Dropping 1 to 2 stops to avoid vignetting

[dugby]

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After testing and research I'm coming to the conclusion that at wide open aperature all lenses seem to vignett, so the sweet spot of all lenses seem to start 1 to 2 stops from the widest.

 

Do the Leitz historians here know whether it was Leica's unwritten rule,if you want to shoot best wide aperature image at

 

1) f1.4, then you should do this with a Noctilux and not the obvious Summilux ?

 

or

 

2) f2.0 then you should do this with a Summilux and not the obvious Summicron ?

[algrove]

I always read the lens manual from Leica to know the best aperture they recommend for optimal rendition, contrast and sharpness. Each lens varies, but as a rule I try to use f4-f5.6 and sometimes f8 when needed.

 

Vignetting is very dependent on lens AND camera. If both lens and camera are Leica then FW starts the process of correction with LR doing the rest for me. Often though I add vignetting once finished with an image for printing. Finny how we don't like vignetting as a rule and then add it to images.

[250swb]

f/4 to f/8 is pretty well the region for the 'best' aperture for any 35mm format lens by any manufacturer, and Leica is no different. The reality though is that you should use the best aperture for the photograph, anything from wide open to fully stopped down is fine if it is needed for DOF or effect. To limit photography only to the 'best' aperture is self defeating, and especially with a Leica lens as f/1.4 isn't so bad compared to f/4, and neither is f/16. Anyway, Leica wouldn't have sold you lenses with all those apertures if they didn't work......hmm?

 

Steve

[pgk]

The 'sweet spot' should be for the image, for which which the 'best' or 'most appropriate' aperture should be used. Vignetting is a characteristic of some lens/aperture combinations and is to me one of the reasons that they are used. If used correctly vignetting at wide aperture can be very effective.

 

Modern Leitz lenses (aspherics) are designed so that they can be used wide open and still perform very well indeed (as far as I'm concerned they are still the 'best', fast lenses to use at full aperture). I've been discussing this recently with others and there is some thought that this may well be when the aspheric surfaces provide most effect (especially if these surfaces are close to the diaphragm - as they are in the 50 and 35 Summiluxes. Stopping down may reduce the influence of the aspheric surfaces). Even so there is some vignetting which is impossible to eliminate.

 

Vignetting can be minimised by using a smaller aperture as you say but IMHO this is placing technical requirements above those which may be necessary to the image. Alternatively software can be used and this can be very effective provided not too much reduction is needed since boosting 'shadows' will increase noise.

[01af]

Do the Leitz historians here know whether it was Leica's unwritten rule, if you want to shoot best wide-aperature image at ...

This is not Leica's unwritten rule but one out of many unwritten rules of photography in general. A faster lens stopped down by one (or two) f-stops usually will vignette less than a slower lens wide open.

 

Regarding the special case of the Noctilux-M 50/0.95 Asph and Summilux-M 50/1.4 Asph—at f/1.4, both will vignette. The vignetting is less but still looks worse with the Noctilux because here, it's basically absent across the better part of the frame (good thing) but then sets in pretty sharply in the farthest corners (bad thing). With the Summilux, vignetting at f/1.4 is worse as it sets in closer to the center (bad) but increases very smoothly and gradually towards the corners (good). So the Noctilux's lesser vignetting at f/1.4 still appears more obvious to the eye of the beholder in most cases.

[tobey bilek]

This is not Leica's unwritten rule but one out of many unwritten rules of photography in general. A faster lens stopped down by one (or two) f-stops usually will vignette less than a slower lens wide open.

 

Regarding the special case of the Noctilux-M 50/0.95 Asph and Summilux-M 50/1.4 Asph—at f/1.4, both will vignette. The vignetting is less but still looks worse with the Noctilux because here, it's basically absent across the better part of the frame (good thing) but then sets in pretty sharply in the farthest corners (bad thing). With the Summilux, vignetting at f/1.4 is worse as it sets in closer to the center (bad) but increases very smoothly and gradually towards the corners (good). So the Noctilux's lesser vignetting at f/1.4 still appears more obvious to the eye of the beholder in most cases.

 

In ACR and LT there are correction sliders and the midpoint can be adjusted to the lens type and start point of the vignetting. I would suggest you do a grey board and color samplers to make it perfect, then record the two settings, amount and midpoint. Adjust to taste for real photos.