p.2 #1 · Sony 50/1.4 aperture stops down automatically at min focus distance like Batis 40mm
DavidBM wrote:
If the iris didn’t change, and the focal length reduced at close distance, it would be faster than f1,4 at close distance if it’s f1.4 at infinity.
I think that is what's happening. The 90mm Macro seems to do it too, and it certainly has focus breathing (as does any IF 1:1 Macro).
It is also a convenient way to use modern electronics and firmware to improve closeup performance where contrast usually is troublesome.
That all being said, I don't think we can safely assume that the [nominal] aperture is actually 1.4 anywhere other than infinity, just like we can't assume that focal length is 50mm at anywhere other than at infinity focus.
p.2 #2 · Sony 50/1.4 aperture stops down automatically at min focus distance like Batis 40mm
Fred Miranda wrote:
Very interesting and I never noticed that!
Do you have Live View Display: Setting Effect set to "On" or "Off"? Try both ways and see if the behavior remains.
Live View is turned on, I will have to figure how to turn this off and report back tonight.
I looked at the B40 pics I posted regarding the aperture automatically closing down, and the B40 aperture looks like it closes down much more than the 50/1.4 (the B40 closes down 2 stops @ MFD according to other reviews I read vs. the 50/1.4 closing down possibly 1 stop at MFD as determined by the camera's light meter and A priority mode testing).
Also, I've only had a few days with the 50/1.4, but the lens is producing some seriously sharp pics and pretty nice bokeh.
p.2 #3 · Sony 50/1.4 aperture stops down automatically at min focus distance like Batis 40mm
The lens is fantastic. However, as others said, this is not an atypical behaviour. I read about quite a few cases were the focal length shortens around mfd (think Nikon 70-200/2.8ii) and the aperture closes slightly.
My two FE50/1.4s show what is described here in manual focus, AF with aperture ring at f1.4 or in A mode. The aperture closes a bit less than when shooting at f1.6 (at infinity), so the light loss is minimal at best and I estimate the effective aperture to be around f1.5 at mfd.
At those distances I don't care at all about this.
Setting effect off doesn't change the behaviour around mfd.
p.2 #4 · Sony 50/1.4 aperture stops down automatically at min focus distance like Batis 40mm
Newtographer504 wrote:
Live View is turned on, I will have to figure how to turn this off and report back tonight.
I looked at the B40 pics I posted regarding the aperture automatically closing down, and the B40 aperture looks like it closes down much more than the 50/1.4 (the B40 closes down 2 stops @ MFD according to other reviews I read vs. the 50/1.4 closing down possibly 1 stop at MFD as determined by the camera's light meter and A priority mode testing).
Also, I've only had a few days with the 50/1.4, but the lens is producing some seriously sharp pics and pretty nice bokeh....Show more →
p.2 #5 · Sony 50/1.4 aperture stops down automatically at min focus distance like Batis 40mm
Newtographer504 wrote:
50/1.4 closing down possibly 1 stop at MFD as determined by the camera's light meter and A priority mode testing).
All lenses lose light (effective aperture decreases) as magnification increases, so seeing some light loss is normal.
I don't think you should see a full stop of light loss at a magnification under 1:2, which this lens can't achieve. So a full stop would be unfortunate, if true.
To test, you need to use a controlled subject, like a full gray card, with a controlled non flickering light source, then check some center points values, and determine the brightness difference between samples at the same exposure.
This would be a good experiment for the legendary Jim Kasson.
