28 'cron falls flat

[jaapv]

Advertisement (gone after registration)

I quite agree with you Chris. I've been using the 28 'cron since I first got the camera, and although I can also take test pictures which show a lot of vignetting and some colour shifts (and on this basis the first of Lars's shots here is clearly the best for me). I have yet to have a 'real world' photo which needs to be adjusted because of it.

 

 

What surprises me about this thread is that your post could have been signed "The old man from the age of real prints" It is not like Lars to go "testing"this way.

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[lars_bergquist]

Well Jaap, I will agree that, especially a couple of f-stops down, the vignetting does tend to 'fall under the table'. But the test pictures did look pretty bad.

 

I would be interested to know exactly what the argument was as to the ExpoDisc vignetting, i.e. from the disc alone, with no influence from the mounting. The little domes in front cast lots of little round pictures all over the front surface of the opal glass, and what emerges on the other side should be a very good approximation of afocal light. Have I missed something?

 

The old man emerging, blinking, from the darkroom

[jaapv]

I can't comment factually, Lars, as I don't own the lens, but in general I find the corrections as implemented on version two of the firmware quite good, making the lenses vignette more or less like they did on film. This applies specifically to my Elmarit 28 vIII an ZI Biogon 21/2.8, so I wonder how much difference can be seen - in real images-on the Summicron 28 comparing M9 to film.

[sandymc]

I would be interested to know exactly what the argument was as to the ExpoDisc vignetting, i.e. from the disc alone, with no influence from the mounting.

 

Lars,

 

I'm afraid we didn't discuss the root cause - the ExpoDisc folks just confirmed that (a) the ExpoDisc does vignette and ( it does so unpredictably, so you can't calibrate it out. To their credit, BTW, their response was both quick and helpful.

 

Regards,

 

Sandy

[UliWer]

So what about another test with a grey card? (I know it is difficult with a 18mm to avoid shadows and reflections as you really have to go very close to the object, but it should work with 28mm).

 

Edit: Some more info about the ExpoDisc:

"The expodisc revealed some serious vignetting either from itself or the MicroNikkor. There was also a colour shift such that the recorded colour temperature varied from 4550K in the centre to 4900K at the image edges. The other calibrators put the colour temperature at 4850K."

 

http://www.swpp.co.uk/professional_imagemaker/camera_calibration/camera_calibration.htm

[chris_tribble]

Lars,

 

I'm afraid we didn't discuss the root cause - the ExpoDisc folks just confirmed that (a) the ExpoDisc does vignette and ( it does so unpredictably, so you can't calibrate it out. To their credit, BTW, their response was both quick and helpful.

 

Regards,

 

Sandy

Sandy - very helpful - thanks (and kudos to ExpoDisc... )

 

Honestly, I'm not in the pay of Leica to boost the cause - I just find myself frustrated when I see the performance of the 26 cron asph on the M9 rubbished on the basis flimsy, false or non evidence.... I attach another real world image in horrible light. Vignetting? Where? Red edge? I don't see it.

 

Maybe we need to spend more time posting photographs of real things?

 

28 cron falls flat? Balderdash is a polite way of summing up my feelings. I won't use the other words beginning with B...

 

Best

 

C:

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!