05-29-2013, 02:37 PM
Hi all,
I read the excellent review on the
Zeiss Sonnar T* 135mm f/1.8 lens
at
http://www.opticallimits.com/sony-alpha-..._za_135_18
There were a couple of things that I wanted to ask, hopeing that perhaps
someone would know the answer. Partial answers are also welcome!
-------
1. "The front element does not rotate thanks to an IF (internal focusing) design."
Sure. But does ANY lens element rotate (inside), or the internal focus translates a
lens in the vertical direction without rotation?
-------
2. "Unfortunately there're no seals against dust and humidity".
What sealing does this refer to?
Sealing at the rim of the front lens along the edge?
Or sealing of the focuser ring (how?).
Or there are "cracks"/discontinuities at various locations on this lens?
-------
3. "In manual focusing mode it operates very smooth but there is a little
play when changing the focus direction - this is typical for non-SSM
Sony lenses."
How big is this backlash? ("play")? Is it consistent between lenses?
--------
4. "the lens shows a little vignetting at f/1.8 (~0.55EV)"
This is at the bottom/top or right/left side, or the corners?
--------
5. Regarding the "screw-driven AF" mechanism on the bottom: I assume that by turning
this around an internal component moves, but the manual focus ring does not turn around.
Could someone try this?
---------
6. Finally, a bonus question. Would manual focusing work by turning the manual focus ring
WITHOUT a camera body attached (i.e. no power); just projecting the light on a piece of
paper?
Best regards,
Sapkas
I read the excellent review on the
Zeiss Sonnar T* 135mm f/1.8 lens
at
http://www.opticallimits.com/sony-alpha-..._za_135_18
There were a couple of things that I wanted to ask, hopeing that perhaps
someone would know the answer. Partial answers are also welcome!
-------
1. "The front element does not rotate thanks to an IF (internal focusing) design."
Sure. But does ANY lens element rotate (inside), or the internal focus translates a
lens in the vertical direction without rotation?
-------
2. "Unfortunately there're no seals against dust and humidity".
What sealing does this refer to?
Sealing at the rim of the front lens along the edge?
Or sealing of the focuser ring (how?).
Or there are "cracks"/discontinuities at various locations on this lens?
-------
3. "In manual focusing mode it operates very smooth but there is a little
play when changing the focus direction - this is typical for non-SSM
Sony lenses."
How big is this backlash? ("play")? Is it consistent between lenses?
--------
4. "the lens shows a little vignetting at f/1.8 (~0.55EV)"
This is at the bottom/top or right/left side, or the corners?
--------
5. Regarding the "screw-driven AF" mechanism on the bottom: I assume that by turning
this around an internal component moves, but the manual focus ring does not turn around.
Could someone try this?
---------
6. Finally, a bonus question. Would manual focusing work by turning the manual focus ring
WITHOUT a camera body attached (i.e. no power); just projecting the light on a piece of
paper?
Best regards,
Sapkas