p.4 #1 · Contax/Yashica Lenses - Which are the best?
You don't have to change the lens design or MTF curves to change the lens performance. You can alter the spacing between certain elements to optimise it for different focus distances. It's entirely possible Zeiss at some point altered the assembly formula so it worked better at long distances / flattened the focus field at infinity. Several of my wides have floating front elements to do this automatically. I've adjusted my Leica 35mm R to work better at infinity by shiming the front element out a bit.
I can second all that's been said about the Vario-Sonnar 35-70/3.4 and the Planar 28/2.8, both brilliant.
However, I'm another who doesn't get excited by the bokeh of the 50/1.4 (far prefer the CV 58/1.4)
p.4 #3 · Contax/Yashica Lenses - Which are the best?
shirozina wrote:
You don't have to change the lens design or MTF curves to change the lens performance. You can alter the spacing between certain elements to optimise it for different focus distances. It's entirely possible Zeiss at some point altered the assembly formula so it worked better at long distances / flattened the focus field at infinity. Several of my wides have floating front elements to do this automatically. I've adjusted my Leica 35mm R to work better at infinity by shiming the front element out a bit.
If you're talking about a noticeable increase in edge and corner resolution, then it will definitely show up in the MTF curves.
p.4 #4 · Contax/Yashica Lenses - Which are the best?
jcolwell wrote:
If you're talking about a noticeable increase in edge and corner resolution, then it will definitely show up in the MTF curves.
Depends what distance the test target was and if the edge and corner resolution is limited by field curvature. I have several lenses that have very good edge and corner performance but are no use for landscape as this occurs at a different focus distance to the rest of the frame.
p.4 #5 · Contax/Yashica Lenses - Which are the best?
shirozina wrote:
Depends what distance the test target was and if the edge and corner resolution is limited by field curvature. I have several lenses that have very good edge and corner performance but are no use for landscape as this occurs at a different focus distance to the rest of the frame.
no test targets, zeiss always tests mtfs on an optical bench at infinity. for some lenses (mostly macros) they do additional tests on the optical bench at closer focus distances. the sort of changes you're talking about would definitely show up in zeiss's mtf measurements.
p.4 #6 · Contax/Yashica Lenses - Which are the best?
sebboh wrote:
no test targets, zeiss always tests mtfs on an optical bench at infinity. for some lenses (mostly macros) they do additional tests on the optical bench at closer focus distances. the sort of changes you're talking about would definitely show up in zeiss's mtf measurements.
Could you point me to a link that documents Zeiss's MTF testing methodology please?
p.4 #8 · Contax/Yashica Lenses - Which are the best?
Toothwalker wrote:
The MTF should a bit higher than shown in this review, but don't expect miracles from a 5-element lens. The 100/3.5 is good, but not spectacular.
I now use the OM 100/2 and an MD 100/2.5 on my A7 (With an MD 100/4 macro on the way, to try out)
If I'd bought the ZF.1 100/2 instead of the ZE, I may well still have it, but the ZE had some very annoying aperture/LV connection quirks on the 5DII and might have been a bit unbalanced/heavy (for me) on the A7. Plus, my favourite OM 100/2 has less CA (still has some) and even creamier bokeh.
p.4 #10 · Contax/Yashica Lenses - Which are the best?
shirozina wrote:
Could you point me to a link that documents Zeiss's MTF testing methodology please?
zeiss explains a lot about it on their how to read an mtf papers found here and some of their contax era data sheets go into more detail about the parameters used than the data sheets on modern lenses. they go on at the end of the "how to read an MTF I" on how some manufacturers cheat by just calculating the mtf rather than measuring it (while zeiss always measures it) and how using colored light rather than white light will impact results (they always specify that white on their data sheets).
i'll have to look again to try and find a source for where they describe it concisely.
p.4 #11 · Contax/Yashica Lenses - Which are the best?
I sent an email to Zeiss to ask if their MTF test and analysis methodology is documented. They responded very quickly to my request about the 100/3.5, earllier this week.
p.4 #12 · Contax/Yashica Lenses - Which are the best?
Wow! I already got an answer. I sent the qusetion this morning (Sunday) and I got the answer this afternoon (still Sunday). I was sent links to the two "How to read MTF Curves" documents that are available through the path that follows the link that sebboh posted above. Here are their discrete links,
p.4 #13 · Contax/Yashica Lenses - Which are the best?
AhamB wrote:
Good research, Jim. I wonder what accounts for the user reports from people saying the MM is sharper in the corners then. Might just be people repeating each other and sample variation at work, or Zeiss actually improved the MM but didn't bother updating the published MTFs and block diagrams, which is perhaps not unrealistic?
Optically identical doesn't mean identical in every way. Olympus, for example, says that the earlier OM Zuiko lenses are optically identical to the later MC ones, but that the latter have multicoating!
Coatings often change over time: moving to a new factory is a reason to expect whatever the latest coating is to be applied.
So one possibility is that people are noticing slightly different contrast with the MM versions. Of course the measured MTF wouldn't change much or at all, because that is not measured in any kind of back or side light.
p.4 #14 · Contax/Yashica Lenses - Which are the best?
Toothwalker wrote:
The MTF should a bit higher than shown in this review, but don't expect miracles from a 5-element lens. The 100/3.5 is good, but not spectacular.
This review was only tested on APSC.
That gives an advantage for evenness (and indeed it does come up very even) but a big disadvantage for central MTF, because you are effectively magnifying part of the image.
Lots of outstanding FF lenses test only OK on APS; it's only super modern FF lenses that have excess (i.e. more than you can see with current tech) sharpness in the centre that show up as outstanding on APS.
Note that the slrlensreview guy DID test the 85 he liked on FF. Zeiss published MTF shows the 100 a bit ahead of the 85..
p.4 #15 · Contax/Yashica Lenses - Which are the best?
My AEJ 3.5 100 does not show more resolution than my 1.4 85 AEG. The major advantage of the 3.5 100 seems to be the weight and a better CA correction. My copy of the 1.4 85 AEG is the better choice for me. At f2 the limiting strong CA and softness of f1.4 has already disappeared. At f2 the 1.4 85 AEG offers better background blur and bokeh than the 3.5 100 at f3.5 which might be used more as a travel or landscape lens. Stepped down - 85mm cropped - both lenses show the same rendering and resolution of infinity details. To get a visibly higher resolution I have to use my AEJ 2.8 135mm which shows bad CA correction at f2.8 and f4. Mostly I use my Contax AEJ 1.4 85 and AEJ 2.8 35. The AEJ 2.8 28 (corner sharpness), AEJ 1.7 50 (CA at f1.7 and f2) AEJ 3.5 100 (3.5 only) and AEJ 2.8 135 (CA at f2.8 and f4) are mostly left at home...
Sep 19, 2017 at 05:33 AM
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p.4 #16 · Contax/Yashica Lenses - Which are the best?
chris9 wrote:
My AEJ 3.5 100 does not show more resolution than my 1.4 85 AEG. The major advantage of the 3.5 100 seems to be the weight and a better CA correction. My copy of the 1.4 85 AEG is the better choice for me. At f2 the limiting strong CA and softness of f1.4 has already disappeared. At f2 the 1.4 85 AEG offers better background blur and bokeh than the 3.5 100 at f3.5 which might be used more as a travel or landscape lens. Stepped down - 85mm cropped - both lenses show the same rendering and resolution of infinity details. To get a visibly higher resolution I have to use my AEJ 2.8 135mm which shows bad CA correction at f2.8 and f4. Mostly I use my Contax AEJ 1.4 85 and AEJ 2.8 35. The AEJ 2.8 28 (corner sharpness), AEJ 1.7 50 (CA at f1.7 and f2) AEJ 3.5 100 (3.5 only) and AEJ 2.8 135 (CA at f2.8 and f4) are mostly left at home......Show more →
Chris,
I think they are talking about the C/Y 85 f/2.8. The 100 f/3.5 has a bit more resolution than the 85 f/2.8, but yes stopped down the 85 f/1.4 has more resolution than either of the smaller sonnar lenses.
