That is the answer I am looking for. Even with body able to shoot at higher ISO, you would still need the faster lens under low light. The talk about pumping up iso to 64000 and use f4 and above with good speed is not possible? Again, not possible is referring to achieve clean clear picture.
It is subjective. Noisier images can be cleaned up a bit with the use of softwares.
If you use a D600 at ISO 6400, it can be seen as clean as long as you do not pixel peep. If you view them at 100% resolution on your computer monitor, you might not like the results.
Will it be acceptable to you? Perhaps you can ask someone here to send you a sample shot SOOC in a low light scene to get a first hand or second Hand experience.
Glenn
Caution: Typos may occur randomly.