Are lens coatings really that necessary?

I began to wonder about this while reading another recent posting

about the coatings on TLR lenses.<p>

Are coatings on lenses really that important? I have used a variety

of coated, multicoated and even a couple uncoated lenses. If I use

them stopped down with a lens hood it is often difficult or impossible

for me to tell a difference in performance other than in those unusual

situations like where I am shooting right into a light source (a

situation I usually try to avoid, or, if I want to use flare as a part

of the picture I should want FLARE, shouldn't I?). In printing bw

35mm availible light pictures I sometimes shoot with 6400 asa film in

nightclubs and similar places, I actually find a little flare that

causes a very slight overall fog helps me print up more tonal shadows

rather than seeing the dark areas go to a very flat black.<p>

The reason I wonder is that I would like to invest in some expensive

lenses in the future if budget allows --- several older view camera

and MF lenses are apparently near matches to their newer multicoated

versions with the exception of multicoating and price. Am I really

going to miss the multicoating if I go for the single coating lenses?

I would think that the number of air to glass surfaces in the lens would be an important factor. I remember reading that without the advent of multicoating, 15 element zooms would not have been possible to make due to flare and ghosting. If the lenses in question only had a few elements or there were not many air/glass surfaces, there may not be much difference between single and multicoat. I also remember seeing that there was a much bigger difference in reflectance between the uncoated and single coat VS the single and multi.

On the View Camera magazine website, there are a number of articles, one of which is a discussion of lens coatings by Ron Wisner. (At least I think it's on the website, it may be in a back issue that you need to order.) The short answer is that coating makes a lot more difference than multi-coating. I recently faced the decision you are now facing, whether to purchase single-coated large format lenses and thereby to save money on the used market. I decided only to purchase the latest multi-coated lenses. I am shooting only color slides. If I were shooting black and white I wouldn't care. If I were shooting color prints, it would be a more difficult decision. Large format lenses last a long time. The lenses, accuracy of focusing on the film plane, and film flatness will affect the optical quality of your pictures more than anything else. Hope this helps.

All my favorite lenses are single coated. If they has multi-coded version I certainly will try them. Probably I can see a little bit difference in some condition. The fun part of photography is that every lens is different. If you like it just use it. I have seen some single coated lenses are very easy to flare but some are not.

Consider than many of Edward Weston, or Ansel Adams' best regarded photos were made with uncoated lenses, and no, it's not that necessary. It is nice to have though.

 

Lens coating lets you shoot in more situations with light falling near your lens. You get less flare and more contrast. You can get away without using a lens hood more often. The more elements you have in your lens, the bigger the difference this makes. If you're using a 4 element Tessar, you'll care much less than if using a 15 element zoom.

 

I agree with previous replies that state single coating over none is a bigger difference than multi over single coating.

 

So, it's not necessary, but _I_ do want it. Since I use only fixed focal length lenses on medium and large formet, I don't care too much between single and multi coated.

I agree about the aethestic part. Lens flares in proper locations can yield neat results. Some of the computer graphics I'm experimenting with allow you to throw lens flares into a scene to give it an added sense of realism. The beach/moon composite on my web page was created with such an effect.

 

mindspring.com/~wseaton

 

However, I'd have to say that more of my shots are ruined by errant lens flares than adding anything to the composition. I have to be far more cautious with my Mamiya lenses than my Nikon ones since I can almost shoot into a super-nova with the Nikkors and not get flare. With the Mamiya C's if there's a street light or hot spot within several degrees out side the frame I'll get flare and weak blacks.

 

Older lenses, cameras and TLRs generally contain simplier optics with fewer, smaller elements and those being closer together, so therfore flare is less of an issue compared to a 10" long, 10+ element fixed 35mm lens with a 3-4" diameter main lens. A non coated 2 1/4 reflex with a 250mm 2.8 lens is going to have problems.

 

//scott

To contribute some factual numbers to the discussion:

An uncoated surface of polished optical glass reflects 4 to 8% of the light trying to get through. The exact amount depends on the refractive index of the glass. So every lens element, having two surfaces, reflects - which means: it loses, or: it throws away - in the magnitude of 10% of the light.

With single layer coating the percentage of reflected light can be brought down to 1% per surface. Such a lens element would only lose 2%.

With multi coating it varies quite a bit, depending on type and number of layers involved. With many multi coated lenses on the market today the number of layers per surface goes up to 3. Our analysis at Carl Zeiss shows, that on some low price lenses only the very first and the very last surface are really multi coated, the others are coated with just a single layer. This could explain why photographers find a significant difference between uncoated and coated, but not so much between coated and "multi coated".

T* coating, the multi layer coating of Carl Zeiss, applies up to 7 layers per surface and brings reflexivity down to 0.2% per surface.

Is it just me, or is anyone else getting a bit tired of Kornelius'

posts ending in (or in fact just being) a plug for the superiority of Zeiss lenses. Though

his technical information is sometimes useful, I find the constant "our lenses are better" undertone to be grating and not something I want to see

in this forum. For me, if anything, they are turning me OFF ever buying Zeiss lenses. Perhaps it's only me, but that's the way I feel.

Anyone who continually hypes their own product is just, to me, a little suspect in terms of objectivity and whatever they say is

tainted by that.

I decided that, being unable to tell the difference between single- and multicoated results on my own equipment, I wasn't going to seek out multicoated used equipment.

 

I'm shying away from uncoated stuff simply because I'm a little lazy, and would like to depend on my equipment a little.

 

Your mentioning 6400 speed film implies B&W to me. If uncoated lenses turn out to be relatively useless for color work you might want to do in the future, you might just be costing yourself an unnecessary couple of hundred bucks before stepping up later.

 

RE: Kornelius -- since being "outed" he doesn't try to hide his connections. Would you prefer a more gee-whiz, smarmy factory rep? I think it's entertaining to have Zeiss employees floating around on sites whose maintainers don't put much credence in designer glass. (And if my livelihood depended in part on the sales of such wildly expensive items, I'm sure I'd say they were great too.)

Don't complain about the guy because he gets paid for giving his opinion, if somebody paid me and Scott for our opinions, we'd be retired by now, but that's our problem. You can ignore me and you can ignore Korn, or not. I think all that technical crap is pretty cool (useful) and at least we <i>know</i> where <i> he's</i> coming from...t

well maybe in <i>this</i> regard...t

A single lens coating only covers a narrow frequency of light. A lens with a single coating may match a multi-coated lens with certain colors, but not others. If a single coated lens was optimized for red light (unlikely) it would perform poorly with violet light or vice versa. I assume most single coatings are optimized for green and thus fall off on reds and violets to some degree. The idea behind multi-coating is that by applying different coatings that are optimized for different frequencies of light, the entire visible spectrum can be covered. Different manufactures coating's are optimized for different freqencies which is one reason why lenses of the same design that are equal in sharpness may produce images of different tonal and contrast characteristics.

I think an answer like Kornelius' is a great contribution. I even think that when we discuss an issue like this, other manufacturers' people should join in and give their technical advice. I sure would like to see what Mamiya, Pentax, Nikon and others have to say about this. I would like to see how they solve the same kind of problem as that would help me when deciding which lens to buy!!!

 

BTW, I have used uncoated, coated and multicoated. Although have never done a "scientific" test with them, my experience shows that what I read above is true: Difference from uncoated to coated to be significant and from coated to multi, I found almost unnoticeable.

 

DeMarchi

There's always the Diana for those who think the worse the technical quality of the lens the finer the image...

 

I think I will stick with Zeiss.

I really don't see the issue with Kornelius' explaining how Zeiss approached an engineering problem and solved it, especially if it's information contributing to this thread. If there's a plug in there, it's minor compared to the facts stated in his response.

 

Hey, if a respected equipment manufacturer wants to post a reply relevant to a discussion and give factual information that isn't blatantly biased (obviously his wasn't) whats the big deal? No one's handing out free cigarettes and personally I think it's comforting that there are some connections out there that are paying attention to what we talk about.

<i>There's always the Diana for those who think the worse the technical quality of the lens the finer the image... I think I'll stick with Zeiss.</i><p>

Precisely my point. For about $800.00 I can buy a used 50f4C for my Hasse. A used 50f4 FLE will cost over $2,000.00. Without a doubt the newer lens is better --- but is it better enough that I should choose between a lens I maybe never can afford and one I maybe can?<p>

As a postscript, today I exchanged 2 older press style LF lenses for a 65 f8 Angulon I intend to use for architectural photos. My dealer (whom I feel I can trust) was delighted; he got two lenses, one of which was somewhat collectible, and I got a lens that will prove quite useful to me and was just gathering dust in his inventory. I could never have afforded the newer version of this lens; I hope to have a lensboard for it in a week or so and try it out. Otherwise, my dealer has promised that I can exchange the 65mm for a 90mm if I prefer.

(Hopefully the last off-topic post in this thread)

 

I don't have a problem with manufacturers posting information about their products as long as they identify themselves and refrain from 'advertising'. I believe Kornelius' posting in this thread complies with both these points.

 

Perhaps Zeiss/Hasselblad should take a good look at the excellent Mamiya site and implement a user-forum area on their Hasselblad pages, since there's clearly demand for more manufacturer information!

I too welcome factual responses from manufacturers. Also opinions (but not adverts, not that I've seen any recently) from people who happen to work for manufacturers.

 

Anyhow, back to the topic. I like the modern, very sharp, high contrast lenses. But I also like older, single- or non-coated lenses. They can have a quality and character all their own, and we can use this constructively. To say nothing of budget considerations. It depends, of course, on what you are trying to achieve with your photography. I feel that anyone working exclusively with modern multi-coated lenses may be losing out, as Stefan indicates.

It made a huge difference in perceived quality when, a few years ago, I moved to antireflective-coated eyeglass lenses. I wonder if the coatings are the same?

a humble response to the original q:

 

--yes