12-02-2010, 11:56 PM
[quote name='Sylvain' timestamp='1291158324' post='4616']
Wim, even though you wrote "'nuff said", I'm afraid you did not say anything :/. I did find the article was not well put together (no explanation whatsoever on graph data collection, etc...) but that what it's trying to say could be rather interesting. Or did I misunderstand everything?
DxO still inks to this article and what I could find in the LL forum wasn't really saying anything else than "no explanation". Care to enlighten me? Doesn't have to be a Wim Encyclopedic answer
TIA,
S.
[/quote]
Hi Sylvain,
I didn't want to butcher DxO, Mark Dubovoy or LL more than already was done, and I was rather disappointed with the matter, hence my cryptic message.
It really did it for me with the claim that there was no use for minDoF type application of lenses, because you wouldn't get less DoF anyway, or something to that extent. As I own a fair number of large aperture lenses, two of which are the fastest AF production lenses available for dslrs, I'd have to call it complete male bovine manure as a result.
Of course, it may well be that camera manufacturers have a few tricks up their sleeve to manipulate the results from a sensor, but the article didn't make sense at all. One thing that is interesting however is that PF or purple fringing, which is an aberration oftentimes considered to be CA (which it isn't by the definition of CA, because it isn't sagittal or transversal in nature), is much stronger than it is with film, and always disappears when stopping down a few stops. Now, this could either be caused by someting to do with the sensor assembly itself and extremely high contrast transitions, the A/D processing, both of these, or generally indeed by anything that causes an increase in contrast due to signal amplication, whether optical or electrical/digital and the signal clipping in a weird way. Since we are talking signal amplification here, that could be caused by this, it it were true.
As BC and GTW indicate, all of this could actually be tested quite easily, by breaking the contacts between lens and camera and just shooting at maximum aperture. I guess I may give this a try myself, too <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.
Kind regards, Wim
P.S.: sorry for my late reply - I am in a new assignation since about 3 1/2 weeks, and I generally have bad to very bad and intermittent or even no internet connections during the week, and currently only very little time during the weekend.
Wim, even though you wrote "'nuff said", I'm afraid you did not say anything :/. I did find the article was not well put together (no explanation whatsoever on graph data collection, etc...) but that what it's trying to say could be rather interesting. Or did I misunderstand everything?
DxO still inks to this article and what I could find in the LL forum wasn't really saying anything else than "no explanation". Care to enlighten me? Doesn't have to be a Wim Encyclopedic answer
TIA,
S.
[/quote]
Hi Sylvain,
I didn't want to butcher DxO, Mark Dubovoy or LL more than already was done, and I was rather disappointed with the matter, hence my cryptic message.
It really did it for me with the claim that there was no use for minDoF type application of lenses, because you wouldn't get less DoF anyway, or something to that extent. As I own a fair number of large aperture lenses, two of which are the fastest AF production lenses available for dslrs, I'd have to call it complete male bovine manure as a result.
Of course, it may well be that camera manufacturers have a few tricks up their sleeve to manipulate the results from a sensor, but the article didn't make sense at all. One thing that is interesting however is that PF or purple fringing, which is an aberration oftentimes considered to be CA (which it isn't by the definition of CA, because it isn't sagittal or transversal in nature), is much stronger than it is with film, and always disappears when stopping down a few stops. Now, this could either be caused by someting to do with the sensor assembly itself and extremely high contrast transitions, the A/D processing, both of these, or generally indeed by anything that causes an increase in contrast due to signal amplication, whether optical or electrical/digital and the signal clipping in a weird way. Since we are talking signal amplification here, that could be caused by this, it it were true.
As BC and GTW indicate, all of this could actually be tested quite easily, by breaking the contacts between lens and camera and just shooting at maximum aperture. I guess I may give this a try myself, too <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.Kind regards, Wim
P.S.: sorry for my late reply - I am in a new assignation since about 3 1/2 weeks, and I generally have bad to very bad and intermittent or even no internet connections during the week, and currently only very little time during the weekend.
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
