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Leica T performs digital lens correction , a claim by dpreview.com


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I assumed in my post there must be, and if there isn't, Leica should add it. It doesn't cost them anything. Or you can use a raw converter that doesn't read the code.

 

The Sony A7 gives you the choice to select which corrections you want to apply (vignetting, CA, distortion) per each lens individually.

 

So far as I am aware, the corrections are always present in DNG. Raw converters can chose to use them or not, as they see fit - e.g., ACR or Lightroom will always use the codes, AccuRaw won't ever.

 

Sandy

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It is not the same.

 

M lenses are corrected for vignetting on digital sensors, and we all know why is it.

 

The problem with the T lenses is different: this is a zoom lens with modest specifications and a very, very high price. Leica is risking their reputation here.

 

The distortion of this lens at the wide end is astounding.

 

This is my point exactly. If they are not going to correct these aberrations, they should not be charging so much for their lenses.

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This is my point exactly. If they are not going to correct these aberrations, they should not be charging so much for their lenses.

Sorry but that's just rubbish. The cost of the lens is affected by a number of different things, of which correction of aberrations through design or manufacturing is just one factor, and we have no idea what Leica's costs are and how cost relates to price.

 

Ultimately the price is the price (and is controlled by what the market will stand) and if you consider the price acceptable you'll pay it and if you don't you won't. Saying that a company is charging too much for its goods is really saying that you want them to sell their goods to you cheaper and, well, we'd all like that I feel sure but that's not how the market works because if a company sells it's goods to you too cheaply then it's likely to go out of business, which is not going to help you with after sales service etc should you need it.

 

I apologise if this sounds like lecturing but I've read too often recently that Leica is charging too much for this or that. If people think the price is too high then they shouldn't pay it.

 

Pete.

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This is my point exactly. If they are not going to correct these aberrations, they should not be charging so much for their lenses.

 

First, we do not know yet what op-codes the Leica prime 23mm F2 writes. Making a high quality prime for digital worthy of the Leica name is expensive.

 

As for the vari-focus (which is not really a zoom lens), the use of op-codes and correction seems appropriate considering it must deal with video.

 

Compare the T lenses to Panasonic's quality digital-video and primes.

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So far as I am aware, the corrections are always present in DNG. Raw converters can chose to use them or not, as they see fit - e.g., ACR or Lightroom will always use the codes, AccuRaw won't ever.

 

Sandy

 

Could you provide me with the official list of allowable charges a lens manufacturer may charge, broken-down into coatings, body material, number of asph surfaces, etc...

 

This way, I can be sure that I get the best lens for the best price.

 

Looking at it this way, I am sure I got taken on all of my M-lenses! :eek:

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Could you provide me with the official list of allowable charges a lens manufacturer may charge, broken-down into coatings, body material, number of asph surfaces, etc...

 

I could. But then you'd never take pleasure from reading a 7 page thread again.

 

Sandy

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Sorry but that's just rubbish. The cost of the lens is affected by a number of different things, of which correction of aberrations through design or manufacturing is just one factor, and we have no idea what Leica's costs are and how cost relates to price.

 

Ultimately the price is the price (and is controlled by what the market will stand) and if you consider the price acceptable you'll pay it and if you don't you won't. Saying that a company is charging too much for its goods is really saying that you want them to sell their goods to you cheaper and, well, we'd all like that I feel sure but that's not how the market works because if a company sells it's goods to you too cheaply then it's likely to go out of business, which is not going to help you with after sales service etc should you need it.

 

I apologise if this sounds like lecturing but I've read too often recently that Leica is charging too much for this or that. If people think the price is too high then they shouldn't pay it.

 

Pete.

 

The cost of correcting aberrations is a huge factor, which would require additional lens elements and more sophisticated designs. The cost gets exponential as the lens gets brighter. With film, there's no easy to correct for the aberrations, so Leica's fast and well designed lenses are worth the investments.

 

But then now it seems like they are trying to use digital correction to cover up cheaper lens designs, while still charging the Leica premium. To me that's just wrong. But sadly, Leica has many fans who would defend Leica to the grave.

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it is hard to say without facts in hand.

 

What did glasses cost to make before mounting them in barrel? Probably more than competitors.

 

It is too early to disregard the overall cost vs value without knowing manufacturing costs.

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The cost of correcting aberrations is a huge factor, which would require additional lens elements and more sophisticated designs. The cost gets exponential as the lens gets brighter.

 

Exactly, although perhaps Leica's subcontractor is using a more sophisticated and costly design than is used for many similar kit zooms. We will only know if this is so and worth it, if objective tests bear it out. (Assuming that more complex and costly designs generally do produce better results.)

 

If you look at Canon's old 24mm TSE lens and compare it with the current one, you will see how much larger and more complex it became in order to be so much better. That cost a lot more too. Software cannot make the old one perform as well as the new one. The good thing about all of this is we can simply examine and measure the results instead of speculating about them.

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The design is Leica's, not by the producing factory. So there is no "subcontractor"

 

Someone designs something and another company produces it under direction. I think that is the definition of a subcontractor. Why be picky about the semantics? I was trying to point out that this design might be more expensive to make than some similar type of lenses... even if it also relies on software correction.

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The cost of correcting aberrations is a huge factor, which would require additional lens elements and more sophisticated designs. The cost gets exponential as the lens gets brighter. With film, there's no easy to correct for the aberrations, so Leica's fast and well designed lenses are worth the investments.

 

But then now it seems like they are trying to use digital correction to cover up cheaper lens designs, while still charging the Leica premium. To me that's just wrong. But sadly, Leica has many fans who would defend Leica to the grave.

I agree that the cost of optical aberration correction can be a large cost so perhaps it would help to compare the cost/price of a lens that we know has outstanding aberration correction such as the 50/2 APO-Summilux-M asph or the 50/1.4 Summilux-M asph against the cost of the T lenses that are apparently not entirely corrected and you'll notice a massive difference in the cost/price between T and M lenses. (For the record, I don't think it would be helpful compare the cost of T lenses against other manufacturers' similar lenses because there are just too many variables for there to be a meaningful comparison.)

 

BTW, your post seems to suggest that correcting aberrations for digital sensors is easier than for film but that can't be right so I must have misunderstood.

 

Pete.

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Because your post suggested the lens was a rebadged design by the manufacturing company.

 

That is not what I said at all. I said this design may be more complex than what is common. "perhaps Leica's subcontractor is using a more sophisticated and costly design than is used for many similar kit zooms." I made no mention of where that design comes from... assuming Leica.

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Someone designs something and another company produces it under direction. I think that is the definition of a subcontractor. Why be picky about the semantics? I was trying to point out that this design might be more expensive to make than some similar type of lenses... even if it also relies on software correction.

 

Of course, this design might be more expensive to make than some similar type of lenses... even if it also relies on software correction.

 

Many, if not all, CSC zoom lenses with wide focal distances use software correction for distortion, but not all zooms are the same (in terms of built quality or optical quality).

 

Software correction may have a price in terms of resolution and contrast.

 

Why Leica allowed a distortion so high in this design?

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I agree that the cost of optical aberration correction can be a large cost so perhaps it would help to compare the cost/price of a lens that we know has outstanding aberration correction such as the 50/2 APO-Summilux-M asph or the 50/1.4 Summilux-M asph against the cost of the T lenses that are apparently not entirely corrected and you'll notice a massive difference in the cost/price between T and M lenses. (For the record, I don't think it would be helpful compare the cost of T lenses against other manufacturers' similar lenses because there are just too many variables for there to be a meaningful comparison.)

 

Despite all of the variables you are comparing the cost to make very dissimilar lenses - M vs. T made by two different companies, one in Germany and one in Asia? When you say cost are you talking about the actual production cost or do you mean the cost to buy the lens? I have no idea of the production cost to make either lens at either place nor the markup that determines the final selling price.

 

But if you look at other APS zoom lenses made in Asia, you can get good fairly well corrected ones for less than what the 18-56 T lens costs. I just made a quick search and see that Sigma's 17-70 2.8-4 APS lens lists at $500 and "seems to be" more difficult to make than the 18-56 for the T. It is available for several cameras but the T is not currently one of them. DPReview makes it look pretty good. None of us can say if the T's 18-56 is better. A Sigma 17-50 2.8 sells for about $570 and looks like a pretty complex design also but maybe the individual elements in the T lens cost more to make? I don't think any of us can say for sure that the manufacturing specs on the T lenses are significantly tighter nor how well they'll do on standard tests.

 

Sigma 17-70mm f/2.8-4 DC Macro OS HSM | C review: Digital Photography Review

 

Considering there are numerous variables - the factory, the methodology, quantities produced, etc, it certainly may be possible for one company to produce a lens with fairly good optical correction of all of these things for much less than another company could make it. Why else would Leica be farming out some lens production instead of building these lenses in Germany or opening a new factory in Asia?

 

I don't know if you are familiar with Canon's 17mm F4 TSE lens. As far as I know it is the only lens of its type and focal length. It has virtually no distortion that I can see and is quite well corrected for c/a with little vignetting. It is built with 18 elements in 12 groups and projects a 104 degree image circle. The mount allows for tilt and shift with independent rotation. It sells for $2500 despite having no competition. What would Leica charge if it made an identical lens in Germany... even leaving the R&D costs aside?

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Why Leica allowed a distortion so high in this design?

 

Size and cost are always tradeoffs and distortion correction is often a solution even if it degrades the image slightly and requires some cropping. Maybe this allowed for some other aspect of the lens to be better?

 

But as I mentioned, I don't apply distortion correction to Canon's tilt shift lenses and it would be complicated to correct them if that were needed. (It isn't.) But the lenses are quite large as a result and are fairly expensive. Although they are pretty cheap by Leica standards and I think they sell quite a lot of them.

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So far as I am aware, the corrections are always present in DNG. Raw converters can chose to use them or not, as they see fit - e.g., ACR or Lightroom will always use the codes, AccuRaw won't ever.

 

Sandy

 

If this is so, then I see the arguments against Leica's policy regarding this issue as an overreaction. Because this means then that the raw, binary image data contained in the DNG file is not overwritten by a distortion corrected version within the camera, rather than simply accompanying it with some codes into the file that is interpreted by the raw converter software to do a specified correction. And it is up to the software whether it allows for ignoring this code or not.

 

Actually, this is nothing different from how white balance is treated in ALL digital cameras, which are able to record raw data. The white balance, whether it is set manually or used in auto mode, means nothing else than storing 3 multiplier numbers within the raw file, one for each color channel. But the actual binary image data is never affected by what white balance was chosen. Then, it is up to the raw converter software what it does with the white balance multipliers contained within the raw file. With certain converters (mostly DCraw and other software that are relying on it) you can completely ignore the set white balance and you can just get the raw data, even without Bayer-demosaicing if you wish.

 

Though it is true that Leica could have been more straight in admitting what does it do for distortion correction on its T lenses, I would say that these issues must be primarily addressed to the software companies like Adobe so that they offer a way to ignore the corrections in the raw conversion workflow.

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Its on DPReview Pete - Leica T (Typ 701) First Impressions Review: Digital Photography Review

 

Interesting apart from the extreme distortion is how much image area is lost in the corrected version - so at 18mm what are you actually getting? 24mm?

 

How does the I corrected image compare to say a 28mm M lens?

 

Me too noticed this.... using the DPReview images, and supposed they are full-file, one could even evaluate, I think, the "effective" focal length of the corrected ones (you need the exact distance of taking, which I suppose is the 1m-2m range) ... it's something like when you use de-distorction tools in PS, loosing "slices" of your picture...

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... I would say that these issues must be primarily addressed to the software companies like Adobe so that they offer a way to ignore the corrections in the raw conversion workflow.

 

Historically, DXO does its own lens testing and makes its own correction models for the DXO Optics raw software converter. Various correction can be turned on or off and adjusted in numerous ways. I don't know if DXO now also uses the embedded correction information when available.

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