How to crop photos on iPhone without reducing quality?

Question

How to crop photos on iPhone without reducing quality?

I've discovered that the crop function in the standard Photos app reduces the resolution of the remaining portion of the photo (beyond what you would expect after removing part of the image). The Photos app seems to re-encode the image at a lower image quality than the Camera app achieved when it originally took the photo.

For example, if a I take a photo with the Camera at 2448x3264 (3.4MB), and crop all four edges a little in Photo, it reduces to 1536x2047 (992K). If I load the uncropped image into Preview on my Macbook, and do the same crop (as close as I can - and I tried to get it very close indeed) - the image is 2107x2860 (2.1MB). Furthermore, when I look at all three images - uncropped, iPhone-cropped and Preview-cropped - at "Actual size" in Preview, it's clear that the iPhone-cropped image has been reduced (ie. it appears "zoomed out", or smaller dpi) compared to either the uncropped or Preview-cropped images.

Does anyone know if there's a way to crop images on the iPhone without reducing the image quality in this way?

iPhone 4S, iOS 5.1.1

Posted on May 18, 2013 2:16 PM

Reply

Answer 1

May 18, 2013 2:58 PM in response to tonefox

Thank you for the quick reply.

Yes, I understand that a crop function should just remove parts of the image without changing the resolution of what remains. But that's not what I see on the iPhone.

Let's say I have a photo taken on the iPhone which is 2000x3000, and there's a VW van in the photo which is roughtly 500x500 pixels in dimension. If I crop the photo to only include the van, I'd expect to have a 500x500 image. And indeed, that's what I see when I crop the photo in Preview on my Macbook.

When I perform the same crop in Photo on the iPhone, however, I get an image of the van which is smaller - only about 375x375 pixels. It's exactly the same part of the photo, but the iPhone seems to reduce the resolution of the remaining image, not just remove the parts that were cropped.

I'm looking for a way to crop an image on the iPhone without reducing the resolution of what remains. Anyone know of an app that can do that?

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Answer 2

goslice

Level 1

5 points

Aug 18, 2013 6:12 AM in response to TJBUSMC1973

Thanks for the input and yes this would give Apple their 'excuse' but consider this...

I was remembering a very highly rated third party Camera App I used to use and I was wondering if it too would do the same thing as the Apple Native App. So I tested it. I took a photo with the Native Camera App and then I imported that photo to Camera+. I edited the photo by cropping it. I then exported the photo back to the camera roll. I followed the email procedure I outlined above (to get the file size) and noticed something very different. The photo edited with Camera+ (a $1.99 App) does not butcher the photo like the Native Apple Camera App does when you crop the photo.

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Answer 3

goslice

Level 1

5 points

Aug 17, 2013 12:23 PM in response to Hunchback Jack

Yeah, I've noticed this for sometime and I'm not sure if others even realize it. The easiest way I know of to illustrate this point is to simply email a photo before doing any cropping (editing) and notice the options for 'size' to send the photo as. In most cases, your photo will be over 2MB in file size under 'actual size.' NOW, edit the same photo. Crop off a VERY SMALL portion of the picture and make the changes by SAVING it as you normally would. Now email that same photo to yourself and notice how drastically the maximum file size has been reduced. Something in the neighborhood of 500-700KB is my guess.

It sure does seem that Apple's Native Camera App will SEVERLY butcher your photo's if you use it to edit them.

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Answer 4

tonefox

Level 6

9,368 points

May 18, 2013 2:33 PM in response to Hunchback Jack

A generic reply: "cropping" simply slices off the edges of the picture. The picture remains at the same resolution, but it's size (pixels wide by pixels high) is naturally reduced.

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Answer 5

Aug 17, 2013 12:43 PM in response to goslice

Many digital camera's in-device editting tools have the same effect.

Just transfer the picture to your computer and then edit it with appropriate software if the quality if that important.

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