Re: Vivitar 35-85 better than Pentax 24-90?
You know, Sometimes I think we underestimate how good some of these older, third party lenses really are. Some of my favourite lenses are third party lenses Same here. (Well spoken, Vic.) As much as I like all of my (too many) samples of Pentax glass, I also cherish some of the special and often unique third-party creations that have also been produced. This is not to say that there are no faults in my 3rd-party gems (nothing will ever beat SMC, for example, and the VS1 35-85/2.8, as much as I love it, is certainly not a perfect lens), but is to say that there are indeed some interesting non-Pentax lenses available for use on Pentax bodies which can also sometimes be quite strong performers in their own right (and sometimes - but certainly not always - be inexpensive to obtain). Fred
Re: Vivitar 35-85 better than Pentax 24-90?
Andre wrote: Could the difference in saturation be caused by a slight difference in exposure (because of diaphragm margin of error)? Could be, but certain VMC coating formulations--or is it the glass?--produced consistently more saturated colors. I can tell at a glance, for example, which of my 28mm prints had been taken by my Series One 28/1.9 or my former Kiron 28/2. It would be instructive to compare a Series One lens against its non-Vivitar twin; presumably they used different coatings. Thus, we'd want to compare the Kiron (1980) against the Vivitar 28/2 (1983), compare the Kiron 105/2.8 macro against the Vivitar Series One 105/2.5 macro, and compare the Tokina AT-X 90/2.5 macro against the Vivitar Series One 90/2.5 macro. The Tokina is no slouch in the saturation department; it has that Nikon-like warmth that makes everyone look as though they've been out in the sun. Fred, you own both macros; is the coloring the same? Of course, these Vivitars were made by Kino Precision Optical and Tokina; I don't know whether those companies would actually change coatings when rebadging their lenses. Kiron also made the 28/1.9 (VMC-coated), so as early as the late 70s Kino knew a thing or two about producing coatings that yielded strong color. [EMAIL PROTECTED]
RE: Vivitar 35-85 better than Pentax 24-90?
It's still true today, all else being equal, a lens design with less elements will be sharper and more contrasty than one with more. For a given focal length and speed, there is an ideal number of elements to optimize the design. More does NOT always equal better when it comes to lens elements. JCO -Original Message- From: Raimo Korhonen [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 22, 2003 12:26 PM To: [EMAIL PROTECTED] Subject: Vs: Vivitar 35-85 better than Pentax 24-90? It used to be so before World War II because of un-coated lenses - but not anymore, even less with multicoating. Not many single-element designs around ;-) All the best! Raimo Personal photography homepage at http://www.uusikaupunki.fi/~raikorho -Alkuperäinen viesti- Lähettäjä: J. C. O'Connell [EMAIL PROTECTED] Vastaanottaja: [EMAIL PROTECTED] [EMAIL PROTECTED] Päivä: 22. tammikuuta 2003 2:04 Aihe: RE: Vivitar 35-85 better than Pentax 24-90? -Original Message- From: Andre Langevin [mailto:[EMAIL PROTECTED]] Sent: Tuesday, January 21, 2003 7:44 PM To: [EMAIL PROTECTED] Subject: RE: Vivitar 35-85 better than Pentax 24-90? snipLess elements for the same amount of correction means more contrast/resolution. The vivitar series 1 varifocal lenses were made that way for maximum image quality, not to save costs, they were MORE expensive than similar true zooms of the time they were made. JCO
Re: Vivitar 35-85 better than Pentax 24-90?
You're absolutely right, J.C. Each added element adds two more medium interfaces (air-to-glass, etc.) and each have their own abberations, no matter how small, to the whole. The more elements a lens assembly has, the more perfect each and every lens in the whole assembly has to be, to the point where to be the 'best,' each element has to be hand-figured to match or compensate for all the others. To work together well, as it were. J. C. O'Connell wrote: It's still true today, all else being equal, a lens design with less elements will be sharper and more contrasty than one with more. For a given focal length and speed, there is an ideal number of elements to optimize the design. I was unaware of that. Is there a list or chart somewhere, or a discussion about this I could read? Thanks for pointing that out. More does NOT always equal better when it comes to lens elements. JCO -Original Message- From: Raimo Korhonen [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 22, 2003 12:26 PM To: [EMAIL PROTECTED] Subject: Vs: Vivitar 35-85 better than Pentax 24-90? It used to be so before World War II because of un-coated lenses - but not anymore, even less with multicoating. Not many single-element designs around ;-) Raimo [...]
RE: Vivitar 35-85 better than Pentax 24-90?
For a given focal length and speed, there is an ideal number of elements to optimize the design. I was unaware of that. Is there a list or chart somewhere, or a discussion about this I could read? Thanks for pointing that out. Well, it's not a science, but you dont see 50mms with 10 elements nor 20mm's with 6. Some zooms get up to 15, but it's going to take incredible quality control to get good results with that many elements IMHO. JCO
Re: Vivitar 35-85 better than Pentax 24-90?
In the 80s, the tendency, at least at Pentax with the M and then the A lenses, has been to cut down on the number of lens elements. But that's because of the availability of better glass and more glass types, not because fewer elements are intrinsically better. --Mike
Re: Vivitar 35-85 better than Pentax 24-90?
J. C. O'Connell [EMAIL PROTECTED] wrote: For a given focal length and speed, there is an ideal number of elements to optimize the design. I was unaware of that. Is there a list or chart somewhere, or a discussion about this I could read? Thanks for pointing that out. Well, it's not a science, but you dont see 50mms with 10 elements nor 20mm's with 6. Some zooms get up to 15, but it's going to take incredible quality control to get good results with that many elements IMHO. The FA*80-200/2.8 has 16 elements (in 13 groups), but it's a truly outstanding lens. -- Mark Roberts Photography and writing www.robertstech.com
Re: Vivitar 35-85 better than Pentax 24-90?
B. BUT on the other hand, the extra air glass surfaces REDUCE contrast (and apparent resolution) That was true before multicoating. Now there's a slight transmission loss for each added element, but better correction can often result in better contrast. --Mike
Re: Vivitar 35-85 better than Pentax 24-90?
There's no way they can get around it, except to make each new element match the previous elements very, very well, and test them together for final figuring. Centering and collimation have nothing to do with the number of elements. You can have a lens with many elements that has zero decentering and a triplet that is badly decentered. --Mike
Re: Vivitar 35-85 better than Pentax 24-90?
For some reason, these two statements don't jibe. Don't match. Like...one person is talking about one thing, and the other person drops a non-sequitur on the pile, and hopes for the best... g Mike Johnston wrote: There's no way they can get around it, except to make each new element match the previous elements very, very well, and test them together for final figuring. Centering and collimation have nothing to do with the number of elements. You can have a lens with many elements that has zero decentering and a triplet that is badly decentered. --Mike Let's start over, sort of... Put a lens in the tube, and it's got a certain amount of spherical abberations and some coma. Change the material (to add color focus correction) and put an image-correcting lens in there, and you get rid of a lot of astigmatism, pinhole distortion, chromatic abberation and other stuff. But, you still have some sort of distortion. Granted, maybe only 5% of what you DID have, maybe clear out on the corners, but still... So, you add another correcting lens and SMC coat all of what you're working with. Look at it again. This time something else shows up. maybe some barrel distortion crept in, *I* don't know. Something... Add another lens to correct that. Eventually, you get a superior lens, and it performs beautifully! *That* is why you add lenses ~ to correct abberations or extend it's capabilities... So I see it, anyhow! And...we've not even mentioned centering or collimation problems. Where did that come from? Not me... That sort of thing belongs to the lens maker (grinder/polisher), so s/he doesn't introduce such... keith whaley
Re: Vivitar 35-85 better than Pentax 24-90?
And...we've not even mentioned centering or collimation problems. Where did that come from? Not me... That sort of thing belongs to the lens maker (grinder/polisher), so s/he doesn't introduce such... keith whaley But it's always surprising to read in many tests that even expensive lenses are not perfectly centered. Does it mean that a (good) repairman could do better (afterwards) than the original lens maker did at the factory? Andre --
RE: Vivitar 35-85 better than Pentax 24-90?
J. C. O'Connell [EMAIL PROTECTED] wrote: There is a trade off to adding elements: A. on one hand they reduced abberations IF precisely ground and placed B. BUT on the other hand, the extra air glass surfaces REDUCE contrast (and apparent resolution). Didn't Super Multicoating (SMC) all-but-eliminate that tradeoff by making loss of contrast nearly inconsequential? [EMAIL PROTECTED]
RE: Vivitar 35-85 better than Pentax 24-90?
yes for 4 to 6 element designs, no for 12 to 15 element desings. JCO -Original Message- From: Paul Franklin Stregevsky [mailto:[EMAIL PROTECTED]] Sent: Wednesday, January 22, 2003 10:07 PM To: 'Pentax-Discuss' Subject: RE: Vivitar 35-85 better than Pentax 24-90? J. C. O'Connell [EMAIL PROTECTED] wrote: There is a trade off to adding elements: A. on one hand they reduced abberations IF precisely ground and placed B. BUT on the other hand, the extra air glass surfaces REDUCE contrast (and apparent resolution). Didn't Super Multicoating (SMC) all-but-eliminate that tradeoff by making loss of contrast nearly inconsequential? [EMAIL PROTECTED]
Re: Vivitar 35-85 better than Pentax 24-90?
On 22 Jan 2003 at 15:40, Keith Whaley wrote: Andre Langevin wrote: But it's always surprising to read in many tests that even expensive lenses are not perfectly centered. Does it mean that a (good) repairman could do better (afterwards) than the original lens maker did at the factory? Andre -- Absolutely not. The only person who can do that, regardless of title, is the person grinding the lenses to fit the various places in the lens body. Just like, if your optician grinds your prescription lens incorrectly, to fit your frames, your glasses will drive you nuts. So will a decent lens. Sure they can Keith, the lens elements may be perfectly formed (stamped, ground, polished, laminated, coated etc) and still be de-centred. The lens elements (including glued pairs or groups) most often float slightly in the mount, the assembly (or re-assembly) is the point at which centring is accomplished in most designs. As far as I recall there is some blurb on the Leica or Schneider web sites with details. Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
Re: Vivitar 35-85 better than Pentax 24-90?
You know, Sometimes I think we underestimate how good some of these older, third party lenses really are. Some of my favourite lenses are third party lenses Vic
Re: Vivitar 35-85 better than Pentax 24-90?
and compare the Tokina AT-X 90/2.5 macro against the Vivitar Series One 90/2.5 macro. The Tokina is no slouch in the saturation department; it has that Nikon-like warmth that makes everyone look as though they've been out in the sun. Fred, you own both macros; is the coloring the same? Sorry, Paul, I don't own the Tokina AT-X 90/2.5 (with its 1:1 Macro Extender) anymore (although I do still have an extra copy of the Extender on hand for future experiments - g). I do still have the VS1 90/2.5 Macro (with its 1:1 Macro Adapter). But, I do have some comparative shots of the (one) same subject, taken with both lenses, though. And, there are indeed a few colors in the subject, which is a homebrew macro test target. So, if there is anything to be gleaned from them, here they are: VS1 @ 4:1 @ f/8 (without 1:1 Macro Adapter) - http://www.cetussoft.com/pentax/v9025/v9025-41-8.jpg AT-X @ 4:1 @ f/8 (without 1:1 Macro Extender) - http://www.cetussoft.com/pentax/x9025/x9025-41-8.jpg VS1 @ 2:1 @ f/8 (without 1:1 Macro Adapter) - http://www.cetussoft.com/pentax/v9025/v9025-21-8.jpg AT-X @ 2:1 @ f/8 (without 1:1 Macro Extender) - http://www.cetussoft.com/pentax/x9025/x9025-21-8.jpg VS1 @ 1:1 @ f/8 (with 1:1 Macro Adapter) - http://www.cetussoft.com/pentax/v9025/v9025-11-8.jpg AT-X @ 1:1 @ f/8 (with 1:1 Macro Extender) - http://www.cetussoft.com/pentax/x9025/x9025-11-8.jpg Does anybody see any significant difference in them? Fred
RE: Vivitar 35-85 better than Pentax 24-90?
Isnt the viv 35-85 a varifocal ( not a true zoom)lens? If so that combined with the narrower range could account for it's better performance. JCO -Original Message- From: Andre Langevin [mailto:[EMAIL PROTECTED]] Sent: Tuesday, January 21, 2003 7:06 PM To: [EMAIL PROTECTED] Subject: Vivitar 35-85 better than Pentax 24-90? From adphoto (then me): 24-90mm- quite good... not as contasty or sharp as the vivitar 35-85mm it replaced... I'm surprised because the 24-90 is a very recent design and the Vivitar an older one. At what focal lenght and aperture was the Vivitar better than the Pentax? the vivitar was noticeability more saturated through the entire range. Especailly at around f3.5 and F11. But from what i have heard that lens was a hit and miss affair. Some were good and some were not. However the pentax wins out because i can use it for sunsets and when ever the sun is low in the sky and for its range. Could the difference in saturation be caused by a slight difference in exposure (because of diaphragm margin of error)? Other PDMLers with similar experience? Andre --
RE: Vivitar 35-85 better than Pentax 24-90?
Isnt the viv 35-85 a varifocal ( not a true zoom)lens? If so that combined with the narrower range could account for it's better performance. JCO Maybe. But are all zooms varifocal lenses that have their focus adjusted automatically by another cam inside the lens? In other words, was a zoom made as a varifocal lens because it was easier to build it this way. Imagine the 35-85 with another internal metal barrel to change focus automatically. Andre --
Re: Vivitar 35-85 better than Pentax 24-90?
It is varifocal. Steve Larson Redondo Beach, California Everyone has a photographic memory. Some just don't have film. - Original Message - From: J. C. O'Connell [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, January 21, 2003 4:15 PM Subject: RE: Vivitar 35-85 better than Pentax 24-90? Isnt the viv 35-85 a varifocal ( not a true zoom)lens? If so that combined with the narrower range could account for it's better performance. JCO -Original Message- From: Andre Langevin [mailto:[EMAIL PROTECTED]] Sent: Tuesday, January 21, 2003 7:06 PM To: [EMAIL PROTECTED] Subject: Vivitar 35-85 better than Pentax 24-90? From adphoto (then me): 24-90mm- quite good... not as contasty or sharp as the vivitar 35-85mm it replaced... I'm surprised because the 24-90 is a very recent design and the Vivitar an older one. At what focal lenght and aperture was the Vivitar better than the Pentax? the vivitar was noticeability more saturated through the entire range. Especailly at around f3.5 and F11. But from what i have heard that lens was a hit and miss affair. Some were good and some were not. However the pentax wins out because i can use it for sunsets and when ever the sun is low in the sky and for its range. Could the difference in saturation be caused by a slight difference in exposure (because of diaphragm margin of error)? Other PDMLers with similar experience? Andre --
RE: Vivitar 35-85 better than Pentax 24-90?
-Original Message- From: Andre Langevin [mailto:[EMAIL PROTECTED]] Sent: Tuesday, January 21, 2003 7:44 PM To: [EMAIL PROTECTED] Subject: RE: Vivitar 35-85 better than Pentax 24-90? Isnt the viv 35-85 a varifocal ( not a true zoom)lens? If so that combined with the narrower range could account for it's better performance. JCO Maybe. But are all zooms varifocal lenses that have their focus adjusted automatically by another cam inside the lens? In other words, was a zoom made as a varifocal lens because it was easier to build it this way. Imagine the 35-85 with another internal metal barrel to change focus automatically. Andre -- Nope varifocal lenses are much simpler optically as well as mechanically. Less elements for the same amount of correction means more contrast/resolution. The vivitar series 1 varifocal lenses were made that way for maximum image quality, not to save costs, they were MORE expensive than similar true zooms of the time they were made. JCO
