A question about crop

brokenlynx

brokenlynx

Suspended / Banned
Messages
36
Edit My Images
Yes
What is 100% crop?

As I understand it isn't this where the image is cropped with no enlargement applied afterward?

I've read a few explanations of this and I'm left slightly confused by the concept as it seems to be explained in terms of the magnification that the crop is applied at. Yet surely magnification of the original image doesn't matter as applying a crop at 100% is surely the same as applying half of that crop at 200%? terminology seems a bit weird.

Can anyone help clear this up? Thanks.
 
In simple terms: A 100% crop is a crop of any portion of the image taken at actual image size (1:1 or at 100% zoom).
For ex: Open your picture in any image editing software. View the picture at '1:1' (or '100% zoom' or 'Actual Pixels'). Select the rectangular marquee tool. Now, if you want a 400 x 300 pixel cropped-sample of the image, fix the dimensions of the marquee selector. Place this marquee on the image. Crop out the rest (eg: by doing inverse of the selection and deleting that portion of the image). The resulting cropped image you get is 100% crop of the original image.

For online postings, this is typically done to look into the details and analyse sharpness / contrast / noise / blur etc (as this will be simpler when posting a sample online, rather than posting the whole image and asking experts / critics to zoom at 100% and review the same. Many online restrictions do not allow large files to be uploaded)

Hope this helps
 
brokenlynx said:
Yet surely magnification of the original image doesn't matter as applying a crop at 100% is surely the same as applying half of that crop at 200%? terminology seems a bit weird.
Click to expand...
Well, I guess I did not exactly address your specific point.
Think of it more like: If I want a 400x300 pixel crop as a sample, then I will have to crop 400x300 at 100% zoom. If you rather want to zoom to 200% and apply "Half of this crop", you cannot do it in terms of Pixels...you will have to apply the crop in terms of size (in cm or inches), but finally view the cropped image at 100% pixel size.
I hope I did not confuse you further :cuckoo:
 
Yep I understand this, basically its a crop taken without enlarging what was cropped into the space that was cut out (just leaving an image the size of the crop).

Makes sense for the purposes described above but still a term that could maybe be better phrased. Thanks.
 
Last edited:
It was 36x24mm film, that became standard. Then first digital camera appears, it was expensive to make sensor of that size. So usually first DSLR came with cropped sensor. Usually 1.6x that mean two things:
1. sensor is physically smaller in case of 1.6 it will be about 22.5x15
2. if all those megapixel fitted into that 22.5x15 then resulting image will be cropped that is same as "zoomed".

I guess it will be 160% crop according to that terminology. Or it can be 62.5% of original size.

As you already know most annoing fact with crop that you can't use middle range zoom lenses as you used on your film camera. Example: most popular zoom L lens is 24-70 or maybe 24-105. This range was proven by years of photographer experience and technology used to create them. In the moment then first DSLR appear standard zooms was starting at 28 not 24, like 28-70. This lens works for you in reportage, you shoot someone on the street, then enter builing and can snap wide anough angle indoor. But if you using DSLR to get 28mm you ll need 28/1.6=17mm, you original 28-70 become somewhat portrait range 49-112 and you need to carry additional wide angle lens. That is why kit lenses of "croped" dslrs are 18-55, that is eqivalent of something 29-88 then mounted on them.

Crop good for wild life telephoto lens, it works as free extender for you )
 
You must log in or register to reply here.
Back
Top