Ask Tim Grey

Today’s Question: What are your thoughts concerning the use of the Freeform Pen Tool (with the Magnetic option) vs. the Magnetic Lasso Tool [in Photoshop]?

Tim’s Quick Answer: In theory I prefer the additional flexibility provided by the Pen tools in Photoshop, but in actual practice I generally find the Lasso and Magnetic Lasso tools are all I really need in the context of photographic images.

More Detail: In essence, there are two sets of features to consider here. One is the magnetic feature, and the other is the method of drawing shapes.

In terms of the magnetic feature, I consider the two tool options to be equal to each other. In other words, you can expect the same basic results with the Magnetic Lasso tool compared to the Freeform Pen tool with the Magnetic option enabled.

Therefore, the key difference for our purposes relates to how you actually create a shape with these tools. The Lasso tools allow you to “manually” draw any shape you’d like, while the Pen tools allow you to define shapes based on vector paths. In other words, with one of the Pen tools you can create a shape based on anchor points, defining (or refining) lines and curves between those anchor points.

So, with either the Magnetic Lasso tool or the Freeform Pen tool you can define a shape based on contrast edges within a photo. In other words, you can create a shape that follows an object within the photo in a relatively automated way.

The key difference is that when you’re finished defining a shape with the Freeform Pen tool, you have a set of anchor points that can be refined just as you might change shapes when creating a path using the other variations on the Pen tool. That provides a degree of additional flexibility, to be sure.

However, I find that for most photographic images a vector shape doesn’t provide a tremendous advantage. The shapes I need to define within a photographic image are generally a bit more complicated than can be easily defined with vectors, and thus I need to use a raster-based shape.

So, again, the Freeform Pen tool provides an advantage over the Magnetic Lasso tool, but that advantage is something I find I generally am not able to really take advantage of in the context of a photographic image.

Today’s Question: I’m seeking clarification [regarding the answer about the warning when moving photos within Lightroom that appeared in the July 24th edition of the Ask Tim Grey eNewsletter]. Should I assume that the Lightroom warning about moving photos not being undoable means that you can’t move the files back to their original location if you change your mind?

Tim’s Quick Answer: You can still move photos back to the original location if you decide you should not have moved those photos in the first place. The warning in Lightroom simply means you can’t “automatically” return photos to the original location using the Undo command.

More Detail: The warning message Lightroom presents when you attempt to move photos within Lightroom makes it sound like once you move photos you will never be able to put those photos anywhere else, and you’ll also lose any other work you’ve performed on the images in Lightroom. In other words, it is a very intimidating message!

What Lightroom is trying to convey with this message is that when you move photos from one folder to another in Lightroom, that is a task that Lightroom can’t keep track of in terms of the history of what has been done with an image. Therefore, you can’t simply choose the Undo command if you later decide you didn’t really want to move the photos in the first place.

However, you can most certainly move photos again if you change your mind. In other words, Lightroom can’t move photos back to their original location through the Undo command, but you can certainly move photos from one folder to another and back again. So, if you move photos to a different folder and then discover this was a mistake, you can select those photos in their new location and drag them to their original location (or any other location you’d like).

The key is to make sure you are always moving photos within Lightroom, not outside of Lightroom. If you move (or rename) photos or folders outside of Lightroom, then Lightroom won’t be able to keep track of those changes, and you will be unable to continue properly managing those photos within Lightroom.

Today’s Question: I am the digital chair for a camera club. We’ve calibrated our projector using a high-end calibration system using the club’s laptop. My question is this: when a guest speaker comes in with their own laptop, if we copy the projector profile from the club’s laptop to the presenter’s laptop will we get the proper calibration?

Tim’s Quick Answer: If you are using a digital connection (DVI) for your projector, you can achieve relatively consistent results among multiple computers, provided all other conditions (including the screen and ambient lighting) remain consistent. If you are using an analog connection (VGA), your results will be less consistent (or even wildly inconsistent) from one computer to the next.

More Detail: When you calibrate and profile a digital projector (just as with a monitor display), you are measuring the behavior of that projector in the specific context of the current environment. That includes the computer (and therefore the display adapter) being used to send information to the projector, as well as the screen being used, ambient lighting conditions, and other factors.

If you are using a completely digital connection (from the computer’s display adapter to the cable to the digital projector) the results will be much more consistent. Therefore, it is possible to get very good results with a single ICC profile shared among multiple computers.

On the other hand, if you are using an analog connection (via a VGA cable), the analog signal (and the conversion between digital and analog) may introduce significant variability from one computer to the next. In this situation I would recommend creating a profile for each computer that will be used with the digital projector.

Today’s Question: Now that you discussed resolution and explained that most photographers need no more than 20 megapixels, what about sensor size and the relation to resolution? There have been a lot of improvements to sensors in the last few years. Can we get the same results at 20 MP on a 1 inch, 4/3 and C size sensors as on a full frame sensor?

Tim’s Quick Answer: Sensor size does indeed have an impact on image quality, with a larger sensor generally providing at least some advantage compared to a smaller sensor, assuming the same resolution for both. However, I would argue that with recent technological advances these differences have become less significant, to the point that you can achieve exceptional image quality even with a smaller sensor size.

More Detail: Assuming two sensors of different sizes but of the same resolution, there are some inherent advantages to the larger sensor size, all other things being equal. By virtue of having a larger sensor with the same resolution, each individual photo site (which I’ll refer to as a pixel in the context of this discussion) will of course be larger. That larger pixel can therefore record what is essentially more information.

With a larger pixel that is able to collect a larger electrical charge, the difference between “empty” and “full” for each pixel is greater, which means the sensor is able to record greater dynamic range. That larger amount of information also means the sensor will yield lower noise levels in the images being captured.

There are other factors involved, of course, but the bottom line is that a larger image sensor at a given resolution will have larger individual pixels, and that will translate into improved image quality measured in a variety of different ways.

However, imaging technology has continued to evolve rather dramatically, resulting in fewer problems for sensors with a smaller overall size. Advances in noise reduction technology have mitigated the challenge of increased noise with smaller sensors, and other advances (such as increased bit-depth) have helped to mitigate the issue of dynamic range.

From an image quality perspective I would still prefer a larger sensor to a smaller sensor, all other things being equal. But, of course, there are other factors to consider including cost, cropping factor, and more. In other words, while I would prefer a larger sensor size from an image quality standpoint, I’m perfectly comfortable using a camera with a smaller sensor, knowing that excellent quality is still possible.

It is also important to keep in mind that the issues addressed here are conceptual. It is possible to have a full frame image sensor that produces images of relatively poor quality, just as it is possible to have a smaller sensor that offers exceptional image quality. Therefore, the sensor size is only one factor to be considered as you evaluate which particular camera equipment makes the most sense for your specific needs as a photographer.

Today’s Question: Every time I move a file in Lightroom I get a warning that this move  cannot be undone, and nor any changes made previously. What are the ramifications of this? Sounds ominous and I hesitate each time. Would I be better off moving each photo with its sidecar using Finder [in the operating system] and re-importing to the other folder?

Tim’s Quick Answer: The warning message about moving photos within Lightroom is a bit ominous sounding, but it should be thought of only as a reminder and not as an ominous warning. My biggest hesitation about moving photos relates to the (perhaps slightly irrational) fear that something will go wrong during that process. But as long as I have a good backup of my existing photos, I’m perfectly comfortable using the option to move images directly within Lightroom.

More Detail: Of course, it is reasonable that you should hesitate when Lightroom indicates that you’re not unable to simply undo the move operation. After all, you can certainly make a mess of things in your Lightroom catalog if you move photos to the wrong location by mistake. However, it is worth keeping in mind that if you do move photos to the wrong location, while you can’t simply undo that step, you can move the photos again to the correct location.

Note, also, that you do have the option to disable this warning about moving your photos. To disable the warning, simply turn on the “Don’t show again” checkbox in the confirmation dialog when you initiate a move operation.

However, I strongly recommend that you do not disable the warning about moving photos. While the warning sounds much more ominous than I consider necessary, the dialog is a good reminder to stop and make sure you’ve dragged the correct images to the correct folder. If you have any doubts at all, click the Cancel button and start over with the move operation.

While the confirmation dialog may sound scary, in my mind it isn’t nearly as scary as the prospect of moving photos outside of Lightroom and then trying to reconnect the missing photos in your Lightroom catalog that will result. So, make sure you have a good backup, and move photos within Lightroom anytime you need to do so.

Today’s Question: I find that I have created a sub-folder, I assume during import [into Lightroom], and I really did not want to. This is preventing me from changing the order of my photos. Can you tell me how to get rid of this sub-folder so I have a single folder?

Tim’s Quick Answer: Cleaning up a folder structure that includes unwanted subfolders is a two-step process. First you’ll want to move the photos from the subfolder into the parent folder, and then you’ll want to delete the (now empty) subfolder.

More Detail: Of course, before setting out on this task I recommend making sure you have a full backup of all of your photos, just in case anything goes wrong during the process of consolidating images from subfolders.

When you’re ready to perform this consolidation task, navigate to the subfolder within Lightroom. Note that it is critical to perform this work within Lightroom, not from your operating system or other software, to ensure your folder structure and file location information within Lightroom remains accurate.

Make sure there aren’t any filters, so you’re able to see all of the photos within the subfolder. Then choose Edit > Select All from the menu (or press Ctrl+A on Windows or Command+A on Macintosh) to select all of the photos in the subfolder. You can then position the mouse pointer over any one of the selected images, and drag-and-drop to the parent folder.

You will be asked for a confirmation that you want to move the photos on your hard drive, which you should of course confirm so that the move operation will proceed. Once the move operation has completed and the subfolder is empty, you can right-click on that subfolder and choose the Remove option. Once you confirm this step in the confirmation dialog, the empty subfolder will be removed.

You can, of course, repeat this basic process to consolidate images from multiple subfolders as needed to cleanup your overall folder structure. For readers who have subscribed to my GreyLearning video training library (http://www.greylearning.com), you can view a video lesson of the process of consolidating folders in Lesson 10 of the course “Lightroom 5: Resolving Organizational Challenges”.

Today’s Question: Can you tell me what the “plus” symbol next to Quick Collection in Lightroom means? I tried to click on the plus but nothing happens. Is there a purpose for this symbol?

Tim’s Quick Answer: The “plus” (+) symbol that appears to the right the Quick Collection in the Catalog section of the left panel in the Library module in Lightroom indicates that the Quick Collection is the current “target collection”. In other words, this is an indication that if you press the letter “B” on the keyboard, the currently selected image (or images) will be added to the Quick Collection.

More Detail: What might not be obvious though is that you can also change which collection is the current target collection. In other words, while the “B” key will cause an image to be added to the Quick Collection by default, you can also set a different collection as the target collection. That, in turn, will cause the letter “B” keyboard shortcut to add the currently selected photo to a collection other than the Quick Collection.

To change which collection will be the target collection for the “B” keyboard shortcut, you can right-click on a collection and choose “Set as Target Collection” from the popup menu that appears.

In this way, you can work with much greater flexibility when using collections. If you are working on a project that involves the images in a single collection, you can set that collection as the target collection to make it easier to add other images to the collection with the simple press of a key on the keyboard.

I do recommend, however, that you set the Quick Collection back to being the target collection when you’re finished working with a different target collection, just to maintain consistent behavior as far as the “B” key adding a photo to the Quick Collection by default.

You can learn more about my approach to using this ability to re-assign the target collection keyboard shortcut in the article “Multiple Quick Collections” in the January 2013 issue of Pixology magazine. If you’re not already a subscriber, you can subscribe today and gain access to this and all other back issues of the magazine. Learn more about Pixology at http://www.pixologymag.com.

Today’s Question: What’s your opinion on the use of vector versus layer masks in general photo editing [in Photoshop], and also the potential utility of combining both types of masks on a single layer?

Tim’s Quick Answer: In most cases I would say that only layer masks (and not a vector mask) should be used in the context of a photographic image. However, there are certainly situations where a vector shape can serve as a good starting point for a layer mask or a vector mask.

More Detail: In a very general way, you can think of a layer mask as being composed of pixels (just like a photographic image) and a vector mask as being composed of a shape (such as a font or a geometric shape). One of the things that makes vector graphics unique and useful is that they can be scaled infinitely without reducing the quality of the shape.

That is because a vector is defined by angles and curves rather than specific pixels. A good example of a vector shape would be the letters in a font. You can resize actual text without reducing the quality of that text, whereas resizing a raster image (such as a photo) will cause some reduction in quality.

The reason layer masks (rather than vector masks) are generally best for photographic images is that the shapes found within photographic images are generally not as smooth an precise as a vector shape. Thus, a bit more flexibility is often necessary.

That said, vector masks can be feathered just like layer masks, so it is not unreasonable to use a vector as the basis of a mask. In some cases, such as when you want to use a mask in the form of text, a vector mask makes perfect sense. In other cases you may find that a vector (such as those you can create with the Pen tool in Photoshop) provide an excellent starting point for a vector mask or even a layer mask.

But again, in general I would suggest that layer masks are most valuable in the context of photographic images, and that vector masks are helpful in a relatively small percentage of situations.

Today’s Question: Does my Lightroom catalogue contain all of my imported pictures AND associated edit recipes [adjustments], or just a link to where the pictures were imported from?

Tim’s Quick Answer: The Lightroom catalog contains a reference to your original image files on your hard drive, and also contains the metadata about your photos including adjustments you have applied in the Develop module within Lightroom.

More Detail: This is perhaps one of the most critical things to understand about Lightroom. The Lightroom catalog does not actually contain your photos, but rather manages information about your photos. You still need to keep the actual photo files on your hard drive.

When you import photos into your Lightroom catalog using the “Add” option, the photos will remain where they are, and references to those photos will be added to the catalog. Similarly, when you import photos with the “Copy” option, the source photos are copied to the destination you specify, and references to those photos are added to your catalog. In both cases you need to retain (and backup!) your actual photo files.

When you apply adjustments in the Develop module, that information is also contained in your Lightroom catalog, so that (for example) if you export an image the new file that is created in the process will reflect your adjustments.

It is worth noting that if you turn on the “Automatically write changes into XMP” checkbox on the Metadata tab of the Catalog Settings dialog, Lightroom will also write standard metadata fields and your Develop adjustment settings to an XMP sidecar file for your RAW captures or to the actual image file itself in the case of other supported image formats. This option provides a form of backup for most of the information about your photos, and improves cross-application compatibility, but is not a complete replacement for your Lightroom catalog.

Today’s Question: I know this is a bit of an old subject, and perhaps the question is no longer really valid or important. But I wonder how many megapixels do we really need? Can you provide some perspective on this?

Tim’s Quick Answer: This is a perfectly reasonable question, and one that I think tends to get the “wrong” kind of attention. In short, while most photographers probably only need a camera with a resolution on the order of no more than 20 megapixels, there are certainly photographers who need more.

More Detail: Ultimately, how many megapixels you need is determined by how large you need to print a photo. Complicating matters slightly is the need to have adequate resolution to crop a photo and still print at a reasonable size, but that is in my mind a secondary concern.

First, let’s consider some extreme scenarios. The first thing a photographer needs to consider when determining their digital camera resolution requirement is how large they want to be able to print their photos. For now, let’s assume the simple resolution numbers required for actually producing a print.

If you need to be able to print up to 40-inches by 60-inches, assuming a photo inkjet print with a 360 pixel per inch (ppi) resolution, you need over 310 megapixels to be represented in the final image. That translates to 14,400 pixels on the “short” side, and 21,600 pixels on the “long” side. For a 20×30-inch print you would need just over 78 megapixels (7,200 pixels by 10,800 pixels).

Of course, this isn’t entirely fair, since you can enlarge (via interpolation) an image with excellent results. As a very general guideline, I recommend limiting your enlargements to no more than about double the width and height of the original capture. So, for a 20×30-inch print you could actually start with a file that represents 10×15-inches of information. Based on the specifications provided above, that translates to a little over 19 megapixels (3,600 pixels by 5,400 pixels).

I think the reason many feel that the megapixel subject is no longer worth discussing is that we’ve reached a point where most photographers will be adequately served by the resolution offered by most digital SLR cameras today. A somewhat “typical” digital SLR with an 18-megapixel sensor enables the production of prints up to about 20×30 inches without much difficulty.

Of course, some photographers need to print much larger than 20×30-inches, and for them a higher resolution camera makes perfect sense. But if you consider 20×30-inches to be a very large print, then around 18 megapixels will be perfectly fine. Beyond that, it is worth considering your needs in terms of output size (and cropping) to determine how much resolution you really need.

But as you can see, with a 40×60-inch print calling for over 300 megapixels worth of information, it isn’t outrageous for photographers to still want ever-greater resolution in their digital cameras. Extremely high resolution cameras may still be a bit expensive, but they do serve a valuable purpose for those who need to produce large output.