should I transcode in Premiere?

[Shooter]

It more likely that you read more thread saying...dont transcode for CS6 because there is no need to (assuming your system is up to it)

Why dont you try it.

[AtticusLake]

I think the editing experience is in that one is not processing the footage on the fly while doing the heavy lifting part of the edit.

That makes sense, particularly if you're changing frame rates. But I think there may be cases where setting the sequence up based on the final product doesn't add a lot of heavy effort -- I think changing the frame size / aspect ration would come under that heading. Like most things, I guess it depends exactly what you're doing.

In your case with the pseud anamorphic mask / framing... what happend to the vertical pixels you "cut off"?

Did you re interpret the PAR?

No, I didn't change the PAR because my output movie used square pixels (same as the camera). I just created a sequence at 2.35:1 -- i.e. 1920x816, square pixels -- dropped the footage in, and edited. That way I was able to fine-tune the compositions by adjusting the vertical position of each clip. (If I'd taped the viewfinder during shooting, this probably wouldn't have been necessary.) The excess tops and bottoms were just off the final frame.

[AtticusLake]

I remember reading somewhere that you should transcode AVCHD files before editing to prevent further degradation when editing / adding titles / ect...

Transcoding will ALWAYS introduce degredation -- that's unavoidable. You're taking lossy-compressed footage, uncompressing it, and re-compressing it in a different lossy format (ProRes). A generational loss of some degree is unavoidable. There is certainly absolutely no way that transcoding can improve your picture.

I really don't think that Premiere is going to do anything bad to your footage just because it's AVCHD. Premiere doesn't care what the format is, it just uncompresses it and works with the resulting frames. The format they started as shouldn't matter at all when compositing titles etc.

One thing that comes to mind is that if you import 8-bit footage, a bad NLE might work in 8 bits throughout; whereas if you transcode to 10 bit, the NLE might then do all the compositing in 10 bits, which would produce better results. However, I'm pretty sure that Premiere is smarter than that and always uses more resolution.