Even DF illumination for 4x objective
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Even DF illumination for 4x objective
Anyone got any advice on how to get great DF on a 4X objective that evenly illuminates the whole field? I have a Nikon Optiphot, but I have heard that some Olympus condensers are easy to adapt to the Nikon dovetail for the substage condenser, and that the olympus condensers have a filter tray for a DF patch stop. Any thoughts?
Re: Even DF illumination for 4x objective
The Olympus condenser dovetail is slightly bigger than the Nikon one. It is definitely possible to use Nikon condensers on Olympus microscopes; I used a Nikon dark-ground condenser on my BH-2 until I found a cheap Olympus one. It may not be possible to use Olympus condensers on Nikon microscopes, I have not tried.
Nikon condensers are usually cheaper than Olympus ones.
Olympus say that their dark-ground condensers are for 10-40× (BH2-DCD) and 10-100× (BH2-DCW).
Olympus condensers for the BH-2 and BX do NOT have a filter tray.
On the rare occasions that I want 4× dark-ground, I use my CK2 inverted microscope with the 40× phase annulus.
Alan Wood
Nikon condensers are usually cheaper than Olympus ones.
Olympus say that their dark-ground condensers are for 10-40× (BH2-DCD) and 10-100× (BH2-DCW).
Olympus condensers for the BH-2 and BX do NOT have a filter tray.
On the rare occasions that I want 4× dark-ground, I use my CK2 inverted microscope with the 40× phase annulus.
Alan Wood
Re: Even DF illumination for 4x objective
Which Nikon series condensers fit, Alan?Alan Wood wrote: ↑Fri Feb 05, 2021 3:09 amThe Olympus condenser dovetail is slightly bigger than the Nikon one. It is definitely possible to use Nikon condensers on Olympus microscopes; I used a Nikon dark-ground condenser on my BH-2 until I found a cheap Olympus one. It may not be possible to use Olympus condensers on Nikon microscopes, I have not tried.
Thanks, John
Re: Even DF illumination for 4x objective
DF with a 4X usually is easy, you don't need a dedicated DF condenser if you can place a stop at the right position in an ordinary BF condenser of using a Phase Contrast ring for higher NA objectives as Alan does.
Dedicated DF condensers are designed for high NA objectives where DF stops on BF condensers provide bad results or even when DF is just impossible with them, but its illuminated field can be too small for a 4X
You can also get good DF even without condenser with a ring light in place of it or laterally illuminating the slide.
Dedicated DF condensers are designed for high NA objectives where DF stops on BF condensers provide bad results or even when DF is just impossible with them, but its illuminated field can be too small for a 4X
You can also get good DF even without condenser with a ring light in place of it or laterally illuminating the slide.
Pau
Re: Even DF illumination for 4x objective
If you have Phase contrast a PH3 or PH2 ring should also provide DF on 4x.
Re: Even DF illumination for 4x objective
John
I do not have a Nikon catalogue that shows their condensers with a circular dovetail fitting, so I do not know exactly which dark-ground condenser I had.
I still have a Nikon Achromat NA 0.85 condenser that fits my BH-2, but I don't know its model name or code. It is taller than Olympus condensers, and can push up the slide if I am not careful.
I guess most Nikon condensers would fit the Olympus dovetail. Large ones like phase contrast and DIC might not fit.
Alan Wood
Re: Even DF illumination for 4x objective
I found a $30 adapter that might let me fit an Olympus condenser onto my optiphot. It's in the post so i'll let you know if it works (although I don't have an Olympus condenser yet, either). I have read that the Olympus Aplanat Achromat condenser can have the top lens unscrewed and patch stop placed for DF and there are Olympus Aplanats available for $300 on Ebay. Is it possible to unscrew the top element of a Nikon Aplanat? - also, the only Nikon Aplanat condenser listed on Ebay is $800!Alan Wood wrote: ↑Fri Feb 05, 2021 3:09 amThe Olympus condenser dovetail is slightly bigger than the Nikon one. It is definitely possible to use Nikon condensers on Olympus microscopes; I used a Nikon dark-ground condenser on my BH-2 until I found a cheap Olympus one. It may not be possible to use Olympus condensers on Nikon microscopes, I have not tried.
Nikon condensers are usually cheaper than Olympus ones.
Olympus say that their dark-ground condensers are for 10-40× (BH2-DCD) and 10-100× (BH2-DCW).
Olympus condensers for the BH-2 and BX do NOT have a filter tray.
On the rare occasions that I want 4× dark-ground, I use my CK2 inverted microscope with the 40× phase annulus.
Alan Wood
Further, there are vintage Olympus Aplanat condensers that have very large top elements, so they may accommodate 4X DF without the need to remove top element.
Re: Even DF illumination for 4x objective
I have a PC turret condenser, but it does not cover 4XPau wrote: ↑Fri Feb 05, 2021 4:04 amDF with a 4X usually is easy, you don't need a dedicated DF condenser if you can place a stop at the right position in an ordinary BF condenser of using a Phase Contrast ring for higher NA objectives as Alan does.
Dedicated DF condensers are designed for high NA objectives where DF stops on BF condensers provide bad results or even when DF is just impossible with them, but its illuminated field can be too small for a 4X
You can also get good DF even without condenser with a ring light in place of it or laterally illuminating the slide.
Several people have told me about these illusive ring lights, but I'm failing to find any on ebay. Also, I would be concerned with LED ring lights for several reasons: 1 - They would pick up too many marks and scratches on slide and coverslips for good DF. 2 - Cheap LEDs are never worth the money. I would need a CRI of at least 85 because I want to shoot video and have accurate colors. 3 - Cheap LED often cause flickering or banding in video. 4. I have a fiber ring light designed for stereo microscopes so is far too big for my compound microscope stage. I think this combination of requirements makes the "right" LED ring light as rare as rocking horse poop
Re: Even DF illumination for 4x objective
Can you remove the condenser upper lens?I have a PC turret condenser, but it does not cover 4X
With my Zeiss condensers it is needed anyway for 4X and less. Some models allow to switch it out and others to unscrew it.
Abbe condensers usually cover the 4X with the upper lens although with some models is still convenient to remove it for low power while others don't allot it at all
Pau
Re: Even DF illumination for 4x objective
Yeah, I can remove the condenser lens, but that is the only glass part of the whole thing - then it would just be the patch stop and the field lens for illumination. I will try itPau wrote: ↑Fri Feb 05, 2021 11:51 amCan you remove the condenser upper lens?I have a PC turret condenser, but it does not cover 4X
With my Zeiss condensers it is needed anyway for 4X and less. Some models allow to switch it out and others to unscrew it.
Abbe condensers usually cover the 4X with the upper lens although with some models is still convenient to remove it for low power while others don't allot it at all
Re: Even DF illumination for 4x objective
There is extra lens (do not remember part #), which has to placed into the condenser's light entrance. I had the same problem with low magnificationmrlowndes wrote: ↑Thu Feb 04, 2021 9:02 pmAnyone got any advice on how to get great DF on a 4X objective that evenly illuminates the whole field? I have a Nikon Optiphot, but I have heard that some Olympus condensers are easy to adapt to the Nikon dovetail for the substage condenser, and that the olympus condensers have a filter tray for a DF patch stop. Any thoughts?
Saul
μ-stuff
μ-stuff
Re: Even DF illumination for 4x objective
Thanks - would be great to know what this is called so I can search for itSaul wrote: ↑Fri Feb 05, 2021 1:58 pmThere is extra lens (do not remember part #), which has to placed into the condenser's light entrance. I had the same problem with low magnificationmrlowndes wrote: ↑Thu Feb 04, 2021 9:02 pmAnyone got any advice on how to get great DF on a 4X objective that evenly illuminates the whole field? I have a Nikon Optiphot, but I have heard that some Olympus condensers are easy to adapt to the Nikon dovetail for the substage condenser, and that the olympus condensers have a filter tray for a DF patch stop. Any thoughts?
IMG_2130-web685x950U100-G14.jpg
Re: Even DF illumination for 4x objective
Aha! C-CEL expander lensmrlowndes wrote: ↑Fri Feb 05, 2021 2:28 pmThanks - would be great to know what this is called so I can search for itSaul wrote: ↑Fri Feb 05, 2021 1:58 pmThere is extra lens (do not remember part #), which has to placed into the condenser's light entrance. I had the same problem with low magnificationmrlowndes wrote: ↑Thu Feb 04, 2021 9:02 pmAnyone got any advice on how to get great DF on a 4X objective that evenly illuminates the whole field? I have a Nikon Optiphot, but I have heard that some Olympus condensers are easy to adapt to the Nikon dovetail for the substage condenser, and that the olympus condensers have a filter tray for a DF patch stop. Any thoughts?
IMG_2130-web685x950U100-G14.jpg
Re: Even DF illumination for 4x objective
Re: Even DF illumination for 4x objective
Found my old link - https://www.photomacrography.net/forum/ ... 98#p250598Aha! C-CEL expander lens...
.................
oh no that's not it
But no part number ...
Saul
μ-stuff
μ-stuff