vb_vmb
Member
hi, i am curious to know about focus shift, pl , i will like to know before buy it, pl explain a little about it
Ziess vs Nokton
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Roger Hicks
Veteran
Try http://www.rogerandfrances.com/subscription/ps firstlook sonnar 50.html about a quarter of the way down.
Cheers,
R.
Keith
The best camera is one that still works!
My lens has been optimized for f 1.5 where the lens back focuses slightly ... I compensate by either focusing then applying a very slight focus rotation to allow for this ... or I lean forward a little as I take the shot. It sounds bizzare I know and at f2.8 it goes slightly the other way so you definitely have to think when you first start using this lens. I'll generally shoot it wide open wherever I can because that's where it shines IMO and this action of countering the slight back focus has become natural to me and looking at my last few rolls of film with this lens I seem to have it under control.
I have to admit I wasn't sure about it initially though and several rolls passed through the Ikon before I started to feel comfortable in my focusing routine and confident of the results.
The lens is simply stunning ... no other 50mm I've used comes close in character except possibly my 1.2 Canon. The Canon has technical issues though that place it a fair way behind the Sonnar especially regarding flare and it suffers from softness towards the edges at wide apertures.
I've never tried a Summilux but I supect that having experienced the Sonnar the Summilux would be the only other 50mm lens I could be happy with.
As an aside I was reading that article from the link posted above on the Zeiss site and noted that the equipment that Cosina use to to test the Zeiss lenses was built and provided by Zeiss ... I can't help wondering if Cosina have the rights to use this gear for testing purposes on their own lenses?
DNG
Film Friendly
I have one that was the original intent, and optimized for f/2.8...
Now, I must confess, I have only used it on my G1 u4/3 camera between 1m-2.5.. between f/1.5 and f/2.8... But, since I focus TTL, the shift between 1m-2.5m is moot....
The focus shift will be seen at those short distances. After 2.5m, (What made the lens design famous + the f/1.5) the shift is basically moot because of the increased DOF of being further back from your subject.
I have used the Sonnar on my M5, but at longer distances with no visible shift in the image.
If you must have super sharp close focus images between f/1.5-f/2.8, The Sonnar is not the lens for you.... An Optimized f/1.5 Sonnar has focus shift below f/2.8, as Keith explained above.
The f/2 Planar is the lens for you. It is a more modern design, and offers sharpness at all f/stops. Or the Voigtlander f/1.5 Nokton in LTM at a slightly less cost than the Planar.
OR, as others had said, You get two lenses in one with the Original Sonnar Optimized for f/2.8. A classic Sonnar look at f/1.5 to f/2.8 at the closest focus, and a very sharp Sonnar from f/2.8 on (on a Film Camera)
Now, I must confess, I have only used it on my G1 u4/3 camera between 1m-2.5.. between f/1.5 and f/2.8... But, since I focus TTL, the shift between 1m-2.5m is moot....
The focus shift will be seen at those short distances. After 2.5m, (What made the lens design famous + the f/1.5) the shift is basically moot because of the increased DOF of being further back from your subject.
I have used the Sonnar on my M5, but at longer distances with no visible shift in the image.
If you must have super sharp close focus images between f/1.5-f/2.8, The Sonnar is not the lens for you.... An Optimized f/1.5 Sonnar has focus shift below f/2.8, as Keith explained above.
The f/2 Planar is the lens for you. It is a more modern design, and offers sharpness at all f/stops. Or the Voigtlander f/1.5 Nokton in LTM at a slightly less cost than the Planar.
OR, as others had said, You get two lenses in one with the Original Sonnar Optimized for f/2.8. A classic Sonnar look at f/1.5 to f/2.8 at the closest focus, and a very sharp Sonnar from f/2.8 on (on a Film Camera)
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Roger Hicks
Veteran
Surely if it's optimized at f/1.5, it's sharp at the focused point at f/1.5 -- as witness the series of pictures in http://www.rogerandfrances.com/subscription/ps firstlook sonnar 50.html. After that, as you stop down, the focus shift means that d-o-f increases behind the focused point, but not in front of it, as the point of sharpest focus moves backwards. In other words, you lean backwards by three or four inches for normal d-o-f at f/2,8, where the effect is arguably greatest.
Then again, how often is the lens going to be used at its closest focus distance at f/2,8? 'Cos that's the only time it's likely to matter much.
Cheers,
R.
Then again, how often is the lens going to be used at its closest focus distance at f/2,8? 'Cos that's the only time it's likely to matter much.
Cheers,
R.
DNG
Film Friendly
Agreed Roger
It only maters if you love tight head shots at f/1.5 on the original lens design. That's too close, unless you like looking at a sharp nose and OOF eyes. But, then you should be using a 75mm instead IMO for a tight head shot at least, maybe a 90mm
DNG
Film Friendly
Didn't think of that... No Live View?...Than that is valid point. But, a head shot from 1m Really?. I use 2m personally, and crop a little if needed, but @ 2m, that is more of a tight head/shoulder shot, and the DOF at 2m & f/1.5 will take of the slight front focus of 1.5", and render the eyes sharp.
kshapero
South Florida Man
i do, too. They all have their unique signature. If money is tight you will not embarrass yourself with Voigtlander lenses.
goo0h
Well-known
How far would you have to go for it to no longer be an issue?
DNG
Film Friendly
About 2m at f/1.5, then the DOF is about 5" deep
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Keith
The best camera is one that still works!
An example of the Sonnar optimized for f1.5 at probably close to it's minimum focusing distance wide open ... it probably could have been sharper over all but shutter speed was quite slow.
Mister E
Well-known
Keith, that shot is super sharp, where it's focused, what looks like about 1-2" in front of the subjects face. You can see all the rows in the stichwork of the pillow he's lying on.
Keith
The best camera is one that still works!
A prime example of why this lens is so tricky ... wide open it's as sharp as anything I've used but getting that sharpness exactly where you need it is a learning curve and sometimes you get it right and sometimes you don't. Judging how far to lean forward as you take the shot varies with distance of course ... it's a lot to think about when all you want to do is take a photograph! 😛
The rendering is the thing that blows me away about the lens though and when I can judge that distance perfectly every time my life will be complete! 😀
From memory I focused on that lead running across his nose!
Mister E
Well-known
So your lens is optimized for f/2.8?
Keith
The best camera is one that still works!
No ... f1.5 which means the Ikon's rangefinder is telling me the focus point is quite few centimeters forward of where it actually is ... especially at this distance.
You have to really like this this lens to put yourself through this sort of thing! 😛
The tip of his nose, and that lead, look sharp to me. Right at the leading edge of the DOF where you'd expect the focus point to be.
Keith's lens is "Cosina optimised" for f/1.5 (the third one they've adjusted for me 🙂). Which means its adjusted to compensate for the shift at f/1.5 as much as possible without throwing the focus too much out of whack when stopped down to f/2.8 and beyond. In practical terms, the focus point at min. focus and f/1.5 is at the leading edge of the DOF, and the DOF shifts backward as the lens is stopped down. Not sure how they optimise in Germany, but that's how Cosina optimises for f/1.5.
Keith's lens is "Cosina optimised" for f/1.5 (the third one they've adjusted for me 🙂). Which means its adjusted to compensate for the shift at f/1.5 as much as possible without throwing the focus too much out of whack when stopped down to f/2.8 and beyond. In practical terms, the focus point at min. focus and f/1.5 is at the leading edge of the DOF, and the DOF shifts backward as the lens is stopped down. Not sure how they optimise in Germany, but that's how Cosina optimises for f/1.5.
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maddoc
... likes film again.
(... my focus also shifts ... after too many beers ...)
The Zeiss Sonnar is an excellent lens. 🙂
The Zeiss Sonnar is an excellent lens. 🙂
Keith
The best camera is one that still works!
It's just simply the best 50mm lens I've ever used bar none and IMO the focus shift once you have a clear understanding of what's actually happening is something that can be dealt with if you have the determination.
My first roll with it was a shocker ... embarassingly bad! 😛
My first roll with it was a shocker ... embarassingly bad! 😛
nasdak
Established
don't know the nocton, but subjects really pop in with the sonnar !
