How important is Mirror Lockup and a Cable Release?

I’ve always wondered how much of a difference a tripod, mirror lock-up and a cable release would make to the sharpness of my images. So, I decided to test for myself.

Test Parameters and workflow:

  • Canon 550D with 18-55 IS II Kit lens at 55mm
  • f/8 at ISO 200 and shutter at 1/60s
  • Shot in RAW, processed Neutral, WB: Shade to 16-bit TIFFs in DPP. No sharpening applied. 300dpi.
  • Center cropped to 400% and exported as 8-bit JPEGs.
  • IS stands for Image Stabilization, MLU stands for Mirror Lock-up, and Cable stands for Cable release. Green shows which was used; Red, which was not.
  • Tripod used was a Benro A3570T with a 3-way HD-38 Ball Head

So, how did things turn out?

Click on the Image for larger view:

The biggest surprise is that there’s hardly any difference, even at 400%! Sure, if I go deeper there are some minor differences in sharpness, but nobody scales up images 600% to view or print. This result is the last thing I expected. Is Ken Rockwell right about tripods being redundant for most scenarios?

What about slower shutter speeds? Here’s another test at f/5.6 ISO 100 and shutter speed at 1 second (everything else being the same – focus on white dot on knife – 400%):

Tripod Only:

Cable Release on Tripod:

MLU and Cable Release on Tripod:

Again, there is an advantage to Cable Release and MLU, but it is very slight, at 400%. Nothing that sharpening can’t cure. I don’t see any difference between MLU and just a cable release on tripod, either. The 35mm equivalent of 55mm on the 550d is about 88mm. Maybe the tests need to be conducted on 200mm and above for the differences to be really noticeable. But for anything below 85mm, the test shows MLU is a waste of time.

A lot of purists complain about a dedicated MLU button not being available on their camera – now I know why. You hardly use it, and even if you did, the scenarios where it might make a ‘huge’ difference are few and far between.