Author Topic: 50d crop mode centering, Smaller format lenses  (Read 3334 times)


  • New to the forum
  • *
  • Posts: 39
  • 550d, 50d, 1N
50d crop mode centering, Smaller format lenses
« on: June 30, 2014, 06:51:12 PM »
Hi all.

Sorry if this has "cropped" up recently and i've missed it, I search the forums every few months about it.

The last thing I've read was Alex talking about a CMOS register.

Basically I really like Crop mode, it was that for 2 second bursts of 12fps on the 550d that made me buy the 50d. I Noticed that the frame was around the same size as a 2/3" broadcast sensor. So I mounted a ENG zoom lens on there, being a wide range fast zoom, 18x at 1.8 constant.

The issue is as we know that the crop isn't centred in the frame, which means at the wide end at decent res I get vignetting, and If I zoom its really nasty as it veers off to the side.

Is there any ideas about on how it could be fixed. Even partially to get some more sensor use without the vignette?

I'm happy to try recompling the raw rec module for the 50d If we can work out if we can address it to centre.

There's clearly something amiss because digital dolly doesn't really work properly either, could be the slower hardware but I assume its to do with the crop.

For other 50d users, as some of you've asked. I'm after a teleconventor and i'll report back if I can get those ENG lenses to work well on 2x and 3x in non crop mode. 

I also assume that fixing this could open up the possibility of using an PL-EF adapter and some PL S16 and 16mm cine glass.


  • New to the forum
  • *
  • Posts: 24
Re: 50d crop mode centering, Smaller format lenses
« Reply #1 on: July 22, 2014, 02:07:56 AM »
I also have a 50d, but I vaguely do remember something about the crop not being in the center by default... I may be wrong but isn't there a electronic "dolly" feature that allows you to move the crop around with ML?


  • Member
  • ***
  • Posts: 102