Ask Tim Grey

Today’s Question: If I stand in the same location, center the same subject, and use the same lens, what changes if I use a Full Frame camera body (with a larger sensor) instead of an APS-C camera body? I want to know what (if any) the lens prospective variations (and Lightroom [Classic] corrections) would be between different camera bodies with different sensor sizes. Or are these corrections dependent only upon the specific lens used?

Tim’s Quick Answer: With the same lens from the same position, using a camera with a full-frame sensor (35mm equivalent) versus a “cropped” sensor (such as APS-C), the only difference would be the cropping of the image circle projected by the lens. If you apply profile-based lens corrections in Lightroom Classic, that correction will take into account the sensor size, to ensure the correction is applied correctly across the frame.

More Detail: Each lens has its own unique behavior, which tends to be most significant with wide-angle lenses. Those behaviors often relate to distortion of the scene and vignetting of the edges of the frame. Many software applications, including Lightroom Classic, enable you to apply automatic corrections to a photo based on the lens that was used. These are generally referred to as profile-based lens corrections.

These corrections will take into account the sensor size of the camera used in conjunction with the lens, so the correction can be applied correctly. For example, a smaller sensor means the image circle projected by the lens is being cropped more than would be the case with a full-frame camera. Therefore, the vignetting that is part of the lens behavior would also be at least partially cropped out of the final photo. The profile-based lens correction therefore needs to apply less vignette correction (in terms of total area) for a photo captured with a cropped sensor (such as APS-C) as compared to a full-frame capture.

The perspective of the scene will not be affected by the cropping of the image circle, assuming the camera position is the same. Only the image circle projected by the lens is cropped to a smaller size, while the projection of the lens remains the same. Thus, you would get the same photo if you captured a scene with the same lens on a cropped versus full-frame sensor, and then cropped the full-frame capture to the same cropping as the camera with the smaller sensor. Furthermore, the profile-based lens corrections will compensate for the differences between the captures with the two different sensor sizes.

Today’s Question: I noticed on one of your photos in the slides strip (from your webinar presentation) there was a “flag” with 3 horizontal lines on the left and an exclamation point on the right. I also noticed this on one of my photos. What is this?

Tim’s Quick Answer: The symbol in question is an indication that there is a metadata mismatch. That means that information in the metadata for the photos on your hard drive does not match the information contained within your Lightroom catalog.

More Detail: One of the more important things to understand about Lightroom Classic is that any tasks you perform with your photos (including metadata updates) should be initiated within Lightroom. If you update metadata outside Lightroom, that information will not be reflected within the Lightroom catalog.

When there is a metadata mismatch for an image, you can click the warning flag icon, which appears as three lines with an arrow to the right of them. That will bring up a dialog where you can choose which direction you want to resolve the metadata mismatch.

If you have made changes to metadata outside of Lightroom (which includes, by the way, opening a raw capture via Adobe Camera Raw directly in Photoshop), you will want to bring those updates into the Lightroom catalog. In the confirmation dialog you would click the “Import Settings from Disk” button if you wanted this option.

If you are certain Lightroom contains the latest metadata updates, you can save those out to the actual image files on your hard drive. In this case you would click the “Overwrite Settings” button in the confirmation dialog.

I should hasten to point out that the metadata mismatch icons you would have seen during my recent webinar presentation were due to the fact that I was presenting using a demonstration catalog, which contains a variety of intentional errors so I can show how to resolve various issues. I like to think I have no such metadata mismatches or other issues in my production catalog in Lightroom Classic. I hope!

Today’s Question: Which is better: guided transform in Lightroom Classic or perspective warp in Photoshop?

Tim’s Quick Answer: Both of these tools are excellent, with a different approach to correcting perspective. While I wouldn’t necessarily say that one is better than the other, I would say that for most typical scenarios the Guided option for transformation is simpler and more effective. Note that this Guided option is available not only in Lightroom, but also in Photoshop via Adobe Camera Raw or the Camera Raw filter.

More Detail: The Guided option for the transformation adjustments in Lightroom as well as Adobe Camera Raw (and by extension the Camera Raw filter in Photoshop) is a powerful and relatively easy way to correct perspective distortion in a photo.

After enabling the Guided option, you can simply drag within the image to define between two and four lines that define areas of the photo that should be perfectly horizontal or vertical. For example, you could drag along the left and right edges of a building, and then along the roof and foundation lines. That would define the lines of the building that should be perfectly horizontal or vertical. When you apply the effect, the image is transformed so that the lines you defined are indeed horizontal and vertical, so the perspective for the photo is corrected.

With the Perspective Warp feature in Photoshop, it is not quite as simple to get a quick correction. To begin with, the Perspective Warp feature makes use of a rectangular shape you can manipulate, rather than simply drawing lines in areas of the image that should be perfectly horizontal or vertical.

That said, the Perspective Warp feature also has advanced capabilities that go beyond the transformation options available in Lightroom or Camera Raw. You can , for example, define more than one rectangle with Perspective Warp, and join them together. So if you had a photo of a building captured from the corner, for example, with sides extending to the left and right, you could define individual rectangles for the left versus right sides of the building, and adjust perspective individually for each.

So, there are some more advanced capabilities available with the Perspective Warp adjustment in Photoshop. However, for most scenarios I think you’ll find using the Guided edit option for the transformation corrections in Lightroom or Camera Raw is faster, easier, and more effective than using Perspective Warp.

Today’s Question: I typically use Lightroom [Classic] initially to process a photo and then use Photoshop to remove distractions like wires, telephone poles, etc. The file is then saved as a TIFF file and appears in my Lightroom catalog. If I want to add additional changes using Lightroom should I start all over or just do the changes on the TIFF file after the Photoshop step?

Tim’s Quick Answer: You can most certainly continue to apply additional adjustments to the TIFF file in Lightroom Classic, and I would recommend doing that rather than repeating all of the image cleanup work in Photoshop again after refining your original image.

More Detail: When you send a raw capture from Lightroom Classic to Photoshop, the source image isn’t actually opened within Photoshop. Instead, a new derivative image will be created as a TIFF or PSD file (depending on the current setting in Preferences within Lightroom).

After saving and closing the TIFF or PSD file in Photoshop, the resulting image will appear alongside the original capture in your Lightroom catalog. You can then continue working with that image in the Develop module as much as you’d like. At this point, of course, those adjustments are probably going to be relatively minor as you fine-tune some of the effects you had applied with previous adjustments.

There’s no need to go back to the original source image to refine your adjustments. Doing so would create a potentially significant negative impact on your workflow, since you would then need to re-create all of the work you had previously done in Photoshop and create a new derivative file as part of that process.

Today’s Question: After I do my post-processing in Lightroom [Classic], should I then import those photos into my Pictures folder on Windows or is that a redundant process taking up space on my hard drive?

Tim’s Quick Answer: No, as far as I’m concerned there is no need to export additional copies of your photos from Lightroom Classic after processing, provided you’re backing up your photos and your Lightroom catalog regularly.

More Detail: Lightroom Classic provides a non-destructive workflow for processing your images. Among other things, that means that when you apply adjustments in the Develop module, you’re not actually modifying the source capture. Instead you’re essentially just creating metadata in the form of the adjustment settings you’ve applied. Lightroom will update the preview for your photos based on those adjustments, but the underlying source captures are not modified.

In part because of this workflow, I know many photographers prefer to export copies of their final processed images, to preserve their adjustments and to provide a backup of those photos. However, I don’t consider this step necessary, and doing so would certainly consume additional hard drive space.

Instead, I recommend making sure to keep your photos and your Lightroom catalog backed up, so that you’ll help ensure you are preserving all of the information about your photos (including adjustments), along with the photos themselves.

Naturally, if you want to share your photos outside of Lightroom you may want to export them. And down the road if you decided to stop using Lightroom (or if Lightroom were discontinued for some reason), you’d want to export new copies of your photos in order to preserve the adjustments as part of those exported copies. But in the context of a normal workflow that revolves around Lightroom Classic, I don’t recommend exporting copies of all processed photos unless you have a specific reason to do so.

Today’s Question: When in manual mode with the shutter button 1/2 way down, besides seeing a meter reading on the back screen of my Sony camera, I also see a histogram of the proposed raw shot. I once read that the histogram on the back of a camera is from a JPEG interpretation of the raw shot just taken. Is this also true for my proposed shot? Does it matter if DSLR or mirrorless?

Tim’s Quick Answer: It is true that the histogram you’re seeing is based on what can be thought of as an in-camera conversion from the original raw capture to a JPEG preview image. However, that histogram can still be considered quite accurate in terms of the potential for the final image.

More Detail: The fact of the matter is, a raw capture isn’t really an image the way a JPEG is. A raw capture is really just a data file that contains the information collected by the image sensor during the exposure, along with other metadata added by the camera. In effect, you can think of a raw capture as not having a real histogram at all. The raw data needs to be interpreted into full pixel information in order to calculate what the histogram should look like.

This is why you will see a slightly different histogram in the camera, in your raw processing software, and with other tools that interpret the raw capture to present a preview or histogram.

Because you are able to interpret the raw capture with quite a bit of flexibility in post-processing, the histogram you see in the camera or before processing can’t be considered the “final word” in terms of the overall exposure and color information for the image. The raw data can be “finessed” a bit, so that you can recover detail you thought might have been lost, or apply various other corrections to the photo.

While the in-camera histogram either before or after a photo is captured certainly can’t be considered absolutely final in terms of the final potential for the image, it does provide a very good sense of what is possible for the image, as long as you haven’t applied very strong adjustments in the camera. For example, if you apply an extreme increase in contrast in the camera, the histogram will reflect that contrast and may lead you to make inaccurate assumptions about the photo.

So, provided you are keeping the in-camera adjustments at relatively neutral values, I would say that the histogram you see either before or after the capture on the camera’s display is going to be quite accurate for evaluating the exposure for the photo.

Today’s Question: I am having a problem with my Canon 50D. Occasionally I have been receiving a “Err 30” which takes a power off/power on to clear. Today I was practicing panning techniques, and it occurred very frequently after 3 or 4 shots. I figure it is at least one of 3 possibilities: a camera/shutter problem, a battery (Watson B-1504) that cannot handle the power requirements, or a slow 8GB CF (SanDisk) rated at 60MB/s. Do you have any suggestions on how to diagnose and fix this problem? I will say that the burst mode indicator of 10 seems rather slow to me, and perhaps it is time to upgrade my camera.

Tim’s Quick Answer: Error 30 on a Canon DSLR indicates a malfunction with the shutter. If this error does not occur very often, removing the battery and replacing it will generally get you back to photography. If the error occurs somewhat frequently I would suggest getting the shutter mechanism replaced, or consider replacing your camera.

More Detail: The “Error 30” message indicates a problem with the shutter mechanism in the camera, but that doesn’t always mean the shutter is failing completely. There are other issues, such as dust or other debris in the camera that can lead to temporary problems with the shutter.

If the problem only occurs once, or very rarely, I would try gently blowing out the camera with a blower such as the Giottos Rocket Blaster (https://timgrey.me/rocket). You could also send the camera in for a professional cleaning and evaluation. However, if the error shows up somewhat frequently, it is an indication that the shutter mechanism is likely failing. In that case I would recommend sending the camera to the manufacturer for repair, or replacing the camera.

The last time I needed to have a shutter mechanism replaced in a DSLR the cost was around $250. That is obviously not terribly expensive compared to replacing the camera altogether, but naturally you might consider using this situation as an opportunity to upgrade to a new or more advanced camera.

Today’s Question: I have a follow up to a recent question. Do you import into a separate catalog for non-culled images first and then import only keepers into your primary catalog? I know several photographers recommend taking this two-step approach as a way of keeping track of images not yet culled.

Tim’s Quick Answer: No, I do not use a separate catalog for my initial import. Instead, I now assign a red color label to all images I import to my master catalog. I use that red color label to identify images that have not yet been reviewed, and then I remove the red color label once I have reviewed a batch of photos.

More Detail: In general I try to keep my workflow as streamlined as possible. As part of that effort, I prefer to get my photos imported into my Lightroom catalog as quickly as possible, creating a backup copy of my photos as part of that process.

To be sure, it is important to me that I review all of my photos, so that I am able to identify my favorites and perhaps delete any outtakes. In my mind, using a separate catalog for that culling process would create more complexity. It also creates a situation where I feel there is always a risk that some photos will never make it into my “permanent” catalog.

Therefore, I prefer to import images into my Lightroom catalog as a first step after capture. As part of that import I assign a red color label to the photos, so I always know which images have not yet been reviewed. As soon as I review a batch of photos, I remove the red color label, so I’ll know those photos have been reviewed.

As part of the review process, of course, I may delete some outtakes. More importantly I will identify my favorite photos with a star rating, so it is easy to determine which photos I want to work with and potentially share. Again, the key is that I try to keep my workflow as streamlined as possible.

Today’s Question: I always have automatically write changes in XMP enabled in Adobe Lightroom Classic. My question is if I copy or export a photo will Lightroom also copy the XMP or will Lightroom embed the metadata in the image?

Tim’s Quick Answer: If you enable full metadata during the export process, Lightroom Classic will include standard metadata in the exported image file, or in an XMP sidecar file for proprietary raw captures.

More Detail: When you export a photo from Lightroom Classic, you have the option to choose which metadata you want to save along with your photos. If you choose to include metadata as part of the export for a photo, the selected (and supported) metadata will be included in the actual image file. If you choose the “Original” option from the Image Format popup and are exporting a proprietary raw capture, metadata added in Lightroom will not be embedded in the source raw image file. Instead, the applicable metadata will be included in an XMP sidecar file that will be exported alongside the raw capture.

Which metadata is included depends in part on the options selected in the Metadata section of the Export dialog. The Include popup allows you to choose among several options for the metadata you want to include with (versus exclude from) the images being exported. For example, you could choose the “Copyright & Contact Info Only” option to only export your information as the photographer, without including any of the capture settings or other metadata added to the images.

You can also choose whether or not you want to include person and location information as part of the metadata being included with the photos you’re exporting.

In addition, keep in mind that even if you enable the option to include all metadata with the exported images, that doesn’t mean all information from Lightroom will be included. For example, pick and reject flags, collections, history, and other details that are specific to Lightroom will not be included with the exported images.

Today’s Question: Is there a reason why your copyright does not include the year? I have been changing this import preset to change it every year.

Tim’s Quick Answer: I exclude the year from the copyright information I add to metadata simply for expediency. This way I can use the same metadata preset without needing to update each year.

More Detail: Traditionally a copyright notice includes the year of first publication. However, including that information is not necessary. In fact, it is not required to include a copyright notice in metadata, nor to actually file your images for copyright protection with the US Copyright Office.

Ultimately, the point of copyright protection is to be able to assert a claim against someone who infringes on your copyright. It can certainly be helpful to file your images with the US Copyright Office, so your claim is officially documented. And anything you can do to help document the date of first publication can also be helpful. In other words, if you need to file an infringement claim, you’ll want to be able to document that the photo in question is yours, and was captured before the infringer published the image that violates your copyright.

So, it can certainly be a good idea to include the year in the copyright notice for your photos. But that is only a metadata value, and doesn’t necessarily relate to the actual date of first publication, and doesn’t actually represent the first publication. I don’t spend much time worrying about copyright infringement, but I’m also confident that if there was infringement I would be able to document the capture date, publication date, and other details of my photos.