ZM C Sonnar 50mm f1,5 - to optimize for 1,5 or not.

[sepiareverb]

Sounds like a design flaw to me. At the least a PITA.

One can only imagine the universal disdain if a Leica lens performed like this...

 

[mfogiel]

Haha, for one Summilux 50 ASPH you can buy 2 C Sonnars and a Planar too... Leica would have made an internal focus compensating helical and would sell this lens for 5000 USD.

 

[sepiareverb]

Haha, for one Summilux 50 ASPH you can buy 2 C Sonnars...

Oh, time to close focus, let me switch Sonnars.

 

[former member]

You would not need a floating element to correct the focus shift. You would need a variable Shim or RF Cam that is tied to the Aperture mechanism.

What I do not understand: why doesn't the DOF at F2.8 cover the focus shift for a lens optimized for F1.5? The shift on the older Sonnars is easily covered by it. The problem is more at F2.

 

[kxl]

Actually, it does... see me comparison in this old thread

http://www.rangefinderforum.com/forums/showthread.php?t=51742
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What I do not understand: why doesn't the DOF at F2.8 cover the focus shift for a lens optimized for F1.5? The shift on the older Sonnars is easily covered by it. The problem is more at F2.

 

[mfogiel]

@sepiareverb
Just like I put the 35/1.2 Nokton on my ZI when I go out shooting in the evening, or the 35/2 Biogon when i go out during the day, I switch the C Sonnars on the M7 the same way... Yes, I know it is not optimal, but the rendering of this lens has no competition.

 

[sepiareverb]

@sepiareverb
Just like I put the 35/1.2 Nokton on my ZI when I go out shooting in the evening, or the 35/2 Biogon when i go out during the day, I switch the C Sonnars on the M7 the same way... Yes, I know it is not optimal, but the rendering of this lens has no competition.

Fair enough, but I don't use fast lenses wide open only in the evening- and don't shoot whole rolls wide open only. Today, I shot the 50/1.4 pre-ASPH at 1.4, 2.8, 5.6 & 11- all on HP5+ pulled to 50. Depends on the image- and changing to the 'other' 50/1.4 would just drive me nuts (moron here).

 

[fixbones]

How pronounced will the focus shift be at f1.5 if i were to shoot a subject say 2-3 meters away?

for subjects between say 2-15 meters, do i have to refocus everytime i change the aperture to compensate for the focus shifts? (not sure if this question makes sense)

I am asking all these questions because i am based in Australia and will be buying from US. So returning it will be a hassle..........

 

[mfogiel]

The focus shift is quite dramatic between f 1.5 and f2.8, then it slows down, and beyond f5.6 it is no longer detectable, so you have to cope with this somehow, even at middle distances. My advice would be to get t he f 2.8 version, then make the following tests:
shoot wide open a cup of coffee from the closest distance and learn how to compensate the shift trying to focus on the back of the cup, shoot a person from 1.5m and again try to focus on the ear instead than on the eyes, and finally when you shoot a landscape, try to focus on something more distant than your point of interest, or on infinity, and see if the sharpness is acceptable. I tend to use this lens most of the time between f 2.8 and f 4.o, where the rendering is most remarkable for portraits, or at f8.0 for street shots.

 

[Michael Markey]

Like fixbones ,I too was wondering the same thing. Following this thread as a fifty is a consideration but new to this aspect. The practical affect of this focus shift would seem to indicate that you need to refocus every time that you change aperture. Is that correct? I ask because the term could suggest unreliable focus despite adjustments .I don`t think this is what is suggested though ?

Mike

 

[fixbones]

mfogiel: thanks for your help !! Saw ur pics on flickr. U do wonders with the sonnar !!!

Just sold my D700 on ebay for a good price 😉 ...... will be putting in an order for a Zeiss ikon anyday now. Very interested with the sonnar and how it renders B & W but being new to RF and also my only 50mm, i think i'll most likely settle with the 50mm planar.

I am definitely getting the biogon 35mm f2, was hoping if the sonnar is for me, at least i'll have a fast lens for when the sun goes down.

 

[back alley]

one of the few images i made yesterday, i was a bit shakey...focus (looking at the photo) was on the end of the arm rest, left side.

 

[fixbones]

Hi ppl,

Would like to thank all of you for your input.
Just completed an order for a silver ZI and also a silver 50mm f1,5 C Sonnar optimized for 2.8 !!!!

Can't wait to get my hands on them !!