Optical Zoom, Digital Zoom

Leaving a friend's house the other day, he spotted a bald eagle perched in the top of a tree across the street.

Using the Wide/Tele rocker on the Mavica, I ran it out to the full optical zoom. You have to be careful when doing this because the indicator will slide across the W->T scale and pause only briefly at the hash mark that indicates you've run out of optical zoom and the camera is going to start applying "digital zoom", i.e. cropping, to get out to its full claimed 16X zoom range.

The lens on the FD88 is a 4.75-38mm f/2.8-3 zoom which, given the 7.21x crop factor of the tiny 1/3" sensor, has a focal length equivalent to a 34-270mm lens on a full-frame sensor. Also, the Mavica can only shoot in its base ISO of 100, although given how noisy it would be at higher ISOs, that's probably not a problem.

Anyhow, here we are using the maximum optical zoom to try and get a picture of the eagle, at full resolution on the "Fine" setting:

I also had the Nikon D800 with me. It was an overcast day and I'd had the ISO set at 400, and the lens I had on the camera was Nikon's trusty 24-120mm f/4 VR, which is a good lens but 120mm isn't a lot of reach on a full-frame sensor.

Here's what the shot looked like with the D800:

Thing is, the D800's 36MP sensor, which has over 27 times the photosites and nearly fifty times the physical area of the one on the elderly Sony, allows one to crop very aggressively if necessary...