Resolution of M43 lenses

Started Mar 31, 2013 | Discussions
zenpmd
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Resolution of M43 lenses
Mar 31, 2013

I do not understand why photozone were a bit critical of the Pana 2.8 constant apeture zoom lens. They waxed lyrical about the Fuji zoom, but the pana resolves more detail - more so than the 1.8 Olympus.

Isnt that really impressive?

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axlotl
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Re: They worry about distortion and corner shading
In reply to zenpmd, Mar 31, 2013

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process. So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive". But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness. They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter. In other words they are complaining about lens attributes which are of no concern in the real world. You will see the CA however if the lens is used on an Olympus camera.

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texinwien
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I disagree
In reply to axlotl, Mar 31, 2013

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

tex

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wildwilly
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Fully agree. nt
In reply to texinwien, Mar 31, 2013
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bowportes
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Re: They worry about distortion and corner shading
In reply to axlotl, Mar 31, 2013

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process. So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive". But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness. They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter. In other words they are complaining about lens attributes which are of no concern in the real world. You will see the CA however if the lens is used on an Olympus camera.

Very good explanation.

Having used many micro four-thirds zooms and primes (from both Panny and Oly), I have found no lens that delivers as consistently, or that is more versatile, than this zoom.  It's a delight to use and yields very high quality images.

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Dr_Jon
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Re: I disagree
In reply to texinwien, Mar 31, 2013

I do agree with you, and added a like, but will say that if the trade-off for the distortion correction is some other attributes that are much better than you would expect but would be very hard to fix in software then it's perhaps not so bad a trade-off, e.g. better flare resistance (err, doesn't seem to do that) or better out-of-focus rendering (I like the 35-100, early days with the 12-35), or less vignetting (no) or less residual spherical aberration (probably not so important with m43 and f2.8) or ...

I have no idea which of these qualities it might have, it may well just be priced to match their production capability to demand. Simply pointing it out as another thing to consider.

(I have both the f2.8 zooms and they are okay if a little over-priced in my view, the latest Canon equivalents are a lot better, especially wide open, but a lot more money, size and weight. Horses for courses I guess.)

P.S. (edit) my GH3 doesn't do a great job correcting the 12-35 and leaves quite a lot of distortion in the JPEGs at the wide end, DXO does a much better job so perhaps I should see what gets thrown away to pay for that. (Actually I don't care, I prefer right-angle corners on rectangles, not triangles sticking out.)

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Anders W
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Re: I disagree
In reply to texinwien, Mar 31, 2013

texinwien wrote:

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

On what grounds do you leap to the conclusion that designing lenses to be software-corrected in one specific regard (geometric distortion) is done only or primarily for the purpose of cutting costs? And what makes you think that the end results (after correction) must necessarily be worse than they would have been for a lens corrected by optical means only?

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

I think of this lens-design strategy as an asset rather than a liability for MFT and I am sure the main reason that some others refrain from taking advantage of it is that it runs into trouble with an optical viewfinder. When you compose, you want to know what you will get once the image is properly corrected. Possible with an EVF, not possible with an OVF.

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Dr_Jon
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Re: I disagree
In reply to Anders W, Mar 31, 2013

One's analogue and one digital. Once it's turned into pixels the rest of the information is gone and to correct it you need to throw some pixels away, stretch some out to cover a wider area and squish some together. The latter one should go reasonably well, the rest lose sharpness.

However with good processing this can be kept down so it's a case of how people feel about that. At the wide end of my 12-35 it needs a lot of correction and the Photozone results do show the centre sharpness is a long way above the edge at all apertures at 12mm, but whether that's software correction or the edges of the lens just being not-so-great in comparison to the centre I have no idea.

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texinwien
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Re: I disagree
In reply to Anders W, Mar 31, 2013

Anders W wrote:

texinwien wrote:

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

On what grounds do you leap to the conclusion that designing lenses to be software-corrected in one specific regard (geometric distortion) is done only or primarily for the purpose of cutting costs?

I never said what you're asking me to defend. Software correction is practically free, however.

And what makes you think that the end results (after correction) must necessarily be worse than they would have been for a lens corrected by optical means only?

I have also not made that claim.

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

Nothing is wrong with it if the end results are as good. I never claimed otherwise. As a matter of fact, I specifically said that most are probably fine with the idea if the cost-savings are shared with the consumer.

I think of this lens-design strategy as an asset rather than a liability for MFT and I am sure the main reason that some others refrain from taking advantage of it is that it runs into trouble with an optical viewfinder.

I don't have a problem with the strategy.

When you compose, you want to know what you will get once the image is properly corrected. Possible with an EVF, not possible with an OVF.

Interesting theory- sounds plausible.

If you have any links to good reading on the subject, I'd be happy to have a look. Might save you some effort trying to retype what you've already written elsewhere.

tex

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Anders W
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Re: I disagree
In reply to Dr_Jon, Mar 31, 2013

Dr_Jon wrote:

At the wide end of my 12-35 it needs a lot of correction and the Photozone results do show the centre sharpness is a long way above the edge at all apertures at 12mm, but whether that's software correction or the edges of the lens just being not-so-great in comparison to the centre I have no idea.

Exactly. While we know that the resolution of the 12-35 after distortion correction is worse than before, we can't know whether the end result is better or worse than it would have been for a lens designed so as not to require any software correction. Correcting one aberration is frequently at odds with correcting others and improving distortion characteristics by optical means may well come at the expense of lower resolution.

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Thorgrem
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Re: I disagree
In reply to Anders W, Mar 31, 2013

Anders W wrote:

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

That's the difference between people who like to talk about he equipment (like photozone) and the specifications and people who like to use the equipment in the real world.

I think that in body correction is the future and not everyone is ready for it.

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Dr_Jon
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Re: I disagree
In reply to Anders W, Mar 31, 2013

Not arguing with that at all (kinda tough to judge though), plus I do like sharpness (can't really add actual detail later) as when being out and about I sometimes take some bird/animal pics that need a lot of cropping.

After a certain point I care about other characteristics on the lens too. For example I have a (rather old now) Canon 70-300 DO lens which is really not that sharp (compared to stuff with Ls in their names) away from the short end. However I just love its rendering of photographs, so every time I consider selling it I take some pics and decide I really want to keep it (okay, then usually take a sharper lens out with me 95% of the time...) For m43 I'd take really nice out-of-focus rendering over absolute sharpness on fast(er) lenses, just I'd like quite a lot of sharpness along with that please, well at least for a grand (UKP) anyway.

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Anders W
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Re: I disagree
In reply to texinwien, Mar 31, 2013

texinwien wrote:

Anders W wrote:

texinwien wrote:

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

On what grounds do you leap to the conclusion that designing lenses to be software-corrected in one specific regard (geometric distortion) is done only or primarily for the purpose of cutting costs?

I never said what you're asking me to defend. Software correction is practically free, however.

If you are not saying that it is done for the purpose of cutting costs, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

And what makes you think that the end results (after correction) must necessarily be worse than they would have been for a lens corrected by optical means only?

I have also not made that claim.

If you are not saying that the results are worse, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

Nothing is wrong with it if the end results are as good. I never claimed otherwise. As a matter of fact, I specifically said that most are probably fine with the idea if the cost-savings are shared with the consumer.

So you are suggesting that it is a matter of cost-savings after all?

I think of this lens-design strategy as an asset rather than a liability for MFT and I am sure the main reason that some others refrain from taking advantage of it is that it runs into trouble with an optical viewfinder.

I don't have a problem with the strategy.

When you compose, you want to know what you will get once the image is properly corrected. Possible with an EVF, not possible with an OVF.

Interesting theory- sounds plausible.

If you have any links to good reading on the subject, I'd be happy to have a look. Might save you some effort trying to retype what you've already written elsewhere.

There are lots of threads on the subject where this has been debated at quite some length. Here is one of them. See particularly the contributions by kenw.

http://www.dpreview.com/forums/post/39680143

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Anders W
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Re: I disagree
In reply to Dr_Jon, Mar 31, 2013

Dr_Jon wrote:

Not arguing with that at all (kinda tough to judge though), plus I do like sharpness (can't really add actual detail later) as when being out and about I sometimes take some bird/animal pics that need a lot of cropping.

After a certain point I care about other characteristics on the lens too. For example I have a (rather old now) Canon 70-300 DO lens which is really not that sharp (compared to stuff with Ls in their names) away from the short end. However I just love its rendering of photographs, so every time I consider selling it I take some pics and decide I really want to keep it (okay, then usually take a sharper lens out with me 95% of the time...) For m43 I'd take really nice out-of-focus rendering over absolute sharpness on fast(er) lenses, just I'd like quite a lot of sharpness along with that please, well at least for a grand (UKP) anyway.

Of course there is more to lens performance than the MTF values. I am in full agreement with you about that. Fortunately, the two MFT lenses I would primarily try to use for subject isolation by means of background blur (Oly 45/1.8 and 75/1.8) both have very good bokeh on top of very good resolution, so I don't have to make a choice between the two virtues.

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texinwien
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Re: I disagree
In reply to Anders W, Mar 31, 2013

Anders W wrote:

texinwien wrote:

Anders W wrote:

texinwien wrote:

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

On what grounds do you leap to the conclusion that designing lenses to be software-corrected in one specific regard (geometric distortion) is done only or primarily for the purpose of cutting costs?

I never said what you're asking me to defend. Software correction is practically free, however.

If you are not saying that it is done for the purpose of cutting costs, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

There's not much to interpret, is there? It's a simple declaration. I'm not sure which words lead you to your interpretation. The statement, "it costs less to build a lens with poor optics, then correct resulting problems in software" doesn't require much interpretation, I don't believe, and your 'restatement' relies on something other than the words I wrote, it would seem.

I could probably add an 'all things being equal' to the front of the statement to make it a little less arguable. I might also replace 'problems' with 'imperfections' then add 'than it does to build a lens with excellent optics in the first place' to the end.

And what makes you think that the end results (after correction) must necessarily be worse than they would have been for a lens corrected by optical means only?

I have also not made that claim.

If you are not saying that the results are worse, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

This is how you should 'interpret' them: all things being equal, it costs less to build a lens with poor optics, then correct resulting imperfections in software, than it does to build a lens with excellent optics in the first place.

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

Nothing is wrong with it if the end results are as good. I never claimed otherwise. As a matter of fact, I specifically said that most are probably fine with the idea if the cost-savings are shared with the consumer.

So you are suggesting that it is a matter of cost-savings after all?

I'm suggesting that, all things being equal, it costs less to build a lens with poor optics, then correct resulting problems in software, than it does to build a lens with excellent optics in the first place.

I think of this lens-design strategy as an asset rather than a liability for MFT and I am sure the main reason that some others refrain from taking advantage of it is that it runs into trouble with an optical viewfinder.

I don't have a problem with the strategy.

When you compose, you want to know what you will get once the image is properly corrected. Possible with an EVF, not possible with an OVF.

Interesting theory- sounds plausible.

If you have any links to good reading on the subject, I'd be happy to have a look. Might save you some effort trying to retype what you've already written elsewhere.

There are lots of threads on the subject where this has been debated at quite some length. Here is one of them. See particularly the contributions by kenw.

http://www.dpreview.com/forums/post/39680143

Will brush up, thanks for the link.

tex

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exdeejjjaaaa
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Re: I disagree
In reply to Anders W, Mar 31, 2013

Anders W wrote:

Dr_Jon wrote:

At the wide end of my 12-35 it needs a lot of correction and the Photozone results do show the centre sharpness is a long way above the edge at all apertures at 12mm, but whether that's software correction or the edges of the lens just being not-so-great in comparison to the centre I have no idea.

Exactly. While we know that the resolution of the 12-35 after distortion correction is worse than before, we can't know whether the end result is better or worse than it would have been for a lens designed so as not to require any software correction. Correcting one aberration is frequently at odds with correcting others and improving distortion characteristics by optical means may well come at the expense of lower resolution.

really ? take a peek @ olympus 12-35/2 or 35-100/2... optical correction adds weight, size and cost+price... but it always better than software correction just because you can always apply the same math on top of that... you don't have any single example of a properly optically corrected lenses (distortion and aberrations) that leads to reduced resolution... just FUD to justify underdesigned lenses to save on size/weight and cost to sell more.

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PC Wheeler
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Re: Resolution of M43 lenses
In reply to zenpmd, Mar 31, 2013

zenpmd wrote:

I do not understand why photozone were a bit critical of the Pana 2.8 constant apeture zoom lens.

I got the sense that price was a perhaps-suble factor in their conclusion; now I own both f/2.8 lenses and am very pleased with them corner to corner on my GH3 even fully open (f/2.8) at all focal lengths.  Happy camper.

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Anders W
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Re: I disagree
In reply to texinwien, Mar 31, 2013

texinwien wrote:

Anders W wrote:

texinwien wrote:

Anders W wrote:

texinwien wrote:

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

On what grounds do you leap to the conclusion that designing lenses to be software-corrected in one specific regard (geometric distortion) is done only or primarily for the purpose of cutting costs?

I never said what you're asking me to defend. Software correction is practically free, however.

If you are not saying that it is done for the purpose of cutting costs, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

There's not much to interpret, is there? It's a simple declaration. I'm not sure which words lead you to your interpretation. The statement, "it costs less to build a lens with poor optics, then correct resulting problems in software" doesn't require much interpretation, I don't believe, and your 'restatement' relies on something other than the words I wrote, it would seem.

I thought that what you said was meant to apply to the Panasonic 12-35/2.8, which, according to you, has "excessive [distortion] for a $1300 lens" and relies "on software correction for a problem that should probably be corrected optically in a premium lens". If what you said was not meant to apply to that lens, what would be its relevance in the present context?

I could probably add an 'all things being equal' to the front of the statement to make it a little less arguable. I might also replace 'problems' with 'imperfections' then add 'than it does to build a lens with excellent optics in the first place' to the end.

And what makes you think that the end results (after correction) must necessarily be worse than they would have been for a lens corrected by optical means only?

I have also not made that claim.

If you are not saying that the results are worse, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

This is how you should 'interpret' them: all things being equal, it costs less to build a lens with poor optics, then correct resulting imperfections in software, than it does to build a lens with excellent optics in the first place.

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

Nothing is wrong with it if the end results are as good. I never claimed otherwise. As a matter of fact, I specifically said that most are probably fine with the idea if the cost-savings are shared with the consumer.

So you are suggesting that it is a matter of cost-savings after all?

I'm suggesting that, all things being equal, it costs less to build a lens with poor optics, then correct resulting problems in software, than it does to build a lens with excellent optics in the first place.

I think of this lens-design strategy as an asset rather than a liability for MFT and I am sure the main reason that some others refrain from taking advantage of it is that it runs into trouble with an optical viewfinder.

I don't have a problem with the strategy.

When you compose, you want to know what you will get once the image is properly corrected. Possible with an EVF, not possible with an OVF.

Interesting theory- sounds plausible.

If you have any links to good reading on the subject, I'd be happy to have a look. Might save you some effort trying to retype what you've already written elsewhere.

There are lots of threads on the subject where this has been debated at quite some length. Here is one of them. See particularly the contributions by kenw.

http://www.dpreview.com/forums/post/39680143

Will brush up, thanks for the link.

tex

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exdeejjjaaaa
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Re: They worry about distortion and corner shading
In reply to axlotl, Mar 31, 2013

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process. So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive". But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness. They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter. In other words they are complaining about lens attributes which are of no concern in the real world. You will see the CA however if the lens is used on an Olympus camera.

dude - how you can claim that you can critically inspect anything if you are using a raw converter that automatically corrects everything for you ? certainly you hardly notice a corner shading when it is forcibly corrected for you :-)... take a red pill.

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exdeejjjaaaa
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Re: I disagree
In reply to Anders W, Mar 31, 2013

Anders W wrote:

texinwien wrote:

Anders W wrote:

texinwien wrote:

Anders W wrote:

texinwien wrote:

axlotl wrote:

The reviewers at Photozone appear not to have fully accepted that post capture lens corrections are now a normal part of the image making process.

Normal according to whom? Not all lenses require as much software correction as others. Some require very little. Some require much more.

So they RAW convert with RAW Therapee, demonstrate 5.8% barrel distortion at 12mm and decry that as "excessive".

It is pretty excessive for a $1300 lens.

But if, like the rest of us, you simply use the camera as designed and allow the distortion to be corrected automatically in camera then all you will see is a mild amount of residual distortion. In addition the Photozone reviewers say that the automatic distortion correction is "lossy" , however those of us who have actually used the lens for several thousand photos, often critically inspected for sharpness, are unaware of this supposed lossiness.

Whether you have noticed it or not, correction is, in fact, a lossy operation. There is nothing 'supposed' about that statement, and the Photozone reviewers are 100% correct.

They also criticise corner shading which is present but which I hardly ever notice in actual photos and if I do, it is easily removed in a RAW converter.

Relying again on software correction for a problem that should probably be optically corrected in a premium lens.

In other words they are complaining about lens attributes which are of no concern in the real world.

Not true. The attributes are of concern, which is why you must apply software correction in order to fix them. The point is, at what price should we expect a lens to be optically excellent? It costs less to build a lens with poor optics, then correct resulting problems in software.

As long as the manufacturers pass on some of the savings they realize from these cost-cutting measures, I think most are OK with the idea. If, however, a manufacturer builds a lens with poor optics and tries to sell it as a premium quality lens, there are plenty of discriminating buyers who won't appreciate the trick.

On what grounds do you leap to the conclusion that designing lenses to be software-corrected in one specific regard (geometric distortion) is done only or primarily for the purpose of cutting costs?

I never said what you're asking me to defend. Software correction is practically free, however.

If you are not saying that it is done for the purpose of cutting costs, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

There's not much to interpret, is there? It's a simple declaration. I'm not sure which words lead you to your interpretation. The statement, "it costs less to build a lens with poor optics, then correct resulting problems in software" doesn't require much interpretation, I don't believe, and your 'restatement' relies on something other than the words I wrote, it would seem.

I thought that what you said was meant to apply to the Panasonic 12-35/2.8, which, according to you, has "excessive [distortion] for a $1300 lens" and relies "on software correction for a problem that should probably be corrected optically in a premium lens". If what you said was not meant to apply to that lens, what would be its relevance in the present context?

I could probably add an 'all things being equal' to the front of the statement to make it a little less arguable. I might also replace 'problems' with 'imperfections' then add 'than it does to build a lens with excellent optics in the first place' to the end.

And what makes you think that the end results (after correction) must necessarily be worse than they would have been for a lens corrected by optical means only?

I have also not made that claim.

If you are not saying that the results are worse, how then should we interpret what you say in the two paragraphs immediately above the question I raised?

This is how you should 'interpret' them: all things being equal, it costs less to build a lens with poor optics, then correct resulting imperfections in software, than it does to build a lens with excellent optics in the first place.

I find no reason to think along such lines. If the end results, after correction, are good, as they are for those MFT lenses with strong barrel distortion prior to correction that I own and use (12/2, 7-14/4, 14-45/3.5-5.6), what's wrong with it?

Nothing is wrong with it if the end results are as good. I never claimed otherwise. As a matter of fact, I specifically said that most are probably fine with the idea if the cost-savings are shared with the consumer.

So you are suggesting that it is a matter of cost-savings after all?

I'm suggesting that, all things being equal, it costs less to build a lens with poor optics, then correct resulting problems in software, than it does to build a lens with excellent optics in the first place.

I think of this lens-design strategy as an asset rather than a liability for MFT and I am sure the main reason that some others refrain from taking advantage of it is that it runs into trouble with an optical viewfinder.

I don't have a problem with the strategy.

When you compose, you want to know what you will get once the image is properly corrected. Possible with an EVF, not possible with an OVF.

Interesting theory- sounds plausible.

If you have any links to good reading on the subject, I'd be happy to have a look. Might save you some effort trying to retype what you've already written elsewhere.

There are lots of threads on the subject where this has been debated at quite some length. Here is one of them. See particularly the contributions by kenw.

http://www.dpreview.com/forums/post/39680143

Will brush up, thanks for the link.

tex

and ?

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