# What happened to DO?



## untitled10 (Mar 5, 2013)

I seem to remember there was a load of chatter about a whole new range of DO lenses from canon, but I havent heard anything since, and no one ever seems to show any interest in the exsisting Do lens's, what are your thoughts on them?


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## paul13walnut5 (Mar 5, 2013)

When I used to sell camera gear the biggest differention was that DO allowed the same optical quality in a smaller lens. There was a big L (400 I think) and plasticy 70-300 IS DO, however the cheaper 70-300 IS was it's peer as far as the final image went.

Perhaps it crops up, just they don't sing and dance about it?


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## TrumpetPower! (Mar 5, 2013)

paul13walnut5 said:


> When I used to sell camera gear the biggest differention was that DO allowed the same optical quality in a smaller lens.



That was the marketing spiel, but it wasn't the reality. The 400 f/4 DO is, I understand, the least impressive of the Great Whites. It's not that it's a bad lens; indeed, it's probably pretty far up there in an overall ranking of Canon lenses. It just falls rather short of the other Great Whites, is all. I understand every other "serious" 400mm option from Canon outperforms it, including a 300 f/2.8 w/ 1.4x, the 400 f/5.6, and, perhaps most damning, the 100-400. And, of course the 400 f/2.8 blows it away.

If it had the quality, it'd probably be hugely successful. But most anybody who's going to blow $6,500 on a 400mm Great White isn't going to be overly concerned about weight...you know ahead of time that that comes with the territory, and it's not like the 400 DO is lightweight in absolute terms -- it still comes in at almost 2 Kg, after all.

If somebody came to me asking for advice, I'd recommend the 300 f/2.8 + 1.4 TC over the 400 DO...you'd save $500, get a better lens, and not add all that much to the weight. If weight is really that important, either the 400 f/5.6 or the 100-400 will weigh a fair amount less than the 400 DO, produce better pictures (assuming you can afford the loss of a stop), and cost a hell of a lot less. Or, if weight is the concern and price isn't, get the 300 f/2.8 II + 1.4x. And if it's just awesomeness at 400mm you're interested in regardless of weight or expense, either version of the 400 f/2.8 is your ticket.

Whatever niche the 400 DO fills, it's a very small one, indeed.

Cheers,

b&


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## jcollett (Mar 5, 2013)

I think the stronger question is why no more DO lenses beyond the two released some years ago? I'm sure there are other focal lengths that would be interesting with DO. I guess Canon simply does not want to invest more money into what their customers have essentially rejected with the 400 and 70-300. Too bad IMHO.


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## Drizzt321 (Mar 5, 2013)

jcollett said:


> I think the stronger question is why no more DO lenses beyond the two released some years ago? I'm sure there are other focal lengths that would be interesting with DO. I guess Canon simply does not want to invest more money into what their customers have essentially rejected with the 400 and 70-300. Too bad IMHO.



Or perhaps they've given up for the moment because, as I understand it, DO is very difficult. Maybe they're working on some R&D into producing the necessary optics at the quality they need, or doing a ton of computer models or trying out several different formulations. It might just be that they had to basically go back to the drawing board when those 2 lenses didn't perform as well as expected.

Or they've just given up entirely because it's too hard for now, and so no point in putting more money into DO.


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## jrista (Mar 5, 2013)

Canon has several sets of patents that were granted for new DO lenses in just the last year:

http://www.canonrumors.com/2012/04/patent-new-diffractive-optic-patents/
http://www.canonrumors.com/2012/12/patent-supertelephoto-do-lenses-with-macro-features/

Based on what the patents cover, it seems as though Canon has spent a lot of time perfecting the diffractive elements to improve their resolving power, sharpness, etc. So far, Canon has patents for:

14mm f/2.8 DO
70-300 f/4.5-5.6 DO IS
600mm f/4 DO IS
400mm, 600mm & 800mm DO Macro w 1:4, 1:1, and 2:1 magnification factors

The last three would be truly amazing lens designs. MFD for Canon's current 400, 500, 600, and 800 lens designs are limited to 12-16 feet out at a 0.15x magnification. A true macro magnification factor would effectively eliminate the MFD in all practical circumstances, as well as allowing real-world macro use for flora, insects, etc. with very comfortable working distances.

Who knows if these will ever see the light of day, but I don't believe DO is dead.


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## TrumpetPower! (Mar 5, 2013)

Drizzt321 said:


> jcollett said:
> 
> 
> > I think the stronger question is why no more DO lenses beyond the two released some years ago? I'm sure there are other focal lengths that would be interesting with DO. I guess Canon simply does not want to invest more money into what their customers have essentially rejected with the 400 and 70-300. Too bad IMHO.
> ...



Very likely a combination of all of the above.

I'm sure there will be more DO lenses at some point in the future. The problem right now is that it's in a tough spot. The normal way these sorts of things work is that the exotic new technology goes first into the expensive early-adopter market; think Tesla and their electric supercar. You don't sell very many, but the much higher than usual profit margins on the exotics then fund the development of a middle-tier luxury model using the same basic technology. Once you've recovered your expenses in that market, you can now afford to bring it to the masses.

When a new technology goes <thud /> with the early adopters, as DO has, it's hard to justify the expense of pushing it farther along the product lifecycle. In this case, that's a bit unfortunate, as DO is much better suited to the bottom end of the food chain than the top. A compact, lightweight superzoom or supertelephoto with fair-to-middlin' optics would sell like hotcakes to the general public if it were priced even half again as much as standard models. Make a 24-300 f/4 - f/5.6 DO the size and weight of the 28-135, price it at $700, and you won't be able to keep them on the shelves, even if the image quality is no better than the 28-135.

The problem is getting the price of the technology down to the level where that's practical.

In other words, I see DO's future with the consumer masses at the low end of the market. I don't think it has a future at the high end, at least not for a long time until after it's been perfected at the low end.

And that's bass-ackwards from the way these sorts of things generally work, so expect it to take a lot longer than you might naively expect.

Cheers,

b&


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## neuroanatomist (Mar 5, 2013)

I had the 70-300 DO for a while (bought used and subsequently sold for the same price, basically a free several-month rental). I really liked the convenience of it, it's the same size (retracted) as the 24-105, and the two lenses together made a great walk around kit. But from an IQ standpoint, it was just okay, and the images from the DO lens needed a fair bit of TLC in post. I owned the lens before the availability of the 70-300L, and today I would not hesitate to get the L version of the 70-300. 

Canon has been very active in terms of filing patents on DO lenses and teleconverters. But I wonder if we will ever see any of those become new products?


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## RLPhoto (Mar 5, 2013)

If canon we're to revamp DO tech, I believe they'd release several major lenses at one time and ditch the older ones immediately to rid themselves of the stigma of the Old DO tech.

Personally, I'd love a 200mm F/2 IS DO the size/weight of a 135L.


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## Mt Spokane Photography (Mar 5, 2013)

untitled10 said:


> I seem to remember there was a load of chatter about a whole new range of DO lenses from canon, but I havent heard anything since, and no one ever seems to show any interest in the exsisting Do lens's, what are your thoughts on them?


Although Canon has filed a number of patents for radial dispersed DO lens elements made by embedding fine particles in a resin matrix, that does not mean its a money making venture to produce them. As Canon noted in the patents, the issue with DO lens elements is to get the particle dispersion even and perfectly spaced so that the correct spectrum is diffracted. Apparently the yield is too low, or else they are waiting for some future date to announce one.

The existing lenses use a diffraction grating sandwiched between regular glass elements as shown below.








If they can make a particle dispersed radial diffraction lens more practical, they will have a potentially higher performance. The price is a question mark.


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## jrista (Mar 5, 2013)

Mt Spokane Photography said:


> untitled10 said:
> 
> 
> > I seem to remember there was a load of chatter about a whole new range of DO lenses from canon, but I havent heard anything since, and no one ever seems to show any interest in the exsisting Do lens's, what are your thoughts on them?
> ...



Just out of curiosity, what makes a DO lens with dispersed particles more effective than the diffraction gratings they use now?


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## Mt Spokane Photography (Mar 5, 2013)

jrista said:


> Just out of curiosity, what makes a DO lens with dispersed particles more effective than the diffraction gratings they use now?


 
Good question. 

Canon has not given up on gratings, here is a patent released in 2012. http://www.faqs.org/patents/app/20120212821

I can only rely on Canon's statement in the patents, but the diffraction varies radially which allows for less CA, but thats assuming the particle dispersion bends the various light rays correctly. 
The gratings are one dimensional and use a glass lens to bend the light.

Here is some reading material, there will be a test tomorrow if we can find anyone who understands it well enough to grade the answers  

http://www.faqs.org/patents/app/20110317276


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