D3 image size confusion
My first post here, and while this one is confusing to me, I am sure one of you will have a perfectly reasonable answer.
I did a camera reset on my D3 and then did a test shooting at S, A & P modes for both Large - Fine JPG and RAW. In the first test I started at P and let the camera pick the exposure. Then I matched exposure (1/800 @ f/6.3) and captured a shutter priority and an A-priority shot. Also, focal length was 95mm on my Nikon 70-200 f/2.8 VR. All JPG shots came out at around 6.5M and the RAW shots at 12.3M. This is where I would expect them.
Then, I went back and set for A-Priority, which is what I have been shooting with recently and locked in at f/2.8. The 95 mm JPGs are now 5.4M, and more interesting, the full 200mm zoomed shots are at 4.2M. Similarly the RAW images are at 10.6M (95mm) and 9.3M (200mm) respectively.
I would have never thought that if you locked in at f/2.8 and zoomed all the way in that it would change the image size, and that drastically to boot!
4.2M as a starting place is tough for sailing, and swimming (my two key subjects) as there is always (for me) some cropping to level photos to the horizon. I'm thinking that I may need to go with an f/stop north of 4 or 4.5 to level-set. Sort of a bummer for swimming though where f/2.8 is what we need indoors.
- Is there a technical answer for what I am experiencing? On an FX camera (with the DX crop setting off) as you zoom or stop down is the image saved on a smaller portion of the sensor? Or is there simply less to save?
- Also, is the solution when shooting A-priority at full zoom simply to back off the f/stop? Or, am I going to have to shoot RAW all the time. (disclaimer - no intention here to start a RAW / JPEG thread
Look forward to your thoughts before I go back out there this weekend.