Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
next PZ lens test report: Sigma AF 150mm f/2.8 EX HSM DG APO macro OS (EOS)
[quote name='Brightcolours' timestamp='1313083375' post='10636']

Nice little "review", One niggle:

"It is also probably slightly more effective a lens to use for portraits, due to it’s combination of shorter focal length, and larger aperture resulting in less blurred shots."

It is not due to the combination of shorter focal length AND larger aperture... the larger aperture counters the shorter focal length instead. So... only the shorter focal length can be attributed for what you have found, not in combination with the larger aperture.

However, your (nice) article lacks images showing this difference, are you really sure it is there?

125 / f2.5 = 50mm aperture

100 / f2 = 50mm aperture

This suggests that the blurring of the background, for both lenses being used wide open, and with similar framing, would have an equal amount of blurring, as both apertures have the same size. So... any differences could then only be in the quality of the blur, the smoothness of it (bokeh) or the slightly wider field of view from the Zeiss making the background possibly a tiny bit more "busy".


I think you've got the wrong end of the stick here...

Typically a longer focal length requires a faster shutter speed for less blurred shots. When I say blurred I'm not talking about background blur, I'm talking about reducing the effect of camera shake.

I'm this regard the Zeiss seems to win on both fronts having both a larger aperture, and a shorter focal length. Obviously the difference is small in both aspects, but it is there.

Regarding background blur, the optical design (shape of glass elements etc) of these two lenses is undoubtedly more important than their focal length/max aperture ratio, but with my calculations I did back in the day, the 125mm focal length trumps the f2.0 aperture... They are so close in the aspect though I considered it not worth mentioning.

Cross sections of the lens designs would perhaps of been a more interesting feature to add to the review.

Messages In This Thread
next PZ lens test report: Sigma AF 150mm f/2.8 EX HSM DG APO macro OS (EOS) - by Guest - 08-12-2011, 12:24 AM

Forum Jump:

Users browsing this thread:
1 Guest(s)