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Thread: Will recoating a lens degrade its performance?

  1. #1

    Will recoating a lens degrade its performance?

    Hi All,

    I know the following is not large format, but I figure large format people have the most experience on the subject so I hope ya'll don't mind;

    I have a Rolleiflex 2.8E3 in near-new condition except for a blemish on the rear lens element of the taking lens about 4mm in diameter. I have had the lens cleaned and inspected by a highly regarded camera repair person. The blemish is more that just dirt, and is some form of damage to the lens surface.

    I know the common widsom is that a small blemish does not affect image quality. However, such blemishes do dramatically affect resale value, and I would like to restore the lens of this nice example of one of the rarer Rolleiflex's to compliment the rest of the camera's condition.

    I am considering having the lens coating removed and reapplied by Focal Point in Colorado to remove the blemish. I have alwyas heard that Focal Point has a very good reputation when it comes to such repairs, and the people at Focal Point have assured me that a recoating would not degrade the lens' performance.

    In contrast to Focal Point's comments, I have read a few posts about how removing and reapplying a lens coating will change the lens surface geometry enough to have a negative impact on images produced by the lens. However, most of the comments seemed to based more on theory and less on actual experience with such a procedure performed by Focal Point.

    I assume that Focal Point's good reputation is well-earned and they do high quality work. In other words, I am not concerned about the obvious ill effects of a poor recoating job.

    Does anyone have personal experience, or know of someone with personal experience in having a lens element recoated? Good results? Bad results? Will a carefully recoated lens perform as new, or worse?

    Thanks.

    --Randall

  2. #2

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    Will recoating a lens degrade its performance?

    Will recoating destroy the value to a collector?

  3. #3
    Moderator Ralph Barker's Avatar
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    Will recoating a lens degrade its performance?

    I have no experience with having lenses recoated, Randall, but I'd offer these thoughts. First, I'm not sure that lens recoating, even if done well, will add to the "collectable" resale value of a classic camera. Part of the lens' original "character" may well come from the materials used in the original coating. So, even if the recoated lens performs well, it may perform differently - a critical point for those who might be interested in the camera. Plus, you'd still be morally obligated to disclose both the blemish and the recoating.

  4. #4

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    Will recoating a lens degrade its performance?

    Randall: As the people at Focal Point will tell you, if the "blemish" is so deep that you would have to grind off (polish off) too much to net it out, then the lens formula and performance is going to be affected. I assume from your post that this is more than a defect in the existing coating. This is damage not easily done to the inside of the fixed lens on this camera. I have used Focal Point for lens recementing and once did have them polish and recoat the front element of a 14" Ektar. The existing coating was so badly marred by "cleaning marks" (careless dry cleaning) that it did fuzz up highlights and this was noticeable on film. The lens came back looking like that front surface was brand new out of the box. The issue I had with the lens was gone and it was plenty sharp afterwards. If this isn't a user camera, and it is just going to be looked at and collected, I do wonder if this type of expensive repair is worth it, but that is your call.

  5. #5

    Will recoating a lens degrade its performance?

    Does the E3 have any specific collector value above and beyond being a Rolleiflex?

  6. #6

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    Will recoating a lens degrade its performance?

    Hi Randal, Is it terribly expensive to have a lens recoated? I have an old WF Ektar that has many cleaning marks and would consider having it recoated if it wasn't an arm and a leg. How can you get in touch with Focal Point? I did a quick Google and couldn't find any info on the net. Thanks, Robert

  7. #7

    Will recoating a lens degrade its performance?

    Everyone, thanks for the replies.

    The Rolleiflex 2.8E3 TLR is one of the rarer versions of the famous TLR, but I would hesitate to say that it is purely a collector model. Furthermore, my interests in the camera is more as a user camera. Thus, I want the best possible performance from the lens. I mention the rarity of the camera simply to convey that the camera is valuable, difficult to replace, and worth fixing if possible.

    Just so its clear, I am looking to remove the old coating and apply a new lens coat, only. Any damage not fixed by a recoat will be left, since I think it is impossible to remove a scratch in the lens and reconfigure the lens surface to its original geometry. I think a substantial portion of the damage is in the coating, and so a new coating would improve things, if not resolve all the damage. My question is directed to whether only removing the old coating and recoating would affect the lens surface geometry enough to have a visible affect on images produced by the lens.

    A little more to the situation:

    The lens on the camera is a Schneider Xenotar 80mm, f-2.8. For those unfamiliar with Rolleiflexes, the Xenotar (and its Zeiss Planar equivalent also found on Rolleiflexes) is an outstanding lens. The Xenotar/Planar produces images which are virtually indistinguishable from a modern Zeiss Planar for a Hasselblad. Thus, the expectations for my Xenotar's performance are high.

    Additionally, I acquired the camera as part of a set of 2.8E3's. The second Rolleiflex is 10 serial numbers apart and has lenses in good condition. Both cameras were purchased at the same time at the same store by the original owner. The images produced by this undamaged Rolleiflex are truly outstanding with excellant sharpness and contrast. (It is hard to tell, but the damaged Rolleiflex appears to my eye to show a little less contrast in some situations).

    That the camera is part of an unofficial set complicates things for me because I want to preserve the set. But, I also want to be sure that the cameras I am using are performing as best as possible.

    If I have doubts about whether a recoating will degrade performance, I won't do it. However, I think this Rolleiflex set is somewhat unique, and I would like to restore the "set" to the best condition I can.

    Thanks for everyone's input.

    --Randall

  8. #8

    Will recoating a lens degrade its performance?

    BTW:
    Focal Point is at www.focalpointlens.com.

    It is about $200 to de-cement, recoat, and reassemble the rear doublet on a Xenotar. More complex doublets cost more to de-cement, etc.

    --Randall

  9. #9

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    Will recoating a lens degrade its performance?

    If it just recoating, then it certainly isn't going to degrade the performance of the lens. If you have one camera that is fine and one with this blemish, shoot them side by side and see if there is any difference at all. With just a coating mark, there is a good chance their performance will be equal. If this issue is going to haunt you or cause you not to use, I have full confidence in Focal Point and they will serve you well.

  10. #10

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    Will recoating a lens degrade its performance?

    You can not just slap any generic coating on a lens. The coating is designed to work specifically with a particular lens. Coatings on different lenses are different depending on the lens. I suspent that Focal Point should know this if they are coating lenses but you should check first. I tried to have a coating put on a lens in Rochester and was told this by the lens technicians.

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