I'm done with lens reviews

Rod McD wrote:

imnotmarvin wrote:

If you're buying from a reputable dealer, you can return a lens if it doesn't meet your needs or expectations for the types of photography you do.

Hi,

This alone may underpin a different approach. There are different rules in different places. I'm not sure where you are. In Australia, where I live, you're not buying it to try it. You're buying it. You can return it if its faulty, and the manufacturer determines under the warranty whether to repair it or replace it. You can't return it just because it didn't meet your needs or expectations and you changed your mind. If it's not faulty, and you changed your mind and just don't want it, well you sell it as a used lens to someone who does want it. Under this business framework, getting it right in the first place becomes more important.

So, yup, I get the best information available..... and read reviews. Same for cars, dishwashers and all the other consumer stuff we spend big on.

TBH, I think the whole 'try it and return it' can and sometimes does lead to all sorts of ill-planned purchasing and unscrupulous using and reselling - as many threads in these forums have shown over the years. At least here, if it's sold as new, it must be new and unused, and not someone else's reject with an unknown history.

I actually agree with you that most of the Fuji range are good lenses. OTOH, some are excellent. The task is to sift out the ones that meet our needs knowing their foibles....

Cheers, Rod

You touch on something that's a particular pain of mine; the idea of "buying" something to test or try and returning for the original seller to either take a hit on as used and pass the loss on to the rest of us, or fraudulently re-package as "new."  We see countless "tests" and "comparisons" here of cameras and lenses where it's transparently obvious that the "tester", so called, had no real intention of actually keeping the item but instead wanted in to just post something to impress the rest of us. US return policies are an invitation to abuse, and frankly, the opinion of some yahoo opining that the latest Canikon XZ2500 is not quite as good at taking pictures of brick walls as his old Soniji POS 25. based on his 29 day trial before returning it, adds no value to any conversation.

Sam in Hawaii wrote:

Rod McD wrote:

imnotmarvin wrote:

If you're buying from a reputable dealer, you can return a lens if it doesn't meet your needs or expectations for the types of photography you do.

Hi,

This alone may underpin a different approach. There are different rules in different places. I'm not sure where you are. In Australia, where I live, you're not buying it to try it. You're buying it. You can return it if its faulty, and the manufacturer determines under the warranty whether to repair it or replace it. You can't return it just because it didn't meet your needs or expectations and you changed your mind. If it's not faulty, and you changed your mind and just don't want it, well you sell it as a used lens to someone who does want it. Under this business framework, getting it right in the first place becomes more important.

So, yup, I get the best information available..... and read reviews. Same for cars, dishwashers and all the other consumer stuff we spend big on.

TBH, I think the whole 'try it and return it' can and sometimes does lead to all sorts of ill-planned purchasing and unscrupulous using and reselling - as many threads in these forums have shown over the years. At least here, if it's sold as new, it must be new and unused, and not someone else's reject with an unknown history.

I actually agree with you that most of the Fuji range are good lenses. OTOH, some are excellent. The task is to sift out the ones that meet our needs knowing their foibles....

Cheers, Rod

You touch on something that's a particular pain of mine; the idea of "buying" something to test or try and returning for the original seller to either take a hit on as used and pass the loss on to the rest of us, or fraudulently re-package as "new." We see countless "tests" and "comparisons" here of cameras and lenses where it's transparently obvious that the "tester", so called, had no real intention of actually keeping the item but instead wanted in to just post something to impress the rest of us. US return policies are an invitation to abuse, and frankly, the opinion of some yahoo opining that the latest Canikon XZ2500 is not quite as good at taking pictures of brick walls as his old Soniji POS 25. based on his 29 day trial before returning it, adds no value to any conversation.

In a day long ago and a land far away.  There were camera stores everywhere.  In 1980 I had two within 5 miles with one a walk from my house.  Then in nearby cities there were many more.   Today - in most of the US if there is one in half a day drive - consider yourself lucky.  At you local camera store - you could look at equipment. You could try equipment out.  Some had loaders you could even take out a run a few rolls of film through.

First the NY mail order stores with extensive ads in the back of camera magazines started the trend of putting the local guy out of business by undercutting him.  Then the Internet finished the local camera store off.  In the US it has been the Internet stores that have pushed - try it if you don't like it send it back model we see today particularly in the US.  I agree - it is not optimal and it is opens up all sorts of Pandora's boxes.  Of course some will abuse the return policies.  Of course some merchants will send out "used" stuff as brand spanking new - although people never really complain that someone else took a car on a test drive before them so it should be considered used and they should not pay full price.  So why should a camera be different?

Today on Amazon you can order shoes and try them out for fit in the comfort of your living room and if they don't fit - send them on back.  It's not Amazon's fault - it is the customer's fault.  We refuse to support the local businesses.  We get what we pay for.

Sam in Hawaii wrote:

Rod McD wrote:

imnotmarvin wrote:

If you're buying from a reputable dealer, you can return a lens if it doesn't meet your needs or expectations for the types of photography you do.

Hi,

This alone may underpin a different approach. There are different rules in different places. I'm not sure where you are. In Australia, where I live, you're not buying it to try it. You're buying it. You can return it if its faulty, and the manufacturer determines under the warranty whether to repair it or replace it. You can't return it just because it didn't meet your needs or expectations and you changed your mind. If it's not faulty, and you changed your mind and just don't want it, well you sell it as a used lens to someone who does want it. Under this business framework, getting it right in the first place becomes more important.

So, yup, I get the best information available..... and read reviews. Same for cars, dishwashers and all the other consumer stuff we spend big on.

TBH, I think the whole 'try it and return it' can and sometimes does lead to all sorts of ill-planned purchasing and unscrupulous using and reselling - as many threads in these forums have shown over the years. At least here, if it's sold as new, it must be new and unused, and not someone else's reject with an unknown history.

I actually agree with you that most of the Fuji range are good lenses. OTOH, some are excellent. The task is to sift out the ones that meet our needs knowing their foibles....

Cheers, Rod

You touch on something that's a particular pain of mine; the idea of "buying" something to test or try and returning for the original seller to either take a hit on as used and pass the loss on to the rest of us, or fraudulently re-package as "new." We see countless "tests" and "comparisons" here of cameras and lenses where it's transparently obvious that the "tester", so called, had no real intention of actually keeping the item but instead wanted in to just post something to impress the rest of us. US return policies are an invitation to abuse, and frankly, the opinion of some yahoo opining that the latest Canikon XZ2500 is not quite as good at taking pictures of brick walls as his old Soniji POS 25. based on his 29 day trial before returning it, adds no value to any conversation.

Agreed on the DoucheTuber "reviews" but I thought the Euros have more consumer friendly return/warranty policies than the USA does.  Typically where I live the 'rental' period is two weeks, not 30 days.

Mr Bolton wrote:

Sam in Hawaii wrote:

Rod McD wrote:

imnotmarvin wrote:

If you're buying from a reputable dealer, you can return a lens if it doesn't meet your needs or expectations for the types of photography you do.

Hi,

This alone may underpin a different approach. There are different rules in different places. I'm not sure where you are. In Australia, where I live, you're not buying it to try it. You're buying it. You can return it if its faulty, and the manufacturer determines under the warranty whether to repair it or replace it. You can't return it just because it didn't meet your needs or expectations and you changed your mind. If it's not faulty, and you changed your mind and just don't want it, well you sell it as a used lens to someone who does want it. Under this business framework, getting it right in the first place becomes more important.

So, yup, I get the best information available..... and read reviews. Same for cars, dishwashers and all the other consumer stuff we spend big on.

TBH, I think the whole 'try it and return it' can and sometimes does lead to all sorts of ill-planned purchasing and unscrupulous using and reselling - as many threads in these forums have shown over the years. At least here, if it's sold as new, it must be new and unused, and not someone else's reject with an unknown history.

I actually agree with you that most of the Fuji range are good lenses. OTOH, some are excellent. The task is to sift out the ones that meet our needs knowing their foibles....

Cheers, Rod

You touch on something that's a particular pain of mine; the idea of "buying" something to test or try and returning for the original seller to either take a hit on as used and pass the loss on to the rest of us, or fraudulently re-package as "new." We see countless "tests" and "comparisons" here of cameras and lenses where it's transparently obvious that the "tester", so called, had no real intention of actually keeping the item but instead wanted in to just post something to impress the rest of us. US return policies are an invitation to abuse, and frankly, the opinion of some yahoo opining that the latest Canikon XZ2500 is not quite as good at taking pictures of brick walls as his old Soniji POS 25. based on his 29 day trial before returning it, adds no value to any conversation.

Agreed on the DoucheTuber "reviews" but I thought the Euros have more consumer friendly return/warranty policies than the USA does. Typically where I live the 'rental' period is two weeks, not 30 days.

To clarify my point that started this part of the conversation, I don't subscribe to the free rental idea of buying and returning. I was referring to buying a lens you intend to use only to find out it isn't as great as advertised. In my experience, this doesn't happen with Fuji lenses unless there's actually a problem with the lens in which case I'd be trading it for another of the same. If there was some actual deficiency with a lens across the entire production (terribly slow AF maybe) then after a couple tries, you'd know it wasn't going to work for you. I think most people with experience have a good idea of what will work and what won't for them which is why I said it would be better to buy and try for yourself as opposed to letting someone else tell you what a deficiency is. Truly only you can decide for your style of photography. Yes, I get trends and that's most people's argument in favor of reviews here but I prefer to form my own opinion.

Brian P Smith wrote:

Pretty much any lens made in the past decade is going to perform more than 90% of people need it to, so I don’t really worry about that kinda stuff. The only except is some of the $100 lenses from off brand manufacturers and even most of them perform admirably!

I think it depends on your expectations.

I went from a Canon M5 + 15-45 to the Fuji X-S10 + 18-55 for 3 months, sold it and just picked up a Z5 + 24-70 F4S and 14-30

I actually liked my Canon 15-45 better than my Fuji 18-55 -- I made a thread about it a few months ago. For a lens that is twice the size and almost 3x the weight, I found it to be somewhat dull and lack detail in the landscape shots I did, even with post processing, compared to my Canon. Part of it was the lens (my XC35 was way better), part was probably X-Trans drawbacks.

On the other hand, my first 2 weeks with the Z5 with the 24-70 and 14-30 kind of has blown my mind how much sharper and more detailed the images are with roughly the same resolution sensor (24 vs 26MP).

While an average print might not show a huge difference between lenses (I have plenty of prints around the house from old cameras with kit lenses), it was pretty apparent when viewing my my higher resolution MacBook Pro, even when fit to the screen and any kind of zooming or cropping just highlighted the differences more.

Personally, the biggest issue is copy-to-copy variation. It's one thing if you were spending $200 on a cheap plastic lens (like the XC 35) and some of them were duds. It's another thing if you're spending $1,000 on the 10-24 WR and it's all over on QC.

Truman Prevatt wrote:

KariP wrote:

Truman Prevatt wrote:

Jeff Biscuits wrote:

Truman Prevatt wrote:

Microcontrast

Actually it is quite real.

Fill me in in one thing, though…

I’ve done a limited amount of image processing in my career which has involved analysing local contrast/gradient. So “microcontast” as that concept of contrast within a small area of an image (whether analog or digital) makes complete sense.

Where it doesn’t make sense to me is when it comes to lenses. It’s a term that’s explicitly differentiated from just “contrast”, and I can’t get my head around how a lens can provide microcontrast to any different degree than it would provide “macro contrast”. In other words, how could a lens have the capacity to alter tonality just because of the proximity of their tones? It seems obvious that a lens can give more or less contrast, but surely there is no way two lenses with the same macro contrast can differ in terms of microcontrast.

So I’ve always assumed that in the context of lens reviews, microcontrast—though a perfectly real and measurable thing—is used in a somewhat mythical way, because in terms of a lens transmitting light, it’s just contrast.

Or is there something I’ve completely overlooked?

Every component of an optical systems reduces local contrast. Film reduces the local contrast of a scene. An outdoor scene can have as much as 20 stops of almost instantaneous contrast change. No film nor digital sensor can replicate that. In film days one had to chose the type of developer. D76 for example contained silver solvents. It was good for reducing grain but it made the edges smoother with slower roll of so reduced the micro contrast. Acutance ( a term for edge sharpness) developers like Ordinal produced negatives with much better micro contrast (sharp edges) but also made the grain more apparent since the hard edges were maintained.

Color filter arrays reduce micro contrast as the edges will be derived by interpolation from neighbor hooding detectors with different color. Cross talk in the sensor will cause a bleeding current across into neighboring detector hence reducing the contrast across the edges and smoothing the edges somewhat similar to the effect of silver solvents in developers.

The final component which may have the biggest impact is the lens. Lenses don't create micro contrast. No component of the imaging system create micro-contrast. That is a function of the scene. Any distortion will show up across edges as an effect of reducing micro contrast. Some aberrations are worse that others. Chromatic aberration resulting from the wavelength dependence on the refractive index will show up across sharp edges. Fixing one aberration can often result in making others worse.

https://www.lensrentals.com/blog/2010/10/the-seven-deadly-aberrations/

In the image they all show up on sharp boundaries between dark and light - the edges. When I ended up having to worry about R&D for both our signal intelligence/electronic warfare systems and optical systems I have to get an immediate education. The consolidation made sense as the big end image processing that the move to digital cameras for ISR was now simply the two dimensional version we did for signals intelligence and EW. For example an edge in an image is detected using the same basic approach as a radar pulse in detected in an EW system. But there is a lot more subtle to the imaging systems. Lens designs - we specified our lens designs to people like Kodak, Corning, etc. Different lens designs and glass formulations were needed for a camera flying at a nominal 30,000 feet on an airborne platform, from one flying on a U2 at 70,000 feet from one flying on the SR71 "blackbird" at 90,000 feet from one flying in space. But the goal was always the same - minimize the micro contrast degradation of the lens. In the 1960's NASA often contracted with Zeiss to design and build their lenses. Some attribute the "Zeiss pop" to the the fact these lenses degrade the scene micro contrast less than other lenses. That was important to NASA for the exploration of the moon during the 1960's and '70s. Often we would trade other properties of the lens to maintain high micro contrast.

So I expect that when people refer to their opinion that lens A has better micro contrast than lens B, what they mean is Lens A reduces micro-contrast to a less extent than lens B.

There is no perfect lens. Fourier optics tells us that. The very fact that there is an aperture between the scene and film/sensor impacts the recorded image. The point spread function tells us exactly what a point source looks like. The fact that all light rays landing on the sensor are not collimated and the interaction with the lens impacts the image. The fact that the index of refraction of all glass is greater than 1, impacts the image. The fact that there are air/glass boundaries (to per lens element) resulting in both reflection and partial reflection impacts the image. The fact that some of the photons scatter of the air/glass boundaries in random directions results in impacting the image. The major impact of all these things results in reducing the local or micro contrast.

Zeiss and Leitz both got their start in designing microscopes that could increase the contrast between the subject and background so people could see the objects better. While there is a difference in the illumination sources the problem in a microscope and camera vs. a lithography systems for the production of semiconductor devices - the problem is the same. That is to maintain sufficient local contrast to maintain the necessary detail at the edges.

Yes,

i have read these facts many times and I think I understand what this is about - there is a measurable thing. BUT ! are basically and normally made good lenses really much different - somehow visually different . I have very (or too often ) often read how people can "see" in an image on a PC screen, that some lens (usually the expensive ones they own ) clearly has more "micro contrast" . I really doubt these observations. How can anyone see some fantastic micro contrast on a rather low resolution screen?

Interestingly enough the best way to see edge contract for a human is on an emissive display at a pixel to pixel mapping because the back lite makes the contrast stand out more to the eye. This is the same as the light box to help people evaluate their negatives. I sure would not through out the issue of the "I spend a lot of money on this puppy so by golly it better be good" bias - that's always a problem.

It is much more difficult to see the difference off a reflective display like a print. Clearly an optical bench with controlled illumination and the appropriate sensor to capture the output of the lens is the proper way. The only place I know that does this and basses tier lens results is lensrentals.com.

Today the major differences between the top of the line consumer lenses like Zeiss Batis, the Leica ASPH line, etc., some Fuji cinema lenses and the next tier down is coatings. The top lenses use very expensive nano-crystal coatings to mitigate reflections at air ground boundary and random angle scattering.

https://photo.stackexchange.com/questions/22151/what-does-a-nano-crystal-coat-do-on-this-lens

Can a person actually see the difference at 100% on a monitor? Some might the same way they can see the difference of the negatives by using a high quality light box and high quality magnifying lope or a high quality grain magnifier that is magnifying on a sharp edge in a negative. I know it is very easy to see for example that dilute Rodinal produces much better edge sharpness (micro contrast) than say a silver solvent developer like D76 with a grain magnifier. So on some lenses at 100% on a good display - some people might be able to tell while others would be all wet. However, inputting a 16 bit TIFF into a program like Matlab or Mathematica or many others, it could become pretty easy to determine. The question then becomes - "does it make in visual difference" in the image hanging on the wall?

The facts and science is OK , but I do not believe in people who claim that they clearly see micro contrast . And some decades ago I had too look in to a microscope quite often

Expensive microscopes were better.... and some binoculars are much better. And some really bad lens was really bad and I had to return it. All other lenses have been OK

Yes

I'm sure it is possible to see subtle differences in 100 or 200% view on my 27" iMac screen - I even believe I see something if I seriously try . But the lens comparing sites and reviews should mention money more often. A 3500€ cinema lens looks better in 200% view than a 750€ prime lens. But how much better ? I do not want to pay the price for a thing I cannot see in a picture.

I did some experiments with D76 and perhaps Rodinal (or something) some 40 years ago and I tried to adjust exposure and other thins to get best possible negatives. Not sure if it was worth the effort . Today we can just add some contrast , sharpening , noise reduction etc etc - and the results are great if the lens is ok and there is no motion blur

A friend inherited a rather expensive and large wine cellar from a relative who was really more than a basic hobbyist. My friend  knew something about wines , but really did not know what to do with all those too expensive bottles he inherited - and took a scientific course in Helsinki University ( not sure why there was such course...) Anyway, it was scientific and there are many methods to "read" and taste wines - and there are really many laboratory methods. The lecturers gave the final lectures and at the end of the course it was just a couple of really determining things left. Is it the price or age of the wine or what is the  real thing ? ... when you enjoy wine in a very good company of good friends , if the food is OK and if the place and the view from the windows is nice - the wine tastes much better. And if someone plays some nice music with real instruments and the discussions get more interesting turns , the wine tastes extremely good and many want to buy a load of it to take the great wine home.

After 2 weeks the wine  you bought is nothing special if you taste it at home alone .

KariP wrote:

Truman Prevatt wrote:

KariP wrote:

Truman Prevatt wrote:

Jeff Biscuits wrote:

Truman Prevatt wrote:

Microcontrast

Actually it is quite real.

Fill me in in one thing, though…

I’ve done a limited amount of image processing in my career which has involved analysing local contrast/gradient. So “microcontast” as that concept of contrast within a small area of an image (whether analog or digital) makes complete sense.

Where it doesn’t make sense to me is when it comes to lenses. It’s a term that’s explicitly differentiated from just “contrast”, and I can’t get my head around how a lens can provide microcontrast to any different degree than it would provide “macro contrast”. In other words, how could a lens have the capacity to alter tonality just because of the proximity of their tones? It seems obvious that a lens can give more or less contrast, but surely there is no way two lenses with the same macro contrast can differ in terms of microcontrast.

So I’ve always assumed that in the context of lens reviews, microcontrast—though a perfectly real and measurable thing—is used in a somewhat mythical way, because in terms of a lens transmitting light, it’s just contrast.

Or is there something I’ve completely overlooked?

Every component of an optical systems reduces local contrast. Film reduces the local contrast of a scene. An outdoor scene can have as much as 20 stops of almost instantaneous contrast change. No film nor digital sensor can replicate that. In film days one had to chose the type of developer. D76 for example contained silver solvents. It was good for reducing grain but it made the edges smoother with slower roll of so reduced the micro contrast. Acutance ( a term for edge sharpness) developers like Ordinal produced negatives with much better micro contrast (sharp edges) but also made the grain more apparent since the hard edges were maintained.

Color filter arrays reduce micro contrast as the edges will be derived by interpolation from neighbor hooding detectors with different color. Cross talk in the sensor will cause a bleeding current across into neighboring detector hence reducing the contrast across the edges and smoothing the edges somewhat similar to the effect of silver solvents in developers.

The final component which may have the biggest impact is the lens. Lenses don't create micro contrast. No component of the imaging system create micro-contrast. That is a function of the scene. Any distortion will show up across edges as an effect of reducing micro contrast. Some aberrations are worse that others. Chromatic aberration resulting from the wavelength dependence on the refractive index will show up across sharp edges. Fixing one aberration can often result in making others worse.

https://www.lensrentals.com/blog/2010/10/the-seven-deadly-aberrations/

In the image they all show up on sharp boundaries between dark and light - the edges. When I ended up having to worry about R&D for both our signal intelligence/electronic warfare systems and optical systems I have to get an immediate education. The consolidation made sense as the big end image processing that the move to digital cameras for ISR was now simply the two dimensional version we did for signals intelligence and EW. For example an edge in an image is detected using the same basic approach as a radar pulse in detected in an EW system. But there is a lot more subtle to the imaging systems. Lens designs - we specified our lens designs to people like Kodak, Corning, etc. Different lens designs and glass formulations were needed for a camera flying at a nominal 30,000 feet on an airborne platform, from one flying on a U2 at 70,000 feet from one flying on the SR71 "blackbird" at 90,000 feet from one flying in space. But the goal was always the same - minimize the micro contrast degradation of the lens. In the 1960's NASA often contracted with Zeiss to design and build their lenses. Some attribute the "Zeiss pop" to the the fact these lenses degrade the scene micro contrast less than other lenses. That was important to NASA for the exploration of the moon during the 1960's and '70s. Often we would trade other properties of the lens to maintain high micro contrast.

So I expect that when people refer to their opinion that lens A has better micro contrast than lens B, what they mean is Lens A reduces micro-contrast to a less extent than lens B.

There is no perfect lens. Fourier optics tells us that. The very fact that there is an aperture between the scene and film/sensor impacts the recorded image. The point spread function tells us exactly what a point source looks like. The fact that all light rays landing on the sensor are not collimated and the interaction with the lens impacts the image. The fact that the index of refraction of all glass is greater than 1, impacts the image. The fact that there are air/glass boundaries (to per lens element) resulting in both reflection and partial reflection impacts the image. The fact that some of the photons scatter of the air/glass boundaries in random directions results in impacting the image. The major impact of all these things results in reducing the local or micro contrast.

Zeiss and Leitz both got their start in designing microscopes that could increase the contrast between the subject and background so people could see the objects better. While there is a difference in the illumination sources the problem in a microscope and camera vs. a lithography systems for the production of semiconductor devices - the problem is the same. That is to maintain sufficient local contrast to maintain the necessary detail at the edges.

Yes,

i have read these facts many times and I think I understand what this is about - there is a measurable thing. BUT ! are basically and normally made good lenses really much different - somehow visually different . I have very (or too often ) often read how people can "see" in an image on a PC screen, that some lens (usually the expensive ones they own ) clearly has more "micro contrast" . I really doubt these observations. How can anyone see some fantastic micro contrast on a rather low resolution screen?

Interestingly enough the best way to see edge contract for a human is on an emissive display at a pixel to pixel mapping because the back lite makes the contrast stand out more to the eye. This is the same as the light box to help people evaluate their negatives. I sure would not through out the issue of the "I spend a lot of money on this puppy so by golly it better be good" bias - that's always a problem.

It is much more difficult to see the difference off a reflective display like a print. Clearly an optical bench with controlled illumination and the appropriate sensor to capture the output of the lens is the proper way. The only place I know that does this and basses tier lens results is lensrentals.com.

Today the major differences between the top of the line consumer lenses like Zeiss Batis, the Leica ASPH line, etc., some Fuji cinema lenses and the next tier down is coatings. The top lenses use very expensive nano-crystal coatings to mitigate reflections at air ground boundary and random angle scattering.

https://photo.stackexchange.com/questions/22151/what-does-a-nano-crystal-coat-do-on-this-lens

Can a person actually see the difference at 100% on a monitor? Some might the same way they can see the difference of the negatives by using a high quality light box and high quality magnifying lope or a high quality grain magnifier that is magnifying on a sharp edge in a negative. I know it is very easy to see for example that dilute Rodinal produces much better edge sharpness (micro contrast) than say a silver solvent developer like D76 with a grain magnifier. So on some lenses at 100% on a good display - some people might be able to tell while others would be all wet. However, inputting a 16 bit TIFF into a program like Matlab or Mathematica or many others, it could become pretty easy to determine. The question then becomes - "does it make in visual difference" in the image hanging on the wall?

The facts and science is OK , but I do not believe in people who claim that they clearly see micro contrast . And some decades ago I had too look in to a microscope quite often

Expensive microscopes were better.... and some binoculars are much better. And some really bad lens was really bad and I had to return it. All other lenses have been OK

Yes

I'm sure it is possible to see subtle differences in 100 or 200% view on my 27" iMac screen - I even believe I see something if I seriously try . But the lens comparing sites and reviews should mention money more often. A 3500€ cinema lens looks better in 200% view than a 750€ prime lens. But how much better ? I do not want to pay the price for a thing I cannot see in a picture.

The only review site that I know of that does optical testing of lenses correctly is lensrentals  They have an optical bench set up.  They make multiple measurements and measure field curvature. They even estimate field curvature at multiple stops.  They also test multiple copies over time.  The opticals houses like Edmonds that support industry and government applications have full functional optical benches and design to user specifications.  They, however, are not doing reviews of consumer grade lenses.  The concept of point spread function and the OTF and companion MTF has been around for a long time.  It seems that it now has become the sweetheart of the photography world.

The good thing about the MTF is it is sensitive all aberrations and/or distortions that impact the fidelity of the projected image vs. the input image.  That is also its weakness.  It is similar to detecting the state of a gasoline engine by testing its exhaust.  It tells you there is a problem but it does not tell you what the problem is.  There are many reasons for the MTF falloff toward the edge of the frame.  It could be from spherical or chromatic aberration.  It could be from field curvature.  It tells you of the issue - it does not tell you why.  The second issue is it does not measure the lens response off of the focal plane.

A tack sharp lens with spectrally scattered bokeh is not a very nice image to look at.  It also a difficult image to perform target recognition  using.

However, YouTube side show is mostly there to promote clicks to make the cash register go cha-ching.  And you are correct, the real questions is "good enough" because best might not be a great value.  The value proposition also can be vastly different for different people.  Quite frankly if posting on social media is the end goal - one really doesn't need much more than a phone.  If the requirement is for a lens for high resolution images from a high altitude aircraft - then the value proposition is much different.

Truman Prevatt wrote:

xtm wrote:

Those who can shoot, shoot.

Those who can't shoot, review.

Those who can neither shoot nor review, become Ken Rockwell.

Where does the "hate" come from. Love him or hate him - Ken Rockwell was the original "influencer" 25 years before it even had a name. Ken Rockwell is an opined PITA - but ofen when one digs deeper one finds our - hey the dude was right although he was a jerk about it.

His site is a viable history of lenses and cameras. Looking for a great lens from the past you can pick up for a song - Ken Rockwell is your guy.

I've known guys like Rockwell in my past. I've worked with them and I've had a few work for me and I've even worked for a few. They are the "shock jocks" of the technical world and they do it for a reason. But he seems to still be going strong and his site has information not available otherwise and it's all there in one location.

He's not to everyone's taste but at the end of the day he doesn't try to be.

Oh I don't "hate" him. He's very informative and professional. Case in point:

If this is the kind of info you're into, then have at it.

xtm wrote:

Truman Prevatt wrote:

xtm wrote:

Those who can shoot, shoot.

Those who can't shoot, review.

Those who can neither shoot nor review, become Ken Rockwell.

Where does the "hate" come from. Love him or hate him - Ken Rockwell was the original "influencer" 25 years before it even had a name. Ken Rockwell is an opined PITA - but ofen when one digs deeper one finds our - hey the dude was right although he was a jerk about it.

His site is a viable history of lenses and cameras. Looking for a great lens from the past you can pick up for a song - Ken Rockwell is your guy.

I've known guys like Rockwell in my past. I've worked with them and I've had a few work for me and I've even worked for a few. They are the "shock jocks" of the technical world and they do it for a reason. But he seems to still be going strong and his site has information not available otherwise and it's all there in one location.

He's not to everyone's taste but at the end of the day he doesn't try to be.

Oh I don't "hate" him. He's very informative and professional. Case in point:

If this is the kind of info you're into, then have at it.

My guess is you are not a Mel Brooks fan either, eh?