Actually increasing the ISO does not lose resolution as an earlier post says, it increases the light sensitivity of the image sensor. This is sometimes necessary in poor/low light situation. What it typically does is add digital noise to your image. Some noise can be dealt with in post processing by software such as Lightroom, or by a plugin such as Noiseware.

I noticed that on first Nikon photo of the post it says it was shot at ISO 1600, already quite high for an entry level camera such as the D5000 or a Canon Rebel.

Later when discussing the EXIF data it says that the exposure bias was set at -0.7 which (if I understand the Nikon terminology correctly) means that the image was purposely being underexposed by 0.7 stops (almost a full stop). Probably not a good idea in low light.

Understanding the relationship of ISO, aperture, and f-stop is important.

The issues are that entry level cameras such as my Canon Rebel XSi coupled with a not very "fast" lens such as Canon EF-S 55-250mm f/4-5.6 will simply not be able to shoot at a shutter speed fast enough to stop the blurring. When you zoom this lens with its variable f-stop to 250mm, you get a maximum aperture of f/5.6.

Let's compare to a lens that can get to f/2.8 at the same zoom level. It is typically very expensive to have a lens that is "fast" across the entire zoom range - such as Canon 24-70 f/2.8 - capable of maintaining f/2.8 throughout the zoom range. This lens sells for $1400 new. A Canon EF 70-200mm f/2.8L IS II sells new for $2500+. These are considered fast because of their maximum f/2.8 aperture capability.

Each full f-stop change doubles or halves the amount of light coming through the lens (e.g., using f/5.6 as the center you would compare as follows: f/4 vs. f/5.6 vs. f/8.

So, if you were shooting at f/2.8 at 1/1000th to freeze the leg motion, to get the same image exposure at f/4 you would have to slow your camera down to 1/500th (possibly getting some blurring), to shoot at f/5.6 (the maximum possible when zoomed with the kit lens), you will have to shoot at 1/250th. So the camera will take 4 times as long to capture the image and it is very likely that the legs will appear blurred. This leaves us with only one out, increase the ISO even more. Doubling the ISO sensitivity is the same as adding an f-stop.

For example exposure-wise, shooting at f/5.6 1/500th ISO 100 is the same as f/4 1/500th ISO 200. Every time you double the ISO, you increase sensitivity by same amount as opening the lens one full stop (e.g., change from f/8 to f/5.6) or doubling the exposure time (e.g., 1/500th vs. 1/250th). To shoot at higher shutter speed, we increase the ISO (in this example if we increase ISO to 400 (vs. original ISO 100) we can now shoot at f/5.6 1/2000 ISO 400 - compared to our original setting f/5.6 1/500th ISO 100 in this example. freezes the legs, adds noise.

Anything above ISO 800 on entry level Canon camera (Rebel XS or XSi) will inject noise into the image and I am not sure what the threshhold is for Nikon cameras but physics are the same in terms of noise and sensor sensitivity. Sometimes we simply have to endure the noise if we are going to get the image at all (because we have to keep cranking up the ISO so the camera can properly expose the image).

Here is a link to a 2007 article on cameraporn.net (ITS NOT PORN) that is a decent explanation of the relationship of the triangle of exposure called ISO, Speed, Aperture http://www.cameraporn.net/2007/12/24/aperture-iso-and-shutter-speed-the-good-kind-of-threesome/

Lastly, here is the camerporn.net link to 60 useful photo web sites (it is helpful to have this in your favorites!) http://www.cameraporn.net/2008/05/12/60-photography-links-you-cant-live-without/

gessman: Thanks for enjoying my pictures. Yes, staying on the move with a camera in hand may become a consuming activity, and stimulating, too. I know what you mean about keeping the viewfinder to your eye. Ha, ha. In fact, I find myself taking pictures without a camera as I stroll or drive around.

As to exposure, I seldom use a grey card. I consult the histogram to make sure enough values appear in the rightmost part of the graph (a little short of pushing up against the right side and blowing out the highlights). I try for a correct exposure in the camera.

Later, during editing with ACR and CS5, I apply simple computer techniques for setting the image grey point and the black and white points. These image settings produce a foundation for color, contrast, brightness, saturation, and overall tonality. I follow a fairly straightforward workflow.

Do you like Gypsies? I took a picture of two in Rome.

gessman: Yes, in my retirement, I've started traveling while paying attention and taking many pictures using several cameras and lenses. This activity I found both satisfying and stimulating.

In my experience, a wide-angle lens opens more photographic opportunities. And one does not have to spend a house payment for a decent one. Meanwhile, I tend to favor a mid-range zoom lens. Again, I use the Sigma 17-70mm f/2.8-4 OS lens nowadays for my walking around lens. On my Canon Rebel T2i, this lens provides an effective FL range of 27 to 112mm. I venture to say this FL range suffices for 95 percent of my photography when just walking around. B&H sells this lens for $469. I took the shot of Florence below with this combo. http://www.bhphotovideo.com/c/product/670047-REG/Sigma_668101_17_70mm_F2_8_4_DC_Macro.htmlquote=gessman]

Wonderful. You've sure been blessed with trips to exotic places and you've taken full advantage of those surroundings. A real pleasure to live vicariously through your eyes and be able to encompass so much of the scene. Thank you. I don't currently have a wide angle but looking at your shots sure makes me want to go out and get one. The stuff I shoot around me here almost demands a long tele 'cause I don't want to see how close I can get to my subject matter. I probably need to broaden my view. Thanks.

So True! I too love a good wide angle shot; it never ceases to amaze me how the mind’s eye can look at a wide angle photo and tune out the fact that the shot is a compressed scene.

I love shooting wide angles close to the ground with a foreground subject expanding into a background subject having sharp front to back focus. I just got my new Nikkor 17-35mm f2.8D last week so I have nothing show worthy yet, I am still learning, but I have seen it done and the results are amazing. I'll post something for your consideration as soon as I get something I especially like.