Subject image quality vs. background image quality?

[Ronald Zigler]

I believe the subject image quality of this picture represents one of my better efforts. It was taken from maybe 20 feet away and with perhaps a 50% crop (is that too severe?). I did some editing on the background to make it a little less distracting. I would like to get a better idea of how and when to adjust an image background if the subject is reasonably sharp. Indeed, is this "acceptably sharp" image quality? Is the background just too distracting? Or, is this simply a matter of personal taste? Could I have done anything different? (I have a hunch I will get a variety of opinions; but I am after all "eager to learn"). Canon 60D, 300mm f4 + 1.4x, @ 1/1000, f8, ISO 640; a tripod was used.

[SteveYoung]

First of all, great job getting the shot! The bg does seem a bit busy to me. Sometimes it helps to smooth things out with a gaussian blur filter, assuming you're using photoshop. I did a quick job here:



Also a bit of sharpening and contrast while I had PS open.

[Ronald Zigler]

Thanks Steve. I'm using photoshop elements, but still need to learn more about how to use it for these kinds of things.

[gary ellwein]

Ronald, Steve's efforts have added more pop to the subject and subdued the bg. My eye is drawn to the large white patch at the bottom of the image. IMHO most or all of it could be cropped without making things too tight.


Gary

[WIlliam Maroldo]

Basically all I am concerned with is getting the exposure, focus and DOF of the subject correct, the rest can be dealt with later in post if needed. One thing you rarely want is the background to be as sharp as the subject, and the use of shallow depth of field is often very useful (advantage of fast lenses). Nonetheless getting the subject's DOF correct is most important.
Learning how to select the subject in the image editor (using masking tools for example) is necessary, and allows the background to be adjusted independantly, usually either by gaussain blurs or aggressive noise reduction to reduce the distracting aspect of a busy background.
The degree of cropping is very easy to underestimate, and the degredation of image quality by what seems to be moderate cropping can be substantial. Percentage that at image is cropped is a bit misleading, and open to confusion and doesn't consider the sensor size (MP). What I find most useful is the size of the cropped image, in megapixels. If you use ACR (assuming you shoot RAW) the MP size, before and after cropping, is shown at the bottom center. Even though you may only require a 250kb image for the web, once you crop even a tack sharp image below 5-6 MP, I find that image degredation becomes noticeable. At 3 MP the image degredation is severe.
I would be interested in how many MP your titmouse image is after cropping. It is pretty sharp, but could be better. It could be due to cropping, or exposure, or something else.
Underexposure can also effect image sharpness a great deal. Less light=less digital information which means less detail. Lightening the image in post does not restore detail.
Digital sensors like alot of light to capture detail efficiently. To me digital photography is a 2 part process; at capture to maximize the data recording capability of the sensor, and post processing to correct exposure. I would suggest strongly studying what is called "exposing to the right" which is how to maximize sensor data capture.
regards~Bill

[Ronald Zigler]

William, the original image is a RAW file. I adjusted the sharpness and cropped the image before converting it to a jpeg. As a jpeg the image dimensions are 2089 X 2879. I may have tweaked the sharpness one more time after the file was converted. I was concerned that I should not over sharpen the image. Yes, I have heard of "exposing to the right". I understand the basic principle behind capturing a subject in good lighting and maximizing the pixels the sensor can read. Thanks for taking the time for the advice and feedback. I am attaching an copy of the full frame image (in a reduced size).

[WIlliam Maroldo]

Hi Ronald, thanks for posting the full frame image. I was able to copy your original image and superimpose it on the full size image to determine the percentage of cropping. It was almost exactly a 66% crop, or only 1/3 of the image remained. With the 18MB Canon 60D sensor you ended up with a 6MP image, which I consider the point that image degredation from cropping can become a problem. But I think that the image is underexposed a bit and that contributed to a less than perfect sharpness IMHO, and 6MP could have been OK. I guess the bottom line is degree of cropping is difficult to determine without running the numbers and cropping itself has limited use as a substitute for getting closer to the subject and/or using a greater focal length lens. Hope I've been helpful. ~Bill

[John Chardine]

I think this image is pretty darn good and I like the repost by Steve, which shows that the image could take some more sharpening without falling apart. Agree with some brightening need of the subject too. Another factor to consider re. IQ is that with the pretty heavy crop you are also zooming in on an image made with the 300 and tc attached. Although a great combo, it will not perform as well as the bare lens at a closer camera-subject distance (so that the size of the subject on the sensor is about the same as with a tc).

[Michael Gerald-Yamasaki]

Ronald,

Greetings. Been working on just this situation... I think your setup would allow f/5.6? Split the 1 stop difference between faster ss and exposure for gain in sharpness (faster ss) and bg blur (open aperture).

I disagree with the estimates of the impact of the crop (since this went from landscape to portrait aspect).... Looking at the crop vs the full image... I would call this a 25% crop from the top.
Chopping the sides off doesn't effect IQ.

That said, the IQ looks good to me with another notch up in sharpening. The only surefire cure for a cluttered background is not having one .

--> just did a calculation on crop. This is actually only an 18% crop from the top - 2879/3456. BTW, my Nikon D3 would produce an image 2832 pixels tall cropping from the sides to transform a landscape to portrait aspect ratio (which has no impact on IQ).

Cheers,

-Michael-