90mm Apo-Summicron-M not apochromatic?

[LarsHP]

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49 minutes ago, lct said:

My point is that it is exactly what i suggested when you explained that the lens was suffering from field curvature. Misalignment. You said no then remember?  As for your 90, you say that you tested it on your M240 and that it showed the same issue put you did not post any pic then or did i miss something. If so would you be king enough to point me to the right pic?

I asked in the 28mm Summicron-M Asph II thread. I may initially have refused that the lens was misaligned based on the fact that it appears to look allright at f/2. However, when stopped down to f/4, it shows severe field curvature. Ron Scheffler posted earlier in that thread that he returned two samples of the Asph II because they were off. The second because it had field curvature. I downloaded his test images and my sample has much more severe field curvature than the sample he refused. 

Regarding the first sample of the M 90mm Apo, I haven't posted a picture taken with that. I haven't seen any reason to do so since I don't have it.

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[LarsHP]

1 hour ago, farnz said:

For balance, LCT doesn't come across as hostile to me.  Persistent, yes, but always courteous.  (Contrast this with the vile online gushings from some members on social media sites with little or no provocation.)

Pete.

He insinuates that I have doubtful motivations for joining this forum and being critical about Leica gear. That comes across as being hostile towards me.

[lct]

2 minutes ago, LarsHP said:

I asked in the 28mm Summicron-M Asph II thread. I may initially have refused that the lens was misaligned based on the fact that it appears to look allright at f/2. However, when stopped down to f/4, it shows severe field curvature. Ron Scheffler posted earlier in that thread that he returned two samples of the Asph II because they were off. The second because it had field curvature. I downloaded his test images and my sample has much more severe field curvature than the sample he refused. 

Regarding the first sample of the M 90mm Apo, I haven't posted a picture taken with that. I haven't seen any reason to do so since I don't have it.

A picture's worth more than a thousand words. So far you claimed that you got (a) field curvature that i did not see anywhere in your pics, only misalignment, (b) purple fringing that i did not see anywhere in your pics either, only mysterious green things i've never seen on my own pics. And (c) all this supported by pics taken with a Kolari mod Nikon body. You are perfectly entitled to show pics taken with non Leica bodies, you may perfectly complain against the Leica QC, you would not be the first one to do that and neither would i. But please don't complain about the design of lenses w/o supporting your claim with relevant evidence, Leica lenses in general and the superb Summicron's 90/2 apo and 28/2 v2 deserve that.

[LarsHP]

33 minutes ago, lct said:

A picture's worth more than a thousand words. So far you claimed that you got (a) field curvature that i did not see anywhere in your pics, only misalignment, (b) purple fringing that i did not see anywhere in your pics either, only mysterious green things i've never seen on my own pics. And (c) all this supported by pics taken with a Kolari mod Nikon body. You are perfectly entitled to show pics taken with non Leica bodies, you may perfectly complain against the Leica QC, you would not be the first one to do that and neither would i. But please don't complain about the design of lenses w/o supporting your claim with relevant evidence, Leica lenses in general and the superb Summicron's 90/2 apo and 28/2 v2 deserve that.

I have already provided the pictures you request. If you can't see it, I can do nothing to help you. Others can. I consider it wasted to continue discussing this with you, so I will stop answering your posts regarding these issues. 

[lct]

2 minutes ago, LarsHP said:

I have already provided the pictures you request. If you can't see it, I can do nothing to help you

Others than Nikon's you mean? Please point me to them and i will study them carefully.

[capo di tutti capi]

When I sell my equipment, I believe that the loss of money is the cost of using it. Rent. 

If the equipment doesn't suit you, you should think the same way

Edited May 18, 2021 by capo di tutti capi

[lookbook]

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vor 9 Minuten schrieb LarsHP:

I have already provided the pictures you request. If you can't see it, I can do nothing to help you. Others can. I consider it wasted to continue discussing this with you, so I will stop answering your posts regarding these issues. 

Which lens do you own -
Order number 11884 ?

[frame-it]

On 5/16/2021 at 4:55 AM, LarsHP said:

However, at shorter distances (about 2 meters and less) the sharpness decreases

Ive never seen this. Perhaps there is a problem with your lens or camera.

[LarsHP]

2 hours ago, lct said:

Others than Nikon's you mean? Please point me to them and i will study them carefully.

I have posted several images in this thread showing LoCA from the M 90 Apo. If you can't see it in those images, it's not my fault. End of discussion. 

[LarsHP]

2 hours ago, frame-it said:

Ive never seen this. Perhaps there is a problem with your lens or camera.

The M 90 Apo has no floating lens element for close focus correction which translates to decreasing sharpness outside the optimum distance (which seems to be medium to long distances). The M 75mm Apo (as well as other lenses) has FLE for that very reason. 

I have talked to one of the premium members here who informed me that the M 90 Apo needs to be stopped down for best sharpness at close distance. In other words, the same as I see and obviously not something with just my sample. 

[LarsHP]

2 hours ago, lookbook said:

Which lens do you own -
Order number 11884 ?

Yes. Judging by the serial number it's probably from 2012.

[LarsHP]

2 hours ago, capo di tutti capi said:

When I sell my equipment, I believe that the loss of money is the cost of using it. Rent. 

If the equipment doesn't suit you, you should think the same way

I agree. As earlier stated, I might sell it, but at the moment I haven't made a decision.

[lct]

1 hour ago, LarsHP said:

I have posted several images in this thread showing LoCA from the M 90 Apo. If you can't see it in those images, it's not my fault. End of discussion. 

I can't seem to see any image of yours coming from an M240 or any Leica camera in this thread. You seem to have posted 9 pictures, all with your Nikon Z6. Am i missing something? If so i'm always open to discussion but you may prefer to end it of course it is just up to you.

Edited May 18, 2021 by lct

[adan]

32 minutes ago, LarsHP said:

The M 90 Apo has no floating lens element for close focus correction which translates to decreasing sharpness outside the optimum distance (which seems to be medium to long distances). The M 75mm Apo (as well as other lenses) has FLE for that very reason. 

I have talked to one of the premium members here who informed me that the M 90 Apo needs to be stopped down for best sharpness at close distance. In other words, the same as I see and obviously not something with just my sample. 

Correct. Which is one reason I never gotten along with the 90 APO - it's a focal length I tend to use only closer than 3 meters. Where, frankly, even an ancient 90mm Tele-Elmarit-M has better resolution wide-open (with lower MTF since the overall contrast is lower - but that is exactly why "unsharp masking" exists ).

[LarsHP]

1 minute ago, lct said:

I can't seem to see any image of yours coming from a M240 on any Leica camera in this thread. You seem to have posted 9 pictures, all with your Nikon Z6. Am i missing something? If so i'm always open to discussion but you may prefer to end it of course it is just up to you.

I don't think you are open to discussion even though you claim so. You seem to disregard or avoid acknowledging my points. For that reason, I see no reason to continue the discussion. I think I have explained my points and posted enough images to say enough is enough.

[ianman]

To be fair Lars it seems to be that lct is very open to discussion. Maybe you are misunderstanding his request but I cannot see what - I think - he is asking for either. That is simply images taken with your Summicron on the M240.

[LarsHP]

In a private message one of the premium members with more than a decade in this forum sent me this link:

https://blog.kasson.com/the-last-word/another-medium-tele-test-summicron-loca/

The scientifically made test clearly shows that the M 90 Apo has LoCA - even stopped down. According to the reviewer, Jim Kasson, the lens needs to be stopped down to f/8 to completely eliminate LoCA. Yes, it is done on a Sony camera, but this is of no consequence for LoCA testing in the center of the image.

[lct]

7 minutes ago, ianman said:

To be fair Lars it seems to be that lct is very open to discussion. Maybe you are misunderstanding his request but I cannot see what - I think - he is asking for either. That is simply images taken with your Summicron on the M240.

Simply this.

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Look here: Leica M

[jdlaing]

Loca loca loca. Just sell the damn lens if it is t good enough for you.

[LarsHP]

3 minutes ago, ianman said:

To be fair Lars it seems to be that lct is very open to discussion. Maybe you are misunderstanding his request but I cannot see what - I think - he is asking for either. That is simply images taken with your Summicron on the M240.

Okay, here it goes (again):

1) I have already explained that I have seen LoCA with another M 90 Apo with an M 240.

2) For LoCA testing it doesn't matter what sensor is used - certainly when the center of the image is concerned. If the sensor-lens relation was to blame, it should be readily visible in an infinity shot wide open, but there the lens performs brilliantly.

3) My Elmarit-M shows about the same level of LoCA as the Apo.