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Thread: 50mm Summilux front focusing

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    50mm Summilux front focusing

    Hi everyone,

    I'm pretty new to rangefinders, so this is a bit of an confounding situation for me. I think my 50mm Summilux ASPH is front focusing - I also have a 35mm lens, and it appears to work fine on the same camera body.

    Has anyone had this type of adjustment made before? What's the best way to go about doing this?

    Thanks in advance!

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: 50mm Summilux front focusing

    Is it new or used? Is this in the US or elsewhere?

    If it's under warranty then you could have this handled via Leica, otherwise it's probably a lot faster to get it adjusted by a third party such as Don Goldberg (DAG) or Sherry Krauter in the US. You could try any of these folks

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    Senior Member Per Ofverbeck's Avatar
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    Re: 50mm Summilux front focusing

    Bought a brand new Summicron 35 ASPH a few weeks ago, and it backfocussed. None of my other lenses have a problem, either on the new M9 or my old M2, so obviously the lens is on a trip to Solms at present.

    So, sure it can happen. And, equally sure, youŽll be told "it has never happened before.."

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    Re: 50mm Summilux front focusing

    When you start looking at 100% on an 18 megapixel, perfectly flat sensor, flaws that used to be elusive start to become easily visible. It is the tradeoff for high resolution digital. On film, most users would not notice most of these slight misalignments of body or lens unless they routinely printed 20x24 or larger...and only then if their enlarger was perfectly aligned, they were using a glass negative carrier and a good enlarging lens. Most people never got even close to that... many photographers never printed over 8x10. Now testing a lens to its breaking point requires no skill at all -- just open up the file and click on the magnifier. So in a way, it is not that the old Leica lenses did not have focus shift or were built so much better before, it's just that the tolerances have to be so much more critical these days. And of course, anything could be responsible for getting a lens out of alignment, and it is not always that it left the factory that way! It could have been knocked around during shipping, or it could just be that your particular body is on one end of the tolerances and your lens on the other, and that particular combo is out enough to make a visible difference.

    The best solution is to send your body(bodies) and lens (lenses) to someone like DAG or to Leica to have them matched. And then keep your eye on things to make sure they don't change.
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    Member JimBuchanan's Avatar
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    Re: 50mm Summilux front focusing

    Quote Originally Posted by panda81 View Post
    Hi everyone,

    I'm pretty new to rangefinders, so this is a bit of an confounding situation for me. I think my 50mm Summilux ASPH is front focusing - I also have a 35mm lens, and it appears to work fine on the same camera body.

    Has anyone had this type of adjustment made before? What's the best way to go about doing this?

    Thanks in advance!
    Unlile the other replies, I will try to help you determine the state of your lens.

    If the infinity stop of the lens is off, your close focusing will be off. To start, take wide open infinity shots of geometric shapes like telephone poles several miles away. This will tell you if your lens is giving you a true infinity focus. Pixel peep at 100%, back the focus ring off a slight amount and repeat.

    If you decide the infinity focus stop/position is giving a good infinity shot, then test the 50/1.4 for focus shift. Most Leica lenses have it. This is the angled ruler shot at about 1 meter, on a tripod. Compare 1.4, 2.0, 2.8 shots and see if the mid-focus point moves back to quickly. It is common for faster M lenses to front focus, wide open, and zero in on the focus point at 1-2 stops down.

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    Re: 50mm Summilux front focusing

    thanks everyone for your help and responses.

    just in case anyone is interested, it turns out the lens was performing great, but rather my brand new M9 isn't focusing correctly. so now it's off to allendale for inspection and servicing...

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    Subscriber Member jaapv's Avatar
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    Re: 50mm Summilux front focusing

    Quote Originally Posted by JimBuchanan View Post
    Unlile the other replies, I will try to help you determine the state of your lens.

    If the infinity stop of the lens is off, your close focusing will be off. To start, take wide open infinity shots of geometric shapes like telephone poles several miles away. This will tell you if your lens is giving you a true infinity focus. Pixel peep at 100%, back the focus ring off a slight amount and repeat.

    If you decide the infinity focus stop/position is giving a good infinity shot, then test the 50/1.4 for focus shift. Most Leica lenses have it. This is the angled ruler shot at about 1 meter, on a tripod. Compare 1.4, 2.0, 2.8 shots and see if the mid-focus point moves back to quickly. It is common for faster M lenses to front focus, wide open, and zero in on the focus point at 1-2 stops down.
    The 50 Summilux asph has no focus shift. That is what aspherics and floating elements are for.
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    Member JimBuchanan's Avatar
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    Re: 50mm Summilux front focusing

    Quote Originally Posted by jaapv View Post
    The 50 Summilux asph has no focus shift. That is what aspherics and floating elements are for.
    I stand corrected, as I got distracted with my reply and forgot the subject lens is the 50 Summilux asph. I hope to acquire the 75 cron, which I expect to be likewise in this quality.
    Last edited by JimBuchanan; 24th March 2010 at 16:31.

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    Re: 50mm Summilux front focusing

    Some snaps from my favorite 50 - the 50 lux pre-asph E43, from the local museum, all at 1.4 here
    My Photography Blog here

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    wilsonlaidlaw
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    Re: 50mm Summilux front focusing

    I think it helps if we define what we all mean by back and front focusing. When I was at university, I did camera and lens testing as my dissertation. My tutor was very insistent that back and front focus applied to the image and not the object. In other words, if the theoretical perfect focus image was in front of the film, that was front focus. That would mean that as far as the photographed object is concerned, front focus would mean that the field nearer the lens than the object would be more in focus. Back focus means that the field further away from the object would be more in focus. However I suspect many people use the terms the other way round.

    Wilson

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: 50mm Summilux front focusing

    Or put another way:

    Front focus - you think you've focused on the eye but the tip of the nose is sharp.
    Back focus - you think you've focused on the eye but the ears are sharp.

  12. #12
    wilsonlaidlaw
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    Re: 50mm Summilux front focusing

    Quote Originally Posted by GrahamWelland View Post
    Or put another way:

    Front focus - you think you've focused on the eye but the tip of the nose is sharp.
    Back focus - you think you've focused on the eye but the ears are sharp.
    Graham,

    Exactly but a load of folks on the Leica Camera Forum, insist it is the other way round. Does not help when you are trying to discuss remedies like adding or subtracting mount shims - "I did what you said but it made my lens worse" etc.

    Wilson

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: 50mm Summilux front focusing

    Quote Originally Posted by wilsonlaidlaw View Post
    Graham,

    Exactly but a load of folks on the Leica Camera Forum, insist it is the other way round. Does not help when you are trying to discuss remedies like adding or subtracting mount shims - "I did what you said but it made my lens worse" etc.

    Wilson
    Can't help people not knowing their a## from their elbow Maybe I'm being unkind and they are thinking of a "different" front/back focus than the rest of the photographic world. I've never seen it defined in any other way and even the folks selling front/back measuring aids refer and document it exactly as we understand it.

    Do you have an example of the confusion?

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    Re: 50mm Summilux front focusing

    funny this discussion is still going on!

    there was no question what i observed was front focusing (i know my anatomy! ) but i was completely wrong in jumping to the conclusion that it was lens - turns out the reason was that the rangefinder was not aligned properly. i sent the m9 to allendale and when it came back, all my lenses were focusing spot on.
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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: 50mm Summilux front focusing

    This kind of morphed from your issue Jerry to a discussion of what is & isn't front/back focus. I suspect you do indeed know your anatomy

    With the RF it doesn't really matter which is off, the rangefinder or the lens because either will result in shots that are off. Now the real trick is trying to fix things when you don't know which is out of alignment - lens, rangefinder or even both (very frustrating). That's why I'm a vociferous supporter of getting everything calibrated together - DAG worked wonders for my system.

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