SE 18 Service

[markowich]

maybe some of you remember the distorsion problems i had with the SE 18mm, if you don't please take a look at the attached jpg. i then sent the lens to leica, where it sat for more than 2 months. today i received the following email, which-for the fun of it, i quote in full (german) detail:

Sehr geehrter Herr Prof. Markowich,
vielen Dank für Ihre Mail und das Bild.
Entschuldigen Sie bitte die Verzögerung in der Beantwortung Ihrer Anfrage.
Der techniker hat Ihre Frage wir folgt beantwortet:

bei Weitwinkeln ist eine Verzeichnung und Vignetierung nicht zu verhindern. Es liegt somit an der Art des Objektives.

Ich hoffe, Ihre Frage beantwortet zu haben. Gegebenenfalls leite ich weitere Fragen an unseren Technischen Infodienst weiter.

translation:

dear prof. markowich,
many thanks for your mail and the image. please excuse the delay in responding to your request. the technician has answered your query as follows:

Distorsion and vignetting cannot be avoided in wide angle lenses. Therefore the issue is due to the type of lens under consideration.

i hope to have answered your query. Otherwise i shall refer further questions to our technical information service.

i am speechless. i have meanwhile emailed stefan daniel to ask him to brand the SE 18mm as 'Not suited for architectural photography'.
speechless about the depth of response.
peter
(copy from LF M9 forum)

 

[cpclee]

wow that looks a bit nasty but then I have no idea how another make's 18mm would perform in this situation

 

[thompsonkirk]

Yes, that's an 18mm lens all right, displaying vignetting & pincushion distortion. As Leica said, this can be expected with ultra-wides. That's why we have software to correct it. In Photoshop, look under Filter>Distort>Lens Correction; or use LR or PTGui or Kekus for Mac.

Kirk

 

[markowich]

Yes, that's an 18mm lens all right, displaying vignetting & pincushion distortion. As Leica said, this can be expected with ultra-wides. That's why we have software to correct it. In Photoshop, look under Filter>Distort>Lens Correction; or use LR or PTGui or Kekus for Mac.

Kirk

thank you, i do know the software correction techniques. but this is hihgly irreguar wavy distorsion, very hard to correct.
peter

 

[thrice]

thank you, i do know the software correction techniques. but this is hihgly irreguar wavy distorsion, very hard to correct.
peter

Not that irregular, very common in SLR ultra-wides (17mm Tamron, 21mm Distagon, 21/2.0 Olympus), and with the tendency to design rangefinder ultrawides with a more retrofocus design these days it is not all that surprising. A little disappointing from Leica, but consider the physical dimensions of the lens as well. The ZM Distagon has less distortion but I'm sure you read into it before settling on the $3000 Super-Elmar.

But yes, hard to correct. Create a profile for it by shooting a grid and then just correct all images in lightroom.

 

[atanabe]

Does not look like "normal" pincushion distortion to my eyes that is within the tolerances advertised by Leica, from their product pdf for the SE 18:

"Top performance. The LEICA SUPER-ELMAR-M 18 mm f/3.8 ASPH. features a lens element with two aspherical surfaces, ensuring outstanding optical performance across the image plane and at all f-stops. With the lens set to maximum aperture and mounted on a traditional Leica M or digital LEICA M8 model, vignetting – an effect which is inherently more prevalent with super wide angle lenses – amounts to a nominal 2.3 stops or 1.7 stops on an M8. Stopping down to f/5.6 reduces the vignetting to a value of 1.3 or 1 respectively. Maximum distortion, in turn, measures only 1.8 percent
and is virtually undetectable to the human eye."

The sample shot posted shows a "mustache" distortion or the subject itself is not a straight a parallel target to start with. Any shots of true parallel targets, horizons etc?

 

[thrice]

I don't see where they mention it being pincushion?

But I do see the distortion graph in the Leica pdf that clearly shows moustache distortion.

The ZM18 distortion is similar but less severe, it is roughly half the deviation the Leica shows.