I've been trying to research full frame sensors vs crop frame sensors, the so called "crop factor / magnification factor," resolution, cropping. The problem I'm having is that I am running into conflicting information and opinions...
To summarize what I want to know: For photography where having good reach is important (wildlife photography), what is really the difference between having a 1.6 crop factor sensor vs having a full frame sensor and cropping the photo in post processing? While I am aware that generally a full frame sensor will have better image quality / lower noise, I think a huge factor that needs to be considered is actually resolution / number / size of pixels, and what it really looks like when cropped.
I've read, the crop factor is really just basically showing a cropped portion of what would be captured on a full frame sensor, so you are not really getting the magnification that you think you are, you are instead getting a pre-cropped image. In these next statements, I'm not claiming that I am correct or that what I am saying is accurate, I am only stating what seems logical to me... The thing about that which doesn't make sense to me is that, you have a large amount of pixels packed into that smaller area, so it really is not like a crop of a full frame sensor because you have the higher resolution within that area. And so when they say a full frame sensor could be cropped to get the same image quality or better as a crop frame sensor, it would seem to me that you'd need the equivalent resolution of pixels for that cropped area. It doesn't seem to me that most full frame sensors have enough resolution/pixels to allow a cropped image of the same resolution that you would get with a crop sensor. To come down to a specific example, though not to limit the discussion, imagine I am comparing my Canon 7D 1.6 crop to a full frame 5d Mark III. I just can't imagine being able to crop a full frame image from the 5D down to what I'd get with the 7D and have the cropped image have enough resolution to equal out.
Additionally, I've read that the larger pixels in a full frame sensor don't carry as much fine detail when you crop down, so the cropping of a full frame sensor would not have the same apparent resolution as a crop sensor image of the same apparent magnification.
Once again, this is all just what I've read and my own thoughts on what it seems to indicate, but I don't claim to know if it's accurate, so I'm asking this question to get input from people with experience and better information then me. I really want top image quality, but I also need as much reach / as little cropping as possible, or at least for a cropped image to have high enough resolution and quality. Thanks for any input or help!