catalog and if so, what is the best way to do it?

Tim’s Quick Answer: I do not recommend keeping backup copies of photos in the Lightroom Classic catalog. As long as you’re sure that you’ve only been working with the primary photos (not the backup copies) within Lightroom Classic, you can remove all the backup images in one step by removing the top-level folder.

More Detail: Having backup copies of your photos in the Lightroom Classic catalog is unnecessary and can potentially be quite problematic. For example, there is the risk of confusion with the duplication of images, which might sometimes result in you updating the primary images, while at other times updating the backup images, so that all your updates are not in one place for a given image.

I do recommend first reviewing the backup images to make sure you haven’t been updating them. For example, you could select all of them and then use the Library Filter bar to check various metadata fields to ensure there hadn’t been any updates in your workflow, such as to confirm that none of those images have star ratings or keywords assigned to them.

Once you’re confident that you’ve only been working with the primary images, the backup copies can be removed from the catalog, without deleting them from the hard drive so you’ll still have your backup. Even when you’re feeling confident, however, I do recommend creating an updated backup of your catalog before proceeding.

To remove the duplicate photos, I recommend simply removing the top-level folder. In the Folders section of the left panel in the Library module, if you have a top-level folder for all the photos (such as a “Pictures” folder) you can right-click on that folder and choose “Remove” from the popup menu. If you don’t see a parent folder for the folders that contain your photos, right-click on one of the top-level folders and choose “Show Parent Folder” from the popup. You could repeat this all the way up to the root level of the hard drive if you need to in order to find the top-level location where the folders containing your photos is located. Then remove that top-level folder, which will remove all subfolders and all photos without deleting anything.

In this case you would of course only be removing folders and photos from the backup drive. All folders and photos (and metadata) from the primary hard drive would be unaffected. More importantly, once you perform this task you’ll have a more streamlined catalog in Lightroom Classic. I do recommend backup up your catalog both before and after doing this work, with the options to perform error-checking and optimization enabled for those backups.

Today’s Question: I started to work on a family project and have scanned a large number of photos. Some of these are saved as PDF documents, but I now realize I need a different format like JPEG to work in Lightroom Classic or Photoshop. How do you recommend I convert the PDFs for the most efficient workflow?

Tim’s Quick Answer: You can easily convert the PDF documents to images in a few different ways. It is also possible to open PDF documents directly in Photoshop, including choosing which pages of the PDF you want to open as images so you can then save them in the desired format.

More Detail: While you wouldn’t normally save a photo as a PDF document, it is certainly possible to do so. For example, you can save an image as a PDF in Photoshop, and as indicated in today’s question, in many cases when scanning photo prints the default may be to save the resulting images as a PDF document. However, applications such as Lightroom Classic don’t support PDF documents, so you would need to convert the documents to images.

There are a number of ways you could go about doing this. If all the PDF documents consist of only one page, you can easily batch process a selection of PDF documents into images using Adobe Bridge. Start by selecting the documents in Bridge, then from the menu choose Tools > Photoshop > Image Processor. This will launch Photoshop and bring up the Image Processor dialog, with the documents from Bridge automatically selected for processing. You can then select the image format and other options and process the documents in batch. If the PDF documents consist of more than one page, however, only the first page will be converted to an image using this method.

Another option is to use the free online Adobe Acrobat PDF to image converter to process a PDF document (including those consisting of multiple pages) to individual images. You simply upload your PDF, choose the image format you want to convert to, and click the Convert button to process the PDF. You can then download the resulting images to your computer. This free converter can be found here:

https://www.adobe.com/acrobat/online/pdf-to-jpg.html

If you have access to Adobe Acrobat Pro (such as with an Adobe Creative Cloud subscription beyond the Photography Plan) you can export all pages of a PDF to images. Simply open the PDF in Acrobat Pro and from the menu choose File > Export To > Image and then choose the image format you want to use. You can then choose the location and filename to use, along with image settings applicable to the format you’ve selected and click the Save button to process all pages of the PDF document to individual images.

Any of these methods will enable you to convert the images that had been saved as PDF documents into an image format supported by other software such as Lightroom Classic.

Today’s Question: After finishing an image in Photoshop I usually save it as a TIFF file, then flatten the layers, adjust the size (reduce the pixel count) and save it as a JPEG. Is there a way to save the finished image as a DNG instead of a TIFF file? If the answer is yes, is there a way of taking all my TIFF files and saving them as DNG files?

Tim’s Quick Answer: There are ways to convert TIFF files to Adobe DNG (Digital Negative) files, but there isn’t much of an advantage to doing so, and there could be a big disadvantage if you discard the TIFF images.

More Detail: Converting a TIFF (or other standard image type) to a DNG file won’t create a raw capture, even though DNG can be used as a raw capture format. In other words, you won’t be getting the advantages of a raw capture by using this workflow. In addition, the DNG file would not contain the layers you created for the TIFF image in Photoshop. Therefore, the only real benefit would be that the DNG file would have a smaller file size compared to the TIFF image.

I strongly recommend retaining the edited file with all layers as a master image to be used for the basis of all output for sharing the image later. In this context it wouldn’t make sense to convert the TIFF file to DNG.

If you did want to convert an image file to a DNG, this can be done very easily in Lightroom Classic or Lightroom using the Export feature. In both applications this command can be found on the menu at File > Export, and as part of the export process you can choose to export as a DNG image. This would enable you to batch export multiple images, by the way.

It is also possible to open a TIFF image in Camera Raw by opening the TIFF image via Adobe Bridge. However, Camera Raw only supports flattened TIFF images, so you would need to flatten the image to use this workflow, which again I don’t recommend. But if you did open a TIFF (or raw or JPEG) image in Camera Raw, you can click on the “more” button (the three dots) on the thumbnail for the image after enabling the filmstrip view. There you’ll find the Save Image > Save Image command (or presets for saved settings) where you can process the image into a DNG file.