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


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The S DNGs that I have looked at do not have software correction opcodes in the DNG. But (a) I might not have looked at the "right" lens, and (B) you could perhaps perform correction on the raw data, although in my view that would be a (very much) less than optimal way of doing things.

 

Sandy

 

Thank you Sandy.

 

I was curious.

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If you have a file where the distortion has been corrected and the image is cropped...and then you want to add in some barrel distortion (anamorphosis) you will be losing even more area and doubling whatever degradation that the interpolation causes.

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Quite true. As far as I am aware Photo Ninja works as a plugin in Lightroom. In that case one could choose the raw conversion of choice, with or without corrections, without going outside one's workflow.

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If you have a file where the distortion has been corrected and the image is cropped...and then you want to add in some barrel distortion (anamorphosis) you will be losing even more area and doubling whatever degradation that the interpolation causes.

 

Are we still discussing the T? Would any T customer care about the above?

 

It is not intended as a professional camera.

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Exactly what Pico said.

Besides some insights on how things work in photography and optics, there is little if any value at all for the prospect buyer of the T system.

Whoever buys the T will want an instrument to take pictures, and will not want to even hear of Raw filters and stuff. The Leica Brandname is enough of a guarantee for him that he carries a real nice system that will in the future hold its value.

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Are we still discussing the T? Would any T customer care about the above?

 

It is not intended as a professional camera.

 

So why any discussion about software vs. optical correction? I thought we were the informed talking about the pros and cons not concerning ourselves whether it matters to the much less knowledgeable typical end user.

 

The average snapshooter and even very few highly experienced photographers really understand all of the perspective issues involved with depicting various subjects using wide and extremely wide lenses. That is a consistent challenge for me when shooting architectural interior photos.

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[...] even very few highly experienced photographers really understand all of the perspective issues involved with depicting various subjects using wide and extremely wide lenses. That is a consistent challenge for me when shooting architectural interior photos.

 

Speaking for myself, I would thoroughly appreciate information concerning exactly that subject. Perhaps it could be covered in a different sub-forum and under a descriptive title. I still struggle with film and wide-angle, specifically 47mm over 4x5, 35mm over 6x12, and 6" over 8x10. Considering using digital instead might provide a breakthrough.

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Speaking for myself, I would thoroughly appreciate information concerning exactly that subject. Perhaps it could be covered in a different sub-forum and under a descriptive title. I still struggle with film and wide-angle, specifically 47mm over 4x5, 35mm over 6x12, and 6" over 8x10. Considering using digital instead might provide a breakthrough.

 

I often have to concentrate on this very issue when shooting interiors. many of my clients want to show maximum space so I often shoot very wide. It is a huge benefit to be able to shoot tethered to a 16inch laptop and study the image. I may move the camera very slightly or re-arrange the furniture. Even plates on a counter will be adjusted several times until they look right.

 

Years of experience shooting wide interiors gives me a big leg up on understanding how to depict space to please my clients. Yes it is often exaggerated and sometimes a close object like a chair is still too large for my taste. There are compromises in everything and using extreme wide angle without crazy perspective distortions (even using perfectly rectilinear lenses) is not easy.

 

I don't see digital being much different than film for any of this and I shot with the widest lenses on film for quite a long time... so whatever I learned about perspective was from when I when shooting film.

Edited by AlanG
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I know, but the Ms are not lenses designed considering software corrections, because they have to perform well on film too.

 

 

I see what you are saying, but doesn't designing lenses for digital sensors introduces new parameters that need to be dealt with...things that do not impact film as much? If this is the case, shouldn't lenses designed for digital sensors be optimized for performance on digital sensors? And when you add a (relatively low for Leica) price point in the equation, doesn't it make sense to use optimist the corrections via channels that yield the best results (ie correct distortion via software and other more complex ones optically)?

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Even my Zeiss MF lenses showed some need for digital correction that I did manually in post from scanned images. My 40mm had a lot of purple fringing. Almost every lens can benefit from some kind of digital correction even if it is only minor. Maybe you want absolutely no vignetting from a copy lens for instance. In the old days, the vignetting of the enlarging lens might compensate for the vignetting of the camera lens.

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Because DPReview made an ill considered remark on the subject

 

We don't know how much they considered it. None of us heard whatever Leica told them. I couldn't give a rat's ass about who is right and who is wrong.

 

In any case most of this discussion is about defending Leica and has little to do with understanding how to get the most out of the T or any other camera or lens. It seems to me that would be one's primary interest before caring how a lens was designed, manufactured or corrected.

 

If Leica's reputation is mostly about how they build their lenses and not about the final end result, purchasing a Leica lens would require more of a collector's mindset than a photographer's.

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In any case most of this discussion is about defending Leica .....

Actually I must disagree. Most of this discussion (or ranting) is really about perceptions of one kind or another. It can be difficult to be objective.

 

As for reputations, well unfortunately Leica isn't the photographic name it once was, in my recent experience. When I was at PCL (as you were too I believe - just a year or so separated us;)), Leicas still had an enviable reputation for producing fabulous cameras. Today I'm afraid Leica's name is not as well known (its probably better known in binocular circles) and I'd suggest that the T system will actually have to stand on its merits far more than many previous Leica cameras, which is why its design is so important.

 

The heated debate on lens optics and software correction is, as has been pointed out before, almost certainly irrelevant to many prospective T purchasers. Perhaps this is unpalatable, but I would expect only a few of its purchasers to use it to its full potential (which is probably true of many cameras).

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In any case most of this discussion is about defending Leica and has little to do with understanding how to get the most out of the T or any other camera or lens.

 

I don't think that's it at all. Some people seem to be saying Leica has designed a crappy lens because "software will take care of it" and then lied about it to people. I just don't think logically either one of those things are true.

 

I think it's more about how far you can go with optics within design, size and cost limitations and where you have to draw the line in the sand to decide what will be corrected by software. With a zoom of any decent range, distortion correction makes a lot of sense.

 

I love some Leica gear but not exclusively. I also love some Canon, Sony and Pentax gear...anyone can make a bad product and many of these companies have. (Example: I love the NEX6 but found the A7r fatally flawed for my needs.)

 

I'm just not convinced there's anything realistically wrong with the T, or its lenses.

Edited by Carbon111
clarity
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re-arrange the furniture. Even plates on a counter will be adjusted several times until they look right.

 

Ah! You know how round objects such as plates become oblong when close to a WA lens, so you NEED Pico's Prop Plates (PPP) which are already oblong. Just orient them to counter-act lens distortion!

 

People who have bought Pico's PPP also buy his perspective correcting Greek Column Plug-in (a reference to architecture; not Ancient Greek erotica).

 

.

 

 

Sent from my Etcha-sketch.

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If a lens is optimised for a sensor it is more than optimised for film. A sensor is far more critical.

 

 

Generally true; in the case of the T zoom, the wide angle distortion would not be accounted for if it were *somehow* used on film. Regardless, the T lens isn't made for film cameras and I doubt it'll be used on one.

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If a lens is optimised for a sensor it is more than optimised for film. A sensor is far more critical.

 

You cannot use a lens like the Vario T on film, due to that uncontrolled distortion and high chromatic errors at the wide end (18mm). I was referring to this.

 

And the same goes for many lenses "designed" for digital systems. Those lenses seem good only after software corrections are applied, but they are more or less useless without those corrections or on film.

 

Residual aberrations are also present in "only optically corrected" lenses, but they are averaged and there is no extreme amounts of any of them. For many brands, in the 80s and 90s the overall level of correction was very, very good (more glasses, aspherical shapes, floating groups, etc.).

 

The current trend in optical design implies substantial presence of one or two aberrations and the software correction is mandatory for making these lenses useable.

Edited by rosuna
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