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RSalles
![Level 3 Level 3](rating3.gif) Joined: 12 Aug 2012 Posts: 1372 Location: Brazil - RS / South
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Posted: Sat Jul 19, 2014 5:21 pm Post subject: |
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RSalles wrote:
Gerald,
I agree with what you've wrote, the main problem is when people begin to "discard" the lens based only on MTF chart datasets...
Example: what picture has more potential to please the the 40's female public portrait, a Leica Noctilux,r a Petzval-type or an Anastigmat/Rapid Rectilinear one? And theese lens for Architecture will be - probably - a disaster compared with the latest MC Rodenstock APO Gandragon.
My understanding is that the Petzval lens is a tool basically for portraiture, where perfect definition is a character of the lens that is desirable in some extent but is not the more important factor,
Cheers,
Renato |
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Gerald
![Level 3 Level 3](rating3.gif) Joined: 25 Mar 2014 Posts: 1196 Location: Brazil
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Posted: Sun Jul 20, 2014 12:15 am Post subject: |
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Gerald wrote:
dan_ wrote: |
The excessive use of MTF charts, as induced by the lens makers nowadays, is only in their commercial advantage. It creates a false demand for sharper and sharper (and therefore more expensive) lenses no matter of their intended use. |
Yes, I agree that the publication of MTF curves by the lens manufactures is basically marketing. However, this does not diminish the importance of measuring MTF.
I think the demand for increasingly sharp lenses is legitimate, and not something that is artificially induced by the lens manufacturers. Of course there are distortions in this process, but the competition will ultimately prevail. To counteract greedy companies like Zeiss and Leica, there will always be companies like Sigma and Samyang, for example.
Except for the higher price (and possibly the larger weight and size), a sharp lens has many practical advantages. For example, the photographer can use the lens wide open without worrying about loss of resolution, do more extreme croppings, make larger enlargements, etc. That is, a sharp lens is more versatile than a soft one.
dan_ wrote: |
Clinical sharpness is rarely the most important characteristic to look for when you make a portrait. Therefor measuring it tells very little about the required optical qualitys of a portrait lens. |
RSalles wrote: |
… what picture has more potential to please the the 40's female public portrait, a Leica Noctilux,r a Petzval-type or an Anastigmat/Rapid Rectilinear one?
……………
My understanding is that the Petzval lens is a tool basically for portraiture, where perfect definition is a character of the lens that is desirable in some extent but is not the more important factor, |
Yes, there is a general perception that a soft-focus lens is better for portraiture than an ultra sharp lens. So tell me, how many soft-focus lenses are available on the market today? If memory serves me correctly, only the AF DC-Nikkor 135mm f/2D and Sony 135mm F/2.8 [T4.5] STF.
Does that mean portraiture is a dying art? Certainly not. The wedding photographers, for example, can be considered as portrait photographers, but the workhorse of a wedding photographer is a very sharp 24-70mm F2.8 zoom lens, not a soft-focus lens.
Now look at the scenario of medium-format that has always been a trench of portrait, fashion and beauty photographers. The portrait lens for the Leica S-System is the APO Macro 120mm F2.5 Summarit, which is an extremely well corrected and therefore extremely sharp lens. The words Leica uses to describe this lens are:
"The perfect portrait lens"
"Apochromatic correction ensures perfect resolution of even the finest details."
Another extremely well corrected and very sharp lens of the Leica S-System is the APO 180mm F3.5 Elmar-S, which Leica describes as:
"It proves to be an excellent portrait lens."
"Sharpness is guaranteed at all apertures and distances."
The situation is similar to Hasselblad, PhaseOne and Pentax systems. Modern professional portrait lenses are all extremely sharp.
What happened to the soft-focus lenses which were so popular in the past? Well, it seems they were simply outdated.
Another conclusion we can draw is that the "theory" that a good portrait requires a low-resolution lens is questionable. But if a photographer really wants to do a portrait with soft focus, he just uses a high-resolution lens and softens the photo with post-processing.
dan_ wrote: |
Has anybody draw MTF charts for soft focus lenses, too |
Sony publishes MTF for its 135mm F/2.8 [T4.5] STF lens, but only for the F8 aperture. I suspect it would be a little embarrassing to publish the MTF for wide open. ![Laughing](images/smiles/icon_lol.gif) _________________ If raindrops were perfect lenses, the rainbow did not exist. |
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RSalles
![Level 3 Level 3](rating3.gif) Joined: 12 Aug 2012 Posts: 1372 Location: Brazil - RS / South
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Posted: Sun Jul 20, 2014 1:10 am Post subject: |
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RSalles wrote:
Gerald wrote:
Another conclusion we can draw is that the "theory" that a good portrait requires a low-resolution lens is questionable. But if a photographer really wants to do a portrait with soft focus, he just uses a high-resolution lens and softens the photo with post-processing.
Yes, but the charming of these lens is that it comes with "pos-processing" built-in! I saw some portraits made with Vöightlander Heliar with its creamy bokeh sharp in the center and soft in the borders, so beautiful that makes me want to "eat" the picture, Never found a portrait like this with another small-format MTF steroided lens...
Cheers,
Renato |
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scsambrook
![Level 3 Level 3](rating3.gif) Joined: 29 Mar 2009 Posts: 2167 Location: Glasgow Scotland
Expire: 2011-11-18
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Posted: Sun Jul 20, 2014 9:18 am Post subject: |
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scsambrook wrote:
This is another interesting thread, to which I'm coming late.
I can't really agree with Gerald who wrote "And the best way to tell if a lens is functioning as it should, is measuring the resolution with a chart. Then someone could contest: "Hey, I can test a lens simply taking photographs." Yes, you can, but this is a dumb way to test a lens! Erwin Puts, a well known author of books on Leica cameras and lenses, created a rule for lens testing, which he called "rule of 500" which is in his own words: "To get a good idea of how the lens performs we need to take at least 500 pictures!" What a dumb rule!" (My added emphasis)
Whilst not demeaning the value of scientific testing in a carefully controlled environment, I'm not sure why it's 'dumb' to test a lens by taking plenty of photographs - at least not for hobby photographers as opposed to the professional journalists or self-publishing bloggers who pontificate on how 'good' a lens is. Sophisticated test equipment in the hands of thoughtful and experienced people may indeed tell us a great deal about the technical performance of a lens, and whether it's properly put together - "functioning as it should" - but it won't necessarily tell us about how 'pleasing' or ‘disappointing’ the lens will be to its user. After all, do we not have lenses to take photographs, to make aesthetically satisfying images that satisfy us according to our own perceptions?
Erwin Puts's 'rule of 500' is neither new nor foolish. In my late teens I was impressed by the common-sense writing of Theo Scheerer who, amongst many other things, wrote that the best way to get to know and understand a lens was to use it on its own for a time. He suggested putting away everything else, using it extensively and then carefully looking at what it and the user turned out between them. That, surely, is sensible. Over half a century after first reading Scheerer I'm more convinced than ever of the wisdom of such a philosophy. There's more to using a lens than we learn from from MTF curves or other laboratory outputs. They certainly have their place but they don't tell the whole story, do they? _________________ Stephen
Equipment: Pentax DSLR for casual shooting, Lumix G1 and Fuji XE-1 for playing with old lenses, and Leica M8 because I still like the optical rangefinder system. |
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ZoneV
![Level 3 Level 3](rating3.gif) Joined: 09 Nov 2009 Posts: 1632 Location: Germany
Expire: 2011-12-02
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Posted: Sun Jul 20, 2014 9:23 am Post subject: |
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ZoneV wrote:
MTF curves are not valuable without knowing how exact are they generated. Are they baed only on the optical design theory, or real measurements. Are they made with broad band illumination and not weighted, or only smaller spectral bandwith.
At which distance or magnification. How are the graphs processed (smoothing).
I do get sometimes MTF curves for lenses I test. But this is not much help - I measure all the lenses myself, to get comparable results.
Gerald wrote: |
Yes, there is a general perception that a soft-focus lens is better for portraiture than an ultra sharp lens. So tell me, how many soft-focus lenses are available on the market today? If memory serves me correctly, only the AF DC-Nikkor 135mm f/2D and Sony 135mm F/2.8 [T4.5] STF.
...
Sony publishes MTF for its 135mm F/2.8 [T4.5] STF lens, but only for the F8 aperture. I suspect it would be a little embarrassing to publish the MTF for wide open. ![Laughing](images/smiles/icon_lol.gif) |
Booth the Sony STF 135 and the DC Nikkor 135 are not soft focus lenses!
The DC Nikkor 105mm/2 and 135mm/2 could be used as soft focus, but with neutral Defocus Control setting this lenses are quite normal.
The Sony STF lens has an apodisation element - there is no soft focus for the sharp image parts, only for the bokeh.
The Canon 135mm/2.8 Softfocus is another option. As far as I remember is should be quite good at neutral setting too. _________________ Camera modification, repair and DIY - some links to look through: http://www.4photos.de/camera-diy/index-en.html
I AM A LENS NERD!
Epis, Elmaron, Emerald, Ernostar, Helioplan and Heidosmat.
Epiotar, Kameraobjektiv, Anastigmat, Epis, Meganast, Magnagon, Quinar, Culmigon, Novotrinast, Novflexar, Colorplan, Sekor, Kinon, Talon, Telemegor, Xenon, Xenar, Ultra, Ultra Star. Tessar, Janar, Visionar, Kiptar, Kipronar and Rotelar.
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dan_
![Level 3 Level 3](rating3.gif) Joined: 05 Dec 2012 Posts: 1055 Location: Romania
Expire: 2016-12-19
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Posted: Sun Jul 20, 2014 3:33 pm Post subject: |
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dan_ wrote:
To come back to the Petzval portrait lens, have a look at this Petzval-made portrait by Jim Galli:
http://tonopahpictures.0catch.com/JesusAt100.jpg
The fine gradation of tones, the mild transition from sharp to unsharp, the ponderate contrast - all are pointing to what's important in the portrait and have a very strong power to express both the inner life of the old man and the photographer atitude on the subject. These, the swirly bokeh and a mild vignetting are the optical qualities one should expect from a Petzval lens.
Used well, as Mr. Galli did, they could be very expresive tools.
Could that be obtained with a modern clinically sharp and contrasty lens and post processing? I very much doubt of it.
Could all this optical qualityes of the lens be intuited by reading its MTF chart? No. If you'd read the MTF of this Petzval your conclusion should be that it's a crappy lens.
Not saying that MTFs are useless. If done properly they succeed well in describing sharpness, contrast, etc. but they can't properly describe all the optical qualities of a lens. And therefore they are quite an improper way to see, for instance, if a Petzval lens is better or worse than other Petzval lens.
In this case (and a lot of other cases) the '500 photos rule' of Erwin Puts seems much more appropriate.
I don't have to make all those photos by myself - I just surf the internet for as many samples as I can find before buying a lens.
They'll reveal the potential of the lens. If what I see is what I want then I'll buy it and use it extensively for a while to get used to it.
If I feel comfortable with it I'll keep it, if not I'll re-sell it (well, that's theoreticaly - in fact, in most cases, my greedy nature makes me keep it anyway ).
And, as always, there is a shortcut : just ask Attila (or other trustfull and experienced members of this forum) and if he says it's a good lens, buy it. ![Wink](images/smiles/icon_wink.gif)
Last edited by dan_ on Sun Jul 20, 2014 3:43 pm; edited 1 time in total |
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kds315*
![Level 4 Level 4](rating4.gif) Joined: 12 Mar 2008 Posts: 16623 Location: Weinheim, Germany
Expire: 2021-03-09
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Posted: Sun Jul 20, 2014 3:37 pm Post subject: |
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kds315* wrote:
Excellent examples Dan, Jim is a master and knows his lenses very well. _________________ Klaus - Admin
"S'il vient a point, me souviendra" [Thomas Bohier (1460-1523)]
http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
https://www.flickr.com/photos/kds315/albums my albums using various lenses
http://photographyoftheinvisibleworld.blogspot.com/ my UV BLOG
http://www.travelmeetsfood.com/blog Food + Travel BLOG
https://galeriafotografia.com Architecture + Drone photography
Currently most FAV lens(es):
X80QF f3.2/80mm
Hypergon f11/26mm
ELCAN UV f5.6/52mm
Zeiss UV-Planar f4/60mm
Zeiss UV-Planar f2/62mm
Lomo Уфар-12 f2.5/41mm
Lomo Зуфар-2 f4.0/350mm
Lomo ZIKAR-1A f1.2/100mm
Nikon UV Nikkor f4.5/105mm
Zeiss UV-Sonnar f4.3/105mm
CERCO UV-VIS-NIR f1.8/45mm
CERCO UV-VIS-NIR f4.1/94mm
CERCO UV-VIS-NIR f2.8/100mm
Steinheil Quarzobjektiv f1.8/50mm
Pentax Quartz Takumar f3.5/85mm
Carl Zeiss Jena UV-Objektiv f4/60mm
NYE OPTICAL Lyman-Alpha II f1.1/90mm
NYE OPTICAL Lyman-Alpha I f2.8/200mm
COASTAL OPTICS f4/60mm UV-VIS-IR Apo
COASTAL OPTICS f4.5/105mm UV-Micro-Apo
Pentax Ultra-Achromatic Takumar f4.5/85mm
Pentax Ultra-Achromatic Takumar f5.6/300mm
Rodenstock UV-Rodagon f5.6/60mm + 105mm + 150mm
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Nordentro
![Level 4 Level 4](rating4.gif) Joined: 24 Jun 2010 Posts: 4713 Location: Lillehammer, Norway
Expire: 2015-01-29
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Posted: Sun Jul 20, 2014 4:01 pm Post subject: |
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Nordentro wrote:
MTF charts is for the pixelpeepers who has interest in modern lenses without character
I care about different lens designs and how different lens design renders and try to use this as a benefit when shooting. Helios 40 is probably not a sharp knife either, but it is loved by many because of it`s rendering. Most lenses are sharp enough IMO! ![Wink](images/smiles/icon_wink.gif) _________________ Lars | Manuellfokus.no |
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iangreenhalgh1
![Level 4 Level 4](rating4.gif) Joined: 18 Mar 2011 Posts: 15679
Expire: 2014-01-07
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Posted: Sun Jul 20, 2014 8:08 pm Post subject: |
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iangreenhalgh1 wrote:
Nordentro wrote: |
MTF charts is for the pixelpeepers who has interest in modern lenses without character
I care about different lens designs and how different lens design renders and try to use this as a benefit when shooting. Helios 40 is probably not a sharp knife either, but it is loved by many because of it`s rendering. Most lenses are sharp enough IMO! ![Wink](images/smiles/icon_wink.gif) |
I fully agree!
The character we so love in old lenses is due to their less than perfect level of corrections - so who cares about technical specs, if it's sharp enough, it's sharp enough!
Petzval lenses have a certain character, that is the whole point of them in use today, and I'm not talking about the swirl, it's the smoothness and gradation of tones:
That was with a 1950s Kershaw projector lens in less than perfect condition, the rendering is so different to any modern lens. With such a shot, does the sharpness matter at all? I think no. _________________ I don't care who designed it, who made it or what country it comes from - I just enjoy using it! |
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Tedat
![Level 3 Level 3](rating3.gif) Joined: 08 Nov 2011 Posts: 800 Location: Berlin/Germany
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Posted: Mon Jul 21, 2014 7:42 am Post subject: |
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Tedat wrote:
Gerald wrote: |
Sony publishes MTF for its 135mm F/2.8 [T4.5] STF lens, but only for the F8 aperture. I suspect it would be a little embarrassing to publish the MTF for wide open. ![Laughing](images/smiles/icon_lol.gif) |
sorry but this is completly bullshit!
The STF is very sharp wide open (and as mentioned not a soft focus lens).. I suggest you to get some more information before you guess the performance or character of a lens. Even if there are no MTF charts, it would be easy to find out how sharp this lens is wide open.
You are also talking about "extreme croppings".. just get the right lens and the right distance and you don't have to crop at all. _________________ Regards
Jan
flickr
Sony A7RM2
Contax T*: Distagon 4/18, Distagon 2/28, Distagon 1.4/35, PC-Distagon 2.8/35, Planar 1.4/50, Planar 1.4/85, Planar 2/100, Planar 2/135, S-Planar 2.8/60, Tessar 2.8/45, Mirotar 8/500, Vario Sonnar 3.4/35-70, Vario Sonnar 4.5-5.6/100-300
Carl Zeiss for Rollei QBM: F-Distagon 2.8/16 HFT, Distagon 2.8/25, Planar 1.4/50 HFT, Sonnar 2.8/85
Konica Hexanon AR: 2.8/21, 1.2/57
Other: Minolta F2.8 [T4.5] 135mm STF, Meopta Meostigmat 1.4/70, Tokina AT-X 2.5/90.. and lots of early M42 Yashinon, Rikenon and Mamiya lenses |
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ZoneV
![Level 3 Level 3](rating3.gif) Joined: 09 Nov 2009 Posts: 1632 Location: Germany
Expire: 2011-12-02
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Posted: Mon Jul 21, 2014 10:51 am Post subject: |
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ZoneV wrote:
Gerald wrote: |
...
What happened to the soft-focus lenses which were so popular in the past? Well, it seems they were simply outdated.
Another conclusion we can draw is that the "theory" that a good portrait requires a low-resolution lens is questionable. But if a photographer really wants to do a portrait with soft focus, he just uses a high-resolution lens and softens the photo with post-processing... |
This thinking "Lets do it in Photoshop" is quite normal at the moment.
I still wait for Photoshop enthusiasts to create a good Trioplan like soap bubble bokeh in post processing
There are tools for this, but not very good one from what I have seen up to now.
And the under corrected Spherical Aberration often used in soft focus lenses is just the other way round - I think there is no way to add this in post processing with good results in all situations. Ok, one could paint every picture one can imaging in Photoshop, pixel after pixel, but I rather take the right lens and see nearly the end result live in the optical viewfinder.
But I agree that MTF measurment is a great tool for lens manufacturers. It allows fast and reliable image quality control both for mass production and for development.
Years ago I applied for a job in the laboratory of a well-known lens manufacturer, there my work would have been MTF measurments at their own lenses and competitor lenses as well. Seems they don´t want to compare their own lens MTF results with results form competitors datasheets. _________________ Camera modification, repair and DIY - some links to look through: http://www.4photos.de/camera-diy/index-en.html
I AM A LENS NERD!
Epis, Elmaron, Emerald, Ernostar, Helioplan and Heidosmat.
Epiotar, Kameraobjektiv, Anastigmat, Epis, Meganast, Magnagon, Quinar, Culmigon, Novotrinast, Novflexar, Colorplan, Sekor, Kinon, Talon, Telemegor, Xenon, Xenar, Ultra, Ultra Star. Tessar, Janar, Visionar, Kiptar, Kipronar and Rotelar.
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bernhardas
![Level 3 Level 3](rating3.gif) Joined: 01 Jan 2013 Posts: 1432
Expire: 2017-05-23
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Posted: Mon Jul 21, 2014 11:25 am Post subject: |
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bernhardas wrote:
dan_ wrote: |
To come back to the Petzval portrait lens, have a look at this Petzval-made portrait by Jim Galli:
http://tonopahpictures.0catch.com/JesusAt100.jpg
The fine gradation of tones, the mild transition from sharp to unsharp, the ponderate contrast - all are pointing to what's important in the portrait and have a very strong power to express both the inner life of the old man and the photographer atitude on the subject. These, the swirly bokeh and a mild vignetting are the optical qualities one should expect from a Petzval lens.
Used well, as Mr. Galli did, they could be very expresive tools.
Could that be obtained with a modern clinically sharp and contrasty lens and post processing? I very much doubt of it.
Could all this optical qualityes of the lens be intuited by reading its MTF chart? No. If you'd read the MTF of this Petzval your conclusion should be that it's a crappy lens.
Not saying that MTFs are useless. If done properly they succeed well in describing sharpness, contrast, etc. but they can't properly describe all the optical qualities of a lens. And therefore they are quite an improper way to see, for instance, if a Petzval lens is better or worse than other Petzval lens.
In this case (and a lot of other cases) the '500 photos rule' of Erwin Puts seems much more appropriate.
I don't have to make all those photos by myself - I just surf the internet for as many samples as I can find before buying a lens.
They'll reveal the potential of the lens. If what I see is what I want then I'll buy it and use it extensively for a while to get used to it.
If I feel comfortable with it I'll keep it, if not I'll re-sell it (well, that's theoreticaly - in fact, in most cases, my greedy nature makes me keep it anyway ).
And, as always, there is a shortcut : just ask Attila (or other trustfull and experienced members of this forum) and if he says it's a good lens, buy it. ![Wink](images/smiles/icon_wink.gif) |
I wanted to take part in this conversation some time ago, but was really busy. Now Dan has said most I wanted to mention and in a much nicer way, than I could have expressed it.
For me personally old lenses are like wine: They come in many different flavors; some fit better for an occasion than others; and there is a substantial component of personal taste involved. Reading about the alcohol content on the label tells you something, but choosing your wine based purely on the measured alcohol content, or claiming that the highest alcohol level is the best wine (after all you could water it down if you wanted) does not really do justice to the rather more complex matter at hand.
And I support the Puts approach not only for lenses but also for wine. Tasting, tasting, and more tasting.
Cheers. |
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Gerald
![Level 3 Level 3](rating3.gif) Joined: 25 Mar 2014 Posts: 1196 Location: Brazil
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Posted: Mon Jul 21, 2014 5:30 pm Post subject: |
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Gerald wrote:
Wow, how many interesting comments! So, as Jack the Stripper liked to say, let's go by parts!
RSalles wrote: |
Gerald wrote:
Another conclusion we can draw is that the "theory" that a good portrait requires a low-resolution lens is questionable. But if a photographer really wants to do a portrait with soft focus, he just uses a high-resolution lens and softens the photo with post-processing.
Yes, but the charming of these lens is that it comes with "pos-processing" built-in! |
A disadvantage of using lenses with built-in "hard-wired special effects" as Petzval and similar lenses is that the effect cannot be canceled or transferred to other lenses. In contrast, focus softening by post-processing is much more flexible:
1) It can be applied to images taken with any lens and any aperture. How about applying softening focus on a fisheye or a super telephoto lens working at F16?
2) The effect can be varied by changing the appropriate parameters.
3) The effect can be applied subsequently; photographer does not need to make the decision at the time when taking the picture.
4) The effect can be undone or modified if the result is not satisfactory.
5) It is cheap.
It is important to note that digital post-processing is a fairly recent technique and therefore is far from being fully developed.
I will now present an example of focus softening using DXO Film Pack 4. The original "portrait" of the tennis player Maria Sharapova was captured with a Canon 500mm F4 lens wide open (even in a dream there is a Petzval equivalent).
The original picture is very sharp but the natural lighting was not good: the white balance is wrong (the image is too redish), and even though Sharapova is a very pretty woman, you can see imperfections and blemishes on her skin. The post-processed picture does more justice to the natural beauty of Sharapova.
I just spent about 5 minutes with the DXO Film Pack 4. I'm sure many of you with more skill and more time than I could do a much better job.
Original picture:
Post-processed picture:
![](http://forum.mflenses.com/userpix/20147/8001_Sharapova2_1.jpg) _________________ If raindrops were perfect lenses, the rainbow did not exist. |
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bernhardas
![Level 3 Level 3](rating3.gif) Joined: 01 Jan 2013 Posts: 1432
Expire: 2017-05-23
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Posted: Mon Jul 21, 2014 5:43 pm Post subject: |
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bernhardas wrote:
Quote: |
I just spent about 5 minutes with the DXO Film Pack 4. I'm sure many of you with more skill and more time than I could do a much better job. |
I prefer to have the job rather done in 1/125 of a second than in 5 minutes by choosing the right tool.
P.S.: Now is the Canon 500 f4 the right tool to take shot of a Tennis Player? Or Not? If yes, why did it not work? I did not really understand your point.
Last edited by bernhardas on Mon Jul 21, 2014 5:53 pm; edited 1 time in total |
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iangreenhalgh1
![Level 4 Level 4](rating4.gif) Joined: 18 Mar 2011 Posts: 15679
Expire: 2014-01-07
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Posted: Mon Jul 21, 2014 5:48 pm Post subject: |
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iangreenhalgh1 wrote:
That processed picture of Sharapova is nothing like the rendering of a Petzval lens at all.
The argument about doing it in PP is like saying 'hey, let's not bother to make cheese the traditional way anymore, now we can make it cheaper in a factory'.
Anyone who has eaten factory-produced cheese knows why they still make traditional cheese - it's 1000x better! _________________ I don't care who designed it, who made it or what country it comes from - I just enjoy using it! |
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bernhardas
![Level 3 Level 3](rating3.gif) Joined: 01 Jan 2013 Posts: 1432
Expire: 2017-05-23
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Posted: Mon Jul 21, 2014 5:56 pm Post subject: |
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bernhardas wrote:
iangreenhalgh1 wrote: |
That processed picture of Sharapova is nothing like the rendering of a Petzval lens at all.
The argument about doing it in PP is like saying 'hey, let's not bother to make cheese the traditional way anymore, now we can make it cheaper in a factory'.
Anyone who has eaten factory-produced cheese knows why they still make traditional cheese - it's 1000x better! |
Haha my brother in law was VP for cheese in a large food multi-national. He never bought the stuff they produced. ![Very Happy](images/smiles/icon_biggrin.gif) |
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Gerald
![Level 3 Level 3](rating3.gif) Joined: 25 Mar 2014 Posts: 1196 Location: Brazil
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Posted: Mon Jul 21, 2014 5:58 pm Post subject: |
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Gerald wrote:
scsambrook wrote: |
Whilst not demeaning the value of scientific testing in a carefully controlled environment, I'm not sure why it's 'dumb' to test a lens by taking plenty of photographs - at least not for hobby photographers as opposed to the professional journalists or self-publishing bloggers who pontificate on how 'good' a lens is.
...
Erwin Puts's 'rule of 500' is neither new nor foolish.
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I do not know where Erwin Puts found the magic number 500 (why not 1000 or 5000 or 10000?). Certainly one does not need to take 500 pictures to discover all the qualities and shortcomings of a lens. Taking 500 pictures to know how a lens performs is a waste of time in my opinion. Today, with modern computational resources, a photographer can know the performance of a lens with only a few dozen test photos. _________________ If raindrops were perfect lenses, the rainbow did not exist. |
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iangreenhalgh1
![Level 4 Level 4](rating4.gif) Joined: 18 Mar 2011 Posts: 15679
Expire: 2014-01-07
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Posted: Mon Jul 21, 2014 6:13 pm Post subject: |
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iangreenhalgh1 wrote:
Puts is right, you need to use a lens for a while, shoot it in different settings with different subjects, different conditions, get to know it, learn it's character, it's strengths, it's weaknesses.
MTF charts are mainly for advertising purposes, they don't tell a photographer very much at all about a lens. _________________ I don't care who designed it, who made it or what country it comes from - I just enjoy using it! |
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ZoneV
![Level 3 Level 3](rating3.gif) Joined: 09 Nov 2009 Posts: 1632 Location: Germany
Expire: 2011-12-02
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Posted: Mon Jul 21, 2014 6:13 pm Post subject: |
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ZoneV wrote:
Gerald wrote: |
..
Today, with modern computational resources, a photographer can know the performance of a lens with only a few dozen test photos. |
As long as one is statisfied with a bunch of data yes.
But cause MTF for a good but not ideal wideangle and a tele lens construction are a bit different, it is not easy to judge wheter a lens is good or not. One need still some comparison measurments.
And this MTF performance says nothing about bokeh, glow, color-transmission...
MTF is only one single part of a lot of lens properties.
I sometimes like vignetting, distorsion, bad MTF values in some image parts, not exact corrected Spherical Aberration. This is very hard or to most parts not expressed good in MTF values. _________________ Camera modification, repair and DIY - some links to look through: http://www.4photos.de/camera-diy/index-en.html
I AM A LENS NERD!
Epis, Elmaron, Emerald, Ernostar, Helioplan and Heidosmat.
Epiotar, Kameraobjektiv, Anastigmat, Epis, Meganast, Magnagon, Quinar, Culmigon, Novotrinast, Novflexar, Colorplan, Sekor, Kinon, Talon, Telemegor, Xenon, Xenar, Ultra, Ultra Star. Tessar, Janar, Visionar, Kiptar, Kipronar and Rotelar.
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Gerald
![Level 3 Level 3](rating3.gif) Joined: 25 Mar 2014 Posts: 1196 Location: Brazil
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Posted: Mon Jul 21, 2014 6:24 pm Post subject: |
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Gerald wrote:
dan_ wrote: |
To come back to the Petzval portrait lens, have a look at this Petzval-made portrait by Jim Galli:
http://tonopahpictures.0catch.com/JesusAt100.jpg
The fine gradation of tones, the mild transition from sharp to unsharp, the ponderate contrast - all are pointing to what's important in the portrait and have a very strong power to express both the inner life of the old man and the photographer atitude on the subject. These, the swirly bokeh and a mild vignetting are the optical qualities one should expect from a Petzval lens.
Used well, as Mr. Galli did, they could be very expresive tools.
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Galli's photo was clearly manipulated ("photoshopped") to give the impression that was taken with an ancient lens.
Anyone who has ever seen as the process of image formation by a lens is, knows that the focus gradually decreases with increasing distance from the focal plane. Plus, when the lens is bad or partially corrected aberrations, this variation of the sharpness is still slower than a perfect lens.
The photo manipulations in Galli's picture are almost crude. I show in the crop below some areas where changes of focus are abrupt and unnatural. It gives the impression that Galli wanted to leave the ears of the model more blurry than it should.
![](http://forum.mflenses.com/userpix/20147/8001_JesusAt100m2_1.jpg) _________________ If raindrops were perfect lenses, the rainbow did not exist. |
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ZoneV
![Level 3 Level 3](rating3.gif) Joined: 09 Nov 2009 Posts: 1632 Location: Germany
Expire: 2011-12-02
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Posted: Mon Jul 21, 2014 6:30 pm Post subject: |
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ZoneV wrote:
bernhardas wrote: |
...Haha my brother in law was VP for cheese in a large food multi-national. He never bought the stuff they produced. ![Very Happy](images/smiles/icon_biggrin.gif) |
Seems to be common
I heard people who work for plastic food packaging prefer glass and ceramic for their own food. _________________ Camera modification, repair and DIY - some links to look through: http://www.4photos.de/camera-diy/index-en.html
I AM A LENS NERD!
Epis, Elmaron, Emerald, Ernostar, Helioplan and Heidosmat.
Epiotar, Kameraobjektiv, Anastigmat, Epis, Meganast, Magnagon, Quinar, Culmigon, Novotrinast, Novflexar, Colorplan, Sekor, Kinon, Talon, Telemegor, Xenon, Xenar, Ultra, Ultra Star. Tessar, Janar, Visionar, Kiptar, Kipronar and Rotelar.
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Gerald
![Level 3 Level 3](rating3.gif) Joined: 25 Mar 2014 Posts: 1196 Location: Brazil
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Posted: Mon Jul 21, 2014 6:44 pm Post subject: |
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Gerald wrote:
Tedat wrote: |
Gerald wrote: |
Sony publishes MTF for its 135mm F/2.8 [T4.5] STF lens, but only for the F8 aperture. I suspect it would be a little embarrassing to publish the MTF for wide open. ![Laughing](images/smiles/icon_lol.gif) |
sorry but this is completly bullshit!
The STF is very sharp wide open (and as mentioned not a soft focus lens).. I suggest you to get some more information before you guess the performance or character of a lens. Even if there are no MTF charts, it would be easy to find out how sharp this lens is wide open.
You are also talking about "extreme croppings".. just get the right lens and the right distance and you don't have to crop at all. |
Maybe you should complain to BH Photo Video that lists the Sony 135mm F/2.8 [T4.5] STF lens as a soft focus lens:
Tedat wrote: |
The STF is very sharp wide open (and as mentioned not a soft focus lens).. I suggest you to get some more information before you guess the performance or character of a lens. Even if there are no MTF charts, it would be easy to find out how sharp this lens is wide open.
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Sharp lens? Kurt Munger found out that the Sony 135mm F/2.8 [T4.5] wide open is poor in the center and crappy at the corners. A Pentacon 135mm F2.8 blows the Sony out of water in the sharpness department. Even the CZJ 135mm F3.5 has more transmission than the Sony (and certainly is sharper, too).
![](http://forum.mflenses.com/userpix/20147/8001_Sonysoftfocuslenssamples2_1.jpg) _________________ If raindrops were perfect lenses, the rainbow did not exist. |
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scsambrook
![Level 3 Level 3](rating3.gif) Joined: 29 Mar 2009 Posts: 2167 Location: Glasgow Scotland
Expire: 2011-11-18
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Posted: Mon Jul 21, 2014 6:54 pm Post subject: |
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scsambrook wrote:
Gerald writes that " . . . Taking 500 pictures to know how a lens performs is a waste of time in my opinion. Today, with modern computational resources, a photographer can know the performance of a lens with only a few dozen test photos."
We are, indeed, all entitled to our opinions - "chacun à son goût" as the saying goes. I accept that a photographer may well have knowledge of the optical properties of a lens after only a few dozen test photos using 'computational resources', but s/he certainly won't yet be well acquainted with it. My experience in using and selling lenses since the 1960s has convinced me that time and experience are at least as important as worshop or laboratory testing in deciding whether a lens is satisfactory or not to its owner.
I have owned more than one lens which 'computational resources' demonstrated to be optically first class, yet which for one reason or another proved disappointing to me. And similarly, I continue to get satisfying results from a lens which laboratory testing shows to have MTF curves which look dispiritingly woebegone. I have another lens which although optically beyond [ my ] reproach has 'ergonomic issues' which take much of the gilt off its operational gingerbread. My initial optics-based euphoria wore off steadily in consequence and now it gets left at home as often as not . . . it certainly took me more than a couple of hundred exposures to reach that point. _________________ Stephen
Equipment: Pentax DSLR for casual shooting, Lumix G1 and Fuji XE-1 for playing with old lenses, and Leica M8 because I still like the optical rangefinder system. |
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bernhardas
![Level 3 Level 3](rating3.gif) Joined: 01 Jan 2013 Posts: 1432
Expire: 2017-05-23
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Posted: Mon Jul 21, 2014 6:54 pm Post subject: |
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bernhardas wrote:
Gerald wrote: |
Galli's photo was clearly manipulated ("photoshopped") to give the impression that was taken with an ancient lens.
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Edit: for me there is nothing wrong with the picture. there is a very slim DOF and the transition from in focus to out of focus is sharp in all areas.
It was taken with a large format camera and we do not know what kind of movements were involved.
Have you looked at his website? If you post a link I am happy to look at your collection of large format pictures?
What makes you an expert in how they should look like?
A couple more can be found here http://tonopahpictures.0catch.com/MichaelandYousef.html and here http://tonopahpictures.0catch.com/Downings/Some%20uncommon%20portaiture.html
I am very sad and disappointed that you accuse a person of manipulation and deception, without doing your research and homework properly. Please take time to have a good look at Mr. Galli's website and have an informed opinion before you post such preposterous accusations. |
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calvin83
![Level 4 Level 4](rating4.gif) Joined: 12 Apr 2009 Posts: 7555 Location: Hong Kong
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Posted: Mon Jul 21, 2014 7:21 pm Post subject: |
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calvin83 wrote:
Gerald wrote: |
Sony publishes MTF for its 135mm F/2.8 [T4.5] STF lens, but only for the F8 aperture. I suspect it would be a little embarrassing to publish the MTF for wide open. ![Laughing](images/smiles/icon_lol.gif) |
Have you ever visit Sony's site to see the MTF of the STF? Sony have publish the MTF of 10/30 LP/mm for both wide open and F8.
http://www.sony.jp/ichigan/products/SAL135F28/feature_1.html#L2_90
You can find a larger version of the MTF diagram here http://allphotolenses.com/lenses/item/c_980.html .
From many reviews and comments from other members I have heard, the STF have very high sharpness in the center at wide open. Take a look at the samples on photozone http://www.photozone.de/sony-alpha-aps-c-lens-tests/390-sony_135_28?start=2 . _________________ https://lensfever.com/
https://www.instagram.com/_lens_fever/
The best lens is the one you have with you. |
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