MarkJones wrote:
[Would you care to elaborate? I know that there is a difference in speed, MFD and one is autofocus but what about IQ, sharpness etc. Mark
I have not owned either lenses so would leave this to someone who has done so. My conclusions are from photos in this forum which you probably already know.
contas wrote:
Your knowledge about zeiss is a kind of "I've heard about", your statement is an insult to Zeiss QC policy.I have my own experiences on both lenses, from outside to inside, they have much higher quality than of today EX Sigma lenses.We all didn't know what is the true in blackbox of coorperation between them.As my recognition lens optics structures like vario-sonnar ( and other planar, tessar...) belongs to the Zeiss and precise mechanical base to hold optics is very high quality, made of alloy metal not like in Canon, Sigma or Tamron lenses.The part I considered look like Sigma is electro-electronic part.So I guess that in coorperation, Sigma did on electro-electronic part, and both of them made many correction to make room for that part.Believing that Sigma can make Zeiss optics is an absurd.In photography they must know who is who and when the coorperation is considered.For Sigma making the luxury lens for their SD camera is only in dream, unless the 2nd larger coorperation is considered....Show more →
The exact wording from Carl Zeiss's reply was, "The [28-80 and 70-200] lenses you mentioned were results of a co-operation with Kyocera and Sigma." and that "the quality control was done by Carl Zeiss according to our specifications."
You are right in that we don't know what is in the black box of cooperation between them. What we do know is that the cooperation did take place. Also by taking apart the Contax N Vario-Sonnar 28-80/3.5-5.6 and the Sigma 28-80/3.5-5.6 lenses, I do find similarities in the autofocus gear train, motor and the EMD between the two lenses, so you are also correct about Sigma contributing to the electro-mechanical part. I have to emphasize however that the electronics are not the same - the Contax N has zoom and distance encoders of far greater resolution than Sigma.
I am no optical expert and won't be able to comment on the optical design. What I do know for a fact is that the Sigma lens has a rotating front element but the Contax N lens has a non-rotating front element, so the focusing helicoil definitely has a different design.
Both lenses are constructed almost entirely of plastic, however, although the Contax N appears to have a more robust feel to it and definitely has better dampening for its focus ring and zoom ring. The Contax N in clearance sales is not that much more expensive than Sigma but you are clearly getting substantial improvements in construction and handling. That said we have to remember the Contax N 28-80 is the budget lens in the Contax N line up. It does have Zeiss' QC standards but even so, not all Zeiss lenses are created equal. The Contax N 24-85 is definitely the better lens with more zoom range, metal construction, ultrasonic motor, full time manual focus, better corrected optically (not necessarily sharper, but aberrations are better controlled) and a better reliability record.
I know you are the one have a real practice on the lens, but today is weekend , I will discuss this with you later certaintly- I like the real .Btw, you wrote : "Both lenses are constructed almost entirely of plastic", so what do you mean?optics? mechanical base? cover? motor gear?.You know what I know so state clearly because around us many people don't know.
Thank you for your very good question. All lenses are made of both metal and plastic, but we know not all lenses have the same construction. Some clear definition is required. My personal definition is for all the glass elements to be in metal housing(s) in order to be considered as "made of metal".
For example, all glass elements of the Contax N 24-85 are in metal housings, even though the exterior shell is a mix of metal and plastic. I would still call that a metal lens.
The Contax N 28-80 fails my personal definition of a "metal" lens. The Contax N 70-200 only meets that definition partially, so I would also call that a fail.
It is hard to evaluate without taking the lens apart. For instance, Sony NEX lenses have metal exteriors, but inside, almost everything is plastic.
It is another debate whether it is important or not. For example, the Contax N 70-300 completely fulfills my definition, but I personally would still rather use the 70-200. Whether you want to base your lens choice on whether it is made of plastic or metal is a personal decision.
Let me summarize this topic! If photographers embrace Cosina-manufactured Carl Zeiss lenses as genuine Carl Zeiss, we should do the same to the Contax N 28-80/3.5-5.6. It is "genuine", despite Sigma's involvement and some similarities to Sigma's own 28-80/3.5-5.6. We also know for certain that when you buy a Contax N 28-80 you are getting a lens which is very significantly different from the Sigma 28-80. Not just higher QC, but both the mechanical design and even the quality of the electronics are of higher quality.
Mescalamba wrote:
For construction, well.. since Bo-Ming is actually converting this lens I would say that he probably knows what hes talking, right?
If you really want to know who made 28-80mm I can ask someone who probably knows that for sure.
Not seem like that. Ok go ahead everyone wants that .
contas wrote:
Thanks guys, as this combo I mostly use for flower shooting so you can see it's pictures on Alt Flower thread.I thought, I discovered something for both sides Zeiss and Foveon when couple them together.Btw, there is an opinion that among SD , the SD9 is the sharpest - and dust cover of SD9 also was removed by me to reduce any obstacle to light path to sensor ( I can't assusure you can do it with other SD).
To answer your question about to converse SA TC to accept Canon mount:
1- Check your lens compatibility with TC you want to converse.
2- I never practiced it, but as my theoretical knowledge ,with SA TC you can achieve only 50% of success another 50% is DIA - destroy in action.
3- If I were you , I'll take Sigma TC for Canon, and the part you must modify is male part : and get SA mount with electrical connector from an old SA lens.
Just un-screw the EF mount and replace by SA mount , un-solder and re-solder electric connectors, you avoid the need of drilling 4 holes on the SA mount ( if you use Canon or others than Sigma for Canon TC you must drill ) .
Good luck. http://i6.ebayimg.com/03/i/000/dc/ag/9f54_1.jpg...Show more →
Thankyou so much , I can't write alot due to not fluence in english , anyway thanks again I will try as you suggest.
Although contas used the word "failed" to refer to my post many times, I do not see how my overall position contradicting his. His position is that the Contax N lens cannot be considered the same lens as the Sigma 28-80. I share the exact same position, and I even supported his view by relating to my own extensive experience in disassembling these lenses. I am not debating with him but adding to what he is saying. I consider myself contas' ally, not his foe.
Contas, by your own reckoning, the PCBs are similar, that implies they are not the same, right? How did I "fail" by claiming the Contax N version is superior?
Your overall position is that the Contax N is superior to the Sigma, but then you "fail" me because I claimed the electronics of the Contax N is superior?
Based on that, I do not see any need to address the rest of your reply, until you demonstrate a consistent position yourself, and that you understand the fact that we share the same views.
Electronics in N mount was probably made by Sigma and glass for 24-85N was made in TOMIOKA Optical, which is today Kyocera Optec. Same should apply on 28-80mm.
Who designed lens is a bit mystery, but considering MTF of 28-80mm I would say Zeiss. Just guess tho..
