This is an image of a back focal plane of a 40x phase contrast objective (Zeiss Neofluar 0.75) that I received recently. As you can see, there is a gray smudge in a top right corner. Could it be a sign of a progressing delamination? So far, it doesn't bother me, because it is always covered by an aperture diaphragm (or a phase annulus), but I was just wondering.
Objective - possible delamination problem?
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- twebster
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Hi ya' Piotr
Yup, that's delamination. Will it progress? Probably not. I have it on good authority (Spike Walker) that delamination doesn't progress without a good reason, such as overheating the objective. I doubt that you can do that with your Zeiss Standard. According to Spike's website (the Ultraphot website) most delamination was caused by over-heating objectives with overly intense microscope lamps used in making videos or by some workers turning the microscope on and leaving it on all day If the image looks OK I wouldn't worry about it. Heck, my 16x Neofluar ph2 has more delamination than that and the images are fine.
Best regards as always, my friend
Yup, that's delamination. Will it progress? Probably not. I have it on good authority (Spike Walker) that delamination doesn't progress without a good reason, such as overheating the objective. I doubt that you can do that with your Zeiss Standard. According to Spike's website (the Ultraphot website) most delamination was caused by over-heating objectives with overly intense microscope lamps used in making videos or by some workers turning the microscope on and leaving it on all day If the image looks OK I wouldn't worry about it. Heck, my 16x Neofluar ph2 has more delamination than that and the images are fine.
Best regards as always, my friend
Tom Webster
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!
Thanks a lot, Tom! My first delamination. I begin to feel like a Zeiss expert
I'm using fibre optic illuminator (thans to Ron!), so excessive heat is not a big concern.
I have some problems with this objective. It is not parcentric nor parfocal with others, although the differences are not huge. And its contrast is not as good as I expeced from a neofluar. My 25x/0.65 seems to have a bit better contrast. On the other hand, this one gives a very nice phase picture. I need to test it more.
I'm using fibre optic illuminator (thans to Ron!), so excessive heat is not a big concern.
I have some problems with this objective. It is not parcentric nor parfocal with others, although the differences are not huge. And its contrast is not as good as I expeced from a neofluar. My 25x/0.65 seems to have a bit better contrast. On the other hand, this one gives a very nice phase picture. I need to test it more.
Piotr
- twebster
- Site Admin
- Posts: 1518
- Joined: Mon Apr 19, 2004 10:55 pm
- Location: Phoenix "Valley of the Sun", Arizona, USA
Hi ya' Piotr
I have a 40x Zeiss ph2 achromatic that is not concentric with the other objectives, too. It doesn't appear to affect the images, though. I have a 40x Zeiss Neofluar non-ohase objective and the 16x Neofluar ph2 objective. The 40x seems to have slightly better contrast than the 16x. I think the phase ring lowers contrast a tad. I find a slight tweak in Photoshop cures that.
Best regards,
PS. If you are really concerned that the 40x phase objective is defective, I'll be glad to take it off your hands for $50.00
I have a 40x Zeiss ph2 achromatic that is not concentric with the other objectives, too. It doesn't appear to affect the images, though. I have a 40x Zeiss Neofluar non-ohase objective and the 16x Neofluar ph2 objective. The 40x seems to have slightly better contrast than the 16x. I think the phase ring lowers contrast a tad. I find a slight tweak in Photoshop cures that.
Best regards,
PS. If you are really concerned that the 40x phase objective is defective, I'll be glad to take it off your hands for $50.00
Tom Webster
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!
Administrator
Phoenix "The Valley of the Sun", Arizona, USA
Think about this...maybe Murphy is an optimist!!!