prashant wrote:
guys, does it really matter that much, MC or SC?
How about some images made with these two?
It's all on a friendly basis. You don't find it informative to know what to look for as far as MC goes? Just took a look at a number of lenses ranging from Rodenstock, Nikkon, Zeiss, Olympus, Pentax and so on. The majority(all but 1!) of these lenses had Green/Magenta reflections. The older Flektogon which is labeled MC had Magenta/Blue reflections. My oldest Nikkor-UD 20mm 3.5 non MC lens has a pure Magenta reflection similar to the non MC Olympus 28 3.5 shown above.
I think this link will answer most of the questions on reflections from single and multi coated lenses.
http://rick_oleson.tripod.com/index-166.html
Here is an excerpt:
Every lens has at least two reflective surfaces, the front and the back. In lenses used for practical photography, there are generally at least six, and there can be 18 or more in complex wide angles or zooms. Each surface presents an opportunity to adjust the color effect of the coating: with, say, six surfaces to coat, the designer can specify six slightly different thicknesses of coating, each corresponding to a different point in the spectrum. If one surface transmits a little extra yellow-green, another a little extra blue-green, a third a little extra orange and so on, the total lens can be balanced to pass a very neutral color of light through to the film. This is why, in some lenses, you will see a number of reflections in different colors: each coating layer is the same Magnesium Fluoride material, each is a single layer, but each is a slightly different thickness to correspond to a different color within the visible spectrum to optimize balance. Not all designers did this – some felt it was better to optimize the entire lens in the center of the spectrum for best overall efficiency, and their lenses tend to have a uniform blue-violet color on every surface....Show more →
The same article comments:
A multi-coated lens may present multi-colored reflections, but so will many single coated lenses. The way to tell a multi-coated lens from a single one is to compare the brightness of the reflections rather than their color: the lens with brighter reflections will be the single coated one.
I have an Olympus 55/1.2 - supposed to be all single coated - and looking at it last night it has the same reflections as the 28/3.5 in the photo from cogitech above.
On my 28/3.5 there are two on the front and three on the back.
I'm calling it multi-coated. I see it in the photos, as well.
(not sure what Tariq means about the two colours on the front of mine being in the same "spectrum", as there is only one "colour spectrum" that I know of).
Also, if you look at this photo of the OM lens line-up, what you will see is a wide variety of coatings. Green is not required for multi-coating.
cogitech wrote:
On my single-coated 21/3.5, there is one colour.
On my 28/3.5 there are two on the front and three on the back.
I'm calling it multi-coated. I see it in the photos, as well.
(not sure what Tariq means about the two colours on the front of mine being in the same "spectrum", as there is only one "colour spectrum" that I know of).
Also, if you look at this photo of the OM lens line-up, what you will see is a wide variety of coatings. Green is not required for multi-coating.
I meant colors of the spectrum. The light yellow/beige color is most likely not part of the MC process at all. It could even be the color of the actual glass or it could be a basic coating of some sort, I don't know. Green is not required but is one of the most commonly seen color reflections in a MC wide angle lens and IS prevalent in the later Olympus wide angle MC lenses and is NOT present in earlier Olympus lenses which we know to not be MC. If the Olympus 24 3.5 is MC, it would go against all known data on the OM lens line to date and it would also be inconsistent with what one observes in the later wide angle MC OM lenses as well as the majority of other lenses in other lens lines. We all know its a good lens anyway, MC or not.
I have in my possession Oly 28 f2, f2.8, f3.5 x 2, CY 28 f2.8, Leica 28 latest. I have just got to sell some of these lenses!
The Oly 28 f2 is nice and sharp wide open but definitely has a little barrel distortion. It is lighter and smaller than either the Zeiss or Leica 28 f2.8's. How does Olympus do that? First, they don't mind a bit of light fall off wide open. Secondly, my Oly 28 f2 isn't really f2, according to my camera's light meter. f2 at 1/500th doesn't look anything like f2.8 at 1/250th. Just maybe it's nearly as bright in the centre, but probably not. At the edges it's dark. It's a nice little lens, and great for use at f2 if you want a smaller lighter 28 f2 than other makers offer. I'm keeping mine.
The Oly f2.8 has more visible CA and sludgier corners than the f2 or f3.5 versions. It's still a nice little lens, and the extra brightness in the viewfinder is very noticeable compared to the f3.5 version, although I always use manual focus screens, so that may accentuate this difference.
I typically use this focal length at f8 - f11, and I'm looking for micro-contrast and apparently extended depth of field. The corners don't matter excessively to me as I'm not doing huge enlargements of landscapes. I just want the best performance over the great majority of the frame, even when parts of the subject may be less than perfectly in focus. The CY beats them all, including the Leica.
If I wanted a lens to shoot at f2.8 as well as at f8, then it would be the Leica.
That settles it then: 1 Leica 28 f2.8, 1 Oly 28 f2.8, and one Oly 28 f3.5 for sale.
I'll keep the Oly 28 f3.5 for its size, the f2 for low-light, and the Zeiss for 90% of the bread and butter.
On the rear element of mine, I see blue/violet, red/pink, and yellow/brown
Is there a reason why a single coating couldn't produce reflections like this? There is an air/coating surface reflection, and a coating/glass surface reflection. Three media, three refractive indices, and two transitions. Aren't we looking at the reflections from two transmissive surfaces? Why can't the air/coating transition be the orange one, and the coating/glass transition be the purple reflection? With multi-coating, you might see three or more reflected images of the same magnification. I don't know too much about this - just throwing some ideas into this very interesting discussion.
Analysis of the colours reflected is not a reliable gauge for quality of AR coatings. It's the overall visible albedo that counts, not a specific spectrum.
It is possible to take multiple examples of a manufacturer's lens lineup say that the AR coating was changed at times by analysis of the colours reflected, but this is a very different test.
It seems a specific case has been overly generalized. A weak green reflection is better than a strong blue one, but a weak blue reflection is better than a strong green one!
olyacme wrote:
Analysis of the colours reflected is not a reliable gauge for quality of AR coatings. It's the overall visible albedo that counts, not a specific spectrum.
It is possible to take multiple examples of a manufacturer's lens lineup say that the AR coating was changed at times by analysis of the colours reflected, but this is a very different test.
It seems a specific case has been overly generalized. A weak green reflection is better than a strong blue one, but a weak blue reflection is better than a strong green one!
Now I'm really confused. At least I have a new word for the day. "Albedo"!
olyacme wrote:
Analysis of the colours reflected is not a reliable gauge for quality of AR coatings. It's the overall visible albedo that counts, not a specific spectrum.
It is possible to take multiple examples of a manufacturer's lens lineup say that the AR coating was changed at times by analysis of the colours reflected, but this is a very different test.
It seems a specific case has been overly generalized. A weak green reflection is better than a strong blue one, but a weak blue reflection is better than a strong green one!
Can we at least say that Anti Reflective Coating does not always equal Multi Coating. There are plenty of lenses which are single coated to reduce reflection and increase light transmission that existed long before Multi Coating came along. Is that not correct?
Tariq Gibran wrote:
Can we at least say that Anti Reflective Coating does not always equal Multi Coating. There are plenty of lenses which are single coated to reduce reflection and increase light transmission that existed long before Multi Coating came along. Is that not correct?
Certainly, and the coatings themselves have evolved as well. It's just that in the general context SC versus MC, especially as determined by colour, is an insufficient basis for comparison. This only works when one is looking at the evolution of a particular lens, or a particular manufacturer's art.
A relatively simple general test is to put (ideally felt lined) rear caps on a pair of lenses, and point them up at an overcast sky. Photograph them side by side and you get a qualitative basis for which lens has the better coatings, by assessing which lens scatters more light back out.
olyacme wrote:
Certainly, and the coatings themselves have evolved as well. It's just that in the general context SC versus MC, especially as determined by colour, is an insufficient basis for comparison. This only works when one is looking at the evolution of a particular lens, or a particular manufacturer's art.
A relatively simple test is to put (ideally felt lined) rear caps on a pair of lenses, and point them up at an overcast sky. Photograph them side by side and you get a qualitative basis for which lens has the better coatings, by assessing which lens scatters more light back out.
That seems like it would just give one a general idea as to the quality of coating, not if its MC or Single coated.
Googling around, one finds this per Olympus lenses:
"According to Olympus America, the way to tell if a lens is
multicoated is to look at the writing on the front. If the lens has an
element letter (eg G.Zuiko) it is single coated. If it lacks the
element letter, and/or has MC on the front, it is multicoated."
From http://brashear.phys.appstate.edu/lhawkins/photo/multicoat.txt
Tariq Gibran wrote:
That seems like it would just give one a general idea as to the quality of coating, not if its MC or Single coated.
What I'm saying is that in the general context this is meaningless information. One can in some cases use colour properties to make strong guesses about the evolution of the coatings within a single manufacturer's lens lineup, but outside of that only direct observations are a meaningful measure.
Tariq Gibran wrote:
Googling around, one finds this per Olympus lenses:
"According to Olympus America, the way to tell if a lens is
multicoated is to look at the writing on the front. If the lens has an
element letter (eg G.Zuiko) it is single coated. If it lacks the
element letter, and/or has MC on the front, it is multicoated."
From http://brashear.phys.appstate.edu/lhawkins/photo/multicoat.txt
...And all that is inconclusive, because a well-known Zuikoholic has this to say about it:
It can be quite tricky to determine whether a lens is single coated or multi coated. The presence of the characters MC on the lens front ring is more or less an evidence, with one pitfall: the ring may have been replaced during a repair or maintenance job... The absence of the MC designation doesn't mean anything either - at a certain moment Olympus decided it had enough of this multicoating marketing hype, all new lenses were supposed to be multicoated anyway, and just removed the two characters. The X.Zuiko type designation also doesn't prove anything. The fast wide angles and the 18mm/F3.5 were designed multicoated from the very beginning and were initially designed (and maybe also produced and marketed) with the X.Zuiko designation!
The fact that the lens has a silver nose certainly has nothing to do with the coating. Although the gradual replacement of the silver nose by the black nose of all Zuiko lenses happened more or less simultaneously with the replacement of single coated lenses by multicoated lenses, the early multicoated lenses (the fast wide angles) had the MC designation but still had the silver nose.
Finally the color of the reflection from the lens is frequently mentioned. Multicoated lenses are supposed to have greenish reflections. Well just have a look at the picture below, scanned from The OM System Lens Handbook, edition October 1984, at the time most if not all lenses were multicoated. All colors are present, and no two coatings are identical.
Are single coated lenses, if and when you think you can determine them as such, to be avoided? Most certainly not! All Zuiko lenses are guaranteed to produce excellent results. To avoid unwanted reflections you are advised to use a lens hood all the time, which will help much more than even the best coating......Show more →
Mine very definitely has the same reflection effect, but I'm pretty sure that's a single coat, going by the propensity for flare in such a simple optical formula. I have a 260XXX serial number for the 28/3.5. My MC 50/1.4 has multiple reflections directly underneath each other in different colors, as opposed to reflections on opposite sides of the front element.
Whether mine is MC or not is still questionable, based on everything so far.
What I can conclude (sort of, anyway) is that the type of coating on the 28/3.5 did change over time. The coatings on prashant's copy looks very much like my silver-nose 21/3.5. My 28/3.5 looks nothing like his.
So, maybe mine is SC, but maybe the formulation is different and/or more internal elements are coated.
Or maybe (just maybe) it is in fact a very late model (427xxx) copy that recieved the "coatings of the day" and ended up MC.
Exactly, early instances of MC was always specifically mentioned/touted by Olympus.
"Finally the color of the reflection from the lens is frequently mentioned. Multicoated lenses are supposed to have greenish reflections. Well just have a look at the picture below, scanned from The OM System Lens Handbook, edition October 1984, at the time most if not all lenses were multicoated. All colors are present, and no two coatings are identical.
Are single coated lenses, if and when you think you can determine them as such, to be avoided? Most certainly not! All Zuiko lenses are guaranteed to produce excellent results. To avoid unwanted reflections you are advised to use a lens hood all the time, which will help much more than even the best coating..."
Inconclusive to go simply by a photo of the lens line. Who knows what techniques were used for that image. The fact is that most sources, and particularly Olympus specific sources, state that older lenses will have MC on the ring if the lens is MC as stated by Olympus themselves. One would think Olympus would know. The overwhelming preponderance of the evidence is that the 28 3.5 is not MC.
From an Olympus FAQ:
" What does MC mean? How can I tell if I have a multicoated lens?
Many early Zuiko lenses were single coated. Those that were
multicoated were denoted by the MC logo, until most of the lens
line was multicoated. Then the MC logo was dropped. It is
generally agreed that the presence of any green reflection, no
matter how faint, is evidence of multicoating, while predominatly
yellow reflections denotes single coating. Zuikos with the
G.Zuiko type designation are more likely to be single coated."
My 28/3.5 is # 457xxx so I guess.......................
tm
cogitech wrote:
Hmmm.
Whether mine is MC or not is still questionable, based on everything so far.
What I can conclude (sort of, anyway) is that the type of coating on the 28/3.5 did change over time. The coatings on prashant's copy looks very much like my silver-nose 21/3.5. My 28/3.5 looks nothing like his.
So, maybe mine is SC, but maybe the formulation is different and/or more internal elements are coated.
Or maybe (just maybe) it is in fact a very late model (427xxx) copy that recieved the "coatings of the day" and ended up MC.
Tariq Gibran wrote:
"But there is not a single reported example by anyone nor in any Olympus literature of there ever existing a 28 3.5 with a ring which read MC. So that pitfall is out completely."
"...as stated by Olympus themselves. One would think Olympus would know."
Tariq, while I can see that your arguments are as valid as mine on this issue, the above quotes are troublesome.
Why?
Because Olympus Japan also has no record of ever producing an MC Zuiko 24-40 f4 lens and I have one sitting on my shelf.
So, it would be putting it lightly to state that Olympus's record keeping is lackluster. If they can't keep track of a lens that they made, how can we expect that coating variations were documented accurately (or at all).
Knowing what I know, I still think it is entirely possible that my 28/3.5 has upgraded coatings (even if not MC) over older versions of the 28/3.5.
After all, if I own a lens that Olympus has no record of, I find it entirely possible that I have a 28/3.5 with coatings that Oly has no record of.
