Dear Duncan,
Thank you very much for the objective. I have already sent it back to you,
so you should receive it today. Although I haven't been able to find out what
causes the problem, at least I am now sure that it is the objective. Your
objective doesn't show the effect, or at least it is not very marked. In fact
you can see a very dim halo, but not as marked as with ours. Funny enough,
appart from that halo, our objective seems to produce a better image than
yours!
As I said, I am still not sure about the cause. Moreover, I still don't know
whether the immersion oil can get into the objective or not! Olympus (UK) told
me that that shouldn't happen unless a rubber seal is broken (eventually due
to excessive pressure while focusing).
The other important question is whether it is really affecting our images
(I mean, when these are real specimens, not just point sources) which, at the
end of the day, it's what matters. I think I'll try to contact P. Shaw who's
got a lot of experience with point sources. The other possibility is to stain
microtubules (that's quite straightforward to me) an compare two orthogonal
images to see if there's any directional distortion. The big problem is... our
system is not working: the scancard is dead and our grant is finished so we
can't afford the new one... Let's hope that some of the applications succeed
and we can get it back to work!
 
Besides, I am very grateful and surprised for the copy of the Light microscopy
book that you sent me. I am quite happy that you found it of some use and I
must say that the Bio-Rad logo looks very nice indeed! If I had known in
advance I would have surely expanded some sections (at least the confocal one)
As you probably imagine, it started as "can't say no to Dave Rickwood..." ;-)
Anyway, I would appreciate any comments that you may have about the book.
 
Thank you very much for your help.
 
Regards
 
Carlos