Publishers of technology books, eBooks, and videos for creative people

Home > Articles

Lens

  • Print
  • + Share This
This chapter is from the book
04fig01.jpg

Click to view larger image

Location: Rijksmuseum Research Library, Amsterdam, Netherlands | Exposure: 1/5 sec | Focal Length: 14mm | Aperture Value: ƒ/8

Okay, this title is a little short, but you have to admit that the title “Lens,” from the Alanis Morissette single of the same name, is a pretty good one. I mean, you can’t expect that there would be a song named “Lens Correction,” unless it was from Adobe Records. But, I figured there really wouldn’t be a record company called Adobe Records, but son-of-a-gun, I did a search and on the website Discogs.com, I found a reference to two songs from Adobe Records. One of them was from the famous Athens, Georgia–based band REM, which ironically is an acronym for Rasterize Extra Masks, which in Photoshop, you would use when you have a vector mask that has been added to a pixel-based layer, and you want to maintain the mask, but convert from paths to pixels, and combine the affected layers into a single merged layer. If that sounds complicated, it’s only because I made it up, and that is part of what we all do when we don’t know the answers to complicated Photoshop questions. Look, Photoshop is kinda “sticky” at times. There are things in Photoshop that nobody knows what they do or if they’re actually connected to anything. Even Adobe doesn’t know. It’s because Photoshop has been around for more than 25 years now, and over these years, some of the Photoshop engineers have added decoy commands and features just for laughs, figuring nobody would ever even try them for fear of damaging their computer. For example, under Photoshop’s Image menu, under Mode, there’s a menu item near the bottom called “Release Virus to OS.” Seriously, who would ever choose that? Or under the Filter menu, under Stylize, there’s a filter named “Erase Hard Drive.” Really? Erase Hard Drive? Oh yeah, I’m choosing that one. Or how about under the File menu, where is says “Open.” Come on! Who in their right mind would choose Open? Open what? Spyware? Malware? Flatware? Glassware? Not on your life. At some point, Adobe is going to have to go in there and clean this stuff up before somebody accidentally chooses “Quit,” and then they’re out of a job.

Automatically Fixing Lens Problems

Camera Raw can automatically apply corrections for common lens problems (like barrel and/or pin-cushion distortion, edge vignetting, and junk like that). It does this by reading the embedded camera data (so it knows which camera and lens you used), and then it searches through its own huge, built-in database of lens profiles to find a profile correction. Then, it applies that profile to fix the problem, and it does a pretty amazing job of it. It’s really fast, and turning this feature on only takes one checkbox. But, what if you turn it on and it can’t find a profile for your lens, or there’s no EXIF data in your image (maybe you scanned it)? You’re about to learn how to handle that, too.

Step One:

Open the image with a lens problem in Camera Raw. Now, if you’ve been using Photoshop for a while, you already know there’s a Lens Correction filter found under Photoshop’s Filter menu, and they’ve updated that with some of the same features as the Camera Raw version, but it’s better to do the correction here because: (1) it’s non-destructive, (2) there are some better options available in Camera Raw, and (3) it’s faster. So I always fix lens problems here, rather than using the Photoshop filter.

Step Two:

Click on the Lens Corrections icon (the fifth icon from the right at the top of the Panel area) and on the Profile tab, turn on the Enable Profile Corrections checkbox. Now, chances are that you’re done. Boom. It’s fixed. That’s because, as I said above, it looks at the camera data embedded in the shot to find out which camera and lens you used, then it searches its internal database for a profile of that lens, and it immediately fixes the photo (as seen here). If it can’t find a profile, it lets you know at the bottom of the panel (as seen in the next step). Also, I usually have to back down the amount of correction just a bit with fisheye lenses by dragging the Distortion slider a little bit to the left (as shown here).

Step Three:

So, what happens in a case like this, where you open a photo and it can’t find a profile automatically, or the image doesn’t have any embedded EXIF data (for example, if you’re trying to fix a scanned image, or an image you copied-and-pasted from another document)? Take a look at the photo here. Camera Raw couldn’t find a profile for it, so in the Lens Profile section, the Make is set to None and the Model and Profile pop-up menus are grayed out. What this really means is that you have to help it out by telling it what equipment you used to take the photo (if you know), or you’ll have to make your best guess (if you don’t).

Step Four:

This was taken with a Canon, so from the Make field I chose Canon, and as soon as I did, it did the rest—it found a lens match and fixed the photo. Now, it’s not always 100% sure it has the right lens match, so it gives you a list of lenses it thinks might be right. You can click on the Model pop-up menu, and you’ll see a list of lenses it thinks it could be (as seen here). You can try out any of the other lenses listed there and see if it gives you a better result than the one that it chose for you (it does a surprisingly good job, so I usually wind up using the one it chose, but every once in a while I find a lens in that list I like better, even though sometimes I know it’s not the actual lens I used). Here, I actually used the 15mm lens, so I chose that from the pop-up menu and then adusted the Distortion a bit.

  • + Share This
  • 🔖 Save To Your Account