jhinkey wrote:
I've never been quite clear on the difference between "smearing" and plain old blurry-ness from not being sharp.
For instance, my 16/3.5 AI is very sharp off in the corners while the 16/2.8D is not all that sharp off int he corners (at any aperture). So is this lack of sharpness of the 16/2.8D due to the lens design (fundamentally not sharp) or to the interaction of the sensor (smearing)? Typical film just can't show the sharpness that a 36MP FX sensor can, so perhaps hid this lack of sharpness or smearing that is evident now with high MP FX sensors.
Unfortunately whether smearing or fundamentally not sharp, the end result is blurry corners. We can't judge a lens alone like in film days but the way it pairs up with the camera body. If it's important to know you can test the lens on a Leica M which has LV and a very thin sensor cover.
douglasf13 wrote:
As far as Loxia, I'm worried that we just have ZM lenses in a new shell, which would be an odd decision.
As an A7R owner (with no native E-mount glass) I would not want to plunk down Zeiss-like $$ on a design that did not perform to a very high standard. I did this with my 135/2 ZF.2 and it performs superbly as I would expect. A compact 35/2 MF lens with electical contacts and aperture control is very much interesting to me, but only if it performs at a very high level for the price I would expect of a Zeiss. Hopefully they tweaked the design . . .
douglasf13 wrote:
I know that theSuede has mentioned that our old A900s had a lower quality AA, and that seemed to cause smearing compared to the D3X at the time, but I think that was independent of the actual sensor stack thickness that we're talking about here. A thicker stack isn't much of an issue, if the materials are good and the lenses are designed for it. The issue is that we all seem to be interested in the performance of lenses not designed for the camera, and that's optimistic when thinner sensor stacks can produce other issues.
I think, ultimately, that the concept of adapting legacy lenses to digital cameras is a tough proposition, now that we're all getting so technical about things like corner performance. Unlike film, where we had a relatively consistent medium for decades, digital sensor sizes and types are not standardized, so keeping a lens for twenty years and expecting it to perform brilliantly on all cameras is going the way of the dodo. I no longer think of any lens that I buy as an option for anything other than the current camera system I'm using, and new advances in digital imagery, like curved sensors, will make things even tougher.
As far as Loxia, I'm worried that we just have ZM lenses in a new shell, which would be an odd decision....Show more →
Douglas, don't forget that the A900 sensor had the glass cover placed further away from the microlenses in order to make the dust less visible, and allow for better ultrasonic vibration, as per Sony's own admission. Knowing what we know today, it is no wonder the 24-70 and 16-35 had corner issues, while they were perfect on film as tested by yours truly.
douglasf13 wrote:
I think, ultimately, that the concept of adapting legacy lenses to digital cameras is a tough proposition, now that we're all getting so technical about things like corner performance.
As far as Loxia, I'm worried that we just have ZM lenses in a new shell, which would be an odd decision.
I agree with both points, though for the second, am hoping Zeiss isn't that stupid.
Regarding the first point - about which I was just thinking too - the cynical side of me thinks it was intentional for Sony to release these cameras sooner than later and trickle out decent native lenses. It gave them the advantage of being the first out of the gate and for lack of options, gave all us gear heads plenty of time to try virtually every adaptable lens on them. We collectively came to the conclusion that despite some lenses, both legacy and modern, the best results will likely be from well-made native solutions. And just as we figured this out... comes Loxia and perhaps finally some quality offerings from Sony too. Less need for marketing spin from Sony/Zeiss to convince us their optimized solutions will be the best - we've pretty much done that work for them.
edwardkaraa wrote:
A thin stack wouldn't have caused any issues with legacy DSLR lenses because most were designed for film, and curiously, even the ones designed for digital don't seem to have taken the sensor stack in consideration (look at the FE zooms, and even the FE 35 corner performance). As far as I'm concerned, Sony's position regarding the sensor cover is undefendable and incomprehensible.
it's important to draw the distinction between lenses that have poor corners due to the sensor stack and those that have poor corners because they're just not sharp lenses. the FE zooms were made to a price point and sony just didn't want to spend/charge what it would take to make them super sharp to the corner throughout the range. i highly doubt they would perform better if you removed the focus stack.
theSuede wrote:
ONT: I'm not to keen on the fact that they (Zeiss) used a 6/4 construction for the planar 50. We have much better performing base constructions nowadays, extended ultrons and other variations on the planar. Optimizing a pure planar for LoCA is impossible outside the 1:1 magnification domain, optimizing it for the other important aberrations together, at the same time, at multiple target distances, is also very hard.
Take a simple and cheap lens, like the Nikon 50/1.8, or the Canon or other corresponding lens. They're already bordering on "really good", and they're simple 6/7 constructions. Then put some more construction effort and production cost into optimizing it. At double the production cost, you COULD get something truly remarkable when you have the shorter RFD of the E-mount. Now, they can never match the production series lengths (and hence neither the production cost optimizations...) of the cheaper lenses - but the "cheap" lenses can retail for about 120-150USD......Show more →
i'm not surprised they did this. i suspect this planar will be a very cheap (by zeiss standards) entry point for the new loxia series. it's a design that has a successful history with zeiss in the contax g 45 and zm 50/2 defining what a lot of people think of as the zeiss look (both the good and the bad). despite it's many defects it should score pretty well on internet review sites using imatest and as alwang says, the lens's harshness makes it super easy to manual focus in an evf (at least the g45 version).
theSuede wrote:
Sony themselves opted for a base construction that gives a totally different character than a planar in their 55/1.8, which I for one definitely applaud. IMO Sonnar>Distagon>Planar>Tessar in image usability and pleasantness. I don't like the edgyness you get from constructions with abrupt aberration line modulations, even though it can give superbly sharp renditions of what is actually IN focus when stopped down a bit. Some find it "interesting", I find it "distracting" and "ugly".
out of curiosity, what are the defining characteristics of a sonnar? it seems to me the latest sony zeiss sonnars don't have a lot in common in terms of lens design with the more traditional zeiss ones i'm familiar with.
sebboh wrote:
out of curiosity, what are the defining characteristics of a sonnar? it seems to me the latest sony zeiss sonnars don't have a lot in common in terms of lens design with the more traditional zeiss ones i'm familiar with.
Zeiss is of course free to call a Distagon a Biogon and a Double Gauss designed lens a Sonnar, as they seem to do with some of the more recent "Sonnar" lenses. It's confusing and just marketing at this point I guess. A bit sad really.
ecarlino wrote:
when i had the D800, i called NikonRepair and asked if i could just change the sensor glass to make it a D800E (after all the concern about moire passed) - they told me the stack and sensor were one and could not be separated.
Roger (via the link i posted above) said that the A7r's stack is glued to the sensor.
The fact that you observe similar performance between the 2 cameras with the same lens also suggests they very similar.
douglasf13 wrote:
That 3mm is a bit of a guess on the part of Roger's team, because it is difficult to measure. Either way, it's just a bit thicker than most of the other cameras, and I don't think the difference would have been huge had it been only 2mm.
I am less certain than you, I guess. It is clearly a step in the wrong direction, when combined with the extremely short register distance.
The important thing is that the lenses are designed for whatever the stack is. Making a super thin stack to accommodate Leica lenses may have caused issues with Sony legacy DSLR and e-mount lenses.
It shouldn't in any meaningful way. The DSLR lenses are much more tele-centric, partly because of the mirror box, partly because of the existing thick sensor stack on the DSLRs. Getting optimum performance out of APS-C lenses on a FF camera HAS to take lower precedence than making the best design for E-mount FF lenses...
While you are right about the lenses needing to be designed for the register distance, my whole point is that a thinner sensor glass would have allowed for more compact lens design, and it would have allowed for better performance from existing, adapted lenses, which would have been a benefit for all, especially at the glacial pace at which Sony rolls out native lenses.
I still think Sony should have made the FE mount larger
There we agree.
which would have allowed more telecentric designs that could have likely been shorter, albeit larger in diameter.
I don't think that any part of the mount prevents an almost perpendicular light path, so I don't know that the design of tele-centric lenses is in any way compromised?
As it stands now, as theSuede has mentioned, any lenses faster than around f2 will essentially be the same size as the DSLR equivalent with an adapter attached, although, like we're seeing with the 55/1.8, the lack of a mirror box still allows for more interesting designs at that size.
The rear element on the 55/1.8 looks very odd. I wonder if it isn't just there to straighten out the incoming light to hit the sensor as perpendicularly as possible? If that is the case, this lens design might also work on longer register distances, with minor modifications...
theSuede wrote:
But it's quite important to remember that there's no real DIFFERENCE between optimizing for a thick stack or a thin stack. You can - as long as you don't have reflection problems between stack elements, like the A7 camera - use whatever you want.
Right, but we do appear to have reflection problems between stack elements, or?
Tariq Gibran wrote:
Great to hear that experience of lenses with the A7r vs D800.
Hopefully someone brings an A7r to Berlin on September 6th... I would love to do some tests of my own. There are limits to internet wisdom, after all (in both directions!).
carstenw wrote:
The rear element on the 55/1.8 looks very odd. I wonder if it isn't just there to straighten out the incoming light to hit the sensor as perpendicularly as possible? If that is the case, this lens design might also work on longer register distances, with minor modifications...
i believe you correct about the purpose of the rear element (i haven't looked at the diagram recently, but that is common with mirrorless), but that means it will be harder not easier to work on cameras with a longer register distance i would think.
edwardkaraa wrote:
To my knowledge no one has done it yet with maxmax but someone on this forum did some bricolage and did it on his own with excellent results it seems.
It is interesting the different design philosophy between the 50mmZA 1.4 with its 8/5 design and this Nokia with a 6/4. These are both planars, aren't they? I recently got the A mount one and it is pretty special. It does have some CA wide open but is still very sharp.
edwardkaraa wrote:
To my knowledge no one has done it yet with maxmax but someone on this forum did some bricolage and did it on his own with excellent results it seems.
Interesting, I'm contacting Dan right now. If they do offer sensor re-position, I'm definitely interested. Thank you for the info.
mogul wrote:
It is interesting the different design philosophy between the 50mmZA 1.4 with its 8/5 design and this Nokia with a 6/4. These are both planars, aren't they? I recently got the A mount one and it is pretty special. It does have some CA wide open but is still very sharp.
I can guarantee you Zeiss had nothing to do with the design of the ZA 50, 24, 55, 35, 24-70/4. Any Zeissness you may see is caused by the T* coatings.
edwardkaraa wrote:
I can guarantee you Zeiss had nothing to do with the design of the ZA 50, 24, 55, 35, 24-70/4. Any Zeissness you may see is caused by the T* coatings.
And your source of information or is it just design philosophy left over from the Minolta glass works? The way it has always been presented is that Sony has Zeiss design the optics and builds the body around it. I am sure it is a little more complicated relationship than that but unless you have information that I am not privy too, I will stick with that explanation.
