Category: Ask Tim Grey

Today’s Question: Could you explain more this statement that was in a prior “Ask Tim Grey”:

“back button autofocus enables you to separate the metering functions of your camera from the focus functions”

Am I right that only the shutter button meters the scene? So if I want to meter a spot on the upper left of the scene but want to focus on low center, how would I do that?

Tim’s Quick Answer: The “back button” focus option available on many cameras obviously enables you to separate the focus and exposure metering features. If you also want to lock the exposure, you’ll either want to employ the auto exposure (AE) lock feature, or employ the Manual exposure mode.

More Detail: In most cases exposure metering on a camera is triggered by the shutter release button. You can generally press the shutter button halfway to initiate the automatic exposure, and then press the button the rest of the way to actually take the photo. But in your example you want to be able to re-frame the scene after establishing exposure settings based on metering in a specific area of that scene.

Obviously you could employ the Manual exposure mode to lock in specific exposure settings. Then it doesn’t matter how you reframe the scene, because the exposure won’t change based on the changes in lighting as you change the framing.

If you want to use one of the exposure modes that enable automatic exposure, you’ll need to actually lock that exposure. Otherwise when you reframe the scene you’ll also cause the metering to update and the exposure settings to change.

The specific options available and method of employing auto exposure lock will differ from one camera to the next. But the basic idea is very straightforward. You can point your camera to the area you want to meter on and press the shutter release button halfway to actually establish exposure settings based on that metering. Then press the “AE Lock” (or similar) button to lock the exposure based on those settings. You can then reframe the scene without the exposure settings changing.

In some cases you simply press and release the AE Lock button to lock the exposure for the next photograph. In other cases you need to press and hold that button. And in some cases you can change the behavior through menu options on your camera. But the point is that many cameras do indeed feature an AE Lock feature.

Making use of “back button” focus along with AE Lock enables you to exercise considerable control while still taking advantage of the automatic features of your camera. You can set focus in one area, establish exposure based on another area, and then frame up the scene without altering focus or exposure settings.

Today’s Question: When I talked to you at an event a few months ago, you mentioned a lens cap that attached magnetically. Can you remind me where I can find that lens cap?

Tim’s Quick Answer: The lens cap I’m using is from a company called Xume Adapters. They produce magnetic filter holders (which I love), as well as a lens cap (which is incredibly convenient). You can find the 77mm version of the lens cap here: http://timgrey.me/77xcap.

More Detail: To my knowledge, the lens cap is not currently available in sizes other than 77mm. And it is important to note that the lens cap is really an accessory to the filter adapters offered by Xume Adapters. So, for example, if you get a set of adapters so you can easily swap filters on a given lens, in place of a filter with a magnetic adapter you can place the Xume Adapters lens cap on the lens, provided the magnetic adapter for the filters is already attached to that lens.

In other words, the lens cap from Xume Adapters makes use of the same functionality as the filter adapters they offer. You can see the Xume Adapters in action (though only for filters, not the lens cap) in an episode of Tim Grey TV via YouTube here:

https://youtu.be/qfOdqsC457s

Today’s Question: I just got a new MacBook Pro, which is my first Macintosh. I have gotten Photoshop installed correctly, but now when I use the “Command+Spacebar” keyboard shortcut to access the Zoom tool, a Spotlight search window shows up. Is there a way to disable this option so the shortcut only works in Photoshop?

Tim’s Quick Answer: You can disable the Spotlight search keyboard shortcut on the Macintosh. To do so, first choose System Preferences from the Apple menu on the menu bar. Then choose Spotlight in the System Preferences window, and click the Keyboard Shortcuts button at the bottom-left of the window. Turn off the checkbox for “Show Spotlight search”, and the keyboard shortcut will be disabled.

More Detail: In addition, you can change the keyboard shortcut for Spotlight search, so that it won’t conflict with Photoshop. To do so, instead of turning off the checkbox for “Show Spotlight search”, click on the keyboard shortcut to the right of that checkbox. Then press a key keyboard shortcut combination on the keyboard to assign a new keyboard shortcut. Of course, finding a keyboard shortcut that won’t conflict with the other applications you use may be a challenge!

Personally, I prefer to turn off the keyboard shortcut for Spotlight altogether. When I want to perform a search I can then simply use the search text field on any Finder window, or click the magnifying glass icon at the far right of the menu bar to bring up the Spotlight search window.

Today’s Question: I scanned a 35 mm slide at maximum resolution (11×17 at 300 pixels per inch). I want the print to be 19 inches (on the long side) and to be as sharp as possible. Will I get better quality if I have Photoshop interpolate the (extra) pixels to adjust the image size, or is it better to reduce ppi (to around 270) to keep the same size file?

Tim’s Quick Answer: My recommendation is to first scan your original transparency at the maximum optical resolution of your scanner. After optimizing and saving your master image, create a copy and resize that copy in Photoshop to the intended print dimensions, at a resolution optimal for your print process.

More Detail: The numbers provided in the question suggest a scanner resolution of about 3,300 pixels per inch. This is based on a 35mm slide scanned to produce an image that is 3,300 pixels on the short side (11 inches at 300 pixels per inch). Since the short side of a 35mm slide is about one in in size that translates to about 3,300 pixels per inch. If the scanner actually offers a higher resolution (such as 4,000 pixels per inch) I recommend scanning at that higher resolution.

After applying all of the adjustments you feel are necessary to optimize the image, I would then save that final result (with all layers intact) as a Photoshop PSD image or a TIFF image. This file can now server as your “master” image for all future output.

When you want to make a print, you can create a copy of your master image, flatten that copy, and resize to the intended print size. I recommend performing that resizing step in Photoshop, although in actual fact today’s printer software also does an excellent job of resizing the final image at high quality.

I recommend resizing the image to be printed based on the “native” resolution of your printer in terms of how image data is processed. This varies among different printers, but in general is around 300 or more pixels per inch. For many photo inkjet printers a resolution of 360 pixels per inch is optimal. But again, the specific number varies based on your printer, and can often range from around 300 pixels per inch up to around 720 pixels per inch.

Let’s assume a printer that renders the final output data at 360 pixels per inch. If you leave the image resolution at 270 pixels per inch in order to not apply any interpolation (or to keep the file size smaller), that image data is still going to be interpolated upward. If you give the printer less data than it needs (360 pixels per inch in this case), the printer software will simply interpolate the image data up (from 270 pixels per inch in this example) to the necessary output resolution. In other words, you may as well resize the image to the final output dimensions in Photoshop rather than having the printer software perform that additional work.

This issue used to be more significant than it is today, because printer software didn’t do as good a job of interpolation, especially compared to Photoshop. However, today’s printer software actually does an excellent job with this interpolation. So resizing to the final output dimensions in Photoshop before printing is not quite as important as it used to be, but I do still recommend this approach as a best practice when printing.

Also note that once the image has been resized to the final output dimensions, you should apply sharpening to optimize that final print. And, of course, sharpening is best applied at the final output dimensions, which is one additional reason to resize in full in Photoshop. That way the sharpening truly is the final step, rather than resizing in Photoshop, then sharpening, only to have the printer software apply a further change in the pixel dimensions during the print process.

Today’s Question: I see some photographers use a lens hood all the time, others only when in strong sun, still others (like me) never. Should I be using a lens hood all the time? Does it alter exposure, make metering more accurate, or offer some other advantage?

Tim’s Quick Answer: The key purpose of a lens hood is to prevent lens flare. Thus, in concept you only need to use a lens hood when the sun position is “in front” of a line formed by the front element of your lens. If the sun is “behind” the front of the lens, the lens itself will provide shade to prevent lens flare. Thus, it is a good idea to always use a lens hood.

More Detail: There are a few points to keep in mind when it comes to lens hoods. As noted above, a lens hood is only truly necessary when the sun is “in front” of the lens. But in reality it is important to keep in mind that you are likely to change your viewing angle from time to time when photographing. In other words, just because the sun is behind you initially, that doesn’t mean it will remain in that position for every photo you capture.

Also, it is important to realize that the “funny” shape of many lens hoods is very much intentional. Each lens hood is designed for the specific lens it is intended to be used with in terms of preventing lens flare without creating vignetting or other artifacts. Therefore, you should always be sure to use a lens hood specifically designed for the lens you are using.

In addition, while a lens hood is really intended primarily to prevent lens flare, it is worth noting that keeping the lens hood on the front of the lens can actually help protect that lens. If you bump a lens into a wall, for example, it is generally preferred to have the lens hood hit the wall rather than the front lens element.

As a bonus, having a lens hood attached to the front of the lens makes you look like a more intelligent and professional photographer. Just make sure you have the hood attached in the “hood” position, rather than in the inverted stowed position that should only be used when you put the lens back in your camera bag.

Today’s Question: I may be digging a little too deep here, but I have a question about the Color Balance adjustment in Photoshop. Is there any reason I should use the sliders in the order they are presented? Or some different order? Does it matter at all which order I adjust the sliders?

Tim’s Quick Answer: Fundamentally, you can move the sliders for the Color Balance adjustment in Photoshop in any order you want. In general I prefer to take a thoughtful approach to applying a Color Balance adjustment, but all that really matters is the final settings you’ve established for the three adjustment sliders.

More Detail: My preferred approach to the Color Balance adjustment is to start with the slider that represents the greatest “need” in the image, and then work my way through the other sliders in a similar fashion.

So, for example, if my impression of a photo is that the color is shifted too far toward magenta, I’m going to start with the Magenta/Green slider for Color Balance. Once I’m happy with the overall balance between magenta and green, I’ll evaluate the photo and consider what the next most-needed slider shift might be.

Perhaps, for example, the image now looks a little too yellow. I would then naturally go to the Yellow/Blue slider to fine-tune the color. Then, in the interest of thoroughness, I would refine the slider position for the Cyan/Red slider.

Once I’ve adjusted all three sliders, I would return to all three (in any order that seems to make sense to me) to further refine the overall color result. But there is no need to worry about the order in which you change the slider values, or how many times you go back and forth among all of the sliders to achieve the best overall balance of color in the photo.

As an added tip, keep in mind that you can use the up and down arrow keys on the keyboard to adjust the value for any slider. Simply click with the mouse in the numeric value for the desired slider to activate that field. Then use the up and down arrow keys on the keyboard to increase or decrease the value for that slider, respectively. And if you hold the Shift key on the keyboard, the up and down arrow keys will shift the value in increments of ten rather than one.

Today’s Question: I recall at a presentation you gave that you said back button focus allowed you to have the choice between continuous autofocus and one shot autofocus at any time. Can you explain how that is possible?

Tim’s Quick Answer: You can have both continuous or one-shot autofocus at any time when using back button focus by simply setting your autofocus mode to continuous autofocus. Then press and hold the focus button on the back of the camera to achieve continuous autofocus. When you want one-shot autofocus, press and hold the button to initially achieve focus, and then release the button so the focus will not change until you press the button again.

More Detail: The ability to instantly switch between one-shot autofocus and continuous autofocus is one of the key reasons I prefer to take advantage of the ability to use a separate button on the back of the camera to initiate autofocus. This provides considerable flexibility when photographing a variety of different subjects under changing circumstances in a short period of time.

In addition, back button autofocus enables you to separate the metering functions of your camera from the focus functions, which also provides considerable flexibility in your photography “workflow”.

For more information about back button autofocus, see the article “Back Button Focus” in the July 2015 issue of Pixology magazine. If you’re not already a subscriber you can sign up today and request the back issues at no additional cost by sending an email to renee@timgrey.com. Details about subscribing can be found here:

http://pixologymag.com

Today’s Question: When I want to add an image I’ve edited in Photoshop as a layer in another image, I can flatten the image, select all, copy, switch to the 2nd image and then past in place and it appears as a layer in the 2nd Photoshop file. When I try to drag and drop the first image onto the tab of the 2nd image nothing happens. Should this alternate method work? What am I missing?

Tim’s Quick Answer: You’re just missing one last step. When you drag a layer to the tab of a different image that is open in Photoshop, the image represented by that tab will come to the front so you are able to see that image. However, you can’t simply drop the image layer on the tab. Instead, after dragging (without dropping) to the tab so that the destination image comes to the front, you can then move the mouse over that image and then drop the layer.

More Detail: The tabs used by default for all open documents in Photoshop can be very convenient for working with multiple images and switching between those images with ease. What many photographers don’t realize is that those tabs can also be helpful for copying layers between the various open images.

The key is that when you drag a layer to a tab for a document, while that document comes to the front so you can actually see it, you still need to move your mouse into the actual image area in order to drop the layer you’ve dragged. You can’t simply drop a layer on a tab in order to add the layer to the image represented by the tab.

For example, let’s assume you have added an adjustment layer to the image represented by the first tab, and you want to add that same adjustment layer (with the same settings) to the image represented by the second tab. In the first image, point your mouse at the applicable adjustment layer thumbnail on the Layers panel. Then click and drag that thumbnail toward the tab for the second image. Hover the mouse in position over that tab until the second image comes to the front, keeping the mouse button held down the entire time. Then continue dragging into the image area, and release the mouse once the pointer is over the appropriate area.

Note that if you are copying an image layer or an adjustment layer that includes a layer mask, the alignment of the layer in the destination document can be important. In that case you can also hold the Shift key on the keyboard so that when you release the mouse the layer you’re copying will be centered in the destination image.

Today’s Question: The free Lightroom iPhone app can automatically transfer every photo you take to a folder in your desktop Lightroom. Why not use it instead of extra manual steps?

Tim’s Quick Answer: There are two key reasons I prefer not to use the mobile version of Lightroom to import the captures from my mobile devices. First, this process leaves the original captures on your mobile device, and as noted in my answer on Friday I prefer to treat my iPhone as a camera, deleting all photos from my iPhone as soon as they are safely downloaded. Second, using the mobile version of Lightroom in this way doesn’t enable me to employ my normal folder structure strategy, requiring some additional “cleanup” work after the import.

More Detail: The “mobile” version of Lightroom does indeed enable you to import photos from your mobile device directly into Lightroom on that device. Those photos will then be synchronized automatically to your desktop installation of Lightroom, provided you have enabled synchronization. The result is that your iPhone (or other mobile device) captures will automatically synchronize to your “real” catalog on your desktop, while still being available on your mobile device.

To be sure, this workflow can be very convenient. However, as noted above, the workflow employed does not align with my own personal workflow preferences. While I often capture photos on my iPhone, for example, I don’t those photos to permanently consume space on my iPhone. I treat my iPhone as another camera to supplement my digital SLR and other cameras, and I want to use the same workflow for all photos I capture, regardless of which device was actually used to capture the images.

For me personally, I want a solution where I can delete the photos from my camera (such as the iPhone) as soon as they have been successfully downloaded (and backed up) to my normal storage. I also want to be able to use my existing folder structure strategy for those captures.

While the use of an application other than Lightroom for downloading photos from my iPhone does add a step to my workflow, this approach also makes it easier to delete the photos from my iPhone during this process, and to maintain my existing folder structure as well.

If Lightroom included an option to delete all photos from my iPhone as soon as they have been successfully copied (and backed up) into my normal folder storage structure, I would be very happy and I would no longer need to use other software for downloading my iPhone images. Until then, the workflow noted in the Friday edition of the Ask Tim Grey eNewsletter provides a solution that works for me.

Today’s Question: What is the best way to get any image from your iPhone into Photoshop? Right now I am simply copying the image and emailing to myself. Then I simply double-click and it comes up in Photoshop.

Tim’s Quick Answer: The “best” way to get images from your iPhone (or other smartphone) to Photoshop depends in large part on your preferences in terms of overall workflow. My personal preference, however, is to treat my iPhone as “just another” camera in the context of photos. Therefore, I prefer to download all of my photos from the iPhone, delete the source images from the iPhone, and then use the same workflow for those images as I would for any other photo, such as those from my digital SLR.

More Detail: To be sure, some photographers prefer to keep all of their photos on their iPhone “forever”. That approach doesn’t appeal to me for several reasons. Most importantly, having all photos captured with the iPhone reside on the iPhone can create a bit of a challenge when it comes to looking for a particular photo. In addition, this approach would prevent me from taking advantage of the variety of other benefits of my image-management workflow when it comes to iPhone captures.

It is possible to import photos directly from your iPhone into a Lightroom catalog. However, I prefer not to use this approach (even though I use Lightroom to manage my photos) because neither Lightroom nor the iPhone Photos app provide an easy way to delete all photos from the phone after they have been successfully downloaded.

It is possible to use the Photo Downloader feature in Adobe Bridge to download photos from your iPhone. You can create a backup copy of the photos during the download process, and also enable an option to delete all photos from the phone after a successful download. This was the method I had been using until a recent Macintosh operating system update caused Adobe Bridge to no longer be able to download photos from my iPhone.

Therefore, at the moment I use the Image Capture application included in the Macintosh operating system to download all of my photos, and then delete all of the photos from my iPhone once I have imported the photos into my Lightroom catalog (copying those photos to an additional hard drive for backup purposes in the process).

Regardless of which software you’re using to manage your photos on your computer, by downloading the images from your iPhone (and then deleting the source captures from the phone, just as you would reformat a media card in your “normal” camera) you can then use the same workflow you already employ to manage your iPhone captures, and open those images in Photoshop as desired.