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Reid Review: 28 2.0 Ultron focus shift
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sreidvt
Guest
I take it, from your criticisms of my methodology, that you haven't actually read the article in question. Unfortunately, that seems to be common on the web. No test or review is "the final word" but conjecture that review is not.
Garry Winogrand was a good friend of my best friend, Ben Lifson. He certainly did care about lenses and recommended certain ones to friends and students. Technical perfection was not necessarily what Winogrand was after. For example, he loved the way the Canon 28/2.8 flared when shot into the sun (think of that girl waving from a float in an NYC parade). Ben bought his copy of the 28/2.8 on Winogrand's recommendation. I later did the same.
I'm always surprised at how comfortable people sometimes are with attributing motives, preferences, etc. to photographers they've never met. It is one thing for a person to imagine Winogrand and quite another for one to imagine that he or she is inside Winogrand's mind.
It's true that people often get caught up in equipment to the detriment of a focus on making pictures. But, on the other hand, cameras and lenses do matter. If it's of interest:
http://www.luminous-landscape.com/essays/Yes_It_Matters.shtml
Cheers,
S
sreidvt
Guest
Hi Again Tom,
I guess you didn't get a chance to read that review. I used the CV 28/2.0 to shoot a $4000 assignment. Does that count as "real life"? For what it is worth, I've worked as a professional photographer for 24 years. In fact, I'm in somewhat of a minority because I use RF cameras (now - in the present) for much of my professional work. SLRs are cameras I use primarily for special purposes.
My reviews have nothing to do with MTF curves.
Cheers,
Sean
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DwF
Well-known
Sean,
While you are picking up the pieces here
, I was curious about my 40mm f1.4 so I mounted M8 on a tripod and focused on a subject (something hanging on a post in my foyer). Examining the results, my lens focused consistent with what I intended. I repeated this from 1.4- f2.8 (stops I use most often). Is this possible ?
I'm pretty sure I got it right. In practice the lens has served me well but on one occasion in particular, I thought I was focusing on eyes and the subject's receding hairline was in better focus. I think that would be consistent with your findings involving focus shift.....but that was also in a pub with pints in play so I never gave it a second thought until reading your review.
No need to respond, I realize beauty (or accuracy in this case) is in the eye of the beholder.
Best regards,
David
While you are picking up the pieces here
, I was curious about my 40mm f1.4 so I mounted M8 on a tripod and focused on a subject (something hanging on a post in my foyer). Examining the results, my lens focused consistent with what I intended. I repeated this from 1.4- f2.8 (stops I use most often). Is this possible ?I'm pretty sure I got it right. In practice the lens has served me well but on one occasion in particular, I thought I was focusing on eyes and the subject's receding hairline was in better focus. I think that would be consistent with your findings involving focus shift.....but that was also in a pub with pints in play so I never gave it a second thought until reading your review.
No need to respond, I realize beauty (or accuracy in this case) is in the eye of the beholder.
Best regards,
David
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sreidvt
Guest
Sean,
While you are picking up the pieces here
I'm pretty sure I got it right. In practice the lens has served me well but on one occasion in particular, I thought I was focusing on eyes and the subject's receding hairline was in better focus. I think that would be consistent with your findings involving focus shift.....but that was also in a pub with pints in play so I never gave it a second thought until reading your review.
No need to respond, I realize beauty (or accuracy in this case) is in the eye of the beholder.
Best regards,
David
If you want to be sure (given your experience with the eye misfocus) test by using a careful focus bracketing procedure with a camera on a tripod. I can explain how to do that if you're not sure.
On the other hand, if the lens seems to be working fine for you with the vast majority of pictures, don't worry about it.
Interesting that the review dealt with many aspects of the lens (including the significant improvement in flare control) yet so many who have never read it seem to think it was all about focus shift.
Cheers,
Sean
DwF
Well-known
Thanks Sean,
Actually, I am good with the lens and wouldn't likely test it again unless I begin to notice issues.
I appreciate that there are many aspects to these lenses. Your review of the 40 was quite enthusiastic I thought. I often compare mine recollection of the only other 1.4 lens I've owned which was a pre-asph 35mm Summilux. I like my Nokton better at f1.4 and f2.
David
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sreidvt
Guest
Since I've dropped in this evening, let me also add that I've never written a review that universally damned or praised any given lens or camera. Each one is considered in terms of the strengths and weaknesses that I observe doing a combination of controlled and repeatable tests as well as "real world" use.
I do not come from the worlds of either technology or engineering but rather studied photography for four years under Stephen Shore and then met informally with Helen Levitt while we were both working on pictures of people in subways. People who don't know me from Adam may not realize that pictures are what I care about (and often what I write about).
Yet, despite this, I understand enough of scientific method to eliminate a lot of confounding variables in my testing. There's a big world between the black or white categorizations people seem so often tempted to make. And even people who care most about pictures still need to know what their tools will do.
Cheers,
Sean
I do not come from the worlds of either technology or engineering but rather studied photography for four years under Stephen Shore and then met informally with Helen Levitt while we were both working on pictures of people in subways. People who don't know me from Adam may not realize that pictures are what I care about (and often what I write about).
Yet, despite this, I understand enough of scientific method to eliminate a lot of confounding variables in my testing. There's a big world between the black or white categorizations people seem so often tempted to make. And even people who care most about pictures still need to know what their tools will do.
Cheers,
Sean
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Freakscene
Obscure member
>Is this possible ?
Yes. Keep in mind that all the variables are interlinked through spherical aberrations. It is easier to design a 40mm f1.4 lens and minimise spherical abberrations to a given standard than to design a 35mm f1.4 lens to meet the same standards. By the time you get to 28mm it gets even harder, which is why the Nikkor 28/1.4 has an aspherical element and a floating element and still shows more spherical aberration than other slower or longer lenses. Retrofocus design for use on an SLR also complicates performance, but this is a somewhat separate issue. Also keep in mind that focal lengths lenses are described by are approximate - that Nikkor is actually about a 31mm lens.
If you want to understand focus shift, learn about spherical aberrations. It's not as complicated as it first seems. Lens design by Milton Laikin and the Canon virtual lens plant are good resources to start with.
Marty
?Yes. Keep in mind that all the variables are interlinked through spherical aberrations. It is easier to design a 40mm f1.4 lens and minimise spherical abberrations to a given standard than to design a 35mm f1.4 lens to meet the same standards. By the time you get to 28mm it gets even harder, which is why the Nikkor 28/1.4 has an aspherical element and a floating element and still shows more spherical aberration than other slower or longer lenses. Retrofocus design for use on an SLR also complicates performance, but this is a somewhat separate issue. Also keep in mind that focal lengths lenses are described by are approximate - that Nikkor is actually about a 31mm lens.
If you want to understand focus shift, learn about spherical aberrations. It's not as complicated as it first seems. Lens design by Milton Laikin and the Canon virtual lens plant are good resources to start with.
Marty
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P. Lynn Miller
Well-known
It never ceases to amaze me how venomous people can be on this forum. It is almost like battle lines are being drawn between two camera lords and we have to declare our allegiance to one or the other. Like there is no middle ground in this feud, all over a measly camera lens that costs, what $500USD... give or take.
I bought the first Ultron 28/2 to hit Australian shores, it was the first new lens I had bought in 20 plus years. I even posted a heap of photos to a thread titled - The Voigtlander Ultron 28mm f2.0... - relating my experience with the lens, the good, bad and the ugly as user. No scientific test, just real life use. I am very happy with my Ultron 28/2 and I am still amazed with this lens ability to resolve detail.
Tom A. shoots more film than most people I know, I bought my Ultron 28/2 because of his enthusiasm and experience. I respect his vast experience and knowledge about all things photographic enough to base some of my decision to buy this lens on his recommendations. While Tom will thoroughly 'test' a lens in real world use, he does not use any scientific methodology in testing, so his opinions will be subjective, but still valuable.
Sean Reid, has apparently scientifically tested the lens. I have not nor will I probably ever read his test and review, which does not in anyway reduce the significance of his work. I simply am not lens review reader, I prefer to beg, borrow or buy the lens and make my own decision. And in today's world that is pretty easy since most retailers will allow you a return period. While Sean's review has no bearing on my opinion of my lens, it still as valid as my or Tom A.'s opinion. Sean has found some focus-shift with his samples in his scientific testing and shared that information with us. To not share this information would be a disservice to the rangefinder community and especially to his paying customers who expect him to deliver a scientific and hopefully objective test of the lens. Sean is simply doing his job. Well done.
What I find most interesting is that the three of us still agree it is wonderful lens to use in the real world, even though our 'testing' methods vastly differ!
I am sorry to hear that there are people who have acquired an Ultron 28/2 and were disappointed, hopefully you have found a lens that will serve you well.
We are very fortunate to live in an era that information can be so freely and quickly shared. And while it is a great resource to hear about other's experiences and share our own, there is no need to be obnoxious and bitter with each other when we have differing experiences and opinions.
It is only a lens...
I bought the first Ultron 28/2 to hit Australian shores, it was the first new lens I had bought in 20 plus years. I even posted a heap of photos to a thread titled - The Voigtlander Ultron 28mm f2.0... - relating my experience with the lens, the good, bad and the ugly as user. No scientific test, just real life use. I am very happy with my Ultron 28/2 and I am still amazed with this lens ability to resolve detail.
Tom A. shoots more film than most people I know, I bought my Ultron 28/2 because of his enthusiasm and experience. I respect his vast experience and knowledge about all things photographic enough to base some of my decision to buy this lens on his recommendations. While Tom will thoroughly 'test' a lens in real world use, he does not use any scientific methodology in testing, so his opinions will be subjective, but still valuable.
Sean Reid, has apparently scientifically tested the lens. I have not nor will I probably ever read his test and review, which does not in anyway reduce the significance of his work. I simply am not lens review reader, I prefer to beg, borrow or buy the lens and make my own decision. And in today's world that is pretty easy since most retailers will allow you a return period. While Sean's review has no bearing on my opinion of my lens, it still as valid as my or Tom A.'s opinion. Sean has found some focus-shift with his samples in his scientific testing and shared that information with us. To not share this information would be a disservice to the rangefinder community and especially to his paying customers who expect him to deliver a scientific and hopefully objective test of the lens. Sean is simply doing his job. Well done.
What I find most interesting is that the three of us still agree it is wonderful lens to use in the real world, even though our 'testing' methods vastly differ!
I am sorry to hear that there are people who have acquired an Ultron 28/2 and were disappointed, hopefully you have found a lens that will serve you well.
We are very fortunate to live in an era that information can be so freely and quickly shared. And while it is a great resource to hear about other's experiences and share our own, there is no need to be obnoxious and bitter with each other when we have differing experiences and opinions.
It is only a lens...
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sreidvt
Guest
Great post and, indeed, it is only a lens. There must be something good in that Sydney water that encourages clarity of mind.
Speaking of which....Just for clarification I should note that I did not see back-focus from the lens but, rather, focus shift. Two very different things of course.
Cheers,
Sean
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P. Lynn Miller
Well-known
Sean,
You can definitely tell I have not read your review. I edited my mistake.
Thanks,
You can definitely tell I have not read your review. I edited my mistake.
Thanks,
Tom A
RFF Sponsor
Sean. I haven't had a chance to go through the 28f2.0 Ultron review of yours - and I by no mean belittle your effort. The MTF curve "slur" was more general. Any lens that I plonk down money for is used before I do it. There are lenses that people laud and I hate and vice versa. Photography is a subjective field and we pick and choose what works for us.
I am still impressed with the 28f2 Ultron and I have not noticed any focus shift in my using it. It is still remarkably sharp at close in and wide open - in my opinion better there than the Summicron 28!
My opinions are really only valid if you shoot like me! Black/white, medium speed film and hand held. If I had to go back to industrial photography, my criterias would be different, though I still think the Ultron would do very well even there. Something like the Nokton 35f1.4 would not do as well, sufficient barrel distorsion to upset clients - but that lens has become my favourite 35 in the last 6-8 month for "regular" shooting.
I like reading tests, even Leica and Zeiss's ones with their pretty curves
and charts. I do understand what they mean and, yes sometimes it has a bearing on how the shot turns out when I try it. Case in point: I tried the new Leica Elmar 24f3.8 Asph last month in Louisville, KY ( Leica USA let me have one for a day and a bit - or five rolls of Acros 100). I have seen the MTF curves for the lens - virtually flat lined at the high end - straight across the board. The lens is good, truly damned good! Virtually no distorsion, image quality at 3,8 as good as you can ever want and all that happens when you stop it down, the depth of field increases but no diffraction, no distortion. It is a "modestly" priced lens by Leica standard (somewhere around $2200-2400) and I feel it is worth it too. I haven't decided if I really need it - but as for wanting it - Oh yes - once I saw the negatives on the light table!
Sean keep testing and I keep shooting my way and all the other people on Rf'f will give their input - between us all, it should be easy to decide what lenses would be interesting to try out. From a practical point of view - most of them are huge improvements on optics from even a decade ago.
I am still impressed with the 28f2 Ultron and I have not noticed any focus shift in my using it. It is still remarkably sharp at close in and wide open - in my opinion better there than the Summicron 28!
My opinions are really only valid if you shoot like me! Black/white, medium speed film and hand held. If I had to go back to industrial photography, my criterias would be different, though I still think the Ultron would do very well even there. Something like the Nokton 35f1.4 would not do as well, sufficient barrel distorsion to upset clients - but that lens has become my favourite 35 in the last 6-8 month for "regular" shooting.
I like reading tests, even Leica and Zeiss's ones with their pretty curves
and charts. I do understand what they mean and, yes sometimes it has a bearing on how the shot turns out when I try it. Case in point: I tried the new Leica Elmar 24f3.8 Asph last month in Louisville, KY ( Leica USA let me have one for a day and a bit - or five rolls of Acros 100). I have seen the MTF curves for the lens - virtually flat lined at the high end - straight across the board. The lens is good, truly damned good! Virtually no distorsion, image quality at 3,8 as good as you can ever want and all that happens when you stop it down, the depth of field increases but no diffraction, no distortion. It is a "modestly" priced lens by Leica standard (somewhere around $2200-2400) and I feel it is worth it too. I haven't decided if I really need it - but as for wanting it - Oh yes - once I saw the negatives on the light table!
Sean keep testing and I keep shooting my way and all the other people on Rf'f will give their input - between us all, it should be easy to decide what lenses would be interesting to try out. From a practical point of view - most of them are huge improvements on optics from even a decade ago.
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Captain
Well-known
Yes I think you may need to take a sip and re-read between the lines. Coming along weeks after the thread has wound down slightly missing Tom's point. That being no one person should base a lens purchase on a single review, yours or anyone else's. Surely you have to admit that's sound advice? As a film user I would be ill advised to use one of your crop factored IR sensitive M8 lens test reviews as my only source of information. Alot of the conflicted discussion comes from the fact those who paid for the review and suggest others also pay to read it, or alternatively challenge the validity of the results in them, rarely highlight the camera specific nature of the reviews. This can lead to people being deterred from a lens when with their camera medium the results would be suburb. Whenever I see discussions move into insecurely quoting resumes and what a certain famous photographer would have said or done then a thread is about to go a bit off course.
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sreidvt
Guest
I saw the imagined ideas about Winogrand but I must have missed the insecure resume post (did you see that one Joe?). If your point is that no one should rely on only one source for any kind of information, I doubt you'll find much disagreement from anyone here.
BTW, Joe once asked an interesting question about which aspects of a lens (tested on a DRF) might also relate to that same lens being used on a film camera. I gave a fairly detailed reply but then the thread was deleted later on. Did you by any chance save that post Joe? Film RF photographers should know that Joe has been quietly advocating (for years now) for more tests of lenses using film cameras. I won't be doing them but perhaps someone else will decide to.
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S
sreidvt
Guest
Interesting tone for a friendly constructive forum. Perhaps you might want to stick to the topic and skip the condescension.
Dan States
Established
Isn't this a case of digital cropped reproduction showing a flaw at magnified amplitude? As a maker of PRINTS I'm more concerned with what is visible at print sizes I make. Is the shift enough to be visible on an 11x14 print?
I do wonder what the shift of focus means for images shot at infinity. One reason many modern high speed lenses look lousy at infinity is that they are shifting beyond infinity.
I do wonder what the shift of focus means for images shot at infinity. One reason many modern high speed lenses look lousy at infinity is that they are shifting beyond infinity.
keithdunlop
www.keithdunlop.com
Why is focus shift worse with digital?
Why is focus shift worse with digital?
Sean posted a link on another forum to an article discussing spherical aberration and what causes focus shift, and it really explained the phenomena quite well. http://www.vanwalree.com/optics/spherical.html. However, It raises a question for me about the appearance of focus shift with digital sensors (I'm going to refer to Figure 1 in the article for my question).
I have read posts where people say focus shift is more visible on a digital sensor than on film. If shooting with a cropped sensor, it seems to me that it would lessen the effect.
Referring to Figure 1 in the article, if using a cropped digital sensor, like the 1.33 crop in the M8, wouldn't the focus point be moved closer to the "circle of least confusion" making the appearance of focus shift less apparent. Look at Figure 1 in the article. If the field of focus at point "C" is narrowed because the lens edges don't get used on a cropped sensor, isn't the focus point shifted to the left, closer to point B?
I'm a photographer, not an optical scientist, so please set me straight if I have this all wrong.
Why is focus shift worse with digital?
Sean posted a link on another forum to an article discussing spherical aberration and what causes focus shift, and it really explained the phenomena quite well. http://www.vanwalree.com/optics/spherical.html. However, It raises a question for me about the appearance of focus shift with digital sensors (I'm going to refer to Figure 1 in the article for my question).
I have read posts where people say focus shift is more visible on a digital sensor than on film. If shooting with a cropped sensor, it seems to me that it would lessen the effect.
Referring to Figure 1 in the article, if using a cropped digital sensor, like the 1.33 crop in the M8, wouldn't the focus point be moved closer to the "circle of least confusion" making the appearance of focus shift less apparent. Look at Figure 1 in the article. If the field of focus at point "C" is narrowed because the lens edges don't get used on a cropped sensor, isn't the focus point shifted to the left, closer to point B?
I'm a photographer, not an optical scientist, so please set me straight if I have this all wrong.
Turtle
Veteran
I hope Sean keeps writing for those who can read. His reviews are rather like the old British 'Ronseal' adverts (wood treatments and stains): "It does exactly what it says on the tin." As one with some, albeit limited, scientific experience, I believe that his tests do support the conclusions drawn, which have only ever been related - now here is the unsurprising bit - to what he has set out to look into. Nothing more and nothing less. It seems that many perceptions of his tests are a product of opinions formed based upon the comments of others who have also not read them, or been able to understand the limitations of the conclusions drawn.
I have no allegiance to anyone in particular and read Tom A's comments with enthusiasm. However, it seems that the issue is that some 'loyalists' wish to see their champions pitted against one another in some sort of warped virtual slugfest! Its actually quite funny when one considers that reading people's comments and restricting one's responses to their actual, rather than assumed, conclusions would see all this disappear. It is also fundamentally related to some people's need to justify their equipment choices in an absolute rather than subjective fashion. There has to be some form of 'proof' that their kit is the right kit and therefore if there is a perception that a particular reviewer has written comments that threaten that choice, even if unrelated to the reason for that choice, they must be attacked.
A review is a review and I respect any review, however unscientific, that is faithful to a stated goal as long as the methodology is appropriate to the conclusions.
If I don't like a piece of kit, I sell it. I do not generally test it to determine objectively why and see if I can justify this from a statistical perspective. That would be daft, because not liking kit, for whatever reason and no matter how irrational, is the clincher. However, there is very often a correlation between the kit I get rid of and the more objective reviews, such as yours. I find less objective testing often gets caught up in the moment and fails to reveal issues that show themselves in time. Liking something is not always a permanent state of affairs! Your diligence is not wasted and there are plenty who understand the claims you are not making as well as those you do. It is so simple I cannot fathom where all the problems come from.
Here is a comment and this is most definitely NOT a snipe at Tom A, so I will be hugely disappointed if someone tries to use it in this fashion. It is however almost certain to be taken personally by someone against whom it was not directed - it is a very general comment and may have no relevance to specific individuals:
Giving kudos to a person who photographs prolifically in no way validates the importance of their opinions regarding the merits of kit. It is about standards not volume - anyone can keep snapping. It is about results. Just because a person has used a lens for 2 years and taken 40,000 images with it does not mean that it is anything other than 'good or good enough for them'. There is this assumption that listening to the opinion of someone who 'has shot with it solidly for two months in the real world' is more valid than someone who has used it for a week during testing, then on assignment. It ALL depends on the scenarios and standards and one cannot take one over the other without knowing something about the final results - the images themselves. What one can see, whether this will matter to you or not, are differences or issues supported by objective and comparative testing. This need not be done under NASA conditions, only those of a high enough standard to show what is intended and without variables of sufficient magnitude to prevent validity.
I am glad Sean and Tom A are happy with what their testing shows them. It seems it is people other than them who have issues with what they conclude! its quite funny really.
I have no allegiance to anyone in particular and read Tom A's comments with enthusiasm. However, it seems that the issue is that some 'loyalists' wish to see their champions pitted against one another in some sort of warped virtual slugfest! Its actually quite funny when one considers that reading people's comments and restricting one's responses to their actual, rather than assumed, conclusions would see all this disappear. It is also fundamentally related to some people's need to justify their equipment choices in an absolute rather than subjective fashion. There has to be some form of 'proof' that their kit is the right kit and therefore if there is a perception that a particular reviewer has written comments that threaten that choice, even if unrelated to the reason for that choice, they must be attacked.
A review is a review and I respect any review, however unscientific, that is faithful to a stated goal as long as the methodology is appropriate to the conclusions.
If I don't like a piece of kit, I sell it. I do not generally test it to determine objectively why and see if I can justify this from a statistical perspective. That would be daft, because not liking kit, for whatever reason and no matter how irrational, is the clincher. However, there is very often a correlation between the kit I get rid of and the more objective reviews, such as yours. I find less objective testing often gets caught up in the moment and fails to reveal issues that show themselves in time. Liking something is not always a permanent state of affairs! Your diligence is not wasted and there are plenty who understand the claims you are not making as well as those you do. It is so simple I cannot fathom where all the problems come from.
Here is a comment and this is most definitely NOT a snipe at Tom A, so I will be hugely disappointed if someone tries to use it in this fashion. It is however almost certain to be taken personally by someone against whom it was not directed - it is a very general comment and may have no relevance to specific individuals:
Giving kudos to a person who photographs prolifically in no way validates the importance of their opinions regarding the merits of kit. It is about standards not volume - anyone can keep snapping. It is about results. Just because a person has used a lens for 2 years and taken 40,000 images with it does not mean that it is anything other than 'good or good enough for them'. There is this assumption that listening to the opinion of someone who 'has shot with it solidly for two months in the real world' is more valid than someone who has used it for a week during testing, then on assignment. It ALL depends on the scenarios and standards and one cannot take one over the other without knowing something about the final results - the images themselves. What one can see, whether this will matter to you or not, are differences or issues supported by objective and comparative testing. This need not be done under NASA conditions, only those of a high enough standard to show what is intended and without variables of sufficient magnitude to prevent validity.
I am glad Sean and Tom A are happy with what their testing shows them. It seems it is people other than them who have issues with what they conclude! its quite funny really.
yanidel
Well-known
I bought the lens two days and did a 10 minutes test on a tripod and M8 to see how sharp was the lens. I came to exactly the same conclusion as Sean :
Good sharpness at F2
Small improvement at F2.8
Decrease in sharpness from F4 to F5.6
Improvement at F8.
So his conclusion about focus shift seems valid to me even if my test had nothing scientific.
But it was only on a tripod shooting a newspaper 1.5 meters away. After that I took it in the street and so far, I am delighted by the lens and focus shift does not bother me in real conditions. The lens is wondefuly built and a great improvement in balance with M8 compared to the previous version.
Good sharpness at F2
Small improvement at F2.8
Decrease in sharpness from F4 to F5.6
Improvement at F8.
So his conclusion about focus shift seems valid to me even if my test had nothing scientific.
But it was only on a tripod shooting a newspaper 1.5 meters away. After that I took it in the street and so far, I am delighted by the lens and focus shift does not bother me in real conditions. The lens is wondefuly built and a great improvement in balance with M8 compared to the previous version.
kshapero
South Florida Man
I read Sean's reviews closely and I read threads and posts on subject here that interest me. I learn a lot and it does help me become a better photog. Thanks to all.