Let's talk about Diffractive Optics...

CyberDyneSystems wrote in post #4023064
When a $1K lens @ f/5.6 has better IQ than a $5k Lens @ f/4... and weighs in at less than 1/3rd the $5K lens..
...Then it's a tough argument for the $5K lens.

5X the cost and over 3 times the weight is a tough price to pay for 1 stop of aperture.

Jaker, it's only about 2x the weight, and that's one key selling feature of the 400DO.
The other one is IS.
Those are easy advantages to grasp.

When it comes to IQ, opinions are divided.
Some experienced folks do maintain their 400DO at f5.6 is better than 400 f/5.6 wide open.
Some even say that 400DO IQ is indistinguishable from their 500 f/4.

I think I saw in a DO lens cross section that there is only one DO element in the 400/4DO lens. I think it just replaces a UD lens.

We all use DO lenses, there is one on every flash gun, either built in or external. Some even use a second in the form of a better beamer or something. This simple DO lens is the well known freshnel lens. Only a mm thick or so, and it acts like a much larger spherical lens.

To really appreciate the pros and cons of a DO lens construction, one would need an all-DO or at least most-DO lens design. It is most certain that such an all-DO lens design could give a 1200/4 or 1200/5.6 lens weighing less than 4 pounds (if the barel was made of plastic). Weight and cost should be a benefit, because DO lenses are pressed and this is a much cheaper construction method.

The fact that the 400/4DO lens is not very well received (with only one DO element) means that an all-DO lens would not deliver all that good IQ.

If I could see a future in DO optics, it would be in low cost, ultra compact and thin cameras. And yet, we see these cigarette box sized cameras using 3 element extended barels for mounting normal glass or plastic spherical lenses. Some Canon high end cameras even utilize UD and aspherical elements to achieve apochromatism, which is the main benefit of DO lenses.

I just think that since Canon can afford to have two lenses in their lineup that don't sell, and since they made research in this area, they just brought out the most descent incarnation of their efforts if only to say: Hey, we also do DO lenses.

cwphoto wrote in post #4028985
There's no DO in those lenses - they're just green.

That's inconsistent labeling from Canon

Lightstream wrote in post #4023067
Some good points here. I notice a lot of people who use the grips secretly wish their DSLR looked bigger (even if they don't admit it or find another (valid) reason to justify the grips.) Note I'm not bashing the grip, but be honest with yourself about why you really want it.

Noooo hohoho!!! My secret plan has been exposed...

Wilt wrote in post #4023030
Canon started with the DO as a means of achieving certain optical goals in a more compact and lighter weight...a good travel lens. The world discovered that proper handling of the DO from an optical perspective required somewhat different techniques, and the world seemed to be more enamored of L lens speed and performance, size and weight be damned. The time seems wrong for DO. Back 20+ years ago, when the world was enamored of smaller and lighter film SLRs (the Olympus OM craze, followed by the Canon AE-1 and Nikon Fm are examples) I think the DO would have wowed the world and been more of a commercial success. Now all the pixel peepers and lovers of huge 'professional looking' dSLR with battery grips (the 1Ds wannbes) make a smaller, lighter, lower performing lens something with few homes.

that sounds about right. Some of the larger DO lens, I think the 400mm (I think and I am not looking it up so forgive me if I am wrong) and that's got some good reviews.

however cost is always a factor. the only way to get everyone to use a DO lens is to make it cheap.

Lightstream wrote in post #4023067
Some good points here. I notice a lot of people who use the grips secretly wish their DSLR looked bigger (even if they don't admit it or find another (valid) reason to justify the grips.) Note I'm not bashing the grip, but be honest with yourself about why you really want it.

that I would agree with, reading the thread about what else people had brought with the 40D it seems that the large amount had brought the grip at the same time.

I am happy with using the 40D with out the grip and don't have any plans in getting it. it's just the right side for my hands. As for power, I got 4 batteries and will last more than a day

it's just my 2gb card isn't big enough.

theflyingkiwi wrote in post #4030226
that I would agree with, reading the thread about what else people had brought with the 40D it seems that the large amount had brought the grip at the same time.

So what? I don't admitting that one of the factors that had me picking up a 40D was the ability to use my current grip with it, but it proves nothing about why I - or anyone else - might want to use a grip.

So let's see if I get this: you don't use a grip because that best suits your hands, but those of us who do use a grip do it for every reason but?

Diffractive optics (just like mirror lenses) will never have that nice, smooth bokeh of normal lenses. It's because of their design.

Here's Ken's take on DO :
http://www.kenrockwell​.com …lenses/70-300mm-do-is.htm

And from wikipedia

And don't you like that nice DO bokeh

wimg wrote in post #4023954
Even so, rather harsh statement. Do you have any facts to substantiate this with?

Kind regards, Wim

I don't know about facts and what would be convincing, we are talking about subconscious drives here; but I agree there does seem to be a pre-occupation with big heavy (and white) == professional, a kind of technology jewelry aspect.

This "technology jewelry" attitude is not new, as pointed out earlier in the thread 20 years ago this focused on the small rather than the large.

A lot of people routinely walk about with quite large any heavy white zooms, do they really need them or would they be better served with a slower zoom or a few primes?

But back to the point, DO does not seem to have the cool factor in marketing terms. Is this due to pre-occupation with the big or with the best image quality?

Lets face it, most people don't need the best IQ, they are not making big prints all the time, they shoot handheld rather than with a tripod so there results will be a long way from the optical capability of even a modest lens. So why do so many have a pre-occupation with equipment image quality? Presumably for bragging rights, or just in case?

Lester Wareham wrote in post #4031198
Lets face it, most people don't need the best IQ, they are not making big prints all the time, they shoot handheld rather than with a tripod so there results will be a long way from the optical capability of even a modest lens. So why do so many have a pre-occupation with equipment image quality? Presumably for bragging rights, or just in case?

snob appeal or bragging rights. we need to face the facts that agressive marketing has made most people in Western civilizations into ad whores...they buy name brand jeans, name brand purses and shoes, pay more for certain name brands of cars (even though they are made with the same parts as the cheaper mass market brand from the same company!), exclusive name brand everything, include L...and the common factor is a recognizable LABEL (or red stripe, in the case of lenses)

In fact, I just realized that 'L' stands for 'Label'!!!

Wilt wrote in post #4031270
we need to face the facts that agressive marketing has made most people in Western civilizations into ad whores...

Amen. Thank you capitalism!

Keith R wrote in post #4030495
So what? I don't admitting that one of the factors that had me picking up a 40D was the ability to use my current grip with it, but it proves nothing about why I - or anyone else - might want to use a grip.

the first comment was an observation of what I had seen. nothing more nothing less.

Keith R wrote in post #4030495
So let's see if I get this: you don't use a grip because that best suits your hands, but those of us who do use a grip do it for every reason but?

the second comment was on the fact that I don't need the grip. nothing more nothing less.

You might have some valued reason for the grip, if you do that's good for you. however there are some people out there who would get the grip to make it look like a 1 series.

Lord_Malone wrote in post #4022883
I was thinking maybe Canon could update the 70-300mm f/4.5-5.6 DO IS USM. Or has Canon given up on Diffractive Optics and the "Green Ring" line? Let's hear your thoughts.

Somewhat back on topic ()

This lens is attractive from the size and weight point of view. The only thing holding me back is the price.

I carry all my gear in one bag (never know when I might need something :rolleyes, and since I could use something longer than the 24/105, this lens would do the trick and will fit into my bag (all the other zoom teles are a bit too long.

Furthermore, since everyone is "going red", I'm thinking that "going green" might be a nice touch.