Lockup for Sensor Cleaning


Today’s Question: Just read today’s Q&A about mirror lock up. Isn’t mirror lock up also used during sensor cleaning?

Tim’s Quick Answer: In a manner of speaking, yes, mirror lockup is used for sensor cleaning. The difference is that in the case of sensor cleaning mirror lockup is handled for you automatically, and is accessed separately from the actual mirror lockup feature.

More Detail: To clean the image sensor on a digital SLR, you of course need to access the actual image sensor. When the camera is not actively capturing a photo, the mirror that enables you to see through the lens will be blocking the image sensor. So, for manual sensor cleaning the mirror must be moved out of the way of the sensor.

In concept, this is very similar to the mirror lockup feature discussed in Monday’s edition of the Ask Tim Grey eNewsletter. However, in this context the mirror is moved with a different feature.

When you enable mirror lockup, you will press the shutter release button twice to capture a photo. The first time you press the shutter release button the mirror will be locked in the “up” position. The second time you press the shutter release button the photo will be captured. This enables you to delay the capture until the vibrations from the mirror movement have subsided.

When you activate the manual sensor cleaning mode for a digital SLR, the mirror will similarly be moved up and out of the way so you can access the image sensor for cleaning. This is essentially the same feature as mirror lockup, simply used in a different context. When you are finished cleaning the sensor, turning off the camera’s power will move the mirror back to the “normal” position.

Note, by the way, that when we use the term “sensor cleaning” we are really referring to cleaning the filter that is mounted in front of the actual image sensor in the camera. And as I hope goes without saying, it is critically important to be extremely careful if you choose to clean the sensor on your own camera, as there is a risk of damage that would not be covered by the warranty (or extended warranty) for your camera.

Deleting Smart Previews


Today’s Question: My computer is running out of storage space. Can I delete the smart previews from my catalog? Can I delete them from the folder that contains my Lightroom catalog, or should I do it within Lightroom?

Tim’s Quick Answer: To delete Smart Previews in Lightroom, I recommend Using the menu command Library > Previews > Discard Smart Previews. You can first navigate to the folder that contains the photos you want to remove Smart Previews for, or even choose the All Photographs collection in the Catalog section of the left panel in the Library module. Then choose the Discard Smart Previews command, and choose the “Discard All” option if you want to discard previews for all photos in the current location.

More Detail: In theory you could simply delete the Smart Previews file from the folder where your Lightroom catalog is stored. However, because you are able to work offline in the Develop module with Smart Previews, there is some risk that you could lose changes you’ve applied to photos based on Smart Previews.

Instead, I recommend using the Discard Smart Previews command from within Lightroom. First navigate to the location that contains the photos you want to discard previews for. As noted above, you could also select the “All Photographs” collection from the Catalog section of the left panel in the Library module if you want to discard all Smart Previews for all photos in your catalog.

You can then choose Library > Previews > Discard Smart Previews from the menu. In the confirmation dialog you can choose Discard All if you want to discard Smart Previews for all photos from the current location, rather than only the selected photos.

I do recommend performing a optimization of your Lightroom catalog after performing this type of task, which can help optimize the catalog and improve performance. This is an option available when you perform a catalog backup in Lightroom, but you can also choose File > Optimize Catalog from the menu to begin the optimization process.

HDR Software Alternative


Today’s Question: I’ve been using HDR Efex Pro from the Nik Collection for some time, and am very happy with it. However, I’ve seen some indications that there may be issues with the older version of the Nik Collection, and I don’t plan to buy the new version from DxO Software. Is there another HDR software application you can recommend as an alternative to HDR Efex Pro?

Tim’s Quick Answer: Aurora HDR from Skylum software has become my preferred tool for creating HDR images, and I recently had the chance to test the new Aurora HDR 2019 version of this software. This update will be available starting on October 4th, but you can pre-order the software here: https://timgrey.me/aurora2019

More Detail: I had long been a fan of HDR Efex Pro, which is part of the Nik Collection. As many readers know, the software was acquired by Google, and ultimately provided as a free download. Since then, the software has been acquired by DxO Software.

The first release of the Nik Collection from DxO Software doesn’t offer any new features, but instead simply provides an update that will ensure more users are able to continue using the software tools included in this collection even with newer software and operating system updates.

It is important to note, however, that if you install the free trial of the Nik Collection from DxO Software, any existing installation of an earlier version of the software will no longer work after the trial period ends. In other words, the previous version of the Nik Collection from Google won’t work anymore, and you would need to purchase a new license from DxO Software to continue using the software.

In part due to these issues, and in part because of the great strides made by Skylum Software, I’ve started using Aurora HDR instead of HDR Efex Pro, and am very happy with the results. The next updated version is Aurura HDR 2019, which will be available on October 4th. You can pre-order this new update directly from Skylum Software by following this link:


Mirror Lock-Up


Today’s Question: I don’t know how I never knew about this, but I just learned that my camera has a mirror lockup feature. Should I leave this turned on always?

Tim’s Quick Answer: I only recommend enabling the mirror lock-up feature when you are using a shutter speed that is at (or very close to) 1/15th of a second. At shutter speeds that are a bit faster or slower than 1/15th of a second it is safe to leave this feature turned off.

More Detail: In an SLR camera there is a mirror that diverts the light from the lens away from the image sensor (or film) and up to the viewfinder. This is what enables you to see the view through the lens when configuring a photo. The mirror then moves out of the way for the actual exposure.

The reason the mirror lock-up feature exists is to enable you to compensate for the vibrations caused by the movement of the mirror. When you enable the mirror lock-up feature, you will generally press the shutter release button twice to capture a photo. The first time the mirror will be locked up, and the second time the photo will be captured. This enables you to have the vibrations from the movement of the mirror dissipate before you capture the photo.

When the shutter speed is a bit faster than about 1/15th of a second, the exposure is so short that the vibrations caused by the mirror movement shouldn’t affect your photo. Obviously the faster the shutter speed (the shorter the exposure time) the less this vibration is a factor.

With exposures that are a bit longer than 1/15th of a second, the portion of the exposure that is affected by the vibration will be very minor compared to the overall exposure, and so the impact on the photo will be minimal (or non-existent).

Naturally, you could simply leave the mirror lock-up feature enabled for all photos to ensure the vibrations caused by the movement of the mirror are never a factor. However, it is only with shutter speeds of around 1/15th of a second where this can be a significant consideration.

Note, by the way, that the mirror lock-up feature is addressed in lesson 3 of my “Photo Gear Quick Tips” course, which you can find in the GreyLearning library here:


DxO Nik Collection


Today’s Question: I have the original Nik Collection purchased years ago. Now that DxO owns it, can I still use it and can I get updates?

Tim’s Quick Answer: You can continue to use the older version of the Nik Collection for as long as it continues to function with your operating system and software configuration. However, you will not be able to receive updates unless you purchase the updated version from DxO Software.

More Detail: Before going any further, I feel it is important to warn against a potential problem if you choose to install the free trial of the Nik Collection by DxO Software. As noted above, the Nik Collection had previously been owned by Google, but is now owned by DxO Software. Google originally offered the software for sale, and then made it free. DxO Software now offers an updated version of the Nik Collection for sale. However, if you install the free trial version of the Nik Collection by DxO Software, it will cause any earlier versions you may have paid for or obtained for free to no longer function. That, in turn, would mean you would need to purchase a new license from DxO Software in order to continue using the software you already had access to.

In addition, the older versions of the Nik Collection will not be updated by Google. Therefore, the only option for receiving updates is to purchase a license from DxO Software for their updated version of the Nik Collection.

As long as you don’t install the trial version of the Nik Collection from DxO Software, you can certainly continue using an earlier version of the Nik Collection. Keep in mind that software updates to your operating system or host applications (such as Photoshop or Lightroom) may cause some or all of the plug-ins to stop working properly. I’ve still been able to make use of the older versions of the plug-ins with my current configuration, but I have received reports from photographers who are no longer able to use the older Nik Collection plug-ins with their software configuration.

So, you may be able to make use of older versions of the Nik Collection for the time being, but at some point you may need to purchase a new copy from DxO Software if you want to continue using these tools.

Combining Catalogs


Today’s Question: Is there a way to combine the Lightroom catalogs we already have that are separate?

Tim’s Quick Answer: Yes, you can merge multiple Lightroom Classic CC catalogs into a single catalog. The key is to use the “Import From Another Catalog” command to import photos and the information about those photos into the catalog you’ve designated as the “master” catalog.

More Detail: While the process of merging catalogs in Lightroom Classic is rather straightforward, it is very important to be organized in this process to avoid problems.

You’ll first want to take an inventory of your catalogs, and make sure those catalogs are in good condition. In other words, you won’t want to have missing photos and other problems in your catalogs before merging them. I also recommend making sure you have everything backed up completely, including your catalogs and your photos.

You then want to identify which catalog will be your “master” catalog, and open that catalog in Lightroom. Then make sure the storage devices for all of your photos (for all catalogs) are connected to your computer, so that all photos will be available.

Finally, choose File > Import From Another Catalog from the menu. This will enable you to import photos from another catalog into the current catalog. I recommend using the option to add other photos where they are rather than moving them, just to avoid added complexity. You can always move photos later after merging catalogs.

You can repeat the “Import From Another Catalog” command as many times as needed, based on how many catalogs you need to merge.

Note that the process of merging catalogs and otherwise streamlining a “messy” workflow in Lightroom is covered in great detail in my “Cleaning Up Your Mess in Lightroom” video course, available in my GreyLearning library here:


Text Outside a Photo


Today’s Question: How do I write text, with white fonts on a black background, below a photo (not in it) using Photoshop?

Tim’s Quick Answer: The key here is to enlarge the canvas size for the image, in order to create empty space around the actual photo. You can then fill that background with black (or any other color) and add text into the area outside the photo.

More Detail: Before enlarging the canvas size for an image, I recommend converting the Background image layer to a normal layer. This will help protect the source image layer and provide a little more flexibility. To quickly convert the Background image layer to a normal layer, simply double-click on the thumbnail for the Background layer on the Layers panel and click OK in the confirmation dialog that appears.

Next, you can go to the menu and choose Image > Canvas Size. In the Canvas Size dialog you can specify the new size for the overall image canvas. You can first change the unit of measure popup to the most convenient option, such as Inches or Pixels. You can then change the values for the Width and Height.

If you want to simply add a set amount of space outside the photo, you can turn on the Relative checkbox, and then enter the amount of space you want to add. For example, if the image is already sized to 8-inches by 10-inches, you could leave Relative turned off and enter “10” and “12” to enlarge by one inch on each side. You could also turn on the Relative checkbox and enter “1” for the Width and Height values.

Note that you can also use the control at the bottom of the Canvas Size dialog to specify which direction the canvas should grow. The default is for the canvas to grow equally on all sides, but you can also specify for example that you only want to grow downward, not upward.

Once you’ve updated the settings in the Canvas Size dialog, you can click OK to apply the changes in the document size, adding space around your photo.

At this point you can add a color to the backdrop. You could simply add another image layer below the layer that had been the Background image layer, and then fill that layer with the desired color. But for greater flexibility (and a smaller file size) I recommend using a Solid Color adjustment layer for this purpose. To do so, first click the “Add Adjustment Layer” button (the half-black/half-white circle icon) at the bottom of the Layers panel, and choose Solid Color from the popup. Then select a color in the Color Picker dialog and click OK. Finally, drag the thumbnail for the new Color Fill layer below the image layer, so that the solid color will appear as a background behind the actual image.

Finally, you can add text within the area of the new border you added. Simply select the Type tool from the toolbox, and adjust the text color and other attributes with the controls on the Options bar. Then click where you want to start creating the text, type whatever you’d like, and click the checkmark button on the Options bar to apply the change.

All of these various elements can of course be refined as needed. You can double-click on the thumbnail for the Color Fill layer if you want to change the background color, and you can double-click the thumbnail for the text layer if you want to refine your text.

Multi-Location Workflow


Today’s Question: I have the good fortune to live in different parts of the country at different times of the year and I have desktop computers at each location. Am I better off using cloud storage via Lightroom CC, which I can then access from multiple locations (at a price), or would it be best to use Lightroom Classic with an external hard drive that I disconnect and reconnect as I travel?

Tim’s Quick Answer: The best solution here depends in large part on your workflow needs and software preferences. Lightroom CC is best if you want to have all of your photos available from any location on virtually any device. Lightroom Classic CC may be the better choice if you won’t want to depend upon an Internet connection for synchronizing your photos between multiple locations.

More Detail: To me the fundamental difference between Lightroom CC and Lightroom Classic CC relates to storage. With Lightroom CC you are essentially storing your source photos in the cloud (on Adobe’s servers), and accessing them via Internet-based synchronization. With Lightroom Classic CC you are storing your photos locally, and therefore could potentially move photos between locations.

Lightroom CC was built from the ground up as a solution for working from multiple locations using multiple devices (including both computers and mobile devices). Therefore, Lightroom CC is a good choice for photographers who want to be able to access their photos from virtually anywhere at any time.

If you’re more comfortable managing your storage yourself, including managing the folder structure based on your own preference, Lightroom Classic CC may be the better solution. For example, Lightroom CC doesn’t enable you to define your own custom folder structure to manage your photos beyond the context of Lightroom CC.

Of course, with Lightroom Classic CC you’ll also need to manage your catalog more carefully. That means, for example, that you may want to keep the catalog files for Lightroom Classic on the same external hard drive as your photos. This will streamline the process of working with your catalog, but it can also negatively impact performance due to the slower speed of an external hard drive compared to an internal hard drive.

On balance, I would say that Lightroom CC provides a much more streamlined workflow provided you have a fast enough Internet connection at all locations to facilitate prompt synchronization. That said, the two versions of Lightroom aren’t completely matched in terms of features. Therefore, I recommend looking at the features of each relative to your own needs and workflow preferences to decide which approach might be best for you. Either approach can work, so it is really a matter of choosing an option based on your own preferences.

Location Metadata Accuracy


Today’s Question: When I travel with my iPhone and take a photo with the intent of using the phone’s GPS feature to record my location, is it better to have WiFi turned on even if I am out of range of any WiFi router? As a corollary, how should I configure my settings when I am photographing abroad, in which case I usually turn off cellular data on my iPhone in order to avoid roaming charges?

Tim’s Quick Answer: Having all three receivers (cellular, WiFi, and GPS) enabled can help speed up the acquisition of more accurate location information that will be included in the metadata for your photos. I recommend turning of cellular data when traveling abroad without an activated cellular data plan, and keeping the phone in Airplane Mode except when want to quickly establish location metadata for a photo.

More Detail: In concept, you only need to have the GPS receiver enabled to obtain accurate location information for your photos. However, there are situations where you either aren’t able to achieve a good GPS signal quickly enough, or where you aren’t able to achieve a signal at all (such as when indoors). The cellular and WiFi antennas in the iPhone can help in these scenarios.

In general I prefer to have my iPhone set to Airplane Mode when traveling internationally, both to help preserve battery life and to avoid unintended cellular data charges. You can also turn off the Cellular Data option in the Cellular settings within the Settings app to help avoid cellular data charges.

I generally leave WiFi turned on, so that I can access WiFi networks more readily and so any nearby WiFi signals can be used to help the iPhone more quickly determine your location.

When I want to quickly ensure the location information on my iPhone is accurate, I will also temporarily turn off Airplane Mode so the cellular antenna is active. With the Cellular Data setting turned off this won’t risk any significant data charges. It will, however, generally provide the fastest location update if there is a cellular tower in range.

To confirm the accuracy of the current location information, I will either make sure I have cached map data when online, or use an app that enables you to view a map even when you don’t have a data connection (such as a navigation app you might use when driving).

What I often find is that my iPhone still thinks I am at a previous location, because it hasn’t yet acquired a signal to indicate a new location. Turning off Airplane Mode will enable a search for cellular networks, which is often the fastest way to update your location information. By watching your current location on a map using an appropriate app, you can confirm when you have an accurate location reference on the iPhone, so you can capture photos with the confidence that location metadata will be accurate.

Note, by the way, that the general concepts here apply to all smartphones, not just the iPhone. By capturing photos with a smartphone that will contain accurate location information, you can then use that information to help manage photos captured with other cameras that might not have a built-in GPS receiver.

Mirror Lenses


Today’s Question: I am sorry, but what is a mirror lens? It is a term and an item I have never come across, in film photography or in digital. Are there any such lenses currently available?

Tim’s Quick Answer: A mirror lens (also called a reflex lens or catadioptric lens) is a lens that employs a convex mirror in place of one or more lens elements. These lenses were smaller and lighter than the more common models, but they don’t offer an adjustable lens aperture, and out of focus areas could create circular artifacts that many photographers found objectionable. Mirror lenses are still available from some manufacturers, such as a 500mm model from Opteka you can find here: https://amzn.to/2QNoNqE

More Detail: When I mentioned mirror lenses in a previous Ask Tim Grey eNewsletter about bokeh, the thought crossed my mind that some readers may not be familiar with these lenses. It also made me realize I might be perceived as a “dinosaur” for making the reference. After all, these lenses were most popular in the 1970’s and 1980’s.

Mirror lenses are commonly used in telescopes, and have also been available as photographic lenses. Many mirror lenses for photography were telephoto, because that is where the key advantage of a mirror lens has the greatest impact. Because a convex mirror is used in place of one or more lens elements that would generally be made of glass, a mirror lens can be significantly lighter (and smaller) than a “conventional” photographic lens.

However, mirror lenses also have some issues that contributed to their lack of popularity today. As noted above, there is no adjustable aperture on a mirror lens. That means you can’t adjust the depth of field with a mirror lens. In addition, if the shutter speed doesn’t provide enough control over the exposure, you may need to add a neutral density filter.

In the context of out of focus areas (as noted in my previous answer about bokeh), mirror lenses can produce ring-shaped artifacts that many photographers found distracting and undesirable. In other words, while a conventional lens would result in bright highlight artifacts in the shape of the lens aperture, a mirror lens would create “donut” shaped highlight artifacts.

So, mirror lenses do have some advantages, but I would say the disadvantages are more significant, which is why they are not in common use by photographers today.