Explanation please.

There is frequent talk on here of cropping, which I understand and do on most of my images. Sometimes, however, there is mention of a 100% crop, what does this mean? To my mind if you do a 100% crop you end up with nothing!! I think I must be missing something, as I do frequently, am I::

Also is there a rule of thumb as to how much one should crop? Or is it personal preference? I have found that too heavy a crop produces a noisy image as in going from this

[IMG]http://i83.photobucket.com/albums/j311/Tinywales/birdsandbutterflies/goldfinch_uncropped.jpg[/IMG]

to this
[IMG]http://i83.photobucket.com/albums/j311/Tinywales/birdsandbutterflies/goldfinch_amongst_the_leaves.jpg[/IMG]

Sorry for the long post and thanks in advance for any help.

Howard

This explains it quite well.
http://www.pbase.com/wlhuber/100_crop_

A "100% crop" means that you are displaying a portion of the photo at 1:1 size on your computer screen (i.e. each pixel that comprises the photo is displayed on a single pixel on the computer screen).

So a K10D photo is 3872x2592 pixels (10 megapixels). You'd need a computer screen with a 3872x2592 resolution to display the whole thing at 1:1. That's about the same as four 1080p HD TVs.

This will depend on what you're going to do with the image after you've cropped it (just viewing on screen/web, or printing too?) and how good the image is in the first place. Your example looks underexposed, so boosting the brightness afterwards increases the noise.

This is a 100% crop from a K10D with DA*300mm.




Dan

How much to crop comes down to personal preference and the quality of the image. Some images will tolerate cropping more than others.

100% crops or views are usually used for examination or testing purposes. As we see from the example above (from you Howard), it often reveals the flaws in the lens and camera to an unflattering degree. Still it can be interesting to see the detail, but really you need a longer or better lens to get a better shot in cases like this.

Dan's example above is exceptional. So good I can hardly believe it is 100%.

I promise!

Taken from this thread.
Dan

...Great advert for the lens and your photography.

A bit off your posted topic Howard, but your image is a bit noisy, and would benefit from a little cleaning up, have you tried "Neat Image" ?
the software is available free but with a few restrictions unless you take the option to purchase. It works great even in the freebie mode.

link

It's also a great advert for a seriously underrated CCD sensor. I've no particular axe to grind here as I don't own a K10 or K200 but I'm constantly amazed by the images the sensor produces.

Super study, Dan.

Regards,

Andrew

Thanks for the link, it's made it much clearer.

I've been put to shame by Dan's goldfinch. What a wonderful image, as you say iceblinker a great testament to the lens and to Dan's photography.

I was aware that the crop was noisy, but is the original noisy as well? I'll give "Neat Image" a try. Another one for the armoury.

Cheers,

Howard

I would work on the original first, the software does a reasonable job even if left to its own selections, it really is amazing, I put everything shot above 400ISO through it before doing any other editing, it doesnt do RAW files though.

It does as a photoshop plug-in

Although I really liked Neat-Image and it was my program of choice but the new Topaz Denoise also works very good and I like it better but it's quite a bit slower.

That depends on how ancient your verion of photoshop is Stefan

Ah yes but you can't blame Neatimage for that.