Originally posted by dgaies I think he meant you don't need the "razor thin" DOF that FF bodies are capable of for landscape work. I don't think that was meant to imply you can't get large DOF with FF.
Thank you! That is what I meant to say.
Neither landscape nor macro work benefit from the thinner DoF of 135mm. Even sports work is better served with more DoF. Commercial photographers and studio photographers usually have complete control over lighting and background so blurring the background is not as important. Even environmental portraits need a good bit of DoF. If you blur out the environment its not really an environmental portrait.
Outside of the high paying field of fine art photography there is not much use for really thin DoF. APS-C and fast glass is more than capable of creating the DoF desired for wedding and portrait work, and if you are not willing to spend the money of fast glass then you wouldn't be buying a 135mm system anyway.
The reason people in these fields chose 135mm is because traditionally APS-C has not been able to offer the SUFFICIENT dynamic range or the high ISO range of 135mm bodies, but that is changing and SUFFICIENT is the key word. There is a point of diminishing returns for high ISO and DR. I know there is someone out there who NEEDs 256,000,000 ISO so he can lock himself in a dark closet and take pictures of his pecker all day, but I hope he is in the minority.