goamules
Well-known
On expired Tri-X 400:
MCTuomey
Veteran
Soeren
Well-known
goamules
Well-known
I've read internet posts for some time about "xyz lens is optimized for close up" or "abc lens is optimized for wide open" or "...for F4..." etc. I don't believe it. Lens designers want their lenses to be optimal for everything.
The faster you try to design a lens, like a sonnar, the harder it is to have good resolution with few aberrations. Perhaps there are a few tradeoffs, and one design factor makes them a little better wide open, but not so good a few stops down. Maybe, but almost all designs are better stopped down. And they weren't designing for esoteric modern phrases like "bokeh" and "drawing rendition." They sat down and said, "let's make a Sonnar type lens at F1.5 with as few aberrations as we can....maybe we can tweak the Zeiss design a little." Then they did it.
Canon made their 50/1.5 based on their determinations for the above, and manufactured all lenses, with tight quality control and checking to that design. How would someone now, 50 years later, change that and "optimize a Canon sonnar for F1.5?" It's a set lens design, it was optimized in 1952.
The faster you try to design a lens, like a sonnar, the harder it is to have good resolution with few aberrations. Perhaps there are a few tradeoffs, and one design factor makes them a little better wide open, but not so good a few stops down. Maybe, but almost all designs are better stopped down. And they weren't designing for esoteric modern phrases like "bokeh" and "drawing rendition." They sat down and said, "let's make a Sonnar type lens at F1.5 with as few aberrations as we can....maybe we can tweak the Zeiss design a little." Then they did it.
Canon made their 50/1.5 based on their determinations for the above, and manufactured all lenses, with tight quality control and checking to that design. How would someone now, 50 years later, change that and "optimize a Canon sonnar for F1.5?" It's a set lens design, it was optimized in 1952.
Brian Legge
Veteran
Usually when people talk about optimizing a lens now, they mean making the focus accurate at one fstop and less accurate at others by moving either changing the shims (moving the full optics module closer or further from the plane) or by changing the distance between the optics (inserting a shim).
Usually that comes up with sonnars as the design has focus shift. Some people prefer the rangefinder to be correct at 1.5 at the cost of it being less accurate stopped down (often compromising around f2.8-4 as beyond that the depth of field makes up for the different).
At f/1.4, the Nikkor 50mm ltm lens is sharp and contrasty up close but flares significantly at distance. Stopped down slightly, its great across the range. Given the 1.4 performance, I think its fair to say that they prioritized near focus image quality over far focus.
Usually that comes up with sonnars as the design has focus shift. Some people prefer the rangefinder to be correct at 1.5 at the cost of it being less accurate stopped down (often compromising around f2.8-4 as beyond that the depth of field makes up for the different).
At f/1.4, the Nikkor 50mm ltm lens is sharp and contrasty up close but flares significantly at distance. Stopped down slightly, its great across the range. Given the 1.4 performance, I think its fair to say that they prioritized near focus image quality over far focus.
peterm1
Veteran
If there is one thing this thread shows it is that Sonnar glass really excels for portraits. I don't know what it is but to me the portraits all look so much nicer. Old lens enthusiasts used to talk about a good lens having a "roundness" to the image or about image "plasticity". I think its this look they refer to. Sharp and yet somehow with a touch of softness as the sharp part of the image fades into out of focus.
goamules
Well-known
You had me agreeing until the last paragraph. The first part you seem to be saying the focus of a sonnar is not linear. But the rangefinder coupling mechanism is, so you may have to shim the lens to make the focus "most accurate" at either close, or infinity. Sure, I'll buy that.
But your last para about a Nikkor being "sharp and contrasty up close" is wrong. There's no "flaring at distance." At F1.4, it has spherical aberration. That is classic "softness", not really flare (loss of contrast due to glass-air interfaces and light bouncing around inside the barrel). Close, far, and middle, it doesn't matter where you focus, wide open it's soft. when you stop down to almost F2.0, the SA clears up - close, far, and middle. Same as any lens.
goamules
Well-known
If you want to see the Canon, Nikkor, and Jupiter3 sonnars compared at three apertures, I've got it here: http://www.flickr.com/photos/garrettsphotos/sets/72157632751282133/detail/
Here is a Canon 1.5 wide open on Fuji 400:
Here is a Canon 1.5 wide open on Fuji 400:
goamules
Well-known
Where will you get an existing Canon lens "optimized?" How will they do it? Are they going to delaminate the lens, regrind the surfaces to some, as yet undefined, curves, then re cement them? Maybe use a new type of glass for a different refractive index? Remount them in a some, as yet undefined, new barrel? Asking the same question over will get my same answer:
ichalov
Newbie
You may also consider getting a cheap LTM body (FSU or whatever you want to invest in having 135 film close-ups at F/1.5) and adjusting its rangefinder to match with your lens at this aperture. You avoid the risks of disassembling the lens if doing so.
Or you may want to try your lenses with some digital mirrorless camera that can do live view focusing. You can learn the focus shift of your lenses by focusing on the same subject at different apertures and seeing how much the scale position changes.
Mark Schretlen
mostly harmless
I have always liked this lens.
M8 in Victoria, BC
M8 in Victoria, BC
goamules
Well-known
Knock yourself out. I wouldn't let anyone crack open my perfect lenses and change them in any way.
Bingley
Veteran
Bingley
Veteran
Bingley
Veteran
Bingley
Veteran
Bingley
Veteran
LeicaTom
Watch that step!
My 1957 Oval Window Volkswagen named "Blauchen" (means small and blue, in German) shot with my 1955 Canon f1.5/50mm lens *wide open* at f1.5 and 500 or 1000/sec ? -ISO/160 - Leica M8 - Late afternoon light - With only minimal photo color channeling in PS2 - The Black and White photo was shot *in camera* not PS.
Enjoy!
Tom
sevres_babylone
Veteran
Mark Schretlen
mostly harmless
M8, wide open
