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Retrofit Lomo Lumam R1 Fluorescence Microscope (an update)
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WalterD



Joined: 06 Jul 2015
Posts: 361
Location: Rotterdam, the Netherlands

PostPosted: Tue Feb 13, 2018 2:43 pm    Post subject: Reply with quote

Hi all,

Nice you're sharing my enthousiasm.

@Pau: that was a slip of the pen indeed. Very interesting links as well.
There will probably be a certain amount of variation between bandwith of leds, depending on make and type, even though they've got the same colour.
The bandwith of exciter filter may differ as well I guess.

@Fan,
This series of objectives was found in technical reference document from Lomo, see below screenshot. Lomo did make a 20mm adapter for the 9x objective for this microscope, based on this and the parfocal principle the other 3 lengths were calculated:

For 9x - 20mm (original adapter legth); 25.0 (table) + 20.0 (adapter) = 45mm
For 21x - 45.0-14.4 = 30.6mm long adapter
For 40x - 45.0-12.4 = 32.6mm long adapter
For 95x - 45.0-12.5 = 32.5mm long adapter

I must say I did not notice any issues at 40x.

Got lots of Lomo items, e.g. some double objectives I'll pm you later this week. The item you mentioned I do not have.


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zzffnn



Joined: 22 May 2014
Posts: 1682
Location: Texas USA

PostPosted: Tue Feb 13, 2018 5:18 pm    Post subject: Reply with quote

Thank you, Walter.

What does that 25.0 in the LOMO tbale mean?

It cannot be physical length, because parfocal height = objective physical length + working distance. For NA 0.2, working distance should ideally be considered, not ignored, for calculating parfocal height.

I already have almost all the LOMO objectives that I would need. But if you have time, please feel free to PM me your for sale list. No rush at all. Thanks again.
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dolmadis



Joined: 07 Dec 2011
Posts: 477
Location: UK

PostPosted: Sat Feb 17, 2018 12:25 pm    Post subject: Reply with quote

WalterD wrote:
Lomo did make a 20mm adapter for the 9x objective for this microscope, based on this and the parfocal principle the other 3 lengths were calculated:

For 9x - 20mm (original adapter legth); 25.0 (table) + 20.0 (adapter) = 45mm
For 21x - 45.0-14.4 = 30.6mm long adapter
For 40x - 45.0-12.4 = 32.6mm long adapter
For 95x - 45.0-12.5 = 32.5mm long adapter



Are these extenders (as in your first post)

https://www.ebay.com/itm/Set-of-4-extenders-to-make-parfocal-LOMO-EPI-objectives-with-M27x0-75-thread/142380243978?hash=item2126861c0a:g:XkwAAOSwY3BZFMDt

The same lengths as

WalterD wrote:

For 9x - 20mm (original adapter legth); 25.0 (table) + 20.0 (adapter) = 45mm
For 21x - 45.0-14.4 = 30.6mm long adapter
For 40x - 45.0-12.4 = 32.6mm long adapter
For 95x - 45.0-12.5 = 32.5mm long adapter



Thanks


John
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WalterD



Joined: 06 Jul 2015
Posts: 361
Location: Rotterdam, the Netherlands

PostPosted: Sun Feb 18, 2018 12:19 am    Post subject: Reply with quote

Good questions! Not completely sure what the actual highlighted table indicates, however the actual working distance as indicated 1 more table to the left remains the same with these extensions. As said the original 9x extension -from Lomo AFAIK- was used as reference for the rest.
@ John: The ones in the ebay listing are similar. In case of doubt don't hesitate to send an email to Rafael from Raf Camera, he is extremely helpful.

Very Happy
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dolmadis



Joined: 07 Dec 2011
Posts: 477
Location: UK

PostPosted: Sun Feb 18, 2018 2:37 am    Post subject: Reply with quote

Thanks.

Raf says "25.0mm, 35.6mm, 37.5mm, 37.6mm".

BR

John
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WalterD



Joined: 06 Jul 2015
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Location: Rotterdam, the Netherlands

PostPosted: Sun Feb 18, 2018 7:21 am    Post subject: Reply with quote

Okay John,

In that case I would stick to that. Pretty sure the adaptors I've got have the dimensions as mentioned in my previous reply.
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WalterD



Joined: 06 Jul 2015
Posts: 361
Location: Rotterdam, the Netherlands

PostPosted: Sat Mar 17, 2018 1:56 pm    Post subject: Reply with quote

As promised here's a short update.

A couple of weeks ago the Canon EOS 5D MK II was installed, the image from the objective projected directly onto the full frame sensor.
With that setup, recently I took pictures from moss, lichen and a spider, see below threads:
http://www.photomacrography.net/forum/viewtopic.php?t=36705
http://www.photomacrography.net/forum/viewtopic.php?t=36679

The collector lens has been relocated a bit closer to the HBO lamp, which results in a more equal light in the image. This issue popped up when changing over from medium frame to full frame camera.

Yes, I received the filterblocks from the Ukraine as mentioned last month. I've made a comparison between the blocks I already had and the ones just received; the differences are subtle. On the other hand some blocks are an improvement as I had delamination issues on barrier filters. Although obviously from the same factory, also the dichroic mirrors may have small differences as well, comparing the resulting images.

The UV filter block from that set came without the designated barrier filter. That filter looks black and blocksmore or less everything above 400nm. Like Pau mentioned in one of a.m. threads, to be able to take pictures with such a setup, the camera should be able to handle that bandwith. Understood some people actually modify their dslr by ... removing a built in UV filter..?

Indeed there are many options and combinations to experiment with, including alternative barrier filters on the new blocks. As it's almost springtime, a set with different small autofluorescent insects will be interesting too.

Smile
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