Today’s Question: I’ve noticed that sometimes when I’m working with an image in Photoshop CS5 and I magnify the image to say 25% or 50%, this provides what I consider to be an ideal cropping for the image. Is there some way that I can crop the image to what I’m seeing on my monitor? I’ve seen references to say a 50% crop or a 100% crop. How does one do this in Photoshop?
Tim’s Quick Answer: There isn’t a simple way to crop based on a zoom setting, in part because the zoom setting is inversely related to the percentage of the image that is visible. There are, of course, several approaches you could use to crop based on the visible portion of the image, though none of them are especially precise.
More Detail: To begin with, you could apply a crop based on the visible image, by manually adjusting the size of the crop box. With the image sized so you can see the area of the photo you want to keep, you can then choose the Crop tool from the toolbox and click-and-drag from one corner of the image to the opposite corner. Of course, because Photoshop will attempt to automatically scroll the image as you near the edge of the visible area, this can be a little tricky.
Instead, you might prefer to simply apply a manual crop to the image. You could constrain the aspect ratio to that of the original photo if you prefer. To do so, choose “Original Ratio” from the popup at the far left of the Options bar after selecting the Crop tool. You can then adjust the corners of the crop box and the original aspect ratio will be maintained.
By making sure that the “shield” area around the crop box is relatively dark, you can also get a stronger preview of the final effect while you’re working to refine the crop. If you click the “gear” icon on the options bar you can set the value for Opacity, using a value of 75% or more to make sure you are mostly only able to see the photo within the crop box without the distraction of the rest of the image.
While it can sometimes be tempting to crop based on a zoom setting where you can only see part of the image, I think it is also important to keep in mind that when you’re in this situation you aren’t able to see what portion of the image is hidden. Instead you might want to create a basic crop based on the portion of the image that is visible, and then zoom out and refine as needed.