Straighten, Perspective and Crop
This week's lesson dealt with the initial pass in Photoshop of a photo that needed help with straightening or changing perspective, and then cropping to set the final picture. The point was made that one should rotate and crop a photo first before applying any kind of correction, such as the addition of new adjustment layers.
The homework was to take pictures that were overexposed, underexposed, and "just right" (in the words of Goldilocks). I will start with that sequence and then show a photo that needed rotation and cropping to regain the horizontal.
Overexposed, Underexposed and "Just Right"
This photo was taken on my Canon G7 in the Programmed mode where the settings were automatic. This is as near as the camera can get to being "just right". This was shot on an overcast day with a light rain. I used a tripod for all of these photos, since the lighting conditions were so strained (at least as far as my little camera was concerned). The photo intentionally had bright highlights and dark shadows to push the histogram to its limits. The levels layer is shown here without needing any adjustments to show the histogram.
The next photo was intentionally overexposed, using the manual setting on the camera. I was guessing here, since my camera does not have any built in histogram. I changed the settings until the image in the viewfinder was very bright. As you can see from the histogram, the highlights are off the scale.
I did add use this levels layer to try and adjust the white point and the middle marker, but as you can see, the blowout of the highlights did not allow for a full recovery.
I took the shot of the palms in several overexposed conditions, and the highlights are not totally blown out; just marginal with a few highlights unrecoverable.
The histogram shows the upper end of the highlights are not recoverable, but most of the picture is.
The next photo was intentionally underexposed using the camera's manual control.
In this case, the histogram shows almost the entire spectrum as being recoverable which I did using the levels layer. I adjusted both the White point and the Middle point.
This adjustment of the underexposed photo compares favorably with the "just right" photo.
Rotate and Crop to Recover Horizontal Lines
This last photo was an experiment in recovery for intentionally rotated initial pictures. I took this photo of the rain gutter that also shows the roof line, two lines which should have been nearly horizontal. The photo was shot in the camera's automatic Programmed mode.
I enlarged the canvas of this picture in two dimensions and laid down an initial precrop selection with the Crop tool that was the size of the original picture. I chose to enlarge the canvas because I did not want to limit my precrop selection size. Trying to guess a post-rotation pre-crop was too hard for me in this case.
I cropped the rotated picture. Then I selected a new crop for capture of the maximum from the rotated picture. Thinking back on things now, I might also have just used the transform tool on the original picture to rotate the entire photo horizontal, and then used the crop tool. Probably would have resulted in the same thing. Oh well. This shows my final selection for cropping prior to the crop.
I cropped the photo, added a levels layer, adjusted the settings and this was the result.
However, I was not too pleased with this result. It seemed to be a little lifeless. So I trashed the levels layer, did a shadows/highlights adjustment, added a curves layer and did an unsharp mask filter (with the shadows/highlight adjustment in place, the additional levels layer did not add much - so I deleted it). This is my final result (not within the real bounds for this homework, but what the heck it was fun to play).
That's all for this week. It was interesting. I learned that my camera is woefully short of having a lens that can capture a decent depth of field. I miss the days of having lens that could go from f 1.4 to f 22. Now that lens worked well. Maybe someday I will have a digital SLR. This exercise showed me that there is a real use for decent lenses.
