Noctilux 095, M9 and green fringes

[hoppyman]

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Plasticman, my answering your comment contains a kind of paradox. You ignore what I post, but this time you did not and you want to comment, but won't see the response! Just a little bit silly.

 

I am not an optical expert by any means and I know that this is a complex and much discussed area, fair enough? When this has come up before, someone posted this link and I found it very informative.

Chromatic aberrations

 

From my understanding reading what I can on the subject, optical factors that can influence this 'fringe' effect include the aperture in use, whether the lens is a wide angle, which part of the field you are examining, whether the subject is out of focus, by how much & in which direction.

 

The image recorded on film or sensor can be affected by overexposure (of the area looked at) and high contrast edges.

 

Capturing a film image with a scanner IS digital although a different process. Also a scanner at 4000DPI will not resolve individual grain, it does resolve grain clumps and you need to take into account aliasing of those in the production of the output pixels too. Further even good scanners cannot duplicate the dynamic range of a good sensor, for example in the M8 and M9. That is another topic again. You cannot directly compare scanned transpaerncy or negative film with sensor capture either but that is a very old topic too.

 

The part of my last post that you have quoted is true but you haven't considered it fully.

Yes you can look at scanned film at high magnifications on your monitor. That is still a digital process and what you are looking at is pixels. In fact unless you are looking at exactly 100% you are not seeing accurately what is there either. Before the hybrid process of film and scanner became popular you would be looking at your film with a loupe maybe or looking at a print. After you digitize your image you can easily look at high magnification on your screen. The analogy I used was that was like looking at a very large print from very close.

 

I don't have that Nocti. I'm not surpised that the 'fringe' effect is visible in the examples shown here thus far, for the reasons I mentioned here. I'm not convinced tht the OP's lens is in any way defective either, which is what I had said.

 

Maybe you can post some examples from your shooting with the Nocti for comment. I'm genuinely interested as I'm sure that others are. To be rigorous you could find or better still shoot some new examples covering those conditions of in/out focus, aperture variation, exposure variation, high contrast edges.

 

I looked through a lot of scanned film and from M8/M9 here. The fastest lens I have is the Summilux 50 ASPH. The only example I could find was in a single frame from some shots with a Summilux 21 ASPH. that the Leica Akademie loaned me for a couple of hours at a Forum meeting. A green 'fringe' is visible at the edge of the frame shot at f/1.4 on a high contrast edge against window light in an interior shot. That is I think ALL of the factors I mentioned before.

 

 

 

 

Even though I have Hoppyman on my ignore list, I saw this passage quoted above:

 

Originally Posted by hoppyman

Elsu, more accurately it is an optical issue which has always been present. However with the advent of digital people can more easily see it when it occurs . That is largely due to being able to magnify images down to individual pixel level.

 

Naturally, film images can also be seen 'at the pixel level' (I'm speaking metaphorically - I don't need anyone to point-out that film doesn't have pixels, as happened the last time I discussed scanned film images).

I have the Noctilux f1, and don't see these sorts of artefacts on film, even when scanning at 4000dpi (which gives a slightly larger final image than the M9 sensor).

 

In any case, film treats the abrupt transition between highly contrasting areas with far more grace than digital. But that is a whole other discussion.*

 

* On second thoughts, it probably isn't "a whole other discussion" - I think it's this very graceful transition that probably masks the unwanted effects of chromatic aberration or color fringes on film. What's more, the physical depth of film, and the layering of the color grains probably also plays its part in softening an effect that is glaringly obvious from a digital sensor.

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[pgk]

Color fringes in out-of-focus areas are a natural effect of how lenses work - just like blurriness in OOF areas.

What an excellent post - this makes sense to me too.

 

So perhaps an absolutely perfect lens would have to have at least 'apochromatic bokeh'. Perhaps Leica are leaving their lens design team some room for a future upgraded 50mm nocti?