« on: January 16, 2014, 12:07:18 AM »
Daniel, I'm no expert to believe! One thing for sure though is that the 1.4X and 2X if they help you to fill your frame, are better than cropping. I've proven that with my 300 2.8 II and converters III.A lot of argument over the relative value of teleconverters and crop/ff depends a lot on the lens.
I believe what some like me are hoping for is more reach while still being able to keep the portability of the 300 plus converters, and for AF improvement. While I might be able to scrimp and afford a 600, I would be seriously challenged to take it where I would most want it. Thus, I want to try out the elusive 7DII.
If you're thinking wide, go full frame for sure.
If you use a teleconverter on a soft lens, you can decrease the resolving power. If you use it on a sharp lens you will increase the resolving power.
Likewise, a soft lens on a FF camera may out-resolve (or at least be close to) that same soft lens on a crop camera, yet with a sharp lens it may be the other way around...
In other words, if you are going long, the lens quality is more important than FF or Crop.
And Jack is definitely right about going wide.... FF all the way! The wider the angle of the lens, the harder it is to design without distortion and the harder it is to make it sharp. If you wanted the same angle of view on a crop camera as 24mm on a FF camera, you would need a 15mm lens. With the same level of design and materials you can not make a 15mm lens as well as a 24mm lens, so just on the glass, FF wins in IQ.....plus there is all the usual stuff about less noise, higher ISO, etc etc...
This is very true: certain lenses are known to disagree with teleconverters - the 100-400L is a good example of that, for multiple reasons. The teleconverter quality also matters - a cheap teleconverter can be worse than cropping a photo. I have an $80ish TC that actually degrades the quality of my 100-400 - a total waste of money.
I have a Canon 1.4 mkii teleconvertor. Just as a cautionary tale... mind telling people which brand the $80 TC is?