Searching for 1.4+ darkfield condenser

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

Moderators: rjlittlefield, ChrisR, Chris S., Pau

JohnyM
Posts: 463
Joined: Tue Dec 24, 2013 7:02 am

Searching for 1.4+ darkfield condenser

Post by JohnyM »

Im struggling to find a darkfield condenser with lower aperture of 1.4 despite of it being quoted in multiple resources. Ie table 2:
http://olympus.magnet.fsu.edu/primer/te ... field.html
I've failed to find any recent or vintage product of cassegrain or bicentric condenser.
I want it to work with 40x/1.3 objective without aperture diaphragm.
Is anyone aware of this type of condenser model?

Pau
Site Admin
Posts: 6052
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

You can't find it just because it is not possible, the maximum NA for DF is 1.00
Pau

Beatsy
Posts: 2105
Joined: Fri Jul 05, 2013 3:10 am
Location: Malvern, UK

Post by Beatsy »

Pau wrote:You can't find it just because it is not possible, the maximum NA for DF is 1.00
...for dry DF condensers, yes. Oil immersion ones go higher (NA 1.3+). Or am I missing something here?

JohnyM
Posts: 463
Joined: Tue Dec 24, 2013 7:02 am

Post by JohnyM »

Pau wrote:You can't find it just because it is not possible, the maximum NA for DF is 1.00
Like Beatsy said, i have few 1,15-1,3 and 1,25-1,4 condensers, am i missing something here?
Looking for mentioned 1,4

Pau
Site Admin
Posts: 6052
Joined: Wed Jan 20, 2010 8:57 am
Location: Valencia, Spain

Post by Pau »

JohnyM wrote: Like Beatsy said, i have few 1,15-1,3 and 1,25-1,4 condensers, am i missing something here?
As you know for sure, the inner aperture of the DF condenser must be smaller than the objective aperture. If you have for example the typical 1.2-1.4 oil DF condenser the objective must be under 1.2, so 1.1 theoretically. I never saw any of to those Cassegrain 1.40-1.50 and Spot Ring (Bicentric) 1.40-1.50 at http://olympus.magnet.fsu.edu in catalogs, brochures, used market..etc

I guess that are no in production and maybe only were experimental or of limited use devices.
There are objectives with NA over 1.5 although not often listed in standard brochures, only used in some advanced flourescence techniques.

Thanks for questioning my too simplified answer, it has obligated me to return to the topic after some years. the physical limit is higher than I supposed.
Pau

JohnyM
Posts: 463
Joined: Tue Dec 24, 2013 7:02 am

Post by JohnyM »

Pau wrote:I never saw any of to those Cassegrain 1.40-1.50 and Spot Ring (Bicentric) 1.40-1.50 at http://olympus.magnet.fsu.edu in catalogs, brochures, used market..etc
Thanks :D

THAT is my problem. Only place where i see it is mentions in literature (multiple times and languages) but never seen one even on photo. I guess i can alway reverse Nikon Apo TIRF 1,49 or similar :lol:

Maybe it's this...
http://www.leitzmuseum.org/Misc-Leitz/O ... 7B%27.html

Post Reply Previous topicNext topic