03-20-2015, 05:35 PM
JoJu,
Canon INC is a $40B company, yes? They are the single largest player in the camera market by about 2x. Optics is a $15T USD industry worldwide. Cameras are a very small part of optics which is already a small industry. The majority of optics are very low volume, very high price units and are tested in methods similar to what I described.
E.g one of the ref. surfaces we have is this: http://www.astro-electronic.de/IMG_2054x.jpg - it is a 37mm f/0.68 lens. It is about a $20k usd part, and the "performance" of the lens is many orders of magnitude higher than a camera lens in its given role (as what allows ref. surfaces to be so high performance is that they only have to work for monochromatic light) while working at an aperture that has never been achieved in a camera lens.
You may argue that 25 copies isn't enough to speak to the entire population - this is true, but then 25 copies is far more than any single, average user will ever use and the gap between the two is nearly 50% so the result is still significant.
So I would say "which is better than others" is incorrect with regards to QC. They do have some better designs, but these designs are coming up on nearly 20 years newer than their competitors and the superiority is not quite as glaring as some make it out to be. Take the 35A vs the 35L for example - sigma's lens clearly has less spherical aberration, less oblique spherical, and a bit less coma, but the difference in the center of the two lenses is "just" perceptible and the corners aren't actually visually that much worse than the 35A from the 35L. If you look at the comparison here - http://www.the-digital-picture.com/Revie...&APIComp=0 - you can see that. The tested 35A seems to be a "bad" copy with a tilted tangential field but you may not have noticed that if I didn't point it out[...] I would say the "general" picture from the lens is okay anyway. Or there's Roger's data, which indicates that the 35A is only marginally better than the 35L for the most part.
Besides, in a couple years I will be designing lenses for a living.
Here's a short list of lenses that are cheaper that any SLR or MILC lens you own, and simultaneously better, optically:
* the lens in your smartphone
* the lens in any "premium" compact camera
* Small-sensor "photo industry" lenses like the ones used for the google street car.
A lens that you wish to out-resolve 20-24mp class FF sensors with requires MTF of 50% at just 30lp/mm. This is extremely low in the grand scheme of things, and nearly all ILC camera lenses are pretty poor optically. From all manufactures. Exceptions are things like canon's 300/2.8L II, 400/2.8L II, the 135mm f/2 APO-Sonnar, etc. Those are merely "good" lenses, compared to all other lenses.
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If you wish to give me advise, I will offer you some as well. The ILC camera/lens industry in total is less than five percent of the total optics industry. Real World Lens Business is so, so, so much more than what fits EF/F/FE/X/u43/etc mount.
Canon INC is a $40B company, yes? They are the single largest player in the camera market by about 2x. Optics is a $15T USD industry worldwide. Cameras are a very small part of optics which is already a small industry. The majority of optics are very low volume, very high price units and are tested in methods similar to what I described.
E.g one of the ref. surfaces we have is this: http://www.astro-electronic.de/IMG_2054x.jpg - it is a 37mm f/0.68 lens. It is about a $20k usd part, and the "performance" of the lens is many orders of magnitude higher than a camera lens in its given role (as what allows ref. surfaces to be so high performance is that they only have to work for monochromatic light) while working at an aperture that has never been achieved in a camera lens.
Quote:
because you're not able to do better at this price
Quote:Good enough varies from individual to individual. I once did some variance analysis for LensRentals on about 25 copies of each the 35/1.4A and the 35/1.4L with obvious duds pre-rejected. The 35L varied 7.8% between copies, the 35A about 13.03%. From that data, sigma allows approx. twice as much variance as canon. Perhaps they have improved in the 8 or so months since I did that, I don't know - but I doubt it.
Testing on production level and being good enough
You may argue that 25 copies isn't enough to speak to the entire population - this is true, but then 25 copies is far more than any single, average user will ever use and the gap between the two is nearly 50% so the result is still significant.
So I would say "which is better than others" is incorrect with regards to QC. They do have some better designs, but these designs are coming up on nearly 20 years newer than their competitors and the superiority is not quite as glaring as some make it out to be. Take the 35A vs the 35L for example - sigma's lens clearly has less spherical aberration, less oblique spherical, and a bit less coma, but the difference in the center of the two lenses is "just" perceptible and the corners aren't actually visually that much worse than the 35A from the 35L. If you look at the comparison here - http://www.the-digital-picture.com/Revie...&APIComp=0 - you can see that. The tested 35A seems to be a "bad" copy with a tilted tangential field but you may not have noticed that if I didn't point it out[...] I would say the "general" picture from the lens is okay anyway. Or there's Roger's data, which indicates that the 35A is only marginally better than the 35L for the most part.
Quote:I am a bit confused. Very very few lens reviewers do anything related to building, designing, etc, optical systems. That doesn't mean they can't criticize things. In the same capacity that I can say Kubrick did a terrible visual rendition of A Clockwork Orange, I can speak about sigma's lens designs and constructions.
YOU are not able to make the design
Besides, in a couple years I will be designing lenses for a living.
Quote:The $4500 lens I have referred to is a photo-industry lens. It even covers a full-frame sensor which is a bit unusual for lenses in general.
But pulling exotic lens design against photo-industry stuff
Here's a short list of lenses that are cheaper that any SLR or MILC lens you own, and simultaneously better, optically:
* the lens in your smartphone
* the lens in any "premium" compact camera
* Small-sensor "photo industry" lenses like the ones used for the google street car.
A lens that you wish to out-resolve 20-24mp class FF sensors with requires MTF of 50% at just 30lp/mm. This is extremely low in the grand scheme of things, and nearly all ILC camera lenses are pretty poor optically. From all manufactures. Exceptions are things like canon's 300/2.8L II, 400/2.8L II, the 135mm f/2 APO-Sonnar, etc. Those are merely "good" lenses, compared to all other lenses.
----
If you wish to give me advise, I will offer you some as well. The ILC camera/lens industry in total is less than five percent of the total optics industry. Real World Lens Business is so, so, so much more than what fits EF/F/FE/X/u43/etc mount.