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Phase One 150 mm AFD f/2.8 lens cast

Guy Mancuso

Administrator, Instructor
Try another lens as well on the DF. Just thinking out loud maybe it's decentered the lens. But my bet maybe tungsten which Is not something to judge with and try Jacks suggestion as well.
 

David Klepacki

New member
Gareth,

Very strange problem you present here. If it were not for your shot with the Rodenstock 90, I would have thought it was the back, since rarely does a lens retain its sharpness when it goes "bad" ... but I guess it is possible. The first thing you need to do is try another 150 and see if you can reproduce the problem. IF so, then have your back thoroughly checked out by Phase One.

David

BTW, when I use a DF and P65+ with a SK110 and a M200-APO, I never need a LCC. The colors are always spot on, regardless of whether I am shooting in tungsten or daylight.
 

Christopher

Active member
Well I would say it's the back under special conditions. My first IQ180 had it, but stronger. I did not even consider a second to keep it. My second back is much better. However, still worse than my old P65. My P65 was I think near to perfect. I was able to shoot white walls under all conditions and never had a LC...
 

gazwas

Active member
Just a quick update as I'm thinking this may have had something to do with heat build up. The camera had been in use or a few hours when I originally noticed the colour and shot the first tests. I shot some tests in daylight today and the files are clean.

Quite surprised if heat is the cause and can make such a difference to the chip but I'll have to keep my eye on things for a few weeks. Apart from this glitch, the 150D is a really great lens and very sharp.
 

ondebanks

Member
It could very well be a heat effect - the Dalsa CCDs in the P40+, P65+ and IQ1x0 series have much higher thermal dark noise than equivalent Kodak CCDs at the same temperature.
 

DrakeJ

New member
Sorry to revive this old thread, but I seem to have a lens cast issue with my 150mm 2.8D as well with the IQ180 and XF which is surprising to me. Have done a few tests to produce raw files for the support team, but if they return with a "it's supposed to be this way" answer, can anyone point me to a resource on a howto LCC-file?

I'll supply two shots, one with a reference of the 80mm LS at f/8 and one with the 150mm 2.8D at f/8:

80mm: https://drive.google.com/open?id=0B3CBLteSfg1xVlJDVFg1SVEtaWc

150mm: https://drive.google.com/open?id=0B3CBLteSfg1xTU1QS01iR2U2bms

(Have not applied lens corrections and it's taken in a small room so there might be color contaminations, but the lens cast should be obvious anyway)
 
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DrakeJ

New member
So Phase One replied and said it was not uncommon that my combination rendered slight lens casts and told me to do a LCC-file.

Looking back at when I tested different portrait lenses, I now see that the rental Phase One 150mm 2.8 lens has the same lens cast. I don't see any casts in either the 55mm LS or 80mm LS.

Can anyone provide me with their best tips on how I do a LCC-file in a studio setting? Shoot an image through the translucent disk into a lit softbox?
 

Wayne Fox

Workshop Member
seems odd a lens that long would create lens cast.

As far as shooting an LCC, doesn’t really matter how you light it, just hit it with light. If it’s a studio situation pretty easy, because you can probably get away with shooting just one and storing it as a user preset. If you vary your f stop, then you might want to shoot one for each of your working apertures, but even that probably wouldn’t be detectable.
 
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