Re: I Just Now "Fully" Realized That I Do NOT Like...
I've seen lenses with round apertures that had horrible bright edges on out-of-focus highlights. And lenses with pentagonal apertures that provide a lovely smooth rendering. And tessars that were at both extremes.
One thing that I believe is true: smooth rendering of out-of-focus details behind the focus plane require slightly undercorrected spherical aberration. The spherical aberration is what fades the edges of the disks that are points when in focus. Most older designs did not fully correct primary aberrations such as spherical aberration when used at wide apertures, so that explains why they show a rendering that to me has a vintage look. But most become quite sharp when stopped down. The trick for a lens with good bokeh is that as one stops down, the sharpening up of those disks (due to reducing the spherical aberration) is matched by those disks becoming smaller (due to increased depth of field). Those are the lenses that seem to render beautifully at all apertures. I have an old Ilex Paragon (an inexpensive but good coated tessar design from the 50's and 60's) that comes closest to that ideal among my large-format lenses. But I usually am trying to make everything sharp, or I'm not that concerned about the rendering of unsharp bits, when using large format. When it matters, that's the lens I usually use, recognizing that I will be giving up a bit of critical sharpness. On the other hand, the very worst lens I own for smooth rendering is a Bausch and Lomb Ic Tessar, from the 40's (though it made a decent enough enlarging lens). That reinforces the point that while design archetypes may have tendencies, they can be and often were tailored to optimize for different qualities.
In medium format, nothing in my collection comes close to the Zeiss Jena Sonnar, 180/2.8 or 300/4, which is a vintage design even in the newer multicoated versions (it was made until about 1990). But in an MTF test, lenses of more modern design (particularly using computer methods) will score better at wider than about f/8.
For a lens to be critically sharp in the focus plane, it usually has to ruthlessly correct every bit of (at least) the primary aberrations. That means those out-of-focus disks will have a well-defined edge and an even brightness across their width. That's a lot better than the bright edges found on some lenses, if smooth rendering is your goal. But smoother than that may require giving up a bit on sharpness.
Here's the final point, however: Whiile bokeh is real, the evaluation of its effects is subjective. Thus, you are generally stuck with having to just try things until you find the lenses that make the images you like. It is not a two-dimensional effect, with only out-of-focus highlight rendering and aperture as the dimensions. There is also the shape of those disks (affected by aperture shape, and of no real issue if the disk fades at the edge but of primary interest when the edges are well-defined), and the relationship of that rendering to the size of the disk as controlled by depth of field or distance from the focus plane. And there are other, more subtle effects. Most photographers for whom this matters buy lenses until they find the ones that make the images they like and sell the rest.
Rick "suspecting that a purpose-built lens like a modern Cooke might be designed around these objectives directly, but bring your checkbook" Denney
Re: I Just Now "Fully" Realized That I Do NOT Like...
Another vote for the Commercial Ektar, or if you need more speed, they also made a 'just plain' 12" Ektar f4.5 if the f6.3 of the Commercial Ektar isn't fast enough. Both came in #4/#5 Ilex shutters which had multi-bladed irises. A friend of mine once did a comparison test between the 14" CE, a 355mm Calumet (a Commercial Ektar clone) and a 14" Kern Gold Dot Dagor. The Kern Dagor had the harshest, most unpleasant Bokeh of the three, with the Calumet and the Commercial Ektar being closely tied - the original Commercial Ektar was nominally better than the Calumet (it is my understanding that the Calumet is slightly reformulated from the original Ektar design), but my friend opted to get the Calumet because it was an order of magnitude cheaper than the Ektar.
All that praise of the Ektar aside (and I do LOVE my Ektars), I think the Heliar is even better. I only have a 240mm in shutter, but I think it has the creamiest, smoothest, most beautiful out of focus areas of any lens I've ever had. At least of anything that I can mount on a field camera. If I could find a 360mm Heliar in a shutter, I'd be in hog heaven.
Re: I Just Now "Fully" Realized That I Do NOT Like...
Wow... thank you for all the replies so far. This a lot to digest.
I guess I'm obsessed with lens "perfection" or at least my uninformed/unpracticed ideas of it. It helps to read your comments and ideas. Researching, studying, deciphering, filtering and distilling information can be very difficult and time-consuming especially when the subject is multifaceted with both objective and subjective information. My head hurts. :)
Re: I Just Now "Fully" Realized That I Do NOT Like...
Quote:
Originally Posted by
Scott Davis
... they also made a 'just plain' 12" Ektar f4.5 ...
I like the old uncoated Kodak Anastigmat (Nr 32, 33, and 34 are the one's I use) almost as much. The only "problem" is that mine are either barrel or in dial-set Compur shutters and preclude use with flash.
Re: I Just Now "Fully" Realized That I Do NOT Like...
Quote:
Originally Posted by
Old-N-Feeble
I opted for dialyte type lenses for everything above normal focal length... 203 Ektar and Fujinon-C's. But it seems that for normal and wide angle needs plasmats are better, for my purposes, than anything else... maybe a 135 WF Ektar which, I think, is a double gauss.
For a nice wide angle, you might consider an old WAR (Wide Angle Rectilinear). Rather dark at usually an f/16 maximum aperture, but they often use wheel-stops with perfectly round apertures. The Protar Series V would be another nice option, though again it only opens to f/18. The Wollensak EWA is also a Double-Gauss, but I've been underwhelmed by its out-of-focus rendition.
Personally, I think the aperture shape is not that important, unless you have echoes of the shape in flares in the image, or the shape is radically different as with an Imagon's discs. The look from a Verito in a Studio Shutter (with a saw-tooth-ragged aperture) is as nice as from a Verito in a barrel with a very round aperture. But some very knowledgeable folks disagree...
Re: I Just Now "Fully" Realized That I Do NOT Like...
Hear, hear! I've gone through about five different ~10" lenses and the only one that has stayed with me for many years is a 10" Commercial Ektar. Last year when I had one stolen, I immediately went on the search for (and found) an even nicer copy. Thank you, Liberty Mutual!
Re: I Just Now "Fully" Realized That I Do NOT Like...
Quote:
Originally Posted by
Old-N-Feeble
<snip> I guess I'm obsessed with lens "perfection" or at least my uninformed/unpracticed ideas of it. <snip>
Its time to send your head to the shop for an overhaul.
Re: I Just Now "Fully" Realized That I Do NOT Like...
Quote:
Originally Posted by
Dan Fromm
Its time to send your head to the shop for an overhaul.
Doc says it's hopeless!! :D
Re: I Just Now "Fully" Realized That I Do NOT Like...
Quote:
Originally Posted by
Old-N-Feeble
Wow... thank you for all the replies so far. This a lot to digest.
I guess I'm obsessed with lens "perfection" or at least my uninformed/unpracticed ideas of it. It helps to read your comments and ideas. Researching, studying, deciphering, filtering and distilling information can be very difficult and time-consuming especially when the subject is multifaceted with both objective and subjective information. My head hurts. :)
Stop looking at lens specs and make some photographs. Any decent lens - and that is just about all of them - has more potential locked up in it than any photographer will fully utilise. There is no "perfect" lens, every single lens ever made is an assembly of compromises.
Re: I Just Now "Fully" Realized That I Do NOT Like...
Quote:
Originally Posted by
E. von Hoegh
every single lens ever made is an assembly of compromises.
Do you mean... *dramatic pause*... even the dagor? :eek: