Re: Cosina Voigtländer APO-Lanthar 90/4 VM officially announced for August release
dan98 wrote: Steve Spencer wrote: dan98 wrote:
Those MTF curves resemble the performance of my Voigtlander SL 90/3.5 APO-Lanthar, specifically in terms of the pronounced mid-zone dip. I am not suggesting that the new 90/4 has the same optical design--it clearly does not--but based on the MTF curves it would seem to have the same primary flaw. If this proves to be true then it would be a disappointment. The 90/3.5 is by far the weakest of the SL APO-Lanthars and is quite an old design, so I would have expected the latest Voigtlander offering to avoid this issue.
The 90/3.5 is also the weakest of the series in terms of control of various aberrations (especially LoCA and purple fringing), and at least here I am confident that the new lens will offer improvements. I believe that the old 90/3.5 is the least APO of all of their APO-designated lenses. Based on the few sample images I have seen, the new 90 produces very little fringing.
Dan, I had the old 90 f/3.5 APO Lanthar and I totally agree with your assessment of it. It is one of the few Voigtlander lenses I have owned in which I was pretty disappointed. I noticed with my copy the same things you mentioned and I do believe it had a pretty substantial mid-zone dip.
That said, the MTF's of this 90 f/4 APO Lanthar do not show a mid zone dip. A mid zone dip is indicated by worse performance (i.e. lower percentage contrast) from 12-18mm from the center than you see in the center *and* than you see in the outer part of the frame (i.e. 18-22mm from the center). When there is a mid zone dip as the name implies performance doesn't just go down in the midfield it comes back up toward the corners.
A gradual decrease in performance from the center to the corners in not a mid-zone dip and that is what we see in the MTF curve for this new 90 f/4 APO Lanthar. ...
....
While there is just a gradual decrease from the center to the corners at 10 lp/mm (which is not a mid-zone dip), there is a pronounced dip at 30 lp/mm and 40 lp/mm in the sagital direction. This is most pronounced at 30 lp/mm and f/5.6, where the value hits a trough at about 12-13mm, and then rises steadily as we move out to 18%, but only for the sagital. This is exactly the same pattern as the MTF curve for the 90/3.5 at f/3.5. In the sagital direction a trough occurs at 12-13%, with the value rising steadily as we move out to 18mm. With both lenses the dip in the MTF curve only occurs in the sagital direction. Regarding the magnitude of the dip, it is is slightly more pronounced with the new lens, although they are really quite similar. It is this similarity that has me concerned, but I agree that the real-world results are what matters.
Where have you seen the MTF curves for the Voigtlander SL 90 f/3.5 APO Lanthar? Please provide a link I would love to see them.
I would not call what we see in the 90 f/4 APO MTF curves a dip. Yes, the values for 30 lp/mm and 40 lp/mm are slightly lower between 10 and 15mm from and rebound slightly at 17mm we are talking less than 5 percent contrast difference. In my view that is not relevant and I certainly wouldn't call this lower contrast a dip given the it is less than 5%. Many sense (see the Leica 35 Summilux FLE here: https://leica-camera.com/sites/default/files/pm-56063-Summilux-M35-TechnicalData.pdf?srsltid=AfmBOorxAAH7mYdXcZL2fUkppJTvbjC2G93F9j50fjH_YjD1QxdoqCwK) have substantial drops and recovery. That Leica lens, which is not the worst Leica M lens--at f/5.6 loses 25% contrast between 8cm and 14cm from the center and then recovers 20%.contrast from 14mm to 19mm, and that mid zone dip is about twice as big at f/2.8.
Ultimately it is a matter of semantics, but I wouldn't call anything in the 5% contrast range and being field relevant, YMMV.
Edit:
I see now your reference to the MTF curve for the old 90 f/3.5 APO Lanthar in that other thread. I don't think we can use that MTF chart. Even the person who posted it did not know how it was computed and suspected that it wasn't measured but was theoretical. That is very different from the MTF Charts Voigtlander is publishing these days that seem to be measured performance.The tell is that the MTF curve in that old thread is implausibly high. If true they would suggest that old lens, that as we have discussed was not a great performer has an MTF curve substantially higher than the current MTF champs like the Leica L mount 90 f/2 APO. It makes the chart implausible as a representation of measured MTF. That MTF curve in that old thread is not at all consistent with my experience of that lens. It would suggest exceptional performance, when my experience was a lens that was quite mediocre.
Re: Cosina Voigtländer APO-Lanthar 90/4 VM officially announced for August release
dan98 wrote: Steve Spencer wrote: dan98 wrote:
Those MTF curves resemble the performance of my Voigtlander SL 90/3.5 APO-Lanthar, specifically in terms of the pronounced mid-zone dip. I am not suggesting that the new 90/4 has the same optical design--it clearly does not--but based on the MTF curves it would seem to have the same primary flaw. If this proves to be true then it would be a disappointment. The 90/3.5 is by far the weakest of the SL APO-Lanthars and is quite an old design, so I would have expected the latest Voigtlander offering to avoid this issue.
The 90/3.5 is also the weakest of the series in terms of control of various aberrations (especially LoCA and purple fringing), and at least here I am confident that the new lens will offer improvements. I believe that the old 90/3.5 is the least APO of all of their APO-designated lenses. Based on the few sample images I have seen, the new 90 produces very little fringing.
Dan, I had the old 90 f/3.5 APO Lanthar and I totally agree with your assessment of it. It is one of the few Voigtlander lenses I have owned in which I was pretty disappointed. I noticed with my copy the same things you mentioned and I do believe it had a pretty substantial mid-zone dip.
That said, the MTF's of this 90 f/4 APO Lanthar do not show a mid zone dip. A mid zone dip is indicated by worse performance (i.e. lower percentage contrast) from 12-18mm from the center than you see in the center *and* than you see in the outer part of the frame (i.e. 18-22mm from the center). When there is a mid zone dip as the name implies performance doesn't just go down in the midfield it comes back up toward the corners.
A gradual decrease in performance from the center to the corners in not a mid-zone dip and that is what we see in the MTF curve for this new 90 f/4 APO Lanthar. ...
....
While there is just a gradual decrease from the center to the corners at 10 lp/mm (which is not a mid-zone dip), there is a pronounced dip at 30 lp/mm and 40 lp/mm in the sagital direction. This is most pronounced at 30 lp/mm and f/5.6, where the value hits a trough at about 12-13mm, and then rises steadily as we move out to 18%, but only for the sagital. This is exactly the same pattern as the MTF curve for the 90/3.5 at f/3.5. In the sagital direction a trough occurs at 12-13%, with the value rising steadily as we move out to 18mm. With both lenses the dip in the MTF curve only occurs in the sagital direction. Regarding the magnitude of the dip, it is is slightly more pronounced with the new lens, although they are really quite similar. It is this similarity that has me concerned, but I agree that the real-world results are what matters.
Where have you seen the MTF curves for the Voigtlander SL 90 f/3.5 APO Lanthar? Please provide a link I would love to see them.
I would not call what we see in the 90 f/4 APO MTF curves a dip. Yes, the values for 30 lp/mm and 40 lp/mm are slightly lower between 10 and 15mm from and rebound slightly at 17mm we are talking less than 5 percent contrast difference. In my view that is not relevant and I certainly wouldn't call this lower contrast a dip given the it is less than 5%. Many sense (see the Leica 35 Summilux FLE here: https://leica-camera.com/sites/default/files/pm-56063-Summilux-M35-TechnicalData.pdf?srsltid=AfmBOorxAAH7mYdXcZL2fUkppJTvbjC2G93F9j50fjH_YjD1QxdoqCwK) have substantial drops and recovery. That Leica lens, which is not the worst Leica M lens--at f/5.6 loses 25% contrast between 8cm and 14cm from the center and then recovers 20%.contrast from 14mm to 19mm, and that mid zone dip is about twice as big at f/2.8.
Ultimately it is a matter of semantics, but I wouldn't call anything in the 5% contrast range and being field relevant, YMMV.
Edit:
I see now your reference to the MTF curve for the old 90 f/3.5 APO Lanthar in that other thread. I don't think we can use that MTF chart. Even the person who posted it did not know how it was computed and suspected that it wasn't measured but was theoretical. That is very different from the MTF Charts Voigtlander is publishing these days that seem to be measured performance.The tell is that the MTF curve in that old thread is implausibly high. If true they would suggest that old lens, that as we have discussed was not a great performer has an MTF curve substantially higher than the current MTF champs like the Leica L mount 90 f/2 APO. It makes the chart implausible as a representation of measured MTF. That MTF in that old thread is not at all consistent with my experience of that lens. It would suggest exceptional performance, when my experience was a lens that was quite mediocre.
Re: Cosina Voigtländer APO-Lanthar 90/4 VM officially announced for August release
dan98 wrote: Steve Spencer wrote: dan98 wrote:
Those MTF curves resemble the performance of my Voigtlander SL 90/3.5 APO-Lanthar, specifically in terms of the pronounced mid-zone dip. I am not suggesting that the new 90/4 has the same optical design--it clearly does not--but based on the MTF curves it would seem to have the same primary flaw. If this proves to be true then it would be a disappointment. The 90/3.5 is by far the weakest of the SL APO-Lanthars and is quite an old design, so I would have expected the latest Voigtlander offering to avoid this issue.
The 90/3.5 is also the weakest of the series in terms of control of various aberrations (especially LoCA and purple fringing), and at least here I am confident that the new lens will offer improvements. I believe that the old 90/3.5 is the least APO of all of their APO-designated lenses. Based on the few sample images I have seen, the new 90 produces very little fringing.
Dan, I had the old 90 f/3.5 APO Lanthar and I totally agree with your assessment of it. It is one of the few Voigtlander lenses I have owned in which I was pretty disappointed. I noticed with my copy the same things you mentioned and I do believe it had a pretty substantial mid-zone dip.
That said, the MTF's of this 90 f/4 APO Lanthar do not show a mid zone dip. A mid zone dip is indicated by worse performance (i.e. lower percentage contrast) from 12-18mm from the center than you see in the center *and* than you see in the outer part of the frame (i.e. 18-22mm from the center). When there is a mid zone dip as the name implies performance doesn't just go down in the midfield it comes back up toward the corners.
A gradual decrease in performance from the center to the corners in not a mid-zone dip and that is what we see in the MTF curve for this new 90 f/4 APO Lanthar. ...
....
While there is just a gradual decrease from the center to the corners at 10 lp/mm (which is not a mid-zone dip), there is a pronounced dip at 30 lp/mm and 40 lp/mm in the sagital direction. This is most pronounced at 30 lp/mm and f/5.6, where the value hits a trough at about 12-13mm, and then rises steadily as we move out to 18%, but only for the sagital. This is exactly the same pattern as the MTF curve for the 90/3.5 at f/3.5. In the sagital direction a trough occurs at 12-13%, with the value rising steadily as we move out to 18mm. With both lenses the dip in the MTF curve only occurs in the sagital direction. Regarding the magnitude of the dip, it is is slightly more pronounced with the new lens, although they are really quite similar. It is this similarity that has me concerned, but I agree that the real-world results are what matters.
Where have you seen the MTF curves for the Voigtlander SL 90 f/3.5 APO Lanthar? Please provide a link I would love to see them.
I would not call what we see in the 90 f/4 APO MTF curves a dip. Yes, the values for 30 lp/mm and 40 lp/mm are slightly lower between 10 and 15mm from and rebound slightly at 17mm we are talking less than 5 percent contrast difference. In my view that is not relevant and I certainly wouldn't call this lower contrast a dip given the it is less than 5%. Many sense (see the Leica 35 Summilux FLE here: https://leica-camera.com/sites/default/files/pm-56063-Summilux-M35-TechnicalData.pdf?srsltid=AfmBOorxAAH7mYdXcZL2fUkppJTvbjC2G93F9j50fjH_YjD1QxdoqCwK) have substantial drops and recovery. That Leica lens, which is not the worst Leica M lens--at f/5.6 loses 25% contrast between 8cm and 14cm from the center and then recovers 20%.contrast from 14mm to 19mm, and that mid zone dip is about twice as big at f/2.8.
Ultimately it is a matter of semantics, but I wouldn't call anything in the 5% contrast range and being field relevant, YMMV.
Edit:
I see now your reference to the MTF curve for the old 90 f/3.5 APO Lanthar in that other thread. I don't think we can use that MTF chart. Even the person who posted it did not know how it was computed and suspected that it wasn't measured but was theoretical. That is very different from the MTF Charts Voigtlander is publishing these days that seem to be measured performance.The tell is that the MTF curve in that old thread is implausibly high. If true they would suggest that old lens, that as we have discussed was not a great performer has an MTF curve substantially higher than the current MTF champs like the Leica L mount 90 f/2 APO. It makes the chart implausible as a representation of measured MTF.
Jul 16, 2026 at 04:59 PM
Previous versions of Steve Spencer's message #17073236 « Cosina Voigtländer APO-Lanthar 90/4 VM officially announced for August release »
