New 50mm APO article/review + Interview with Peter Karbe at overgaard.dk

[Overgaard]

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I just finished my article on the 50mm APO-Summicron-M ASPH f/2.0 with photos taken over the last year, as well as an interview with the lens designer Peter Karbe at Leica Camera AG.

 

leica.overgaard.dk - Thorsten Overgaard's Photography Pages - Leica 50mm APO-Summicron-M ASPH f/2.0 samples and interview with the lens designer Peter Karbe

 

Enjoy!

 

And feel free to comment here or there, or e-mail me if you think there should be more stuff or you have corrections to suggest.

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[lct]

According to Peter Karbe:

You get to learn the aberrations … and in the 50 APO they are hard to find!

Peter Karbe should have followed the teaching of some LUF members here. He would have learned that purple fringing shown by the 50/2 apo is mainly due to its chromatic aberrations.

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[biglou]

Thorsten, i see on the picture that the shader of your summicron lost almost all the black anodisation at the edge.

Mine is following the same path.

Next time you see Herr Doctor Karbe it would be nice to suggest an unobstruvise little piece of black something to protect this part, all the better if it was possible to fit it on already sold lenses.

Thanks a lot, interesting review.

[freitz]

The Article was a nice read. Thanks for putting it together.

 

I have recently tested this lens against the Lux and noticed something very interesting I am hoping someone can elaborate on.

 

In testing, the same shot on a tripod in the same light; Lux at f/1.4 1/500 of a sec. 200 ISO produced a darker image than the APO at f/2 1/500 of a sec. at 200 ISO. It seems that the glass in the APO absorbs lights better than the Lux. Which would make sense when your article references more details in low light. Hopefully others have experienced the same. If this is the case the APO should be better in lowlight than the Lux. What are your thoughts / experiences?

[Mornnb]

Fantastic interview. And fully explains the price premium Leica carries.

[MarkP]

The Article was a nice read. Thanks for putting it together.

 

I have recently tested this lens against the Lux and noticed something very interesting I am hoping someone can elaborate on.

 

In testing, the same shot on a tripod in the same light; Lux at f/1.4 1/500 of a sec. 200 ISO produced a darker image than the APO at f/2 1/500 of a sec. at 200 ISO. It seems that the glass in the APO absorbs lights better than the Lux. Which would make sense when your article references more details in low light. Hopefully others have experienced the same. If this is the case the APO should be better in lowlight than the Lux. What are your thoughts / experiences?

 

Maybe because because the f-stop and t-stop are not the same.

[MarkP]

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This lens is starting to tempt me, but perhaps I'll wait and see if a 2.0/35 APO-Summicron is around the corner.

[biglou]

This lens is starting to tempt me, but perhaps I'll wait and see if a 2.0/35 APO-Summicron is around the corner.

 

There is one already, the first 8 elements summicron M 35mm.

Still excellent but less contrasty by today's standards.

The 50 Apo grows on me with time and i appreciate it more and more.

[CheshireCat]

According to Peter Karbe:

Peter Karbe should have followed the teaching of some LUF members here. He would have learned that purple fringing shown by the 50/2 apo is mainly due to its chromatic aberrations.

 

He perfectly knows that.

He says "hard to find" rather than "absent".

And hard to find they are: you need to overexpose, pixelpeep, and know where to look in order to find them.

 

No lens is perfect, not even the excellent 50 APO.

[Overgaard]

According to Peter Karbe:

Peter Karbe should have followed the teaching of some LUF members here. He would have learned that purple fringing shown by the 50/2 apo is mainly due to its chromatic aberrations.

 

Please educate me on this. Which lenses exist that are perfect without purple fringing in extreme contrast conditions?

 

I haven't compared or measured, but I would say the 90mm APO is quite good, and the 50 APO as well. The 0.95 Noctilux less controll.

 

If I go with older R lenses it can get quite extreme on a digital sensor.

[freitz]

Maybe because because the f-stop and t-stop are not the same.

 

Does anyone have the T stop for the APO? I am curious how this relates to the 50 LUX and Noct.

 

The light absorption is different from my testing between these three lenses even at the same f stop.

[CheshireCat]

In testing, the same shot on a tripod in the same light; Lux at f/1.4 1/500 of a sec. 200 ISO produced a darker image than the APO at f/2 1/500 of a sec. at 200 ISO.

 

Are you saying that the Lux gets less light at f/1.4 than the APO at f/2 ?

Maybe you meant the Lux at f/2. Please double check.

[CheshireCat]

I would say the 90mm APO is quite good, and the 50 APO as well. The 0.95 Noctilux less controll.

 

Uhm... I think there's a reason why Karbe evaded replying to the 90 APO question

[freitz]

Are you saying that the Lux gets less light at f/1.4 than the APO at f/2 ?

Maybe you meant the Lux at f/2. Please double check.

 

The Lux at 1.4 1/500 sec shutter and 200 ISO is darker than the same exact shot of the APO at f/2 1/500 of a sec and 200 ISO. So yes I think the Lux is getting less light to the sensor even at a larger F stop.

 

When both at f/2 the Lux needs to be at 1/250 at 200 ISO to produce similar lighting to the APO at 1/500 at 200 ISO.

 

The colors and backgrounds are different but the lighting on the subject is where the biggest difference is for me. This was a controlled test on the tripod with controlled lighting.

Edited April 6, 2015 by freitz

[CheshireCat]

When both at f/2 the Lux needs to be at 1/250 at 200 ISO to produce similar lighting to the APO at 1/500 at 200 ISO.

 

The colors and backgrounds are different but the lighting on the subject is where the biggest difference is for me. This was a controlled test on the tripod with controlled lighting.

 

If the colors and backgrounds are different, then it is not the same exact shot.

Has anyone else experienced this 1 T-stop difference at f/2 ?

[freitz]

If the colors and backgrounds are different, then it is not the same exact shot.

Has anyone else experienced this 1 T-stop difference at f/2 ?

 

The colors and backgrounds are different because the lens draws differently. That is what I meant to say. I should have clarified more.

 

Also I should mention at other stops it seemed to be between 1/2-3/4 of a T-stop difference.

[biglou]

I made a quick check with Leica monochrom.

At 2 apo summicron gives a speed of 180

Same two summilux asph 250

This with lens recognition

 

When off,

Apo summicron 180

Summilux asph 125

 

Did not take the pictures to check the results but this seems somewhat to contradict the other results above.

 

M9 apo summicron 12, summilux 12 when lens recognition off

goes to 12 and 15 with lens recognition.

 

All in all i don't think there is such a difference between lenses, tipically T stop versus F stops is quite small unless you speak about zoom with a lot of lenses inside and some more loss of transmited light.

 

Vignette correction by firmware may be different between lenses and could explain some of the difference

Edited April 6, 2015 by biglou

[Lenshacker]

The Article was a nice read. Thanks for putting it together.

 

I have recently tested this lens against the Lux and noticed something very interesting I am hoping someone can elaborate on.

 

In testing, the same shot on a tripod in the same light; Lux at f/1.4 1/500 of a sec. 200 ISO produced a darker image than the APO at f/2 1/500 of a sec. at 200 ISO. It seems that the glass in the APO absorbs lights better than the Lux. Which would make sense when your article references more details in low light. Hopefully others have experienced the same. If this is the case the APO should be better in lowlight than the Lux. What are your thoughts / experiences?

 

What camera did you use?

 

Much depends on the angle of incidence that the light hits the sensor. A lens that is farther out from the sensor will do better than one that is closer in.

 

Did you have lens detection turned on? Turn off lens detection and look at the vignetting that occurs with each lens. That should give an indication if it is the angle of incidence coming into play.

 

With purple fringing- try using an IR cut filter, the CA that is occurring is in the IR region. I have one Ultra-Achromatic lens that is corrected for IR and Visible. Need to buy an adapter for it.

Edited April 6, 2015 by Lenshacker

[freitz]

What camera did you use?

 

Much depends on the angle of incidence that the light hits the sensor. A lens that is farther out from the sensor will do better than one that is closer in.

 

Did you have lens detection turned on? Turn off lens detection and look at the vignetting that occurs with each lens. That should give an indication if it is the angle of incidence coming into play.

 

With purple fringing- try using an IR cut filter, the CA that is occurring is in the IR region. I have one Ultra-Achromatic lens that is corrected for IR and Visible. Need to buy an adapter for it.

 

Camera - M240

Lens detection - ON

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Hallo,

Look here: Leica M

[CheshireCat]

Much depends on the angle of incidence that the light hits the sensor.

 

Indeed, but it shouldn't change much with both lenses at f/2, and exposure level measured in the center.