I have promised this post on many previous occasions and have finally got round to writing it up - so apologies if you have been waiting for it.
One of the absolute delights on the 7D , aside from an excellent AF system.....that works!, is the mode select dial.
Coming from the 1Dmk3, changing mode was always a two finger, or two handed affair, and not always easy when wearing gloves.
With a mode select dial, you can change modes easily without your eye even leaving the viewfinder if you need to. This particular feature was never one of the factors for me when selecting the 7D, as it was something that you find you work around when you don't have it, but by you don't half notice the ease of operation when you do have it.
For bird photography, I found I need three basic sets of 'settings'.
Bird in flight against a clear sky background, bird in flight against a cluttered background, say against trees or fields in the distance, and then of course static subjects on the ground, or on posts etc.
Well the 7D comes with three instant dial sets of custom settings - how handy is that!!
So here is how I have mine (and Jac's camera as well as we might end up swapping around gear) configured.
C1 - clean background bird in flight
I start with a default exposure of Av mode, ISO400 and f5.6, as my emergency 'hit the button' start point in case of an unexpected opportunity. If I have a bit of time to set up, then these are fine tuned to the light conditions. I also always have RAW, neutral picture style and AWB set, as I can use Capture One to redefine the white balance accurately if needs be.
So for birds in flight, I am looking for a moving subject so AI servo selected for the AF, with the manual zone AF, with the central 9 points selected. This way I can get the subject with no risk of anything else, as the background is clean.
If I need to be more precise, it is a very quick job via the Q button to change to a different AF mode such as point of point plus expansion.
Exposure is defaulted to a start point of +1 f stop of exposure, but again refined based on the light at the time. Drive speed is set to high, which is 8fps on the 7D
C2 static subject e.g bird on a stick
For static subjects, the main differences are exposure and AF settings.
Exposure is set to zero compensation this time, with the AF mode set to One Shot as my subject is now static. AF point selection is now on single point mode.
C3 - cluttered or 'dirty' background
For moving subjects against a dirty or cluttered background, then the settings change again. AF mode is back to AI servo, AF set to point plus expansion. Exposure is set to just +1/3 as the general background will now start to play an effect and needs to be balanced in.
I have found that these settings give me great results, and I can change mode quickly when subjects shots of opportunity come my way. This was something that was totally impossible with the 1Dmk3 could do, without going into a number of levels of sub menu. By which time, your subject is likely to have been the other side of the hill - not good.
As I say, these are my starting points which can be modified to suit the conditions at the time, to suit the light.
Two other tips. When the camera switches itself into sleep mode, the amended settings will revert to how they were set when you switched the camera on, but if you go to the third of the 'spanner' settings, or tools I 'spose, then go to camera user setting and the register, and assign the changes to the relevant mode, but make sure you register to the mode you are shooting in. It doesn't default to the mode you are in.. If you don't do these steps, when you 'wake' the camera back up, you will have to go back through and reset everything again.
Remember to put the C settings back to your own defaults and register the settings, as you will get a shock when you get that target off opportunity and you are trying to shoot it at completely the wrong settings.
Hope these are helpful to you, if you are a 7D user, and if you are still persevering with the 1Dmk3 - then perhaps you can only dream and weep :-)