Thursday, September 23, 2010

F300EXR – Review Part 9 – Depth of Field Explored

Now *this* was interesting … I had promised to devise a test to determine if Fuji added two ND filters for the 3-level aperture in the F300 or if perhaps they had mercy on us and added a real aperture somewhere in there.

So I set up the tripod(s) about 5 feet from my lovely Canon Lens coffee cup (thanks Nick) with a door knob about 6 to 8 feet behind it. This ration of 5:8 in subject / background distance at close quarters will give pretty nice blur at 270mm, even for these small sensors.

As a reference for DOF, I also shot the D700 in this test with the 70-300VR on tripod but from an extra foot back as I was unable to get focus that close (the EXR cams were in macro mode.)

Now … sensor size differences predict a pretty massive difference in depth of field. The crop factor for this 1/2” sensor with this lens is 5.4, which means that f/5.6 should have DOF equivalent to about f/30 on the full frame sensor. (5.4 * 5.6 = 30)

So here is how the D700 shot the scene at f/5.6.


And here is the F300

DSCF0310_f300_5_6[1] Yeah … that’s pretty different :-)

To verify that the F300 has not changed from the F70, here it is

DSCF4847_f70_5_6[1] Same DOF. The entire test was shot at 400ISO in order to get shutter speeds that were comfortable for the F series cams. They max out at 8 seconds.

So, without further ado, I show you the complete set of crops. And yes, you absolutely *must* click through, lest someone think I expect you to judge from the 400px blog version :-)

DOF_test_exr_d700_crops[1] Some observations from this test:

  1. The F300 has a real aperture at f/16!!! DOF increases.
  2. The D700 retains smoother bokeh past the point at which I expected it to match. But it gets close at f/40, which is close enough to the calculations when you consider how approximate the formula is.
  3. There is vignetting wide open on the F70 and F80, this has been known for a year and is confirmed in this test.
  4. There is *no vignetting* wide open on the F300 at 270mm. Well done Fuji!

1 comment:

wayne said...

Very interesting Kim! Thank you for your efforts :)

Wayne N