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Archive 2014 · Zeiss Loxia line

sebboh
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p.7 #1 · Zeiss Loxia line

hiepphotog wrote:
Removing the AA filter doesn't mean the sensor stack thickness would change. I don't think the initial intent using the AA self-canceling filter was to maintain the thickness (more like to reduce the cost). What I am uncertain is that whether the optical thickness or the physical thickness would be the main cause for the poor edge/corner performance in RF WA (not clear in the lensrental blog). If it is the latter, there might be remedy for such (changing the former would really mess up the native lenses). I know both Maxmax and Lifepixel can offer different sensor stack thickness...Show more →

my understanding is that both matter. it sounds like for best performance with lenses designed for film the optical thickness needs to be minimized as the lenses were not designed to undergo any diffraction after exiting the rear element. unfortunately minimizing optical thickness means minimizing physical thickness as well and changes the backfocus distance (i forget by how much, i think Maxmax actually gave edward a quote what their minimum possible stack could be). this means the mount needs to be moved closer to the sensor for native lenses to maintain infinity focus (although AF lenses allow focus past infinity, so depending on the distance they might still reach infinity). if shooting exclusively adapted lenses, they just need to get slightly shorter adapters. using these new loxia lenses could be a problem though as zeiss will probably give them a hard stop infinity, perhaps they will also make adjustment of the infinity stop easy though?

i've been tempted to try having this done on my a7 since i don't have any native glass and have access to a lathe so shorting my adapters wouldn't be too difficult. i keep meaning to look at the tear down of the a7 though to see if it would be possible to simply move the mount back a little closer to the sensor by removing shims or trimming something. sadly it's rather far down on my to do list at the moment...

Aug 27, 2014 at 02:10 PM

hiepphotog
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p.7 #2 · Zeiss Loxia line

sebboh wrote:
my understanding is that both matter. it sounds like for best performance with lenses designed for film the optical thickness needs to be minimized as the lenses were not designed to undergo any diffraction after exiting the rear element. unfortunately minimizing optical thickness means minimizing physical thickness as well and changes the backfocus distance (i forget by how much, i think Maxmax actually gave edward a quote what their minimum possible stack could be). this means the mount needs to be moved closer to the sensor for native lenses to maintain infinity focus (although AF lenses allow focus past infinity,...Show more →

So from what you said, that would mean only optical thickness would matter, since changing physical thickness while maintaining optical thickness would be pointless. I only use adapted lenses as well so losing infinity on native lens is not a big deal. However, if it involves major trimming or custom made adapter, that would be too much of a hassle. I bought the Hawk v3 adapter to prepare myself for this and my LA-EA3 is already a tad too short, but they might not be short enough.

Aug 27, 2014 at 02:22 PM

sebboh
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p.7 #3 · Zeiss Loxia line

hiepphotog wrote:
So from what you said, that would mean only optical thickness would matter, since changing physical thickness while maintaining optical thickness would be pointless. I only use adapted lenses as well so losing infinity on native lens is not a big deal. However, if it involves major trimming or custom made adapter, that would be too much of a hassle. I bought the Hawk v3 adapter to prepare myself for this and my LA-EA3 is already a tad too short, but they might not be short enough.

yup, basically you want all the glass gone except for the thinnest possible hotmirror. there is somebody on the forum that removed all the cover glass himself and shortened his m-mount adapter. haven't seen many images from them though.

Aug 27, 2014 at 02:31 PM

phigment
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p.7 #4 · Zeiss Loxia line

Hey, if this catches on, the Phigmenttech LM-NEX adapter should be well suited for this and M-mount lenses. The adjustment screws can bring the adapter thickness down by about 0.15mm from nominal.

Aug 27, 2014 at 02:35 PM

sebboh
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p.7 #5 · Zeiss Loxia line

phigment wrote:
Hey, if this catches on, the Phigmenttech LM-NEX adapter should be well suited for this and M-mount lenses. The adjustment screws can bring the adapter thickness down by about 0.15mm from nominal.

sounds good!

i should add that thinning the stack will almost certainly hurt the performance of these new loxia lenses a tiny bit since they will almost certainly be designed with sony's ~2mm stack in mind.

Aug 27, 2014 at 03:02 PM

sirimiri
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p.7 #6 · Zeiss Loxia line

What an interesting read.

As an aside/jibe, sensor stack sounds much better than "sensor toppings"

Aug 27, 2014 at 03:08 PM

philber
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p.7 #7 · Zeiss Loxia line

I beg to differ with the learned members above. The RX-1 proves how good a lens designed for a specific camera can be when Zeiss get involved (I am not sure if it is a Zeiss or a Sony-Zeiss lens). The Touit 12 shows how good a Zeiss lens can be even when designed for a very touchy camera (the NEX 7). The Sony-Zeiss FE 55 shows how good a lens can be for the A7 camera, even though I don't care much for it and will put mine up for sale tomorrow. My guess is that the Loxia will show that (a) Sony don't mis-design senor covers and glass toppings to the point that even forum members look like experts in comparison (no offence meant, yuo guys have forgotten more in a day than I've leanred in a year), and (b) Zeiss know how to take those parameters into account.
Simply put, their 50 Loxia must outperform the FE 55, or Zeiss will look like complete fools, which is not their custom. Considering how many people thing highly of that lens, the Loxia should be interesting, to say the least. Forget the theory and glass toppings, they are not members of FM anyhow...:-)

Aug 27, 2014 at 03:51 PM

sebboh
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p.7 #8 · Zeiss Loxia line

Aug 27, 2014 at 04:09 PM

mogul
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p.7 #9 · Zeiss Loxia line

Interesting side track while waiting for the announcement...I have a comment that is probably wrong but I have read that a true 50 is harder to design than a less than 60. Curious if the new lens is a 50 or 50ish. Zeiss really isn't competing with Sony if the lenses do draw differently.

Aug 27, 2014 at 04:18 PM

carstenw
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p.7 #10 · Zeiss Loxia line

I have heard something similar, which would be backed up by all the 55s and 58s being designed. I cannot imagine that this is because of the huge demand for slightly longer than 50mm lenses, so it might be a constraint in the design process which is eased by the longer focal length.

Aug 27, 2014 at 04:22 PM

sebboh
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p.7 #11 · Zeiss Loxia line

part of that has to do with the design restriction caused by the mirror box on slrs. a 55mm or 58mm can be closer to a symmetric design without running into the mirror than a 50mm. you'll notice that there aren't near as many 58mm rangefinder lenses. generally though, the longer the focal length the more design freedom i would think.

personally, i prefer 58mm to 50mm.

Aug 27, 2014 at 04:30 PM

Steve Spencer
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p.7 #12 · Zeiss Loxia line

I prefer a less than 60, so I would be quite happy if that were actually true. I don't think it matters if it is 50, a 55, or a 58 as far as competing with the Sony/Zeiss 55 f/1.8. Whatever it is would be pretty close to the Sony/Zeiss lens and most people would make the decision on whether they wanted AF or not.

Aug 27, 2014 at 04:31 PM

Jeff Kott
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p.7 #13 · Zeiss Loxia line

mogul wrote:
Interesting side track while waiting for the announcement...I have a comment that is probably wrong but I have read that a true 50 is harder to design than a less than 60. Curious if the new lens is a 50 or 50ish. Zeiss really isn't competing with Sony if the lenses do draw differently.

Instead of paraphrasing, I'll post a quote from a Joseph Wisniewski post on Photonet post on July 11, 2011:

"You're close. John actually nailed it. A symmetric pair of achromats is a very good design, the reversed rear group cancels many aberrations of the front group, it makes the math and ray tracing easy, which was a "good thing" back in 1955, when lens designers drew large versions of the lens, and did their ray tracing by hand with ruler, pencil, slide rule, and lots of tables. At f1.4, the two most popular designs were the planar and the double Gauss, with the planar being easier to treat mathematically.

Both the f1.4 planar and double Gauss with late 1950s glasses are nearly "square" lenses, just about as thick as they are wide. A 58mm f1.4 double Gauss is about 43mm in diameter, and about 40mm thick, and the nodes are nearly coincident, the focal point is smack in the center, half the lens is in front of the 58mm plane, half is behind it, which brings it to about 38mm from the focal plane, just enough to clear an SLR mirror (24mm * sqrt(2) + 5mm for the shutter and film gate). Get your hands on the right glass, and you can make it thinner and push it to 55mm.

58mm was 1.34x the diagonal of the format. Photographers found this to be an awkward "dancing bear" of a lens, too long for a normal, too short to feel like a "portrait tele", which sort of starts at 2x the diagonal (the reason the 85mm is so popular with the 43.3mm diagonal 35mm format). Nikon, Topcon, etc. launched their 55mm and 58mm fast normals in the late 50s, and got laughed at by photographers. So, the camera companies went back to the drawing board and said "we can make a very ugly, asymmetrical 45mm f1.4, but it will not be as sharp as a 58, and it will have more distortion. Or, we can split the difference between 43mm and 58mm and do a 50mm, half as offensive, aesthetically, as the 58, half as offensive, optically, as the 45."

Here's the thread link:

http://photo.net/leica-rangefinders-forum/00Z2iy?start=20

Aug 27, 2014 at 04:33 PM

carstenw
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p.7 #14 · Zeiss Loxia line

That mostly sounds quite logical, except for the part about photographers in '50s. There were 50mm lenses earlier than that ('20s and '30s), and the 55/58mm would have been the latecomers rather than early to the party, so the story is a little backwards in that aspect. I think probably Oskar Barnack was the one to establish the 50mm lens as the standard lens on the 135 format, and the reason may have had something to do with movie cameras, since his first camera was meant as a film emulsion test device for movie camera work.

Aug 27, 2014 at 04:45 PM

rscheffler
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p.7 #15 · Zeiss Loxia line

philber wrote:
I beg to differ with the learned members above. The RX-1 proves how good a lens designed for a specific camera can be when Zeiss get involved (I am not sure if it is a Zeiss or a Sony-Zeiss lens). The Touit 12 shows how good a Zeiss lens can be even when designed for a very touchy camera (the NEX 7). The Sony-Zeiss FE 55 shows how good a lens can be for the A7 camera, even though I don't care much for it and will put mine up for sale tomorrow. My guess is that the Loxia will...Show more →

Hi Philippe,

Not sure about others here, but my feeling isn't that Sony mis-designed their sensors or their system in general, just that the way they've launched the system, it seems they're expecting a lot of early adopters to adapt legacy glass to these cameras. This presents a problem when the legacy glass in question is from the film era, or more specifically is Leica M system, where sensor topping thickness is a critical factor in final image quality.

A current trend here seems to be the desire to downsize, which the a7 series allows very nicely compared to DSLR systems. But the correspondingly smallest lenses, unfortunately, are often for rangefinder systems, precisely the lenses that are most sensitive to sensor topping thickness. Therefore the reason there's much discussion here about why Sony's sensor topping decision was potentially a mistake. They could have designed it to be thinner from the outset and it would have been part of the system spec for all of their lenses and would have worked better with most adapted glass. But now that's pretty much too late. We'll likely never know exactly why this decision was made. Maybe their expectation is that a ~2mm thick topping is more durable or that it's what most other current systems are based around and therefore will work better with modern adapted glass from other DSLR systems (thus ignoring the RF outlier).

If the sensor topping specs are known ahead of time, any competent lens manufacturer will take it into account when designing their lenses. That's obviously impossible for lenses already out on the market designed for different system parameters. But without doubt, Zeiss is privy to Sony's future plans and certainly knows enough information to design fully corrected lenses for the system

I see Loxia as a ZM successor because outside of the minuscule rangefinder market, the ZM line, at the wider end, is a poor option for adapting to mirrorless systems. It's pretty much dead in the water and Loxia is a chance for Zeiss to optimize a set of compact lenses for proper digital compatibility.

Regarding the 50.. to me the question is whether it will be a lower cost alternative to the FE55, thus essentially being like the competent ZM 50 Planar (or a slower ZE/ZF Planar version), or instead will be a mini-Otus? With Samyang releasing an E mount 50/1.4 soon, I'd wonder how much opportunity Zeiss sees for the lower end of the market, other than with diehard Zeiss fans?

The 35/2 isn't so unexpected because there is the expectation of an AF 35/1.4 from Sony and it keeps the size relatively compact.

It will be very interesting to see how close Zeiss can keep the 28mm and wider lenses in this line to the size of the ZM line, which are already larger than most of the Leica equivalents, even though many are symmetrical-based designs, which supposedly should be more compact...

Aug 27, 2014 at 07:08 PM

mogul
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p.7 #16 · Zeiss Loxia line

Another way to look at it is fill another niche and design a camera for range finder lenses and capture all those fuji, Leica, and Zeiss diehards with a modern camera.

Aug 27, 2014 at 07:25 PM

Keith B.
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p.7 #17 · Zeiss Loxia line

Matt Grum wrote:
Interchangeable lenses with built in curved sensors is a possibility, but I mentioned that more as an example rather than something I think it likely to happen. There's just no way to know for sure that Sony will carry on making full frame E-mount cameras if they don't sell as many A7s as they expect to.

Not many people will want relatively heavy full frame lenses for their APS-C NEX, so it's just not as safe an investment as, say buying a ZF Zeiss prime.

I think that Zeiss would not have started this Loxia venture if they thought that Sony was to be their only platform in the marketplace.
Who else makes 24x36 digital cameras?

Aug 27, 2014 at 08:21 PM

johnctharp
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p.7 #18 · Zeiss Loxia line

Keith B. wrote:
Who else makes 24x36 digital cameras?

Neither Canon nor Nikon will leave this market alone forever; Canon in particular has invested heavily in mirrorless focusing.

Aug 27, 2014 at 10:39 PM

freaklikeme
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p.7 #19 · Zeiss Loxia line

Keith B. wrote:
I think that Zeiss would not have started this Loxia venture if they thought that Sony was to be their only platform in the marketplace.
Who else makes 24x36 digital cameras?

Canon, Nikon, and Leica, but they already make lenses for all three.

Aug 27, 2014 at 10:39 PM

freaklikeme
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p.7 #20 · Zeiss Loxia line

johnctharp wrote:
Neither Canon nor Nikon will leave this market alone forever; Canon in particular has invested heavily in mirrorless focusing.

I hope they're investing an equal amount in improving their sensor output.

I think Canon's work on mirrorless focusing has been driven more by the video market than a desire to make mirrorless cameras, but I could be wrong. It wouldn't surprise me to see their entry-levels go mirrorless as a cost-savings measure to keep them competitive, but I'm betting they'll still have an EF mount.

I don't know about Nikon. I'd say the DF and 810 are pretty clear indications of where their heads are at in regards to enthusiast/entry-level pro cameras.

Aug 27, 2014 at 10:57 PM

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