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Thread: Significance of ultra focus to purchasing decision

  1. #1
    Senior Member Ed Hurst's Avatar
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    Significance of ultra focus to purchasing decision

    This is my first post, so hello to everyone...

    I am thinking about my purchasing strategy into the world of medium format digital. It is something I want to do fairly soon. However, like many of you, I am befuddled by the choices in front of me, mainly because of the rapid pace of technical development in this arena. I want to jump into the technology, but don't want to commit to something that will rapidly date or be too expensive to upgrade.

    My criteria are resolution (or course), dynamic range and low noise. Nothing original there of course!

    Here's my question... One of the ways of avoiding being left behind by technical advances is to use interchangeable backs which can be replaced as things improve. On the other hand, Hassey emphasises the benefits of an integrated system, partly on the basis of the possibility of precise focusing compared to interchangeable backs (with their inherent need for an interface between body and back, which might hamper precise sensor to subject distances). From your experience, is this a genuine issue in favour of an integrated body? Or is it just marketing-speak, leaving the possible benefits in favour of interchangeable backs? On the other hand, perhaps Hassey's policy of supporting upgrades negates this benefit?

    Any thoughts?

    Best wishes in advance.

    Ed

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    Workshop Member lance_schad's Avatar
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    Re: Significance of ultra focus to purchasing decision

    Ed,
    Welcome to the forum. You mention the Hasselblad system, are you considering the Phase One system or others as well?

    I am not too familiar with the way that UltraFocus operates on the Hassy system, but can speak from experience that it is very rare that we have experienced a Phase One back in any of the mounts that are offered (H,V,Phase/Mamiya,Contax) experience focus issues, especially on brand new bodies.

    The Phase One backs are built to the specifications for the mount it is constructed for.

    Also another thing that PhaseOne is going to build upon is their Lens+ technology which currently corrects for CA and Purple Fringing in the current version of CaptureOne 4.1x for Mamiya lenses, Hasselblad V/H lenses and Contax lenses. They are going to be extending that technology to correct for barrel distortion and pin cushioning in the forthcoming Pro version of Capture One which should ship next month.

    They have also announced earlier Focus+ technology that will add to the sharpness of the RAW file . More details should be coming out at Photokina on this technology.

    So yes Phase One is selling a branded body/lens solution that is bundled with their backs, but also developing and supporting other platforms as well, even for brands that are no longer being manufactured.

    If I can be of any additional assistance please feel free to contact me.

    Lance
    LANCE SCHAD - Digital Transitions - Phase One,Mamiya | Leaf,Arca-Swiss,Cambo, Profoto
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    Re: Significance of ultra focus to purchasing decision

    Hasselblad's "ultra focus" is marketing fluff. Phase/Leaf/Sinar/Hassy all spec their sensors with a tolerance of a few microns. There is no need to calibrate a body to a particular back. Out of dozens of systems on mamiya/contax/hassy (in sales and rental) I don't recall having to replace or repair any due to miscalibrated focus issue.

    More important is overall AF performance. This varies by subject matter, lens, ambient light etc. So the best thing to do is borrow/rent one of each system you are considering and use it in a real world situation.

    Doug Peterson, Head of Technical Services
    Capture Integration, Phase One Dealer
    Personal Portfolio

  4. #4
    JEM_DTG
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    Re: Significance of ultra focus to purchasing decision

    Hasselblad's UltraFocus technology is most certainly not marketing fluff. Fancy name for an obviously effective feature of their cameras.. sure.

    More important than the mechanical placement of the sensor in regards to the back/body mount, is the relationship of the sensor as it translates to the rest of the optical system (ie. IR Filter array, CCD cover glass, lens assembly, and auto-focus system). The ultra-critical placement of imaging sensor allows for greater (than other current manufacturers) optical sharpness by maximizing critical focus adjustment, eliminating diffraction introduced by the IR/CCD cover glass assembly, and more accurate auto-focus capability. This diffraction is common to ALL CCD assemblies used in today's digital backs, and introduces varying amounts of diffraction based on the sensor and back manufacturer's specifications and lens systems used.

    UltraFocus is part of several optical improvements found in the H3D/II (or H2F/CF) series systems, known as Digital APO Corrections (DAC). This is capability Hasselblad has been developing since the release of the H1D at Photokina 2004, and has matured to the point that it simply out performs the recently released, "comparable" corrections found in competitive systems (ie. PhaseOne, Leaf, & Mamiya).

    The advantages of the UltraFocus are visible, sharpness improvements and greater optical clarity. This happens to be accomplished by the precise collimation of the sensor in relation to the rest of optical and mechanical system. As a matter of fact, the calibration specs are clearly stated in each camera's "System Status" menu.

    My suggestion would be to draw your own comparison with these systems, and determine where certain advantages lie within your own shooting parameters. I proper dealer, both Hasselblad and PhaseOne, could assist in the process, and be wealth of knowledge in helping you find the right system for your application(s).

    Regards,

    Jordan Miller
    DTG

    as the lens' optical performance is known, given the f-stop / focal length / focus distance / etc., and in turn the affect of the IR/CCD cover glass assembly is known, and in tu

    Quote Originally Posted by dougpetersonci View Post
    Hasselblad's "ultra focus" is marketing fluff. Phase/Leaf/Sinar/Hassy all spec their sensors with a tolerance of a few microns. There is no need to calibrate a body to a particular back. Out of dozens of systems on mamiya/contax/hassy (in sales and rental) I don't recall having to replace or repair any due to miscalibrated focus issue.

    More important is overall AF performance. This varies by subject matter, lens, ambient light etc. So the best thing to do is borrow/rent one of each system you are considering and use it in a real world situation.

    Doug Peterson, Head of Technical Services
    Capture Integration, Phase One Dealer
    Personal Portfolio
    Last edited by JEM_DTG; 22nd September 2008 at 16:01.

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    Re: Significance of ultra focus to purchasing decision

    Quote Originally Posted by dougpetersonci View Post
    Hasselblad's "ultra focus" is marketing fluff. Phase/Leaf/Sinar/Hassy all spec their sensors with a tolerance of a few microns. There is no need to calibrate a body to a particular back.

    Doug Peterson, Head of Technical Services
    Capture Integration, Phase One Dealer
    Personal Portfolio
    As I understand it, "Ultra Focus" has nothing to do with calibrating a back to a camera as you have stated Doug. Like DAC, it's based on intregration of the lenses ... i.e., data from the lenses being used to fine tune the AF.

    Hasselblad info:

    "In the H3D camera, information about lens and exact capture conditions are fed into the digital camera engine for ultra-fine-tuning of the auto-focus mechanism, taking into account the design of the lens and the optical specification of the sensor."

  6. #6
    JEM_DTG
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    Re: Significance of ultra focus to purchasing decision

    fotografz,
    You're right (sort of). UltraFocus is one of the products of this calibration. See my post above. There is meta-data being fed back and forth from lens through to the back, and vise-versa, to maximize the performance of the entire opto-mechanical system.

    Regards,

    Jordan MillerDTG

    Quote Originally Posted by fotografz View Post
    As I understand it, "Ultra Focus" has nothing to do with calibrating a back to a camera as you have stated Doug. Like DAC, it's based on intregration of the lenses ... i.e., data from the lenses being used to fine tune the AF.

    Hasselblad info:

    "In the H3D camera, information about lens and exact capture conditions are fed into the digital camera engine for ultra-fine-tuning of the auto-focus mechanism, taking into account the design of the lens and the optical specification of the sensor."

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    Re: Significance of ultra focus to purchasing decision

    Hasselblad's UltraFocus technology is not a marketing fluff as mentioned above.

    As with some of our Leica lenses, many lenses have front or back focusing at different apartures (relative to the reference focusing aparture)

    In SLR cameras, to utilize the Viewfinder in the best possible manner, camera allows you to focus wide open, and then aparture is set to the correct value just before the actual exposure.

    The focus at that aparture may be slightly different than wide open, and the DOF may not be enough to compensate for this slight shift.

    According to Hasselblad information, one assumes that the camera, knowing which lens is in use, compensates for this difference, i.e. moves the AF point very slightly in the correct direction.

    These may be theoretical because of very slight differences. Most can go unnoticed. But in the actual pictures I have taken with H3DII, I can say that I have never seen anything this succesfull, also coming possibly from the excellent quality of the HC lenses.

    This has nothing to do with coupling of the DB to the camera. (That is the annoying part which is the marketing strategy). I hate it myself too, because I will not be able to upgrade my 31MP camera in the future, even with a future Hasselblad product.

    My words don't have the meaning that Hasselblad has a better AF speed, or does not defend the other annoying things I have been experiencing with this camera. All cameras have strong and weak points, and when it comes to AF accuracy and correction of many errors usually present in MF, Hasselblad ranks in a very good place.

    How about starting a "weak points" of the current MF cameras? I have a lot about mine.

    Seyhun
    H3DII-31, 5DII, M8, NEX-3 and Camera collection
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    Senior Member Graham Mitchell's Avatar
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    Re: Significance of ultra focus to purchasing decision

    Quote Originally Posted by Ed HUrst View Post
    Or is it just marketing-speak, leaving the possible benefits in favour of interchangeable backs?
    It's marketing nonsense. Hasselblad also sells interchangeable backs. Just ask the Hasselblad dealer if they have problems with those. I'm guessing he will say they've never had that issue

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    Re: Significance of ultra focus to purchasing decision

    Quote Originally Posted by foto-z View Post
    It's marketing nonsense. Hasselblad also sells interchangeable backs. Just ask the Hasselblad dealer if they have problems with those. I'm guessing he will say they've never had that issue
    What part of: "Ultra Focus has nothing to do with fitting the back to the camera" do you not understand?

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    Senior Member Graham Mitchell's Avatar
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    Re: Significance of ultra focus to purchasing decision

    Quote Originally Posted by fotografz View Post
    What part of: "Ultra Focus has nothing to do with fitting the back to the camera" do you not understand?
    I answered the original poster's question, which was:

    "Here's my question... One of the ways of avoiding being left behind by technical advances is to use interchangeable backs which can be replaced as things improve. On the other hand, Hassey emphasises the benefits of an integrated system, partly on the basis of the possibility of precise focusing compared to interchangeable backs (with their inherent need for an interface between body and back, which might hamper precise sensor to subject distances). From your experience, is this a genuine issue in favour of an integrated body?"

    I have no idea what you're talking about.

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    Re: Significance of ultra focus to purchasing decision

    Quote Originally Posted by foto-z View Post
    I answered the original poster's question, which was:

    "Here's my question... One of the ways of avoiding being left behind by technical advances is to use interchangeable backs which can be replaced as things improve. On the other hand, Hassey emphasises the benefits of an integrated system, partly on the basis of the possibility of precise focusing compared to interchangeable backs (with their inherent need for an interface between body and back, which might hamper precise sensor to subject distances). From your experience, is this a genuine issue in favour of an integrated body?"

    I have no idea what you're talking about.
    Exactly. We're all correct because we've been answering two separate questions:
    1) Does the Hassy H platform focus with accuracy and speed?
    2) Does this have anything to do with the fact the back+body are "integrated" (i.e. artificially locked out of competitors products)?

    Nobody has anything but good things to say about #1. The platform focuses well and though it can't compare to a action-driven camera like the 1D III or D3 it is pretty darn good for the medium format world. So is the focus of the Phase One 645 / Mamiya AFD III.

    What I call fluff is trying to say this is a function of a closed back-body-lens system. Adjusting fine-focus for lens characteristics is something all the current camera manufacturers do.

    The bottom line remains: get both in your hands and shoot them. If you see better AF on one system shooting in a situation typical for you then it doesn't matter why.

    Doug Peterson, Head of Technical Services
    Capture Integration, Phase One Dealer
    Personal Portfolio

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    Re: Significance of ultra focus to purchasing decision

    Sorry, I guess you didn't read the whole thread. The discussion moved on to Ultra Focus and also mentioned Phase One's Focus Plus.

    Fact is, Ultra Focus is not marketing nonsense, and how it works was explained by 3 different responders.

    In my experience, non integrated or non dedicated digital backs sometimes need shims for specific cameras ... I needed to have a digital back calibrated to my Contax 645 before it would focus accurately with the Zeiss 80/2 ... so did my buddy ... and that was a dedicated back.

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    Re: Significance of ultra focus to purchasing decision

    Marc,

    I agree completely...I recently purchased an Alpa TC with H1A adapter for my H3D II 39 back. It was missing a few shims and after a month I returned the whole camera and back adapter as it would not focus correctly even with the correct shims.

    With digital the precision for detail is very precise. Anything that helps us maintain critical focus is helpful. Indeed the Alpa is very precise when it works but it relies on a very imprecise focusing implementation. I would describe it as precisely imprecise. (?) That may work with film where the DOF is great but it really does not (for me) with digital devices.

    I must say that the ultra focus paradigm has made me very suspect of other implementations of autofocus. It is so easy to miss critical focus with MF digital that any process that improves our capture success is well worth the effort.

    My success rate with the Alpa was abysmal...and I have a lot of experience with zone focus and hyperfocal focusing. Previous use of large format and MF Rangefinder was of little use in this case. I think as Guy has realized...buyer beware.

    So I need to evaluate wide angle options on the H3D...28 and 50 for the near term.

    Bob Moore

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    Re: Significance of ultra focus to purchasing decision

    Ed,
    I did not mean to start all of this. Bottom line which I should have mentioned in my first post was to try out all your options and go with what works for you.

    Keep in mind that it is not only product itself but also the dealer that you make a relationship with. Everyone has their own individual threshold for file quality and also customer service.

    After all the hardware is similar, but it is workflow and support which really set them apart.

    Bob that is a shame to hear about the ALPA. I know you had your mind set on that solution. In the past few months on the ALPA's that we have sold worked perfectly with the backs that we mated with them w/o shims. Even for folks that may have already owned their ALPA for a year or two sent it to us when they purchased their back and we tested it to make sure it was working properly then shipped it back configured.


    Anyway best of luck and I can help please let me know.
    L

    p
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    direct/cell:610-496-5586 office:877-367-8537x224
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    Re: Significance of ultra focus to purchasing decision

    Lance,

    Thank you for the response. When the Alpa was on it was very very good. Just hard to make it work the way it was set up. You are right that dealer support is everything...would have made a great difference in this instance.

    With warm regards,

    Bob Moore

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