Tuesday, May 23, 2017

THE DELIGHTS AND DANGERS OF CROPPING YOUR DIGITAL FILES

Whenever I discover an interesting subject for my fine art portfolio I usually cover it well. Photographing it from multiple angles and using different focal lengths—carving it up into detailed sections. It’s interesting that no matter what I see at the moment when I photograph the actual subject when I revisit my images (months, sometimes years later) I always see another way to create a new—often better—version of the image by simply cropping it differently. And then I kick myself for not doing that crop in camera!  Why? What’s the big deal about simply cropping that image file?  Well, if you ever want to print that image as a wall print, say larger than 11x14”, how many pixels can you afford to loose and still make a stunning print?


As an example here’s the resulting cropped image from one of the “record-shots” of a cool old truck….I photographed 6-years ago…

f5.0 @ 1/1250 sec., ISO 400; Lens @ 200mm

After I reworked the rather boring record shot over in camera raw and with some tone mapping in Photoshop this crop made the image far more compelling. (albeit a bit cliche´.) 

Here’s the original record-shot….


You can see why I passed over this image and concentrated on several other unique images (of the hundreds I took) that did not need cropping.  So, back to file size in our digital world. Unlike in our medium format film days we can’t just willy-nilly crop away half or three quarters of our image area and expect to make a quality wall print. It all depends on what you’re starting with. Since our film has been replaced by a digital sensor it’s not just how many pixels your camera has…it’s the size of the sensor—don’t expect a four/thirds sensor to perform like a full-frame sensor! That’s why just carving-up a small sensor to make it 25 or 30mp’s is currently folly, because when you reduce cell site size you increase noise.

My Pro-DSLR produces a RAW file of, on average, 30MB. When converted to a jpeg the resulting file is 15 to 25 MB.

So, this is how my jpeg evolved from capture thru editing and cropping…
  1. The original CR file was: 26.88MB
  2. The converted CR to Jpeg was: 15.99MB
  3. TheCropped Jpeg was: 9.43MB
  4. The edited Jpeg with tone mapping is: 11.75MB
The cropping I did (not quite half the image area) really reduced my file size. Fortunately, I’m starting with a pretty healthy file size (but I could really use a 50MP sensor!) and my Photoshop edits with the tone mapping increased my final file size to a usable 11.75MB.  So, this post capture crop worked for me—this image looks good at 200% in Photoshop—but it would have been even better if I had moved in closer and created it like my crop!  

’Til next week….

Author:  Jerry W. Venz, PPA Master Photographer, Craftsman
Training site:  http://www.LightAtTheEdge.com
Client site: http://www.TheStorytellersUsa.com

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