Please...if any passing mite would be kind enough to help.Your assumption is correct, but only if you PRINT the image at the same size. Given that cameras have different densities of pixels, a print at the maximum size for each sensor will probably result in a different physical print size, and thus a different ability to identify the bird in question. Thus, whether you wish to or not, QUALITY of the captured image WILL play a critical role in your pursuit of bird identification
Thinking of moving from superzoom to DSLR.
A question concerning image size, not quality :
imagine three cameras
Superzoom (small sensor, say focal 5,6-112mm) : equivalent full frame 28-560
DSLR with 1,6 crop sensor+lens 70-300 : equivalent full frame 112-480
DSLR full frame+lens 100-400 : full frame 100-400.
Imagine next a small bird
Take the maximum equivalent full frame (EFF) focal length common to all three set-ups : 400
If a picture is now taken with all three cameras set at this EFF 400, and ignoring quality, then I believe that the size of the bird will be identical in all pictures, and all that will change is the area covered by the remainder of the picture, increasing considerably from superzoom, through 1,6 crop to full frame. Is that right ?
Suppose that EFF 400 is insufficient to identify the small bird.Using the digital zoom facilities on a point-n-shoot camera will not give you ANY additional ability to identify a small bird - on the contrary, usage of the digital zoom facility is likely to make this task MORE difficult. As a matter of interest, you can zoom into your captured images, to pixel level if needed, on most DSLR's in the field
With the superzoom, I can use digital zoom say up to 4 times.
Zooming up digitally, using a stabilizer (monopod), and spot-metering, then whatever the conditions, I can usually get enough to identify the bird, see its colours, and take a photo which won't win any prizes...
So far as I understand, I cannot do that in the field with DSLRs, that is they don't have digital zoom.
Therefore how difficult will it be to spot-meter on a small bird without any digital zoom ?
And even if that is achieved, is it "frustrating" in the field to take such a small picture, even if knowing that later on, eg in Lightroom, the image can be cropped and blown up ? (I realise quite subjective).
On equipment : had intended to go with EOS 7D+100-400, until held in a shop. Seemed just too heavy. A problem which I think would be compounded in Kruger, sitting at the wheel of a vehicle, both windows down and pivoting the body clockwise or anti depending on where the interest lies.I cannot comment on the canon range of equipment, but given my understanding of your requirements, especially when it comes to the WEIGHT of the equipment, and without any focus on the quality of the image, I would suggest that you consider looking at the lighter lenses from Nikon and the (recently announced, bottom of the range) D3200 DSLR body. This DSLR is approximately 24MP which will give you incredible cropping ability from a DX-sized sensor. Couple this to the 55-300VR lens (which is a very light, competent lens, but certainly not the fastest or most robust around), it will give you an equivalent zoom ability of approximately 450mm. I suspect that this camera will be better than many people anticipate and will certainly produce better images than (most) point-n-shoot cameras.
Then tried the 100-400 on a less weighty body : EOS 600D (ex Rebel). An improvement (surprisingly to me because the weight reduction was merely 250g ie from 2180g to 1930g excluding batteries I think). Still on the heavy side, maybe tolerably heavy, though I'm a bit skeptical.
Is the canon 70-300 (non-L version : well-reviewed, so far as I could read) a reasonable alternative ? Put on a 600D body, overall weight would reduce down to 1200g.
Pleasant predicament to be in, but if I could benefit from experience, would be most appreciative.
Sorry for lengthy post.
You should note the misconception that a crop-sensor will give you better zoom capabilities with an equivalent lens than on a full-frame camera - IT DOES NOT - it simply captures a central portion of the image available - it does NOT BRING THE IMAGE CLOSER, as a more powerful zoom would do.
You may be better off with more pertinent advice by clearly articulating you needs and wants, to a point of listing preferences of each. That way a better understanding becomes available to those that could provide some advice and guidance based on their own experiences.....