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Thread: purple highlights

  1. #1
    Jamesmd
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    purple highlights

    Hi all

    is the purple for highlights out of focus ?

    James

  2. #2
    Jamesmd
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    Re: purple highlights

    ups i forgot the photo just a sec

  3. #3
    Jamesmd
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    Re: purple highlights

    here it is
    Last edited by Jamesmd; 13th October 2009 at 05:20.

  4. #4
    Jamesmd
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    Re: purple highlights

    its A900 CZ 1.4/85

  5. #5
    Senior Member douglasf13's Avatar
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    Re: purple highlights

    Quote Originally Posted by Jamesmd View Post
    its A900 CZ 1.4/85
    Hi, James. I'm not exactly clear on what you are asking.

  6. #6
    Member Arjuna's Avatar
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    Re: purple highlights

    It looks like there may be some chromatic aberrations on the edges of the structure protecting the microphone?

  7. #7
    Jamesmd
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    Re: purple highlights

    the edges of the mic suspension are purple , some times I have that and some I don't , is this because highlits are aout of focus and lens does that ( it has a name I imagine , distortion or .. )
    james

  8. #8
    Jamesmd
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    Re: purple highlights

    it only happens wide open or close to wide open .

    James

  9. #9
    Administrator Bob's Avatar
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    Re: purple highlights

    Sensor flare perhaps.
    If you have C1, try, under the lens correction tab, "Purple Fringing".
    -bob

  10. #10
    Senior Member edwardkaraa's Avatar
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    Re: purple highlights

    The ZA 85 sometimes does that.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

  11. #11
    Jamesmd
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    Re: purple highlights

    does having a VU filter on anything to do ?

    I'll try C1

    Thanks

    James

  12. #12
    Senior Member douglasf13's Avatar
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    Re: purple highlights

    Quote Originally Posted by Jamesmd View Post
    does having a VU filter on anything to do ?

    I'll try C1

    Thanks

    James

    A UV filter may very well be an issue. When I received the A900, I noticed more aberration with UV filters compared to my APS-C cameras (and I never used UV filters on MFDB,) so I quit using UV filters unless harsh conditions require it. These were expensive Heliopans, BTW. I don't really want to open this can of worms on the debate regarding whether we should take off UV filters or not, but you may want to test it for yourself.

  13. #13
    Senior Member edwardkaraa's Avatar
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    Re: purple highlights

    Quote Originally Posted by douglasf13 View Post
    A UV filter may very well be an issue. When I received the A900, I noticed more aberration with UV filters compared to my APS-C cameras (and I never used UV filters on MFDB,) so I quit using UV filters unless harsh conditions require it. These were expensive Heliopans, BTW. I don't really want to open this can of worms on the debate regarding whether we should take off UV filters or not, but you may want to test it for yourself.

    That is interesting Douglas. I was assured by Zeiss that high quality UV filters do not cause any visible image degradation and they even recommended using one in order to avoid cleaning the lens front element. They recommended B+W and Heliopan (obviously because they use Schott glass, which belongs to Zeiss).
    M262 ZM 25/2.8 35/1.4 50/2 85/2

  14. #14
    Jamesmd
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    Re: purple highlights

    And what about a shylight , would that be better for protection ?

    I'll try same shot same conditions Without the UV.


    Cheers

    James

  15. #15
    Jamesmd
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    Re: purple highlights

    I imagine if we want quality the best is nothing on the lens if not needed , and take care as we allways have , no ?

    James

  16. #16
    Administrator Bob's Avatar
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    Re: purple highlights

    All filters introduce some degree of image degradation.
    if you insist, a B+W 010 MRC is one of the least offensive.
    -bob

  17. #17
    Jamesmd
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    Re: purple highlights

    ok, back to the store tomorrow , couldn't we have chosen a cheaper hobby

    Thanks
    James

  18. #18
    Senior Member douglasf13's Avatar
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    Re: purple highlights

    Quote Originally Posted by edwardkaraa View Post
    That is interesting Douglas. I was assured by Zeiss that high quality UV filters do not cause any visible image degradation and they even recommended using one in order to avoid cleaning the lens front element. They recommended B+W and Heliopan (obviously because they use Schott glass, which belongs to Zeiss).
    After being brow beaten by the likes of Thom Hogan and Iliah Borg in regards to UV filters hurting IQ**, I still resisted removing them for a while. However, when I received the A900, I was just running around the house firing test shots wide open on a couple of primes, and I noticed some shots were a bit soft with some purple fringing in the highlights. I removed my Heliopan multicoated UV filters, and the problems were gone. I haven't really done a scientific test, nor have I tested things since that day, but it was enough to push me over the edge. Now I just use them in harsh conditions.

    Please, don't take my word for it, though. Try it out. Granted, I am a bit skeptical of Zeiss' position on this, because who knows what real reason they have for such a recommendation? However, I may just be crazy


    note:
    **there are some Nikon telephotos that actually come with a protection filter, and the lens design takes that into account.

  19. #19
    Senior Member edwardkaraa's Avatar
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    Re: purple highlights

    I have been using UV filters for at least 27 years so it's going to be difficult to quit this bad habit

    In my own experience, I have seen some flare caused by the filter in extreme backlighting conditions, and also some mirroring of the light sources in night shots. I have never noticed an increase in CA, so it would be interesting if someone could do a controlled test. Anyhow, I still prefer the security of the filter and willing to live with a small loss of IQ.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

  20. #20
    Subscriber Member Georg Baumann's Avatar
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    Re: purple highlights

    Quote Originally Posted by Jamesmd View Post
    ok, back to the store tomorrow , couldn't we have chosen a cheaper hobby

    Thanks
    James
    Yeah, but propper cables make around 5% of the total costs that a recording setup comprises. The Dynaudio Air are like the A900 in the DSLR world, you would not have a cheapo cable running to your console either.



    P.S.
    On another note, ahem, can I just say, as a friendly observation, from musician to musician, from colleague to colleague, you might want to find a new spot for you dried flowers or whatever that pot is on your Air. It is not a good idea to place anything on them. This will have a unpleasant influence on your highs in the mix and your EQ would be messed up.

    I was torn between the Air, Blue Systems and the LSR 4328P for my 5.1, ended up with JBL becuase I got a price hard to believe. Love the Air for classics a wee bit better. Beautiful speakers, very flat response.
    Last edited by Georg Baumann; 16th June 2009 at 22:29.

  21. #21
    Jamesmd
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    Re: purple highlights

    Hi Georg, fun to talk about Air on a CA thread . . That is left surround ,I calibrate them weekly and it's fine . It's a film premix room with the academy film eq aplaid . Don't worry it's fine and measured . The real reason for the pot is that directors and producers lean on them or leave there coffe there , so I opted for the flowers better . I do sound desing not musician , but I would love to be . We can talk of our stuff on private if you want or well bore people here.

    Great that you recogniced the system and a surprise

    Cheers

  22. #22
    Super Duper
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    Re: purple highlights

    Quote Originally Posted by Jamesmd View Post
    Hi all

    is the purple for highlights out of focus ?

    James
    Use or non-use of filters isn't necessarily the issue you are experiencing. The Zeiss ZA 85/1.4 exhibits some CA and/or sensor bloom in some conditions without any filters attached to the lens.

    Much of it can be cleaned up by checking both the Purple Fringing and the CA boxes in Phase One C1. Most, but not necessarily all of it all of the time, will be removed.

    Marc

  23. #23
    Jamesmd
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    Re: purple highlights

    Hi Marc , I have C1 and I'll try it for sure , but I normaly use aperture . Do you know if aperture has some way of doing the same thing ?

    Thanks

    James

  24. #24
    Senior Member Eoin's Avatar
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    Re: purple highlights

    James, When I got the ZA 85 and used it for the first time I though "yuck". Lots of purple fringing and LoCA. But the more I use it and have refined my exposure technique the less I see this problem.

    I don't know if the purple fringing is a sensor bloom problem or a lens problem.
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

  25. #25
    Senior Member edwardkaraa's Avatar
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    Re: purple highlights

    Quote Originally Posted by Eoin View Post

    I don't know if the purple fringing is a sensor bloom problem or a lens problem.
    It's probably the combination of both. Some high contrast lenses like the ZA85 and ZF100 seem to cause it more often than other lower contrast lenses. Though it's not really the lens' fault.

    The ZA85 does has a very particular LoCA that shows in certain situations. Doesn't disturb me though.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

  26. #26
    Subscriber Member Georg Baumann's Avatar
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    Re: purple highlights

    Quote Originally Posted by Jamesmd View Post
    The real reason for the pot is that directors and producers lean on them
    THAT I would consider a declaration of war with an immediate response of the strongest possible measure.


  27. #27
    Super Duper
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    Re: purple highlights

    Quote Originally Posted by Jamesmd View Post
    Hi Marc , I have C1 and I'll try it for sure , but I normally use aperture . Do you know if aperture has some way of doing the same thing ?

    Thanks

    James
    Well, I normally use Light Room for it's faster workflow. But when the occasional need to process an image with CA like the ZA 85/1.4 sometimes produces, or when processing a more troublesome high ISO files from the A900, I just import those images into C! which generally does a better job at both of those functions than most anything else ... at least better than LR/PS does.

    I have Aperture on my machine, but never use it. So I can't remember if it has CA/Purple Fringing correction or not. Probably CA ... but C1 does it so well and so easily, and it's a relatively infrequent need ... if you have C1 I'd recommend it.

    However, it would be good for you to look and see if Aperture has a decent ability to remove CA since it's your favored workflow.

  28. #28
    Senior Member viablex1's Avatar
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    Re: purple highlights

    Quote Originally Posted by Bob View Post
    All filters introduce some degree of image degradation.
    if you insist, a B+W 010 MRC is one of the least offensive.
    -bob
    that is what I always heard ...

    also for purple fringing, a quick and dirty is to use hue saturation and choose blues or whatever, works like a charm provide you dont have any relevant hues close to it...

  29. #29
    Senior Member Braeside's Avatar
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    Re: purple highlights

    Unfortunately Aperture STILL lacks CA controls. You have to use a plugin like PTLENS to eliminate it with Aperture, this means creating a huge TIFF file. I'm really hoping Apple add CA control to the next release of Aperture (if it ever comes).

    Best CA tools I have seen are in DxO, but unfortunately they don't support all of my lenses, and have a particular green tint problem at present (with the A900).
    David Anderson

  30. #30
    Senior Member ryc's Avatar
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    Re: purple highlights


  31. #31
    Jamesmd
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    Re: purple highlights

    just discovered you all talk about C1 Pro , no ?

    Thnaks

    James

  32. #32
    Senior Member douglasf13's Avatar
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    Re: purple highlights

    What's interesting is some say that UV filters, if anything, should probably help with purple fringing, not hurt, so I'm probably crazy!

  33. #33
    Jamesmd
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    Re: purple highlights

    PTLenns doesn't manage to fix it .

    james
    Last edited by Jamesmd; 13th October 2009 at 05:21.

  34. #34
    Senior Member Eoin's Avatar
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    Re: purple highlights

    James,

    Where is the CA in this photo?. Is it the edge of the table?.
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

  35. #35
    Jamesmd
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    Re: purple highlights

    Hi Eoin, yes and the top of the tin much more, Ill send beter file

  36. #36
    Senior Member Braeside's Avatar
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    Re: purple highlights

    Sorry I should have been clearer, PTLENS fixes CA (Transverse but not Longitudinal though). It doesn't generally fix PF.

    DxO does make a good job of fixing PF.
    David Anderson

  37. #37
    Jamesmd
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    Re: purple highlights

    here it is
    Last edited by Jamesmd; 13th October 2009 at 05:21.

  38. #38
    Senior Member Braeside's Avatar
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    Re: purple highlights

    That is longitudinal CA - see the green around the out of focus at the rear of the lip of the can and the magenta at the out of focus at the front of the can.
    David Anderson

  39. #39
    Senior Member Eoin's Avatar
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    Re: purple highlights

    OK, for those of you (like me) who use Aperture, you may already know that the moire removal sliders in the Raw fine tuning brick can be used to remove light CA.
    If the CA is stronger and the moire sliders do not remove it you can then use the Colour brick and carefully select the offending CA and play with the H,S,L,R sliders to zone in on the CA and eliminate it without having too much of an impact on the tones in your image.
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

  40. #40
    Jamesmd
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    Re: purple highlights

    I've just done the same shot with and without VU and its worst with.

    Ill send pics right now .

    Can you do similar test to se if you have it ?

    its 100 ISO , 1,4 F .

  41. #41
    Senior Member Eoin's Avatar
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    Re: purple highlights

    How does that look
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

  42. #42
    Jamesmd
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    Re: purple highlights

    here they are

    first without vu filter
    second with vu filter
    Last edited by Jamesmd; 13th October 2009 at 05:21.

  43. #43
    Jamesmd
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    Re: purple highlights

    much better , yes Sir . that was with color , no ? I tried moire and didn't work.
    thanks !!

    so I can fix it , but , what about the lens , should it do that ?

  44. #44
    Senior Member douglasf13's Avatar
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    Re: purple highlights

    Hey James, I'm a little confused. Are you saying that the CA is worse with the UV filter, or without? The labeling on the pic you posted contradicts the statement you made prior to it. Thanks.

  45. #45
    Senior Member Eoin's Avatar
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    Re: purple highlights

    James,

    From what I know with the ZA 85, if you blow the highlights (overexpose the brightest part) you will see this purple fringing or what others call sensor bloom. Reason being there is too much light hitting the sensor in the area of the highlight. The best advice I can give or suggest is you try different exposures of the same scene where you reduce each exposure by 1/3 of a stop and see if the purple will disappear for you.
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

  46. #46
    Jamesmd
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    Re: purple highlights

    sorry , it was worst with the filter on.

    I have been shooting the same pic with CZ 85 1,4 and SONY 50 1.4 an they do the same , from 1.4 to up to 2.8 or so .
    Could a couple of different persons do the try please ?

    grrr ,nothing worst than thinking your camera might be wrong , it can drive you nuts

  47. #47
    Senior Member douglasf13's Avatar
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    Re: purple highlights

    Well, maybe I'm not crazy after all That is exactly what I noticed in my very basic tests last December with filters on and off using those two lenses. It looks like we need some more exacting tests on the matter.

    I don't think there is anything wrong with your camera. It's just the nature of the beast.

    p.s. you may want to edit your pic post so people don't get confused
    Last edited by douglasf13; 17th June 2009 at 10:10.

  48. #48
    Jamesmd
    Guest

    Re: purple highlights

    yes Eoin , it gets better under exposing .

  49. #49
    Jamesmd
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    Re: purple highlights

    edited Douglas , thanks

  50. #50
    Senior Member Eoin's Avatar
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    Re: purple highlights

    With large aperture lenses you are always prone to this, there is a fine line between a correctly exposed image and one where you get this purple fringing. I would think there is nothing wrong with the lens. But leave the filter off for the moment.

    I know my favorite lens of all time, the Canon 85L used to do this quite regularly until I began to understand what effected it. Sometimes the dynamic range is just too much for the sensor to handle and you need to make a decision what you want, highlights or shadows and shoot accordingly.

    Another thing you may wish to do with Aperture is turn down the Boost (50-75%) in the raw fine tuning brick. then learn your camera's exposure meter, Douglas has some settings you can use with the creative styles, neutral setting with -1 saturation, -3 brightness and -1 zone. This will I believe get the histogram to correctly or in as near as possible reflect what the RAW exposure is like and not what the in camera jpg is.

    Then you can use the RGB histograms on the back of the camera to see if you are clipping the highlights. I know it's frustrating, but you need time to understand and evaluate what's going on and how best to use the indicated camera exposure meter with what is actually going on in the raw file.
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

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