weirdness on 50mm RB67 lens

[markfitzgerald]

Hi, I'm hoping someone here can give me a quick idea of what is up with my lens. I'm new to shooting, developing and printing B&W and have been playing around with medium and large format for about a year. My previous experience was with 35mm. I purchased an RB67 not too long ago, and wanted to purchase a 50mm lens for it. I saw one on ebay that looked good (it was described as mint, specifically purchased for one photoshoot) and when I received it, it did indeed look good. I've shot a few rolls, and other than it being slightly soft on occasion (which may be me or may be the lens - at this point I'm not sure I've paid enough attention to the floating element) it looks pretty good. My only question has to do with a "ring" or a "halo" I see when I view the lens at a certain angle. I have no idea what it could be - it doesn't look like separation. To my untrained eye, it looks like the antiglare coating was applied but not to the whole lens. I have attached a photo link. I'm wondering if this is normal-ish and nothing to worry about, or if I should look for another specimen of this lens. Thanks for any input, and I apologize if this isn't the best place to post this. I didn't see a forum to discuss equipment, other than antiques.

 

[480sparky]

I can get all sorts of weird reflections in my copy, but I can't get any 'halo' effect. Can you see any evidence of it from the rear?

 

[markfitzgerald]

None that I can see. I can't even see it if I'm looking directly at the lens from the front. I'd say it's something with the back side of the front-most element. It's very apparent when you see it, like in the photo. I'm probably just paranoid.

 

[Trail Images]

I might take a real hard look with some kind of magnifying glass or loop. Years ago I had a 65mm that had fungus growing in it. Mine did show up as a bit of softness in images however. Thankfully the group who I bought it from replaced it immediately with a grade better unit after I sent it in and they reviewed the unit with having the problem too.

 

[480sparky]

I noticed the 'halo' you're referring to is not perfectly round. What happens when you look at it so it's visible then you rotate the lens along the optical axis? Does the halo turn with the lens?

 

[markfitzgerald]

This doesn't appear to be fungus, but that's a good idea..I'll see if magnification helps. It's very odd. I asked the seller whether it was normal or not, and he got really indignant and said there was absolutely nothing wrong with that lens and it was practically brand new and he shouldn't even have sold it, blah blah blah. He offered to buy it back with a 40% "restocking fee" so that gives you an idea on how that conversation went.

 

[markfitzgerald]

I noticed the 'halo' you're referring to is not perfectly round. What happens when you look at it so it's visible then you rotate the lens along the optical axis? Does the halo turn with the lens?

Yes, it appears to move when the entire lens rotates. It doesn't move at all when I adjust the floating element.

 

[gone]

I agree, it doesn't look like separation, but it might be haze. That's all I can think of, and since you mentioned the photos were sometimes soft, that would be my guess based on your one photo here.

40% restocking fee. What a jerk. I would file a paypal claim and force him to take it back w/ no fee, or contact my credit card company and file a claim. If you paid cash, it's yours until you can sell it.

 

[480sparky]

Yes, it appears to move when the entire lens rotates. It doesn't move at all when I adjust the floating element.

Then I'd say there's an issue with it. Maybe haze. Maybe coating separation. Maybe fungus. Might even be fungus etching.

I would think flare or reflections would be round, and not appear to rotate with the lens. I'd be sending it back.

 

[ic-racer]

I'd send it back unless it is a 'project' lens. You don't know if it is just 'haze' that wipes off or fungus damage to the coating (that does NOT wipe off).

Below are before and after pictures of a Fujinon SuperWide 125mm that I was able to salvage. Looks "Mint" from the outside but KEH appropriately listed it as "BGN." The haze wipes off easily, the damage stays. In this case it was worthwhile, but there is residual permanent damage.

 

[flavio81]

If you can send it back, then do it. Otherwise a camera tech can rather easily dissasemble the lens (Mamiya RB lenses are easy to dissasemble) and try cleaning it. If it's haze or dirt it will be restored to "like new". If it's lens separation, then he/she will not be able to repair it, unless he/she knows how to re-cement lens groups.

 

[markfitzgerald]

Thanks everyone, for all the replies. I can't send it back, unfortunately. I'm pretty sure it's not haze or dirt, since it has a bit of that purplish antiglare color to it. If it's separation, there's no hard edges to it, which is what I'm used to seeing in the sample pictures of lens separation that I've googled. I'll look around for someone to maybe take it apart and see what's what. I have a sample picture on my flickr page that was scanned at 1200dpi. This one was pretty sharp, for what it's worth. https://www.flickr.com/photos/30768704@N03/17852928026/in/dateposted-public/

 

[flavio81]

Mark,

It can also be oil or some other liquid that deposited inside.

Also forgot to mention that lens separation is a common problem on Mamiya RB lenses depending on the climate. A shame, really, for otherwise Mamiya-Sekor is a very interesting lens maker.

As for the sample pic, theoretically such a lens defect will not diminish resolution, only contrast.

 

[mesantacruz]

Mark,
I hate to sound like a jerk, but if you said that the halo rotates with the lens, it seems to be an issue with the lens. If the guy said 40% restocking fee, he's trying to discourage a return. in this case, both eBay and PayPal favor the buyer. He has to take it back with no restocking fee. Message him again and let him know, is there something we can do? if not I will contact both paypal and eBay. If he says you have to pay return shipping say no. The item was not listed correctly. Final thing you want to do is contact PayPal and eBay. Yes trying to arm wrestle you into keeping it.

Again I've had my fair share of bad, sneaky sellers. This tactic has always worked out in my favor. If I knowingly purchased something with a known issue or bought as-is... I wouldn't do this.

 

[markfitzgerald]

I'm pretty sure at this point I've had it too long, since it's been a few months since I purchased it, but thanks for the advice. And no, you don't sound like a jerk at all, don't worry about it.

 

[Xmas]

I'm pretty sure at this point I've had it too long, since it's been a few months since I purchased it, but thanks for the advice. And no, you don't sound like a jerk at all, don't worry about it.

Mine a 50 mm C #317xx is similar.

 

[MattKing]

Is there a reason that this is in the "Antiques and Collecting" subforum?

I'm just concerned that my owning one of these lenses makes me an "Antique".

 

[John Koehrer]

The ring's not normal and may be permanent. Or not.
I've got a couple of junkers around the house that have similar marks that are not removable.
It could be residue from condensation being allowed to dry. It can be rock hard.

 

[Xmas]

The ring's not normal and may be permanent. Or not.
I've got a couple of junkers around the house that have similar marks that are not removable.
It could be residue from condensation being allowed to dry. It can be rock hard.

I got mine new in box in 85 - with ring. It is not visible from rear of the lens...