What's the difference between these lens. They look identical and appear to have the same specs.
Thomas
What's the difference between these lens. They look identical and appear to have the same specs.
Thomas
In modern plasmats, it is widely recognized that the "APO" label is pretty much just marketing. All modern plasmats are APO corrected.
It's like Dodge putting "Hemi" on some of their engines. Pretty much all modern gasoline engines have hemispherical heads and have for at least a decade.
Agree with Brad.
The term APO as a sales/marketing feature comes from Canon's marketing particularly of their telephoto lenses, some LF leneses were already technically APO lenses and the term just added to the badging.
The only fly in the ointment is a small number of LF APO lenses may be newer designs.
Ian
Although the term "apo" has indeed been used as a marketing tool, the Symmar S line
would not have met this criterion at the time it was manufactured, especially since the
Germans tended to have a very strict definition of apo in terms of process lenses. To
my knowledge, Rodenstock was the first to label a general-purpose plastmat as "apo". And the newer "Apo Symmars" are not just relabeled Symmar-S lenses but a more modern tweak with different glass. Some of the glass change as I understand it was mandated by the EU to bypass radioactive or toxic elements, but in the meantime there have also been steady improvements in lens engineering by all the major manufacturers, and the newer lens lines do generally seem sharper and better corrected.
Now that goes against what I've read where Symmar S leneses were relabled as APO Symmar, I think one focal lenght was redesigned but that was a maverick design.
Ian
In general, the Symmar-S series was specified to cover 70 degrees while the Apo-Symmar series was specified to cover 72 degees. It's only in the 360 and the 480 focal lengths that the coverage specifications match.
Schneider's literature for the Apo-Symmar says "By the use of special types of glass a further reduction of the 'secondary spectrum' is achieved, leading to a clear improvement in image quality, especially in the outer field..."
The detailed optical and mechanical specifications in the full Schneider data sheets also differ between the two series.
I've used, on the job, a 300/5.6 Symmar-S and a 135/5.6 Apo-Symmar. Obviously not to make the same pictures. Both were of the highest quality and extremely sharp; the 135 A-S was one of the most contrasty lenses I've ever used. There was an improvement in that regard between 1972 (the 300) and 1992 (the 135). Realistically speaking, I'd be happy a with a lens from either series.
Yes you're correct, Brad. But I don't personally know if the switch to eco-glass in the
very newest lenses was an optical improvement or not. I converted to Fuji lenses some
time back, when they were in fact well ahead of the Symmar-S line in performance.
Competition has largely ironed that difference out, and the latest lenses by Fuji, Nikon,
Rodenstock, and Schneider all appear to be stellar, though there always seems to
be a bit of wiggle room in the exact standard of an "apo" designation itself.
Perhaps Canon revived the term in the modern era, but it's a rather old one. It's a fundamental aspect of good lens design, and goes back to when lenses were designed with pencil and paper.
According to the Oxford Dictionary online, Ernst Abbe (1840-1905) is credited as the inventor of the apochromatic lens.
Bookmarks