p.3 #1 · Optical superiority vs Lens Profile Corrections
chez wrote:
Again, you are comparing manual focus lenses against auto focus lenses. Surely you can see that to add the ability to autofocus at the speeds demanded by today’s cameras, the bulk and weight of the lens must be increased.
The bottom line here is use whatever lens achieves your goals. I’ve seen enough boring simple photos taken by the so called magnificent optical designed lenses and amazing photos taken by those so called “lenses for the masses” to know today’s lenses are all capable of producing great photos…it all depends on the person pushing the shutter.
David Alan Harvey shot most of his magnificent book Cuba with a Fujifilm aps-c X-T1 and a Fuji lens. He must have had a good copy.
p.3 #2 · Optical superiority vs Lens Profile Corrections
'..you are comparing manual focus lenses against auto focus lenses.'
Indeed I am. My aim is to debunk (refute is a better word, but I am writing for for the US audience) the wrong-headed belief of 'bigger=better optically and smaller=poorer and needs profiles', that is widely held to be the truth when it is clearly not.
The hidden criterion is that the meme is for AF lenses only, but that was not specified, was it? It can be done with AF, as witnessed by the many superb last (and this) century AF lenses. A few examples, from a long list:
Pentax 77/1.8 is a featherweight 270g; Pentax 31/1.8 is 350g; Minolta AF 50mm f/1.4 is 235g; Minolta 100mm f/2 440g; Sony 85/1.8 370g. And bear in mind it only takes one counter-factual observation to destroy a theory. Or in this case, a silly industry claim.
Thank you for amplifying my point with: 'to add the ability to autofocus at the speeds demanded by today’s cameras, the bulk and weight of the lens must be increased.' You are saying that the reason those lens are so large and heavy is because of the *market demand* for modern AF performance. Not because the extra weight/size is to deliver *stronger optical performance*!
Your last para is irrelevant, still, it's true of course. ;-)
p.3 #3 · Optical superiority vs Lens Profile Corrections
I think we are making this more complicated than it has to be
Let’s assume the premise is true, that by not correcting barrel distortion, other optical issues can be better corrected.
These other optical issues (spherical aberration, coma and astigmatism) all reduce lens resolution, so it’s plausible that correcting for these issues at the expense of some barrel distortion could improve the MTF
Therefore, the lens design which results in a better MTF at the expense of some digital distortion correction would be the better lens design.
bonus points if it’s also resistant to flare, focuses close, and has nice bokeh
p.3 #4 · Optical superiority vs Lens Profile Corrections
Better MTF after corrections right? Do we know if Mfgs published MTFs are before or after correction. If before, then we really have nothing to go on by looking at MTFs do we? Hopefully published MTFs are after correction....
aCuria wrote:
I think we are making this more complicated than it has to be
Let’s assume the premise is true, that by not correcting barrel distortion, other optical issues can be better corrected.
These other optical issues (spherical aberration, coma and astigmatism) all reduce lens resolution, so it’s plausible that correcting for these issues at the expense of some barrel distortion could improve the MTF
Therefore, the lens design which results in a better MTF at the expense of some digital distortion correction would be the better lens design.
bonus points if it’s also resistant to flare, focuses close, and has nice bokeh...Show more →
Aug 22, 2024 at 05:59 AM
AmbientMike Offline • • • • • • [X]
p.3 #5 · Optical superiority vs Lens Profile Corrections
JohnDizzo15 wrote:
Just as the subject states. I wanted to get a feel for members around these parts and their preferences with regard to whether they'd prefer an optically superior lens at the cost of added size and weight; or instead, prefer a smaller and lighter lens that requires a heavy-handed profile correction either in camera or in post.
Bonus points for expounding on perspective.
As a side note, if anyone can help me with cross-posting this to the other brand forums, I'd greatly appreciate it, as I'm interested to hear from all the shooters around these parts. Thanks in advance.
It tends to irritates me that even 1970's and older lenses cover the entire frame, hardly ever have massive distortion or vignetting, but new lenses often do.
p.3 #6 · Optical superiority vs Lens Profile Corrections
tsdevine wrote:
Better MTF after corrections right? Do we know if Mfgs published MTFs are before or after correction. If before, then we really have nothing to go on by looking at MTFs do we? Hopefully published MTFs are after correction....
Yeah better MTF after corrections is what matters.
p.3 #7 · Optical superiority vs Lens Profile Corrections
While the Voigtlander 35mm apo and 50mm apo are two of my favorite lenses, their MF, F2, have optical vignetting and are around the ideal focal length for compact lenses. I wonder how small Voigtlander could make a MF 28mm f1.4 APO or an 85mm f1.4 APO. Take a look at how big the Zeiss Otus lenses are which are also MF. Supposedly Zeiss made them so large to have no compromise F1.4 lenses at various focal lengths.
I will admit on the other hand the Voigtlander lenses do make me wonder if compact high end AF F2 primes could be made. For example, could the Sigma 50mm f2 have the IQ of the Voigtlander APO if it was 1,300 instead of 640? Part of me wonders if it's more a market perception issue than a technical issue since if you could buy an AF 50mm f1.4 for $850 why would you buy an AF f2 for 1,300.
p.3 #8 · Optical superiority vs Lens Profile Corrections
I would say
if a lens is super sharp, I don't mind lens profile corrections. eg. 20-70 G
if a lens is soft, any corrections will only muddy the waters. Previous gen zooms.
I am most astonished by some of Samyang/Rokinon lenses, eg. their FE 135 AF has nothing to correct whatsoever (basically no distortion and very very little vignetting), it puts GM to shame at half the price and 200g lighter. Of-course any paid professional should still pickup GM for AF edge.
Same goes for their 50mm F1.4 II, I don't how they packaged a F1.4 lens with no distortion and vignetting in 420g.
Watch Dustin Abbot's comparison of corrections required for -
p.3 #9 · Optical superiority vs Lens Profile Corrections
tsdevine wrote:
Better MTF after corrections right? Do we know if Mfgs published MTFs are before or after correction. If before, then we really have nothing to go on by looking at MTFs do we? Hopefully published MTFs are after correction....
aCuria wrote:
Yeah better MTF after corrections is what matters.
Most, if not all, MTF-curves released by manufacturers seem to be computer calculated rather than actually measured values. If the before or after software correction of the images... I don't know but either value will be calculated anyway. At best the curves work as marketing material only.
Aug 22, 2024 at 02:09 PM
Steve Spencer Offline • • • • • • • Upload & Sell: On
p.3 #10 · Optical superiority vs Lens Profile Corrections
aCuria wrote:
Yeah better MTF after corrections is what matters.
Well, it is one of the things that matters. If a lens has better MTF after correction, but the vignetting correction causes problems with noise in the corners and edges then that would matter to me, and a lens that maximized MTF after the corrections might still have design elements that make the bokeh less desirable to me. There are always lots of factors when evaluating a lens and balancing them is tough. Using software correction can sometimes help that balancing act, even if doesn't result in better MTFs after correction, and sometimes it might lead to better MTFs after correction but upset the balance of the attributes. MTFs after correction is what matters for sharpness, but sharpness is just one attribute and for me often not the most important attribute so maximizing that if there are other tradeoffs would often not produce the lens I want.
p.3 #11 · Optical superiority vs Lens Profile Corrections
philip_pj wrote:
[...]
Pentax 77/1.8 is a featherweight 270g; Pentax 31/1.8 is 350g; Minolta AF 50mm f/1.4 is 235g; Minolta 100mm f/2 440g; Sony 85/1.8 370g. And bear in mind it only takes one counter-factual observation to destroy a theory. Or in this case, a silly industry claim.
Thank you for amplifying my point with: 'to add the ability to autofocus at the speeds demanded by today’s cameras, the bulk and weight of the lens must be increased.' You [chez]are saying that the reason those lens are so large and heavy is because of the *market demand* for modern AF performance. Not because the extra weight/size is to deliver *stronger optical performance*!
You are right about many things. Picking the Pentax lenses as examples of light weight AF lenses is somewhat misleading though:
I owned the SMC-P FA 77/1.7 limited and still have the 31mm. Just as a lot, or most actually, Pentax lenses at the age of 20-30 years they show a lot of LoCA. The limited series are also barely AF lenses: the AF works with an engine in the camera, a long screw and a noisy gear mechanism in the lens. The AF wasn't exactly very fast and the precision can also be questioned. No dampening when focusing manually. I still like the 31mm for some black and white work though.
In the case of heavy complicated new era lenses it seem as at least some of them are bigger and heavier _and_ performs better than older versions. The new, big and heavy, generation of fast 50mm lenses are examples of that. I seriously doubt any manufacturer make bigger and heavier lenses to impress on americans driving trucks.
