Lossless vs lossy raw format for big zooms

[Borad]

I have a nice view from a fairly tall building so I like to zoom then digitally enlarge to see what I can see. I know I want my next camera to save in raw format, but how significant is the difference between lossless and lossy? I read that the raw on some cameras is lossy and they don't tell you and I'm not sure how worried I should be about that.

 

[480sparky]

In terms of magnifying the image to see more detail...you won't see any difference.

 

[D-B-J]

I did a small test on my D800 today between the 14bit lossless compressed and uncompressed files. Underexposed and over exposed by about 3 stops, adjusted in Lightroom back to proper exposure. The verdict? I couldn't see one ounce of difference in the files...

 

[Borad]

I would expect that verdict, though you're probably able to snap uncompressed photos faster because there's less processing time needed. But there would be some quality difference between lossy and lossless.

 

[480sparky]

There's a similar discussion here.

 

[480sparky]

I don't see any more detail in one than the other.

 

[Borad]

I don't see any more detail in one than the other.

I deleted what you're referring to due to the images being labeled incorrectly, but here's the correct image:

As I said in the deleted post, I think I lossless or uncompressed is best for some of the extreme zooming I do. When you're trying to see faces through an airplane window or read signs 10 miles away you need all the help you can get.

If you look at the dark bottom of the vertical gold thing, there's a slight difference. Also, the bottom half of the shadow above the vertical gold thing contains more pronounced lines, and a different number of them in the compressed photo.

 

[480sparky]

If I can't tell the difference between the two, in terms of any more detail in one than the other, the labels become a moot point.

Different? Yes. More detail? No.

If there really was 'more detail', then I'd be able to readily identify the 'gold thing'.

 

[Borad]

"More accurately reproduced" may be a better thing to shoot for than "more detailed." This test should be done with something that has numbers or letters so we can really tell if they look right. But any clearly noticeable difference between lossless and lossy is enough to get me to choose lossless.

 

[480sparky]

Then quantify the differences toward a meaningful result. Yes, they're different, there's no doubt.

But do the differences mean anything usable?

 

[Derrel]

Then quantify the differences toward a meaningful result. Yes, they're different, there's no doubt.

But do the differences mean anything usable?

Let me offer an analogy. The uncompressed shot above, it looks as if there are 10,001 angels dancing on the head of a pin; in the compressed shot above, it looks like just 10,000 angels dancing on the head of an identical pin. In other words, the degree of "difference" one is imagining in this example is the subject of very heated and fanciful debate only among the believers in angels that can dance on pin heads. The rest of us see NOTHING meaningful, at all, in any way.

 

[bratkinson]

In the Canon world, RAW format images can be saved as "Large" or "Medium" or "Small". I always choose "Large" to get the most detail possible. But, with the camera mounted on a tripod and taking 3 identical shots, one at each setting, would there be an easily noticeable difference when viewed as an entire picture? Probably not.

But when enlarging those images, that's where the difference would show up...'edges' of items. Think of a diagonal object, such as a yard rake leaning against a wall. Now visualize that as a staircase when viewed from the side. With "large" RAW (or JPG files, for that matter), the 'steps' on the staircase would be quite small, and the differences between light areas (the wall behind the rake) and the rake handle would be quite discrete. In the "small" format, what was 4 adjacent 'boxes' (pixels) of one light color value each in the 'large' is 'averaged' by the computer in the camera to be one single value in a single box the size of one of the 4 original boxes. In short, some detail is lost. In all likelihood, unless one blows up the picture to 'poster size', the differences won't be terribly discernible.

Consider this, my first digital camera was 3mp Canon G3 point-and-shoot. The pictures, even when projected on an 8'x8' screen were quite acceptable. Are the pictures from my current 22+mp 5Diii clearly more sharp on the same screen? Not to the average viewer. In my estimation, the resolving 'power' of the sensor, lens, and even the noise level have more of an affect on image quality than original image size. Even reduced quality pictures posted on this forum are more than acceptably sharp.

In reference to the tall building referred to by the OP, unless the shot has a large DOF -AND- shot from roughly half-way up the building, DOF issues and non-parallel-sensor-to-the-building issues will result in more loss of IQ than how many megabytes the image is compressed to.

 

[Borad]

OK, I don't even care about raw any more because none of my software seems to properly support raw files. I even downloaded an extension for Irfanview that supposedly supports it but I think it's buggy. I wanted to save the image below in lossy raw and see if it's still legible, but I can't make it happen. I'll settle for whatever format my next camera will have.

 

[480sparky]

Your camera didn't come with software that can read the raw files it creates?

 

[Borad]

I created the file with Microsoft Paint and Irfanview by pasting in a snapshot from a website and editing it. My camera is my Nokia Lumia 520 cell phone which doesn't support raw files.