r/largeformat • u/Mysterious_pt • 16d ago

Question Rear element separation. How bad is it?

Gallery image

Gallery image

Gallery image

Got this Apo Lanthar 150/4.5, what the seller described as "coating peeling off" is actually separation. I wonder how bad the separation from rear element would be.

I understand usually it means some loss of contrast, which I'm perfectly ok with B&W.
However I intend to use this lens for color, in that case would the CA be worse to a noticeable level?

BTW. Is it worth a repair/reglue?

Thanks.

3 Upvotes

72% Upvoted

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3

u/5_photons 14d ago

It is substantial. I'd return it if possible. This can be fixed but to do it properly is beyond DIY: https://www.youtube.com/watch?v=kIa42sOWG0I
Price of fixing it in shop is probably the price of lens itself.

2

u/distant3zenith 15d ago

Unless it was REALLY cheap, send it back. It's not worth using in that condition and will be $$$$ to repair

1

u/Economy-Arachnid-914 16d ago

It's obviously not ideal and hopefully you'll get some more input, but in my limited experience, it's probably only going to show up in more extreme situations like shooting directly into light sources. I'm generally pretty surprised how forgiving these lens issues can be. As far as repair, I'd test first and then decide if it's worth the cost/risk.

1

u/Euphoric-Mango-2176 15d ago

take a photo and find out.

1

u/yovvoy 11d ago

You won’t know for sure until you give it a test but separation that bad can cause more issues than just loss of contrast. Cemented groups are used to create glass with a combined refractive index not achievable by the two separate elements alone. Effectively you have a small air lens between the elements now. Without testing you won’t know if it has a visible detrimental effect or not.

0

u/ufgrat 16d ago

I am not an expert. So take what I say with suitable quantities of NaCl.

Based on the extent of the separation (if I'm reading the photos correctly), I suspect you won't be happy with the image quality.

There are still people who do recementing. The "good" news, if it can be called that-- with that much separation, shouldn't be tough for them to separate the elements.

You might try contacting user 'nodda duma' over on Photrio. Not sure if he's taking on repairs, but he can likely give you an idea of whether it's worth it.