p.5 #1 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Tariq Gibran wrote:
Roger's blog at LensRentals does keep a running database of exit pupil distance but the Loxia is not there yet. The ZM 35/2 Biogon is though and is listed as 34mm's. Maybe you are thinking of this database?
If anyone has both the ZM 50/2 and Loxia 50 on hand, they could try and take a picture of the exit pupil from the rear of the lens in order to show us if they're the same size or not. I'd imagine that they would be. Granted, it may be difficult to line things accurately. If someone has both lenses, they could just eyeball the size and let us know if the exit pupils are about the same size/distance away.
p.5 #2 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
douglasf13 wrote:
If anyone has both the ZM 50/2 and Loxia 50 on hand, they could try and take a picture of the exit pupil from the rear of the lens in order to show us if they're the same size or not. I'd imagine that they would be. Granted, it may be difficult to line things accurately. If someone has both lenses, they could just eyeball the size and let us know if the exit pupils are about the same size/distance away.
If anyone has both lenses, then while they're at it, it would be great to see some comparison shots with those two lenses on an A7r or A7.
I've got a ZM 50/2, so if anyone in the Bay area gets a Loxia 50, I'd be happy to get together with you to take the test shots (we could also compare with my 50 cron).
p.5 #3 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Steve Spencer wrote:
I thought somebody who has a subscription to Lloyd Chambers site, where I understand he publishes the exit pupils, reported this, but maybe I am remembering incorrectly. I think you have a subscription, so you can tell me whether I am off base or not. Maybe he hasn't posted this information yet, and maybe he has the exit pupils are different. I could easily be wrong. But I think the general point I was making still applies. The 35 Loxia definitely does quite a bit better than the ZM 35, or at least it seems that way so far, and Zeiss did something to improve that performance. They seem to be saying that they tweaked it for the cover glass. Why should we doubt them? It seems like the simplest reason for the increase in performance and it is what they said they did. Until I see evidence it is something else I will go with that explanation....Show more →
Lloyd only publishes ray angle to sensor, not the exit pupil. The site has this info only for subscribers. I am subscribed to the Leica guide, so the Loxia aren't included, so I wouldn't know if this info is published.
p.5 #4 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Tariq Gibran wrote:
Here is an article on the Zeiss ZM lenses by Puts where he interestingly says of the ZM 50/2 Planar:
"For several generations the Planar design has tried to challenge the Summicron 50mm and never became as good. Now at last we have a lens that equals the Summicron-M 50mm and is even a trace better in the curvature of field area."
Also by the look of the Loxia, I'd guess the cron also has the bokeh advantage.
I think you need to look beyond the MTF 50 numbers. The full MTF graphs show a different picture (and I think this was one of Roger's points in including them). In the full MTF graphs you see the ZM 50 f/2 has more resolution in the centre whereas the Summicron may have a bit better resolution in Zone C. I don't see a clear edge for the cron. It is much more nuanced than that.
p.5 #6 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
I fail to see how the cron is better than the planar in this MTF
Btw, with all due respect to Roger for the great job he's doing, I cannot but notice the weirdness of some of the results he's been showing. For instance, the MTF of ZM 50 planar are totally against my experience with this lens, which is supposed to have a traditional bell shaped curve. The W like field curvature he obtained is really strange.
p.5 #7 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Steve Spencer wrote:
It is much more nuanced than that.
At the level that both the Planar and Summicron are at, it ultimately comes down to rendering preference I suppose.
One thing I thought I noticed when the first Loxia 50 images appeared was a more familiar look/ fingerprint to the classic Hasselblad 80 Planar. The MTF's of the ZM vs Loxia Planar look a bit different, with the Loxia taking a noticeable zone B dip (Sagittal) whereas the ZM is more perfect in this zone. Looking at the MTF for the classic Zeiss Hasselblad 80 Planar also shows a Zone B dip of the Sagittal curve, though the Loxia MTF is much more perfect in general by comparison. Perhaps I'm trying to read too much into this MTF aspect (zone B Sagittal dip) resulting in a similar fingerprint, I don't know.
Also by the look of the Loxia, I'd guess the cron also has the bokeh advantage.
Something must be off with that lensrental's test of the 50 Summicron, because, even though it was my favorite 50mm on the M9, I found the differences between it and the ZM 50/2 to be subtle, depending on what you like. It certainly didn't have the same resolution from center to middle to edge.
Roger actually acknowledged that his measurement may be off for that lens, because someone questioned the readings being the same for the whole field wide open. Roger never got back to it, so I'm not sure what happened.
" ...it’s possible there are typos. I double checked when collecting and again as I entered data, but the article took so long to write as I tried different ways to present the data that I might have transposed something going from one form of presentation to another. I’ll have to get the original machine tracings out and double check."
Either way, due to different sensor and topping designs, we're at the point where tests are starting to become meaningless, unless they're all done on the camera in question. The Zeiss blog says that "The Loxia lenses are optimized for digital full-frame sensors, and factor the approx. 2.5 mm thick low-pass and infrared filters in, situated in front of the sensor of the corresponding Sony cameras."
I think there's a very good chance that the Loxia 50 will be better overall than the 50 Summicron on the A7 series, at least in terms of resolution.
p.5 #9 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
edwardkaraa wrote:
I fail to see how the cron is better than the planar in this MTF
Btw, with all due respect to Roger for the great job he's doing, I cannot but notice the weirdness of some of the results he's been showing. For instance, the MTF of ZM 50 planar are totally against my experience with this lens, which is supposed to have a traditional bell shaped curve. The W like field curvature he obtained is really strange.
Yeah, I think we're all starting to learn that various MTF tests need to be taken with a grain of salt, because the sensor stack makes such a difference. Even with the Leica digital cameras, the thinner stack can change the characteristics of a lens, albeit to likely a lesser degree than some of the other stacks out there.
p.5 #10 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Tariq Gibran wrote:
At the level that both the Planar and Summicron are at, it ultimately comes down to rendering preference I suppose.
One thing I thought I noticed when the first Loxia 50 images appeared was a more familiar look/ fingerprint to the classic Hasselblad 80 Planar. The MTF's of the ZM vs Loxia Planar look a bit different, with the Loxia taking a noticeable zone B dip (Sagittal) whereas the ZM is more perfect in this zone. Looking at the MTF for the classic Zeiss Hasselblad 80 Planar also shows a Zone B dip of the Sagittal curve, though the Loxia MTF is much more perfect in general by comparison. Perhaps I'm trying to read too much into this MTF aspect (zone B Sagittal dip) resulting in a similar fingerprint, I don't know.
p.5 #12 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Steve Spencer wrote:
Yes it is.
Thanks! That really makes things interesting, because, in terms of the A7 series, we really don't know how the two lenses compare on the camera, since the ZM mtfs are likely quite a bit different on-camera.
p.5 #13 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
douglasf13 wrote:
Thanks! That really makes things interesting, because, in terms of the A7 series, we really don't know how the two lenses compare on the camera, since the ZM mtfs are likely quite a bit different on-camera.
Yeah, I'm very curious how these two compare on the A7's.
p.5 #14 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
douglasf13 wrote:
If anyone has both the ZM 50/2 and Loxia 50 on hand, they could try and take a picture of the exit pupil from the rear of the lens in order to show us if they're the same size or not. I'd imagine that they would be. Granted, it may be difficult to line things accurately. If someone has both lenses, they could just eyeball the size and let us know if the exit pupils are about the same size/distance away.
As long as you're comparing an f/2.0 lens to an f/2.0 lens, size should (almost) linear to distance when you just look into the lens from behind - if you take care to look at both from the same distance, that is.
And in this case, larger is better, unless you get mechanical vignetting. The aperture ratio f/# sets the ANGLES behind the rear principal plane, not the diameters or distances (for the central ray). So a larger "image" of the aperture means it's further away.
Further away decreases the edge/corner angles, but does absolutely nothing for the central angles. In the center, the only thing that gets shifted is SA, i.e absolute fine detail contrast at WO and maybe 2/3 - 1+2/3 stops down. If the rear principal plane is at infinity, the corners have the same ray angles to work with as the center - as you roughly get in a fully bi-telecentric lens.
p.5 #15 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Steve Spencer wrote:
I think you need to look beyond the MTF 50 numbers. The full MTF graphs show a different picture (and I think this was one of Roger's points in including them). In the full MTF graphs you see the ZM 50 f/2 has more resolution in the centre whereas the Summicron may have a bit better resolution in Zone C. I don't see a clear edge for the cron. It is much more nuanced than that.
You ALWAYS want to look a bit further than the MTF50
If all lenses had the same "character" and also identical tangential/sagital responses, then MTF50 would tell you most of the story (except CA/LoCA). Considering how different the slope of the MTF curve can be, an MTF50 at 30lp/mm can mean quite a few different things for what MTF you get at 10lp/mm and 50lp/mm.
MTF50 is useful for a first assessment, not much more. Lenses with identical values here can be very different when you look at the image results subjectively.
p.5 #16 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
BTW, the NEWER Zeiss MTF graphs are with a 2mm AR-coated UVIR plate included AFAIK. And that goes back to about the somewhere in between the first ZE-line lenses.
At least that condition is when we get the most similar results from an identical machine...
p.5 #17 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
theSuede wrote:
BTW, the NEWER Zeiss MTF graphs are with a 2mm AR-coated UVIR plate included AFAIK. And that goes back to about the somewhere in between the first ZE-line lenses.
At least that condition is when we get the most similar results from an identical machine...
So we should assume that the mtf graphs for the ZM lines is before the 2mm plate, since they're older?
p.5 #18 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
I think so. Don't take that a confirmation, but it would figure. I know Mr Putz's zm measurements are without cover plates, and they match Zeiss' original shapes pretty well.
p.5 #19 · Zeiss Loxia 50mm f:2.0 Vs Sony-Zeiss FE 55 f:1.8
Does anyone have their Loxia yet? This thread is the only first impressions post on the Loxia lenses here on FM and it's two months old. Not much to fin on Google.
