Olympus 17/1.8 review

Started Nov 17, 2012 | Discussions
noirdesir
Forum ProPosts: 10,822
Like?
Re: SLow focussing seems body reltated mostly
In reply to Jorginho, Nov 18, 2012

Jorginho wrote:

Agreed hence my reply. I felt he was like I wrote down. I was not being rude but I was being straightforward with him. I simply said how I felt. Not how he behaved as a fact, just how it came across to me. I did not call him names, I did not say he is arrogant. I said that to me his reply felt like this and that...How is that rude? Also he does not get into my remakr at all, only that point that I had to read the whole review. Again....I was wrong..okey. I was 100% correct he used an Oly (as CA and PF with a 20 mm 1.7 is clear sign of not using a Panasonic body...). So for the point I made it was absolutely not necessary to read his review. To me it seemed he had some trouble with the critique, but I am not sure. I don't know.

I would consider your expectation that every impression mentioned needed to be prefaced with a disclaimer as unreasonable (and thus rude).

Reply   Reply with quote   Complain
rrr_hhh
Veteran MemberPosts: 5,916Gear list
Like?
Re: Olympus 17/1.8 review
In reply to Acrill, Nov 18, 2012

Acrill wrote:

I do not have the Panny 20mm so the new 17mm looks very compelling.

Frankly, I think it is a great lens compared to the competition. I'm looking at the Lenstip resolution charts for the old Olympus 17mm 2.8, and that old boy beats the following lenses, hands down:

Pentax smc DA 35 mm f/2.4 AL

Canon EF 35 mm f/2.0

Samyang 35 mm f/1.4 AS UMC

Carl Zeiss Distagon T* 35 mm f/2 ZF/ZK/ZS/ZE

and probably others.

Obviously there are other factors to consider than just the MTF chart, but both the old and new Olympus 17mm lenses appear to be "world class" lenses from a resolution point of view.

Any big flaws in my analysis?

Beware, because some reviewers aren't offering really comparable results when you change format. I don't remember what Lenstip does, but you should read about their method before drawing any conclusion directly from their numbers.

-- hide signature --

rrr_hhh

Reply   Reply with quote   Complain
noirdesir
Forum ProPosts: 10,822
Like?
Re: Macrocontrast vs. Microcontrast
In reply to Anders W, Nov 18, 2012

Anders W wrote:

noirdesir wrote:

Ming Thein wrote:

I think there may be some confusion between microcontrast, macrocontrast and resolution here. On the full size images, the 17/1.8 has slightly better microcontrast in the center than the other two, but macrocontrast is definitely lower.

Ming,

A few years back I tried to figure out a definition for the term microcontrast. Since the most comprehensive way to measure contrast of a lens is a full MTF curve, lenses with different amount of microcontrast should have characteristically different MTF curves. To this day, I keep being surprised that I have not seen a single person talk about this (how microcontrast is reflected in a MTF curve).

I showed a generic example of two lenses with very different character in this post:

http://forums.dpreview.com/forums/post/35584548

and discussed it further in this post:

http://forums.dpreview.com/forums/post/37010026

Of note is that all full MTF curves that I have seen, eg, from DxOmark, always start at one, ie, 100% contrast. That is obviously not really correct as every lens + camera system has some internal flare. While one naturally can normalise all MTF curve to one, this would clearly paint 'foggy' lenses in a much better light than it should be. My idea of what you mean with macrocontrast would be the contrast at essentially target resolution of zero, whereas microcontrast would be the contrast at finer resolutions, whether that is the contrast below the resolution of the MTF50 value as I insinuated in the first post I linked to above or the contrast just above that resolution, I don't know.

And since nobody has rigorously defined microcontrast to my knowledge yet, so far I can only answer that by comparing lots of full MTF curves of lenses which are claimed to either have good or bad microcontrast to see whether there is a pattern (or whether the term microcontrast either covers a wide array of lens behaviours or is just not used very consistently).

It is certainly true that the usage of the term "microcontrast" is not well defined. However, it is obvious to me that it must originally have been coined in contradistinction to global contrast or macrocontrast, and thus refers to contrast at frequencies (resolution criteria) some distance away from zero. At the same time, I have the impression that at least some people use it in reference to contrast at fairly low frequencies rather than very high ones, lower frequencies arguably being more important for perceived image quality at ordinary display size.

It is my impression that it has been coined both in contrast (no pun intended) to global contrast AND to resolution. If we take MTF50 as resolution, this would mean the contrast somewhere between 0 and the 50% mark but some people (like DxO or DPreview with their extinction resolution) consider a much lower contrast for their 'resolution' definition.

As I referred to in my first linked post, the difference between Leica and Zeiss has sometimes been referred to as Leica focussing on resolution and Zeiss on microcontrast (hence my attempt to visualize what might lie behind these different labels people put on lens characteristics).

Like you, I have come to the conclusion that we need to consider the entire MTF curve for a better understanding and I have therefore, like you, looked with interest at the curves now regularly published by DxOMark as part of their lens reviews:

My conclusion after having gone through this exercise for quite a few lenses is that good lenses tend to have MTF curves rather similar to the red curve in the hypothetical diagram you link to, i.e., the curve is fairly close to a line sloping downwards at an angle approaching 45 degrees. Bad lenses tend to have curves more resembling a hyperbolic function (1/x), i.e., they decline very rapidly as the resolution criterion increases from zero to some 10 or 20 lp/mm and then taper off more slowly as the resolution criterion increases further. I can't remember seeing a curve resembling the blue graph in your hypothetical diagram. Would you agree with this somewhat schematic description of mine?

Yes, it is also my impression that the better lenses are closer to a straight line and less good ones exhibit a (larger) positive second derivative (except for the very end of the curve). For two lenses with the same MTF50 value, a straight MTF curve clearly has higher contrast than one that is negatively deviates from that straight line. A purely diffraction-limited lens would exhibit a straight line, which is another indicator that getting close to that straight line might indicate very low other aberrations.

What I have seen has left me more comfortable with the MTF-50-percent criterion used by most test sites. While the result at that contrast level (which, as you probably know, is said to be chosen because it correlates well with human perception of image quality although I have seen no description of the research that this contention presumably rests on) won't tell us everything, it is likely to be strongly correlated with the results we would see if the contrast requirement were set a bit higher.

I am less happy with the fact that DxO themselves set the contrast criterion used for their lens scores significantly lower than other sites (they use 20 percent rather than 50), both because the differences between lenses are likely to be less clear-cut in this contrast region and because I think it is less important for perceived image quality how a lens does in this contrast region at anything resembling normal display size and viewing distance.

Yes, I too find DxO lens scores a bit puzzling as they do not seem to correlate very well with anecdotal evidence (and while anecdotal evidence is often somewhat biased, overall it does correlate with what matters: how much humans like the final result).

Reply   Reply with quote   Complain
noirdesir
Forum ProPosts: 10,822
Like?
Re: Olympus 17/1.8 review
In reply to rrr_hhh, Nov 18, 2012

rrr_hhh wrote:

Acrill wrote:

I do not have the Panny 20mm so the new 17mm looks very compelling.

Frankly, I think it is a great lens compared to the competition. I'm looking at the Lenstip resolution charts for the old Olympus 17mm 2.8, and that old boy beats the following lenses, hands down:

Pentax smc DA 35 mm f/2.4 AL

Canon EF 35 mm f/2.0

Samyang 35 mm f/1.4 AS UMC

Carl Zeiss Distagon T* 35 mm f/2 ZF/ZK/ZS/ZE

and probably others.

Obviously there are other factors to consider than just the MTF chart, but both the old and new Olympus 17mm lenses appear to be "world class" lenses from a resolution point of view.

Any big flaws in my analysis?

Beware, because some reviewers aren't offering really comparable results when you change format. I don't remember what Lenstip does, but you should read about their method before drawing any conclusion directly from their numbers.

Exactly, if you have test results on cameras with the same MP count and you then integrate the LP/mm to LP/PH (picture height), you start to get somewhat comparable results (but you still have different AA filters to contend with).

Reply   Reply with quote   Complain
sansbury
Regular MemberPosts: 231
Like?
Re: Olympus 17/1.8 review
In reply to Ming Thein, Nov 18, 2012

Ming, have you ever looked at (through?) the Pany 12-35? I'm considering the 12 and 17, but the same money gets me the 12-35 and a bottle of good Scotch whisky, not to mention focal lengths from 17-35, weather sealing, and IS in case I decide to get a Pany body someday. The slower aperture and size don't really bother me.

The thing that does bother me is that Oly can clearly make AWESOME primes, like the 60 and 75, and even the 45 deserves some mention, while the new 17 appears to be merely "good." The stupid little kit zoom which nobody likes is already a good lens by any absolute standard--I've been printing a wall full of 17x22 prints taken with it. If I am going to bother with primes that each cost 3-5x as much, I want a clear difference and not just in aperture. The 45/60/75 all do that.

The 17 is a nice piece of jewelry but for nearly 50% more than the 20/1.7 I feel like I'm paying for bling rather than lens. 17 is such a basic length for me--I grew up with a 35/f2 Nikkor so my brain is wired at this length--that I am going to give it a try since the 20 often is just not quite enough, but I can't shake the feeling that buying this lens is encouraging Oly to make more overpriced black lens hoods rather than awesome sweep-the-field lenses.

And yes, if the announced Schneider 14 lives up to the reputation of S-K lenses, I'll be opening my wallet.

Reply   Reply with quote   Complain
captura
Forum ProPosts: 12,907Gear list
Like?
Re: Olympus 17/1.8 review
In reply to Ming Thein, Nov 18, 2012

Ming Thein wrote:

Hi everybody,

I've had a final version of the 17/1.8 for a couple of days now and just posted my review:

Comparative lens review: The Olympus M. Zuiko Digital 17/1.8

As usual, leave a question here or on the site and I'll do my best to get back to you.

Enjoy and have a good weekend!

Ming

-- hide signature --

www.mingthein.com

Thank you kindly for your interesting review, and same to the commenters.

I was a bit concerned about the pre-production version of the 17-1.8; was it un-representative?

Can some of your test results be quickly re-checked at a later date, using a production lens?

I would also love to see a comparison with the 14-2.5, which is my personal favorite lens.

 captura's gear list:captura's gear list
Fujifilm X10 Sony Alpha NEX-7 NEX5R Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 R Sony E 55-210mm F4.5-6.3 OSS +9 more
Reply   Reply with quote   Complain
Anders W
Forum ProPosts: 17,076Gear list
Like?
Re: Macrocontrast vs. Microcontrast
In reply to noirdesir, Nov 18, 2012

noirdesir wrote:

Anders W wrote:

noirdesir wrote:

Ming Thein wrote:

I think there may be some confusion between microcontrast, macrocontrast and resolution here. On the full size images, the 17/1.8 has slightly better microcontrast in the center than the other two, but macrocontrast is definitely lower.

Ming,

A few years back I tried to figure out a definition for the term microcontrast. Since the most comprehensive way to measure contrast of a lens is a full MTF curve, lenses with different amount of microcontrast should have characteristically different MTF curves. To this day, I keep being surprised that I have not seen a single person talk about this (how microcontrast is reflected in a MTF curve).

I showed a generic example of two lenses with very different character in this post:

http://forums.dpreview.com/forums/post/35584548

and discussed it further in this post:

http://forums.dpreview.com/forums/post/37010026

Of note is that all full MTF curves that I have seen, eg, from DxOmark, always start at one, ie, 100% contrast. That is obviously not really correct as every lens + camera system has some internal flare. While one naturally can normalise all MTF curve to one, this would clearly paint 'foggy' lenses in a much better light than it should be. My idea of what you mean with macrocontrast would be the contrast at essentially target resolution of zero, whereas microcontrast would be the contrast at finer resolutions, whether that is the contrast below the resolution of the MTF50 value as I insinuated in the first post I linked to above or the contrast just above that resolution, I don't know.

And since nobody has rigorously defined microcontrast to my knowledge yet, so far I can only answer that by comparing lots of full MTF curves of lenses which are claimed to either have good or bad microcontrast to see whether there is a pattern (or whether the term microcontrast either covers a wide array of lens behaviours or is just not used very consistently).

It is certainly true that the usage of the term "microcontrast" is not well defined. However, it is obvious to me that it must originally have been coined in contradistinction to global contrast or macrocontrast, and thus refers to contrast at frequencies (resolution criteria) some distance away from zero. At the same time, I have the impression that at least some people use it in reference to contrast at fairly low frequencies rather than very high ones, lower frequencies arguably being more important for perceived image quality at ordinary display size.

It is my impression that it has been coined both in contrast (no pun intended) to global contrast AND to resolution. If we take MTF50 as resolution, this would mean the contrast somewhere between 0 and the 50% mark but some people (like DxO or DPreview with their extinction resolution) consider a much lower contrast for their 'resolution' definition.

As I referred to in my first linked post, the difference between Leica and Zeiss has sometimes been referred to as Leica focussing on resolution and Zeiss on microcontrast (hence my attempt to visualize what might lie behind these different labels people put on lens characteristics).

Didn't you mean to say somewhere between the 100% and the 50% mark here rather than between 0 and 50%? If yes, then I am all with you.

Like you, I have come to the conclusion that we need to consider the entire MTF curve for a better understanding and I have therefore, like you, looked with interest at the curves now regularly published by DxOMark as part of their lens reviews:

My conclusion after having gone through this exercise for quite a few lenses is that good lenses tend to have MTF curves rather similar to the red curve in the hypothetical diagram you link to, i.e., the curve is fairly close to a line sloping downwards at an angle approaching 45 degrees. Bad lenses tend to have curves more resembling a hyperbolic function (1/x), i.e., they decline very rapidly as the resolution criterion increases from zero to some 10 or 20 lp/mm and then taper off more slowly as the resolution criterion increases further. I can't remember seeing a curve resembling the blue graph in your hypothetical diagram. Would you agree with this somewhat schematic description of mine?

Yes, it is also my impression that the better lenses are closer to a straight line and less good ones exhibit a (larger) positive second derivative (except for the very end of the curve). For two lenses with the same MTF50 value, a straight MTF curve clearly has higher contrast than one that is negatively deviates from that straight line. A purely diffraction-limited lens would exhibit a straight line, which is another indicator that getting close to that straight line might indicate very low other aberrations.

Yes, that's a good way of putting it, I think.

What I have seen has left me more comfortable with the MTF-50-percent criterion used by most test sites. While the result at that contrast level (which, as you probably know, is said to be chosen because it correlates well with human perception of image quality although I have seen no description of the research that this contention presumably rests on) won't tell us everything, it is likely to be strongly correlated with the results we would see if the contrast requirement were set a bit higher.

I am less happy with the fact that DxO themselves set the contrast criterion used for their lens scores significantly lower than other sites (they use 20 percent rather than 50), both because the differences between lenses are likely to be less clear-cut in this contrast region and because I think it is less important for perceived image quality how a lens does in this contrast region at anything resembling normal display size and viewing distance.

Yes, I too find DxO lens scores a bit puzzling as they do not seem to correlate very well with anecdotal evidence (and while anecdotal evidence is often somewhat biased, overall it does correlate with what matters: how much humans like the final result).

Yes. As I have understood it, using 50 percent as a standard contrast criterion implies a break with past tradition, where resolution was often measured using a very low contrast criterion ("extinction resolution"). I find reason to think that the modern practice is better here.

One further question: Would you agree with my assessment that, as far as Ming's images let us judge, the 20 has a better MTF curve than the new 17/1.8? I must admit, I am a bit disappointed at the showing of the 17/1.8 here. I hadn't really expected it to beat the 20 in this regard but I had hoped/expected that it would do about as well. If that had been the case, I would probably have been ready to exchange my 20 for the 17/1.8. Now, I am not so sure.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +21 more
Reply   Reply with quote   Complain
Anders W
Forum ProPosts: 17,076Gear list
Like?
Re: Olympus 17/1.8 review
In reply to noirdesir, Nov 18, 2012

noirdesir wrote:

rrr_hhh wrote:

Acrill wrote:

I do not have the Panny 20mm so the new 17mm looks very compelling.

Frankly, I think it is a great lens compared to the competition. I'm looking at the Lenstip resolution charts for the old Olympus 17mm 2.8, and that old boy beats the following lenses, hands down:

Pentax smc DA 35 mm f/2.4 AL

Canon EF 35 mm f/2.0

Samyang 35 mm f/1.4 AS UMC

Carl Zeiss Distagon T* 35 mm f/2 ZF/ZK/ZS/ZE

and probably others.

Obviously there are other factors to consider than just the MTF chart, but both the old and new Olympus 17mm lenses appear to be "world class" lenses from a resolution point of view.

Any big flaws in my analysis?

Beware, because some reviewers aren't offering really comparable results when you change format. I don't remember what Lenstip does, but you should read about their method before drawing any conclusion directly from their numbers.

Exactly, if you have test results on cameras with the same MP count and you then integrate the LP/mm to LP/PH (picture height), you start to get somewhat comparable results (but you still have different AA filters to contend with).

Yup. In order to make the Lenstip results, expressed in lp/mm, comparable across sensor sizes, you need to apply a conversion factor. For example, in order to compare the results for the 17/2.8 with any FF lens tested on an FF sensor, you need to divide the results for the 17/2.8 by 2 (or 1.96 if you want to be precise). Then there are other complications on top of that. The sensors used for the test should ideally have the same pixel count and an AA filter of similar strength.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +21 more
Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Re: Olympus 17/1.8 review
In reply to Anders W, Nov 18, 2012

I have filmed it now, so all can see. The difference is huge in medium lighting conditions. (1600 ISO f1.7 1/40 s shutterspeed). Again: daytime, it is okey.

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Re: Olympus 17/1.8 review
In reply to noirdesir, Nov 18, 2012

1) I did read his review because he mentioned it here. I browsed it remember.

2) The disclaimer is an example. The difference between GH2 and EPL5 as you will see wihtin an hour os so is/can be huge. It is not just some sort of disclaimer. I mean it in a way that is usefull not just to circumvent some nonsensical discussions. You will see with my video's of both systems on a GH2 the 20 mm 1.7 is as fast or faster thn the 45 mm 1.8 on either Oly or Panny. We are not nitpicking here. I am not.

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Re: SLow focussing seems body reltated mostly
In reply to noirdesir, Nov 18, 2012

You need an hyperbole to make a point. I did not say that, I say it IS necessary here because on other body the experience is very different. Not just a little. The lens simply behaves differently on a GH2 body (for instance) when it comes to the IQ "problems" he notes AND the AF speed. It is quite dramatic in my opinion....

You said the 20 mm i sknown to be slow....Just wait a couple of moments. On a GH2, even in low light, it is almost instant.

I have never heard that unreasonable by itself is some how rude. Rude means impolite, bourish, insulting, disrespectfull. In no way was I disrespectfull etc. But you are free to think diffewrently. I find your behaviour towards me on the rude side.

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
bluelemmy
Contributing MemberPosts: 797
Like?
Re: Olympus 17/1.8 review
In reply to sansbury, Nov 18, 2012

I had the 12mm but sold it because to my eyes the performance of the 12mm was little better than the 12-35.

The only reason I have kept the 20mm, much as I like it, is that it slips onto my camera body and takes so little space that I can carry it everywhere with me.

I have the 25mm Panasonic but it is so big that i rarely use it. I have a feeling that my gear will rationalize soon to lenses 7-14. 12-35, 45mm, 35-100 and 100-300 plus the 14-42 compact zoom. Plus GH3 and Gh2. I already have all of these except GH3 and 35-100. The one lens I'd never get rid of is the Olympus 45mm.

I'll sell the 20 and 25 and I reckon I'll have a complete outfit then. Luckily for me, I take pictures for money so the outer reaches of lens performance simply unnecessary.

-- hide signature --

David
www.dthorpe.net

Reply   Reply with quote   Complain
noirdesir
Forum ProPosts: 10,822
Like?
Re: Macrocontrast vs. Microcontrast
In reply to Anders W, Nov 18, 2012

Anders W wrote:

noirdesir wrote:

Anders W wrote:

It is certainly true that the usage of the term "microcontrast" is not well defined. However, it is obvious to me that it must originally have been coined in contradistinction to global contrast or macrocontrast, and thus refers to contrast at frequencies (resolution criteria) some distance away from zero. At the same time, I have the impression that at least some people use it in reference to contrast at fairly low frequencies rather than very high ones, lower frequencies arguably being more important for perceived image quality at ordinary display size.

It is my impression that it has been coined both in contrast (no pun intended) to global contrast AND to resolution. If we take MTF50 as resolution, this would mean the contrast somewhere between 0 and the 50% mark but some people (like DxO or DPreview with their extinction resolution) consider a much lower contrast for their 'resolution' definition.

Didn't you mean to say somewhere between the 100% and the 50% mark here rather than between 0 and 50%? If yes, then I am all with you.

I think there might be different definitions of microcontrast, as you said that "at least some people use it in reference to contrast at fairly low frequencies rather than very high ones", thus it could be contrast at resolutions between the 0 and 50% mark (but closer to the 50% mark) or it could be the contrast a bit above that.

One further question: Would you agree with my assessment that, as far as Ming's images let us judge, the 20 has a better MTF curve than the new 17/1.8? I must admit, I am a bit disappointed at the showing of the 17/1.8 here. I hadn't really expected it to beat the 20 in this regard but I had hoped/expected that it would do about as well. If that had been the case, I would probably have been ready to exchange my 20 for the 17/1.8. Now, I am not so sure.

I'm not sure, my general impression from his review is that the two lenses are relatively close (with a few notable differences like LoCA and vignetting that favour the 17 mm), and closer than I though they would be. But evaluating MTF from a few crops is something I am not really comfortable with, I'd put more weight on his overall comments which I would assume to be based on a lot more (test) images than the ones shown.

Reply   Reply with quote   Complain
noirdesir
Forum ProPosts: 10,822
Like?
Re: SLow focussing seems body reltated mostly
In reply to Jorginho, Nov 18, 2012

Jorginho wrote:

You need an hyperbole to make a point. I did not say that, I say it IS necessary here because on other body the experience is very different. Not just a little. The lens simply behaves differently on a GH2 body (for instance) when it comes to the IQ "problems" he notes AND the AF speed. It is quite dramatic in my opinion....

The problem is that one cannot know a priori whether a disclaimer is necessary. From your perspective with your knowledge, it might have seemed obvious that a disclaimer would have been necessary but you cannot blame Ming for not having that knowledge and thus not knowing that a disclaimer was necessary.

Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Re: SLow focussing seems body reltated mostly
In reply to noirdesir, Nov 18, 2012

Well, was that not my suggestion after I tiold him what my findings were? Again: you say the slow focussing is so well known...I should know that, isn't it? How come that you do not demand the same from Ming when it comes to the behavioru of this lens on Oly bodies? Is that not also well known?? That is my thought on this.

We have this polemic it seems over what? I wrote this "So I think it is important to note you tested it (most likely, I did not read it) on an Olympus body. On a Panny body, the story is different."

And he says: that I first shoudl read. His only response. I simply can get such a response if you read this. Again: I am clear I did not read it and was right in my assumption. If your onluy response is liek his, how is that kind. He could have said so many things in a kind way and the3 simplest would be "You are correct in your assumption, I used the OMD and said so but you did nt read it" or something like that. If a collegue responds lie that, I go to the collegue to find out what's wrong. Because that is an abrupt respinse (and one of the synonyms I found for being rude btw).

Now, the slow focussing...Is this slow focussing? It is instant. It is as fast as my 45 mm 1.8 on an Oly and even a bit more consistent. That is why ti is important

GH2 with the 20 mm

Youtube refused my EPL5 test will try again...

Edit: it worked.

EPl5 and the 20 mm in medium light conditons

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Re: SLow focussing seems body reltated mostly
In reply to Ming Thein, Nov 18, 2012

Rerreading this I wonder which conclusions I drew were wrong or needed your review to be read. Most of the conclusions if not all were after I  did my own testing and on my own camera's...

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Here my tests with 20 mm on EPL5 and Gh2
In reply to Jorginho, Nov 18, 2012

Here Anders A9nd others), lighting conditions and everything else is identical. Both are set at S-AF and same (they are not the same) focussing points etc. Same f settings. Not scientific, but consistent with my findings in somewhat low light...



Gh2 with 20 mm 1.7 on it AF

EPL5 with 20 m 1.7 on it.

Why would someone with a GH2 want to have the 17 mm 1.8 Oly with the argument it focusses faster. Could be faster, but not appreciably I think. My be on the OMD it is dofferent still. I don't have the cam.

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
Jorginho
Veteran MemberPosts: 7,024Gear list
Like?
Re: SLow focussing seems body reltated mostly
In reply to noirdesir, Nov 18, 2012

Where did I blame him for not knowing somehting? Pointing one to some things he did not knwo or notice is not blaming...What a strange remark...

 Jorginho's gear list:Jorginho's gear list
Panasonic Lumix DMC-G1 Panasonic Lumix DMC-GH2 Olympus PEN E-PL5 Panasonic Lumix DMC-GH4 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS +9 more
Reply   Reply with quote   Complain
Anders W
Forum ProPosts: 17,076Gear list
Like?
Re: Macrocontrast vs. Microcontrast
In reply to noirdesir, Nov 18, 2012

noirdesir wrote:

Anders W wrote:

noirdesir wrote:

Anders W wrote:

It is certainly true that the usage of the term "microcontrast" is not well defined. However, it is obvious to me that it must originally have been coined in contradistinction to global contrast or macrocontrast, and thus refers to contrast at frequencies (resolution criteria) some distance away from zero. At the same time, I have the impression that at least some people use it in reference to contrast at fairly low frequencies rather than very high ones, lower frequencies arguably being more important for perceived image quality at ordinary display size.

It is my impression that it has been coined both in contrast (no pun intended) to global contrast AND to resolution. If we take MTF50 as resolution, this would mean the contrast somewhere between 0 and the 50% mark but some people (like DxO or DPreview with their extinction resolution) consider a much lower contrast for their 'resolution' definition.

Didn't you mean to say somewhere between the 100% and the 50% mark here rather than between 0 and 50%? If yes, then I am all with you.

I think there might be different definitions of microcontrast, as you said that "at least some people use it in reference to contrast at fairly low frequencies rather than very high ones", thus it could be contrast at resolutions between the 0 and 50% mark (but closer to the 50% mark) or it could be the contrast a bit above that.

Yes, but I was thinking about your example with the hypothetical MTF curves and Zeiss versus Leica. In that example, the "Zeiss" (with a presumed focus on microcontrast) beats the "Leica" (with a presumed focus on resolution) at contrast criteria higher than 50 percent whereas it is the other way around at contrast criteria lower than 50 percent.

One further question: Would you agree with my assessment that, as far as Ming's images let us judge, the 20 has a better MTF curve than the new 17/1.8? I must admit, I am a bit disappointed at the showing of the 17/1.8 here. I hadn't really expected it to beat the 20 in this regard but I had hoped/expected that it would do about as well. If that had been the case, I would probably have been ready to exchange my 20 for the 17/1.8. Now, I am not so sure.

I'm not sure, my general impression from his review is that the two lenses are relatively close (with a few notable differences like LoCA and vignetting that favour the 17 mm), and closer than I though they would be. But evaluating MTF from a few crops is something I am not really comfortable with, I'd put more weight on his overall comments which I would assume to be based on a lot more (test) images than the ones shown.

OK. Then we simply have quite different perceptions. To my eyes, there is a very clear difference in contrast in favor of the 20 not only at very low frequencies (macro contrast) but also at higher ones. Look at the crops from the bottom-right corner, for example. The individual lines in the grid below the window is clearly visible in the shot from the 20, even wide open, whereas they nearly disappear into a gray patch in the corresponding shot from the 17/1.8. Similarly, the joints (lines) between the concrete blocs in the same corner crops are clearly visible in the shot from the 20 but hardly visible at all in the shot from the 17/1.8.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +21 more
Reply   Reply with quote   Complain
Anders W
Forum ProPosts: 17,076Gear list
Like?
Re: Here my tests with 20 mm on EPL5 and Gh2
In reply to Jorginho, Nov 18, 2012

Jorginho wrote:

Here Anders A9nd others), lighting conditions and everything else is identical. Both are set at S-AF and same (they are not the same) focussing points etc. Same f settings. Not scientific, but consistent with my findings in somewhat low light...



Gh2 with 20 mm 1.7 on it AF

EPL5 with 20 m 1.7 on it.

Why would someone with a GH2 want to have the 17 mm 1.8 Oly with the argument it focusses faster. Could be faster, but not appreciably I think. My be on the OMD it is dofferent still. I don't have the cam.

Not sure what you mean when you say they are set at "same (they are not the same) focusing points etc." There are quite a few variables that might explain why the cameras do differently when it comes to hunting in this particular scenario. Have you seen Timur Born's account of how focusing works on the E-M5?

http://forums.dpreview.com/forums/post/42140214

This might give you a few ideas about how to make thinks more well-behaved with the E-PL5.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +21 more
Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum MMy threads