Lens Haze Question

[swandy]

I have someone shipping me two versions of the Olympus Zuiko 50mm f1.4 lens to purchase one of. (For use on an EP2 - currently have an Oly 50mm f1.8 but not happy with the focusing of it.)
One lens has - according to the seller - "very minor hazing on the outer edges of an inner element". Since - based on what he as said about the other aspects of the two lenses - this is the one I would normally prefer, what do I look for in testing the lens? Especially as far as image quality being effected - what types of shots should I take and what should I look for in the shots?

Thanks for any advice,
Steve

 

[sangio]

I have someone shipping me two versions of the Olympus Zuiko 50mm f1.4 lens to purchase one of. (For use on an EP2 - currently have an Oly 50mm f1.8 but not happy with the focusing of it.)
One lens has - according to the seller - "very minor hazing on the outer edges of an inner element". Since - based on what he as said about the other aspects of the two lenses - this is the one I would normally prefer, what do I look for in testing the lens? Especially as far as image quality being effected - what types of shots should I take and what should I look for in the shots?

Thanks for any advice,
Steve

Hi Steve:

I assume you'll be getting the lens at a great price to justify taking a risk with the haze?

Since you'll have two copies of the lens, compare images taken with each one, and also your current lens, under the same conditions. I'd include some shots with a strong light source in the frame to see how that affects the contrast and flaring. I'd also place the light source in different parts of the frame.

I don't know if you can recognize fungus vs haze, but I don't think I could. So, I would also take the lens to someone who knows what they're looking at and make sure that the haze isn't fungus.

regards
Santo

 

[Tullio]

In my experience, haze usually causes softness, blurry blobs on the image. If haze is located close to the center of the lens, it will also affect focusing, specially on cameras that use contrast-based focus. Personally I would not pay a dime for it. There are way too many good lenses being sold on eBay.

 

[swandy]

Thanks guys.
The lens is from an Ebay seller that I have dealt with in the past. (Got a really nice Zuiko 100mm f2.8 from him.) The haze is not in the middle - it is (according to the seller) around the edges of one of the interior elements. And since using these lenses on the m4/3 cameras means manual focus anyways, I don't think it would affect the contrast-based focusing system anyways.
Thanks for responding,
Steve

 

[Abbazz]

I recently bought a Pen Zuiko 42/1.2 lens for cheap, because the lens was listed as "cloudy". I knew that many Pen 42/1.2 lenses had a problem of elements separation in the front doublet and I had also read that elements separation could sometimes be cured by "baking" the lens in order to melt the Canada balsam to recement the separated elements. I first tried to put the lens in my kitchen oven at 120°C for one hour and noticed a small improvement, but not much. So I tried again, this time setting the temperature at 150°C for one hour. All the cloudiness is gone and the lens is now clear as crystal.

Of course, this only works for lenses that suffer from cloudiness due to element separation and not to other causes (fungus, sticky residue, oil from the aperture blades, etc.).

If you want to try it at home, be warned that baking a lens to recement separated elements only works for old lenses cemented with Canada balsam, which can be melted by heating it, and not for modern synthetic cements, which are usually cured by ultraviolet exposure. Always put the lens or lens elements in a cold oven and increase the temperature slowly. When the lens is done, switch off the oven and let the lens cool down inside the oven without opening the door to avoid any thermal shock. If you can, it is better to take out the glass elements needing recementing instead of treating the whole lens. If you have to bake to whole lens, first make sure that there is no plastic part in it and no hybrid element (glass element covered with plastic to give it an aspherical shape). Last but not least, it might not be a good idea to heat a Russian lens with lots of tractor grease on the helicoid...

Cheers!

Abbazz

 

[Amin]

Not for the faint of heart, Abbazz! Also, might not be a bad idea to keep the oven vent fan going during this process :ROTFL:.