Zoom vs crop melting my brain

<p>Hi all,<br>

So I took some fun photos at the beach yesterday of our two dogs playing.<br>

When in Digital Photo Professional if I view the (raw) image at 50% zoom in Quick Check, it<br>

looks beautifully sharp. I then wanted to crop it in Trimming tool to make the photo mostly<br>

their faces but when I crop it the resulting image looks really blurry and disappointing.<br>

Is there anyway to crop in on a part of the photo and keep that nice crisp quality?<br>

P.s. I am using a Canon EOS Rebel T4i with a 50mm prime lens and I have Photoshop elements to play with.<br>

Thanks!</p>

Hi Laura. To judge sharpness you pretty much have to view the image at 100%. Anything more or less is

going to use some sort of algorithm that either removes pixels or create pixels.

 

If you crop into a small area, the software will have to create a lot of pixels. Most software applications

don't do this that well. Even Photoshop doesn't do this really well. OnOne sells Perfect Resize which is

possibly the best product in the market for activities like this.

 

Good luck!

--Wade

<p>The problem here isn't the sharpness of the original image; it is the fact that you cannot crop indefinitely. At some point, you have too little resolution left (the software does not create pixels when you crop to a small area, it only removes them - so your 18 megapixel image will become a lot less than 18 megapixels).<br>

With the tool Wade mentioned, you can gain back part of the crisp quality when you crop a lot, but there are limits. At some point, if you crop out a very small part of the image, you will have very little information left which you cannot blow back up to full image size.</p>

<blockquote>

<p>To judge sharpness you pretty much have to view the image at 100%</p>

</blockquote>

<p>I disagree with this (to some extend). To judge sharpness, you have to define what is acceptable to you, and what is sufficient for the intended output. If I am going to downsize everything to websized images, I can do with a bit less sharpness. Looking at 100% of a complete image is like looking at a wall-sized print - not always useful.</p>

<p>Can you show us the original and the crop you want? When you view a file you shot raw with a Rebel at a 50% zoom, I'd think you should still maintain pretty good quality. But then how much further are you cropping when you say you're just framing their faces? That might be much more of a zoom and there's where your loss is occurring. If you like it enough and are not terribly happy with the cropped quality, try keeping it really small within a much larger frame (on screen) and then fill that frame with a neutral gray fill. If it's cropped to be just two faces, keeping the image small might work pretty well and then the viewer is less likely to be disturbed by the imperfections. A small image or print can have high impact if it's the right image. Of course, I'd need to see for myself just how degraded the crop is before deciding whether it's salvageable.</p>

I think she means that at the same magnification Zooming and Cropping show two different results, which shouldnt happen. In that case it might be that what you are trying to do is not just cropping but cropping AND enlarging to original size and the loss happens while enlarging, as they said in the other replies there is a limit in how much you can enlarge.

You don't give us any numbers to work with so I will try an example.

 

You start with, let us say, a 2400 pixel wide image.

 

You zoom to 50% making the image look 1200 pixel wide.

 

Yes, things look sharper when you make them smaller.

 

On that sharp 1200 image you crop out a 400 pixel wide image of the dogs' heads. That shows the same area of the dogs heads as if you cropped an 800 pixel wide image out of the 2400 pixel wide image.

 

The 400 wide pixel crop looks just as sharp as it did on the 1200 pixel wide 50% zoom image.

 

Now, when you go out of 50% zoom mode the 400 pixel cropped image goes back to an 800 pixel wide image, the same width that it occupied on the 2400 pixel wide image.

 

That would be the same sharpness, or lack thereof, as if you cropped the 800 pixel wide image of the dogs' heads directly from the 2400 pixel wide image.

 

When you are zooming in or out you are not making the image larger or smaller you are just making it look larger or smaller while you work on it. When you get out of zoom mode it again appears its actual size.

 

============================================

 

If you were to resize from 2400, or whatever, to 1200 pixels pixels wide. the image would be sharper. If you were then to crop out a 400 pixel wide image of the dogs' heads it would stay as sharp but you would only have a small 400 pixel wide image. If you tried to resize it bigger to 800 pixels wide then the image would again get less sharp.

<p>You can not crop to less than about 1/4 of the photo. If you crop to much less than that you will have a photo that really is only good for printing very small or displaying on-line. If that's all you care about, remember that if you crop to 1/4 of a 1/4 of the image you are going to get a photo about 1,000 pixels across. That's not bad, but I've seen people try to crop to much smaller sizes than that. Sometimes people want to crop to a person's face (or a pet's face) from a photo that shows that person or animal in action with a few others, so really if they cropped to the whole person or animal they would be cropping to a size smaller than 1/4 of the image. Then cropping to just the face is cropping to a much smaller than 1/4 of that crop, so instead of cropping to 1/16 of the image (about 1 megapixel), they are cropping to 1/30 or even 1/50 of the whole image. That's much less than half a megapixel. The resulting image shows blur, because there was movement in the scene, which they didn't realize was happening, and they are trying to display an image at more than 100% size. It's crazy what people think they can do with a photo from a high resolution camera. It's like they think it's magic or something.</p>

<p>Ali baba: you re correct, I think that's the problem. I am trying to crop and enlarge and there results the loss. Oh well, live and learn.<br>

Thank you all for your replies!</p>