Q? About Cropping Photos - Does it Affect Overall Quality or Not?

[Barking Mad]

I can't remember the exact thread is located, that I read this morning, where someone requested a C&C and in response a poster mentioned that the cropping of the photo might have affected the photo - as in made it appear a little fuzzy or something akin to that. This is the 3rd time I've heard that cropping a photo in PP can affect the overall quality of the image, but it was the first time I'd actually seen someone mention it out here.

Is this always the case?

I ask because I crop a lot of photos and I've never noticed a NOTICEABLE difference but perhaps that's because I'm just not as attuned to it as pixel peepers are.

I crop photos for prints that I sell at local tourist traps (Maine is notorious for stuff like this, and who am I to complain...novice or not, they sell!) as well as the prints for photo card sets, etc. It's mostly images of flowers, lighthouses, and seascapes.

It's a hard habit to break, especially seeing as how I have a penchant for centering almost everything (yeah I know, I need remedial photography lessons ASAP...rules of thirds, etc.), which is yet another hard habit to break.

So what is the general consensus about this?

 

[paulk_68]

Cropping generally only effects photos when you crop an image and try to keep it the same size. If you took a picture that measured 11 x 14 inches and removed 25% of it while trying to keep the same measurements and resolution, the pixels get pulled apart because something has to replace that missing 25%. So, if the image was just a little out of focus to begin with, it will look even more out of focus once the pixels are stretched.

I hope that made a little sense, I'm still working on my first cup of coffee...

 

[Big Mike]

When you crop an image (and then re-save it) you are basically tossing out the unwanted part of the image. As mentioned, this matters when you want to keep the resulting image the same 'size' as the original.

For example, lets say you have an image that is 4000 pixels by 3000 pixels (12 megapixels). Then you crop it to 3000 x 2500 pixels....well now you only have 7.5 megapixels. That is still plenty of resolution for screen viewing, so it shouldn't look any worse on the screen, but if you want to make a large print, that's where the lack of resolution will start to make a difference.

Images for viewing on a monitor don't need nearly as much resolution as you need for printing (especially large prints)...so as long as you only plan on web viewing or making small prints, you can crop quite a bit without worrying too much.

Alternatively, you could use a non-destructive workflow by using software like Adobe Lightroom. When you crop in Lightroom, it doesn't toss out the leftover parts of the image, it just remembers where you want to crop....so you can go back to the original image size at any time.

 

[KmH]

Like Mike said the key is that when you crop you have fewer pixels left in the image after the crop.

The pixels get bigger if you enlarge what you have left to the same after the crop. I don't know what "pulled apart" means. You are using fewer pixels to fill the same space so they have to be rendered larger to fill the space.

If you crop an image deeply the individual pixels can get big enough, when enlarged, that the eye can begin to see the straight lines that make the sides of the square shaped pixels and the image is said to be 'pixelated'.

You may have heard the term 'crop in the viewfinder'? That's so you don't have to throw away image information (pixels) if you crop in post processing.

 

[paulk_68]

Like Mike said the key is that when you crop you have The pixels get bigger if you enlarge what you have left to the same after the crop. I don't know what "pulled apart" means.

It means that I couldn't think of the word "enlarged" when I posted,.. I did come up with "stretched" which is close, lol.

 

[c.cloudwalker]

Learn to crop in camera. Meaning: compose your image when you shoot it. Depending on your shooting conditions it is not always possible (sports and some news stuff come to mind) but in most cases it is.

90% of my personal/art/b&W work is printed on 11x14 paper and includes part of the film as a border to show that it is full frame. Part of the reason is to say "I know what I'm doing, I don't need to crop" but it is also a way to keep the grain quality the same throughout my work.

 

[Barking Mad]

Thanks guys!

I completely understand what you've said and the reasons behind it.

I don't think I've ever paid attention because the prints that I sell in local shoppes are typically never any bigger than 5x7 and the photo-card sets are all 3x5. And I think it answers another question I had in an earlier post about a picture I had printed out at 16x20 looking pixilated...I cropped off the sides and a great deal of the bottom of the image.

KmH....Yeah I have heard about cropping in the viewfinder, but like the novice I am, I just thought, "Nawwww, it's cool, I'll just lop off what I don't want in Picasa/Picnik in PP."

And yes I use low-end software because something about PhotoShop makes me uneasy. I have an unopened box of Elements that I've yet to install and am probably going to get Lightroom too.

Thanks again!