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Thread: Alpa's HPF rings

  1. #1
    photohagen
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    Alpa's HPF rings

    let's assume i shimmed my db and also installed the ring properly as per instructions. how accurate is the distance scale on these hpf rings especially at closer distances? can i use a laser distance meter, dial up the distance on the ring, and get accurate focus?

    richard

  2. #2
    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Alpa's HPF rings

    Yup. Therein lies the whole point of the shim, HPF and disto exercise.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

  3. #3
    Senior Member Thierry's Avatar
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    Re: Alpa's HPF rings

    Yes Richard, Graham is right and of course it is then a 100% accurate.

    As a reminder, here you can get the detailed information how the shimming works and is done, and why it is so important.

    Alpa adjustable back adapter

    Best regards
    Thierry

    Quote Originally Posted by photohagen View Post
    let's assume i shimmed my db and also installed the ring properly as per instructions. how accurate is the distance scale on these hpf rings especially at closer distances? can i use a laser distance meter, dial up the distance on the ring, and get accurate focus?

    richard
    Thierry Hagenauer
    [email protected]

  4. #4
    Senior Member danlindberg's Avatar
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    Re: Alpa's HPF rings

    Yes, it is very precise indeed. I was a little hesitant in the beginning but can also confirm that the combination Disto 5 and HPF rings on a correctly calibrated Alpa is totally reliable.
    Alpa FPS MAX TC | Alpagon 32Hr | Helvetar 75 | Schneider 120N | Leaf Aptus II 5 Leaf Credo 60 | www.danlindberg.com

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    Re: Alpa's HPF rings

    Thierry, pet peeve of mine, often irked by companies like Alpa. Can you please say it's "extremely accurate" or such? Nothing is ever 100% accurate.

    This reminds me of when it was claimed pre-launch the S2 would "not moire" (the qualitative version of "100%"). Engineering wise everything will moire in the right situation. Engineering wise nothing is 100% accurate.

    The S2 is a great camera and the HPF are a great tool. Like I said, just a pet peeve.

  6. #6
    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Alpa's HPF rings

    I have one for my 90 on the way. Along with a Disto 5 as well.

    BTW Paul at Optechs got a bunch in.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Alpa's HPF rings

    I would love one for my 60 but with my Tilt Swing knobs i would need a custom adjustment to my lens knobs. Thierry I wonder if they could make one without the focusing knobs not the screw in pins but without the whole focus ring around the HPF and make it thinner. I know major tooling but be interesting to hear what they had to say about it.
    Photography is all about experimentation and without it you will never learn art.

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  8. #8
    Senior Member Thierry's Avatar
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    Re: Alpa's HPF rings

    Doug, why "irked by Alpa"?

    Fact is that one can focus exactly where one wants the focus to be, and not meters or 1/10s of a meter behind or in front, WHEN the digital back is shimmed precisely, with exactly precision needed when focusing, not more but also not less.

    Is that a better way to say it or still too much?



    Best regards
    Thierry

    Quote Originally Posted by dougpetersonci View Post
    Thierry, pet peeve of mine, often irked by companies like Alpa. Can you please say it's "extremely accurate" or such? Nothing is ever 100% accurate.

    This reminds me of when it was claimed pre-launch the S2 would "not moire" (the qualitative version of "100%"). Engineering wise everything will moire in the right situation. Engineering wise nothing is 100% accurate.

    The S2 is a great camera and the HPF are a great tool. Like I said, just a pet peeve.
    Thierry Hagenauer
    [email protected]

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    Re: Alpa's HPF rings

    Doug: you are preaching to the wall

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Alpa's HPF rings

    Quote Originally Posted by TH_Alpa View Post
    Fact is that one can focus exactly where one wants the focus to be, and not meters or 1/10s of a meter behind or in front, WHEN the digital back is shimmed precisely, with exactly precision needed when focusing, not more but also not less.
    In all fairness it's probably also worth adding that so long as the back is shimmed, AND the HPF ring is aligned correctly with the lens infinity mark then you'll have a very accurate match of focus distance to distance on the HPF ring. Aligning the HPF ring with the helicoid isn't difficult but with wide lenses even a very minor misalignment would result in things being off vs a distometer reading.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

  11. #11
    photohagen
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    Re: Alpa's HPF rings

    an important variable not mentioned: where do you line up the laser to take a measurement? i assume it's parallel to the sensor. and if so, approximating where the sensor is located each and every time can be less than 100% accurate.

    rh

  12. #12
    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Alpa's HPF rings

    Yes to the film plane or in this case to the sensor.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  13. #13
    Senior Member Thierry's Avatar
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    Re: Alpa's HPF rings

    That's of course correct, Graham.

    AND, to be complete, with calibrated lenses to be able to have precision with ALL used lenses.

    Thierry

    Quote Originally Posted by GrahamWelland View Post
    In all fairness it's probably also worth adding that so long as the back is shimmed, AND the HPF ring is aligned correctly with the lens infinity mark then you'll have a very accurate match of focus distance to distance on the HPF ring. Aligning the HPF ring with the helicoid isn't difficult but with wide lenses even a very minor misalignment would result in things being off vs a distometer reading.
    Thierry Hagenauer
    [email protected]

  14. #14
    Senior Member Thierry's Avatar
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    Re: Alpa's HPF rings

    Dear Guy,

    I don't think Alpa is going to produce accessories for other brands.

    Best regards
    Thierry

    Quote Originally Posted by Guy Mancuso View Post
    I would love one for my 60 but with my Tilt Swing knobs i would need a custom adjustment to my lens knobs. Thierry I wonder if they could make one without the focusing knobs not the screw in pins but without the whole focus ring around the HPF and make it thinner. I know major tooling but be interesting to hear what they had to say about it.
    Thierry Hagenauer
    [email protected]

  15. #15
    Senior Member dchew's Avatar
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    Re: Alpa's HPF rings

    For me, the HPF/D5 is not only accurate, but also the most efficient way to focus. I know some, including Jack I think, have had success using live view on the IQ back. I still struggle with live view for focusing, but I admit I haven't given it the full College Try.

    If the subject is relatively close you can flip down the little corner foot on the D5, then position the D5 right on top of the camera with the foot up against the back of the camera. Makes it fairly stable without the need for mounting the D5 onto the camera. If you are really anal - sorry precise - you can add a zero adjustment to the D5 to add a small amount that accounts for the difference between wherever you set the base of the D5 and where the sensor plane is. But for my setup it is only like 0.02 feet / 0.0061m (yes, the D5 can go out 4 dec places in meters!).

    I THINK the D5 is the only real effective option that works well for this application. The video feature makes all the difference.

    Dave

  16. #16
    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Alpa's HPF rings

    Quote Originally Posted by TH_Alpa View Post
    Dear Guy,

    I don't think Alpa is going to produce accessories for other brands.

    Best regards
    Thierry
    Well maybe so but it is for lenses and it could be a nice market.
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

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    Re: Alpa's HPF rings

    you can also set the D5 to display ft-decimal ft, to match the HPR ring markings

  18. #18
    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Alpa's HPF rings

    Thanks need to figure out the D5 when it gets here
    Photography is all about experimentation and without it you will never learn art.

    www.guymancusophotography.com

  19. #19
    Senior Member dchew's Avatar
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    Re: Alpa's HPF rings

    Quote Originally Posted by jlm View Post
    you can also set the D5 to display ft-decimal ft, to match the HPR ring markings
    Yeah, that's how I have mine set, 0.00 ft to match the foot-scale HPF rings I have.

    I debated which HPF rings to order, since 0.00 feet is more accurate than 0.00 meters. But if you look at the HPF distance tables it turns out to be almost a wash. The tables are in three significant digits, i.e. x.xx until less than 1 meter or foot, where they switch to 0.xxx. So at just under 1 meter you get 0.999 in meters but still 3.28 feet. Once you get under a foot, which is almost never for me, do you get the third decimal on the ft scale. Too much thinking to matter!


    Dave

  20. #20
    photohagen
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    Re: Alpa's HPF rings

    i am no longer skeptical. i received my hpf ring yesterday. installed it and tested it today. every setting from my laser to my ring gave me perfect focus.

    thanks to everyone for their input. merry christmas!

    rh

  21. #21
    Senior Member dchew's Avatar
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    Re: Alpa's HPF rings

    Quote Originally Posted by photohagen View Post
    every setting from my laser to my ring gave me perfect focus.
    rh
    Yeah, ain't it great?! For Doug's benefit, I'll translate that to very very nearly perfect focus.

    Merry Christmas everyone.

    Dave

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    Re: Alpa's HPF rings

    Quote Originally Posted by Guy Mancuso View Post
    I have one for my 90 on the way. Along with a Disto 5 as well.
    I've had very good experience when using HPF rings and the Disto 5. No idea of the absolute accuracy but it seems pretty spot on.

    I realise this is a digital forum and I use film but for those interested here are some images; all tripod mounted:

    http://rdubois.zenfolio.com/p285878686

    Also for those interested, here I used the Alpa using zone focusing (Warning: there are many pictures); those with Alpa TC image 67 onwards.

    http://rdubois.zenfolio.com/p574705449

    The combination of the Alpa TC and Nikon D3s for very low light worked well.

    The Alpa TC worked really well in difficult conditions (loots of dirt/dust/moisture). The only gripe I had (reported to Alpa) was that the finger grip is very slippery in hot humid conditions and when the hands get sweaty there is a risk of the camera slipping off the hands. I've had a new (walnut) grip made with far deeper indents for the fingers.

    All in all though both in New Zealand (holiday) and India (work) this camera gave a very good experience. It is beautifully built, small enough to use as a street camera and the detail provided by the 60mm, f 5.6 Apo Helvetar is simply outstanding.

    Dubois, December 2011

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