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Balsam seperation, lens seperation on 9.5mm Zeiss B Speed


Jeremy Saltry

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Hey all. Just wanted your thoughts. My 9.5mm took a slight drop onto a floor from 2-3 feet up. Nothing too bad but when I put this lens up on a Red 2k crop sensor it seemed to have a much more pronounced creamy or dreamy wide open look than before. I thought this may have just been in my head. 

After inspecting the lens, I noticed that there is some pronounced lens seperation around the edges of the front element. 

I have heard that this can cause a loss of a stop in regards to light transmission. I just was curious if anyone has experienced this before and if it will negatively impact the image. Ive attached two photos for reference. 

 IMG_4297.jp2

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I can't open your images, but separation shouldn't cause a stop of light loss.

Worst case scenario, if a whole doublet separated, you would end up with 2 more glass to air surfaces, which if those glass surfaces were uncoated would result in maybe an 8-10% loss of light transmission, way less than a stop (50%). But separation at the edges only affects a small area of the whole element, so any light loss would be very minimal, and if you stop down it may not affect the image at all. From what I've seen of separation I usually can't tell any difference. 

If you feel like the lens image quality has altered after a drop, it may be due to something else, like an element that has shifted or cocked.

A lens tech familiar with Zeiss Super Speeds could quickly project the lens to assess if it seems out of tolerance.

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