Semantics of "100% crop"

[xroxer]

Just semantics and not very important but I was wondering the following:

The term 100%crop initially confused the heck out of me. I read some old dpreview threads on it and found that while I understood the definition it still seemed a very poor choice of terminology.

IIUC from previous threads on this topic, 100% crop means that 1 pixel of your display represents 1 pixel of the photo. Why even consider the display which is variable?

Why not just use %crop wherein the % refers to the amount of pixels left from the original photo?

 

[Janoch]

What do you mean 'display is variable'?

A pixel has always been a pixel on any of my monitors??

 

[xroxer]

The display definition and resolution is variable from one display to the next. 100% cropped photos using one display can be totally different than 100% cropped photos using a different display. If my display has the same number of pixels as my camera then 100% crops are just the original photo. Correct? If so this is poor terminology IMO.

 

[Janoch]

The display definition and resolution is variable from one display to the next. 100% cropped photos using one display can be totally different than 100% cropped photos using a different display. If my display has the same number of pixels as my camera then 100% crops are just the original photo. Correct? If so this is poor terminology IMO.

I doubt you have a monitor with that resolution.. or you have a very old camera!

I don't know, what you mean with 'display definition', but if you cut out a 200x200 pixel section of you photo, it will show up as a 200x200 pixel image on every monitor...

The terminology is perfectly fine imho....

 

[xroxer]

Definition = number of pixels

Resolution = pixels per unit area (distance between pixels)

When people ask to see a 100% crop they mean "I want to see it zoomed in". Problem is that if your monitor has a high resolution (4k and 8k coming) then your 100% crop is really not that zoomed in is it.

I guess my problem is that 100%crop does not tell you how much has been cropped unless you know the photo resolution and the original camera used. Or am I missing something?

Makes more sense to me to hear this is a 10%crop (i.e. - there is 90% of the photo missing). It tells me just how zoomed in the photo is compared to the original. There is probably a better way but that is IMO only.

 

[Jestertheclown]

The display definition and resolution is variable from one display to the next. 100% cropped photos using one display can be totally different than 100% cropped photos using a different display. If my display has the same number of pixels as my camera then 100% crops are just the original photo.

The term "100% crop" is grammatically and technically meaningless.

If we assume that 100% of an image is all of it; it can't be anything else, then a 100% crop must be none of it.

Correct? If so this is poor terminology IMO.

It's worse than poor terminology. Much worse.

 

[LynniePad]

Just semantics and not very important but I was wondering the following:

The term 100%crop initially confused the heck out of me. I read some old dpreview threads on it and found that while I understood the definition it still seemed a very poor choice of terminology.

IIUC from previous threads on this topic, 100% crop means that 1 pixel of your display represents 1 pixel of the photo. Why even consider the display which is variable?

Why not just use %crop wherein the % refers to the amount of pixels left from the original photo?

I've always taken a "100% crop" as being a portion of an image taken without any prior reduction in resolution, and this can then be examined in detail to assess resolution or some other feature.

When submitting images to a Photo forum, it's not really convenient to upload a full resolution image, so many contributors submit samples from the centre and edges.

The default image viewer shows the image 1:1 with the available pixels on the display, but dedicated pixel-peepers can expand the image much more than this. The image viewer for Picasa goes to 1500% or thereabouts.

Here's a 100% crop at high magnification, with the pixels showing.


Feather detail as shown by PhotoStudio.

 

[xroxer]

After some more thinking it seems "100%crop" refers to a process and not a specific result. It essentially means "crop" your original photo using the definition of your current monitor.

In other words, if your monitor is 1080p (1080x1920) and your photo is 5472x3648 your crop will be 1080x1920 section out of the full 5472x3648 print.

it is pretty easy to see how the terminology gives you zero information.

 

[LynniePad]

After some more thinking it seems "100%crop" refers to a process and not a specific result. It essentially means "crop" your original photo using the definition of your current monitor.

In other words, if your monitor is 1080p (1080x1920) and your photo is 5472x3648 your crop will be 1080x1920 section out of the full 5472x3648 print. image.

Yes, it's the process, but the crop can be any size.

Cropping the original to exact monitor dimensions would be theoretically the optimum way of displaying a part of the image, but in most cases there's various Windows frames or application borders that take up space.

For special purposes, I sometimes do an extreme crop and then enlarge the the crop before uploading. This can be done by zooming-in and taking a screen shot. Picasa is handy for this.


Small central crop, enlarged. (note pixelation)


Original

 

[Mike_PEAT]

When people ask to see a 100% crop they mean "I want to see it zoomed in". Problem is that if your monitor has a high resolution (4k and 8k coming) then your 100% crop is really not that zoomed in is it.

No. They want to see a crop of the image that's neither zoomed in, or zoomed out. It's at 100%, and you crop or grab a portion of the image.

If I say it's a 200% crop, the cropped portion has been zoomed in 200%, and if I say a 50% crop it's been zoomed out to 50% of the full size of the crop to show more of the image in the crop!

I guess my problem is that 100%crop does not tell you how much has been cropped unless you know the photo resolution and the original camera used. Or am I missing something?

It doesn't matter how much has been cropped, as the cropped portion of the image shows what the poster wants to show. Anything other than 100% is a distortion of the image.

If I post the eye of a bird the fills a 1" square on the screen and say it's a 100% crop, you can imagine how big the rest of the image is. Again saying it's 100% you know it's neither enlarged or reduced in size.

Makes more sense to me to hear this is a 10%crop (i.e. - there is 90% of the photo missing). It tells me just how zoomed in the photo is compared to the original. There is probably a better way but that is IMO only.

What does it matter how much is missing...it could be a picture of one bird or 10 birds, but if you're showing an issue you have with the camera/lens it's important that the crop is at 100% and not enlarged/reduced!

 

[Mike_PEAT]

The display definition and resolution is variable from one display to the next. 100% cropped photos using one display can be totally different than 100% cropped photos using a different display. If my display has the same number of pixels as my camera then 100% crops are just the original photo.

The term "100% crop" is grammatically and technically meaningless.

If we assume that 100% of an image is all of it; it can't be anything else, then a 100% crop must be none of it.

I can have a 200% crop, or a 50% crop...meaning cropped portion of the image has been enlarged/reduced in size vs. the original image. For instance the following is a 40% crop, the cropped portion is reduced in size to 40% of the original size in order to fit on a screen to show the full extent of the damage:

Correct? If so this is poor terminology IMO.

It's worse than poor terminology. Much worse.

It's a misunderstanding of the actual terminology.

 

[Jestertheclown]

When people ask to see a 100% crop they mean "I want to see it zoomed in". Problem is that if your monitor has a high resolution (4k and 8k coming) then your 100% crop is really not that zoomed in is it.

No. They want to see a crop of the image that's neither zoomed in, or zoomed out. It's at 100%, and you crop or grab a portion of the image.

If I say it's a 200% crop, the cropped portion has been zoomed in 200%, and if I say a 50% crop it's been zoomed out to 50% of the full size of the crop to show more of the image in the crop!

I guess my problem is that 100%crop does not tell you how much has been cropped unless you know the photo resolution and the original camera used. Or am I missing something?

It doesn't matter how much has been cropped, as the cropped portion of the image shows what the poster wants to show. Anything other than 100% is a distortion of the image.

If I post the eye of a bird the fills a 1" square on the screen and say it's a 100% crop, you can imagine how big the rest of the image is. Again saying it's 100% you know it's neither enlarged or reduced in size.

Makes more sense to me to hear this is a 10%crop (i.e. - there is 90% of the photo missing). It tells me just how zoomed in the photo is compared to the original. There is probably a better way but that is IMO only.

What does it matter how much is missing...it could be a picture of one bird or 10 birds, but if you're showing an issue you have with the camera/lens it's important that the crop is at 100% and not enlarged/reduced!

That makes sense.




"It's good to be . . . . . . . . . Me!"

 

[Gerry Winterbourne]

Just semantics and not very important but I was wondering the following:

"Just" semantics? Semantics is the study of meaning so as you are concerned about the meaning of the term it is vital, not "just".

The term 100%crop initially confused the heck out of me. I read some old dpreview threads on it and found that while I understood the definition it still seemed a very poor choice of terminology.

All languages including the technical terms (or jargon) of ant specialism develop organically. There's usually a choice between a long, convoluted and precise description (that might help a newcomer) and a punchy word or expression that is quick and easy to use.

"Lens" is Latin for lentil; long before photography people used the word to describe something that is neither edible nor transparent; and later to an assemblage of such things into a device that contains several such things plus a range of mechanisms. That too "seem a very poor choice of terminology" but as soon as everyone learns it it's quick, easy and convenient.

IIUC from previous threads on this topic, 100% crop means that 1 pixel of your display represents 1 pixel of the photo. Why even consider the display which is variable?

You need to be careful about the semantics of variable. I use a two monitor display; the monitors have different pixel sizes but both sizes are fixed, not variable. If I look at a 100% crop image on both monitors they display it at slightly different sizes but they show the same information.

If I want to compare images of the same scene taken with two different cameras with different MP counts, the 100% crop allows me to see differences between them; and, moving on from the 100%:100% view, if I adjust the percentages in proportion to pixel resolution I can compare how well the two cameras display the scene.

This is a very useful thing, not just for my own camera but also other cameras. If I download a 100% crop from you it doesn't matter if my monitor has different sixe pixels than yours. What matters is that I can compare it with a 100% crop from my or someone else's camera: all at the same pixel size - the size of my monitor's pixels.

Why not just use %crop wherein the % refers to the amount of pixels left from the original photo?

Because that is far les useful. It isn't quite useless as a term but while I use 100% crop in its conventional sense quite often I use the equivalent of what you are suggesting about once a year. Better to use a longer description occasionally and the brief one for common usage.

There is another factor to consider too. Whatever the logic of coining the term 100% crop in its present meaning, it does have that meaning and is used and recorded in thousands, perhaps millions, of places. To move to a new term now wouldn't wipe out all those records so we'd simply have two terms instead of one for "image pixel to monitor pixel matching" and two meanings for 100% crop - the present meaning and your new one.

That won't happen; no one would thank you if it did.

--
---
Gerry
___________________________________________
First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne
[email protected]

 

[Mike_PEAT]

Here's a 100% crop at high magnification, with the pixels showing.


Feather detail as shown by PhotoStudio.

If the image has been magnified, it's NOT a 100% crop. It looks like a 1600% crop (just guessing). The 100% refers to whether the image has been enlarged, reduced, or actual size.

For instance the following example is a 40% crop, the image has been reduced in size to 40% of the original so the image fits on the screen:

If I had left the size at 100% it wouldn't fit in this window.

 

[LynniePad]

Here's a 100% crop at high magnification, with the pixels showing.


Feather detail as shown by PhotoStudio.

If the image has been magnified, it's NOT a 100% crop. It looks like a 1600% crop (just guessing). The 100% refers to whether the image has been enlarged, reduced, or actual size.

What you are not considering is that I did not alter the image BEFORE I did the crop, therefore it was a 100% crop. If I choose to display the cropped part of the image at a different enlargement to display the original pixels, that is purely a matter of choice. To add a delicious complication, this representation of the crop actually involves an image with lots of pixels.

Would you have preferred that I display the crop at about 0.15 x 0.20 mm which would have been the original size on the sensor? 1600% was a pretty good guess, BTW

 

[xroxer]

I have to agree with this. After seeing some of the responses here I feel that people don't understand just how dumb a term it is.

If 100% crop means take a full image (100%) and cut a smaller image out of it (crop it) then it is complete nonsense. If you then say to someone "this is a 100%crop" it tells them zero useful information. I don't understand how people can't see that?

If 100% crop means map your monitor 1:1 with the image and crop the exact definition of your monitor out (this is the actual definition IMO) then it is still meaningless as you need to know the monitor definition and the original photo definition to understand anything.

 

[xroxer]

Completely disagree. On this forum and everywhere else when I see a request for a 100%crop it is so people can pixel peep and check sharpness.

Cropping a small portion out of a large picture and then viewing it at full size on your monitor is the same as zooming.

Problem is that 100%crop tells you zero information about the original photo size.

 

[xroxer]

It is a 100% crop according to your definition. In fact any size picture is a 100% crop. See how meaningless it is!!

The term should tell you exactly how big the original photo was compared to the crop. It doesn't.

 

[Leonard Migliore]

After some more thinking it seems "100%crop" refers to a process and not a specific result. It essentially means "crop" your original photo using the definition of your current monitor.

In other words, if your monitor is 1080p (1080x1920) and your photo is 5472x3648 your crop will be 1080x1920 section out of the full 5472x3648 print.

it is pretty easy to see how the terminology gives you zero information.

I believe the term "100% crop" came from Photoshop, where the image magnification is given in terms of pixel magnification (Since Photoshop is a pixel-level editor, there are many situations where you need to blow up the image beyond recognition). If you set magnification to 100%, you get 1 image pixel per monitor pixel, except for Mac Retina displays where you seem to get 1 image pixel on 4 monitor pixels. But back before Retina it was always 1:1.

So if you wanted to show someone all the grisly pixel detail from an image, you set Photoshop to 100% and cropped the image to suit. Presto: 100% crop.

 

[xroxer]

Leonard,

That explanation is EXACTLY the same as what I explained in the post you quoted. You just explained it better