I take weekly Sunday morning walks with a birding group, truth is I'm a mammal guy. With this being the first walk with the 7100 I decided to take the 70-300mm VR. These shots are right out of the camera with Whitebalance adjusted to Cloudy from Auto WB-1 Picture control set to Landscape. These were the only adjustments made to the image. This is a shot of a Snowshoe Hare running flat out.
75mm ISO 400, 1/1600 f/4.5
Here is the same shot @ 100% crop of the image.
The light conditions were brutal with threatening snow and heavy overcast skies. I thought that folks might be interested in an example
Thu 04-Apr-13 12:06 AM | edited Thu 04-Apr-13 12:08 AM by larrycurrlymoe
I can see what you mean. These shots were taken with the camera in 1.3 Crop mode. Which would turn the 75mm into about 150mm shot (35 mm equivalent) as is shown in the EXIF data. i thought the quality of images shot in this mode might be of interest to folks. Unfortunately I was unable to switch back to straight DX format during the series, I was busy I am impressed that the "doubling" effect of cropping on a cropped sensor turned out this well in poor lighting, and colouring conditions. Turbo
I use the x1.3 crop for more distant wildlife and find it useful. However, unlike the D800 and other cameras, the non cropped area does not get grayed out and a lined box is visible instead. This caught me out a few times when I forgot that I was on crop mode and then found the subject was outside the area! Oops
<<I really like the 1/3 crop and the grey out area does not bother me.>>
I've got used to it now, just a small learning curve.
<<Because only part of the Sensor is used, is the High ISO capability reduced?>>
I have not witnessed any difference on ISO capabilities, but haven't really pushed the boundaries on that as light here the last 3 weeks has been excellent allowing high shutter speed at between ISO100 and 400.
I just purchased a D7100 as an addition to my D800 for the times when I am using a telephoto to catch closeups of smaller objects, i.e., not for landscapes. I reasoned that the D7100 is giving me 24 MP while, in comparison, the D800 in DX mode is giving me 15 MP. However, I see no value to the 1.3X crop mode of the D7100 except to have smaller files. The fact is that 1.3x crop mode simply crops the DX sensor before taking the photo as opposed to cropping a DX image in post-processing with an editor. Again, other than saving space on your memory card by 'pre-cropping', it buys you nothing.
Other than facilitating more rapid shooting (quite useful for sports, wildlife, etc), you're exactly right: The 1.3 crop mode is nothing more than an optical zoom. It doesn't really increase the "reach" of lenses. It just cuts down on the amount of sensor real estate being used. You can get the exact same result by cropping full images in post.
BUT...there is still real value in increased frame rates and longer bursts before filling the buffer, not to mention the value of having smaller files to transfer/manipulate in post, so I think it does have some advantages.
<<It doesn't really increase the "reach" of lenses>>
Of course it doesn't, but on the D800 where the DX border is in a greyed box it's a great tool for learning to keep a bird in flight within a smaller area, also to concentrate on the subject, not the surroundings.