B&L Balplan Pol Adapter

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microb
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B&L Balplan Pol Adapter

#1 Post by microb » Tue Jun 30, 2020 7:14 am

Hi,

I got one of these 15mm tall pol adapters that fit (in a Blaplan catalog) right under the head.

But there are no optics like the DIC adapter has. So doesn't this extra distance mess things up since this is not an infinity system with a lens tube in the head.

Thanks,
Ted
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apochronaut
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Re: B&L Balplan Pol Adapter

#2 Post by apochronaut » Tue Jun 30, 2020 11:50 am

No. See the snswer in the active Balplan thread.......I came to this post after.

microb
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Re: B&L Balplan Pol Adapter

#3 Post by microb » Tue Jun 30, 2020 3:05 pm

apochronaut wrote:
Tue Jun 30, 2020 11:50 am
No. See the snswer in the active Balplan thread.......I came to this post after.
Sorry for all the links below, but I'm trying to summarize and figure out where the focusing is being done.

So is it true that if an epi were installed, the same objectives would work? These objectives do not actually state anything about the tube lens (TL) like other ones that have an infinity symbol or 160mm or 215mm. So I guess I made a mistake buying a 215mm marked objective with plans to use it with an Balplan epi set-up, but I guess that 215mm is for some other series.

As mentioned in the linked references below, wporter says that he did not use a relay lens in the objective to camera path. So where is the tube lens in that case? I thought the lens in the objective turret was to compensate for the extra turret length like a BH2 reverse mount turret has a lens for. And I thought the above and below optics in the DIC was to compensate for that adapter's thickness. But then again I thought a 215mm would be needed to work on the epi.

BACKGROUND REFERENCE LINKS
So the DIC adapter which wporter shows here(viewtopic.php?f=5&t=9731#p82952) and I showed here (viewtopic.php?f=5&t=7327#p64518) has optics above and below the prism. So I assumed that with an epi the objectives marked 215mm had to be used to account for the epi's height and the when the DIC is added, it's above and below lenses made it fit into the reflective light path.

You posted here (viewtopic.php?f=5&t=3712&start=60#p83173) saying it is a split optics system with a light path that acts like an infinity path , but wporter here (viewtopic.php?f=5&t=9731&p=83176#p82958) states that for pictures he just hooked a camera's sensor with no relay lens.

As I found out here (viewtopic.php?f=5&t=3712&start=30#p82075) there is a doublet in the objective holder. So I thought that would be like the lens in the BH2 reverse objective holder.

apochronaut
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Re: B&L Balplan Pol Adapter

#4 Post by apochronaut » Tue Jun 30, 2020 4:30 pm

You have to look at the Balplan as an infinity corrected system.
The Balplan uses 5X, 10X, 20X and 40X epi semi-objectives with an unspecified tube length on them. The 2.5X and the 100X that are specified in the same system appear to be the same objectives used in the diascopic Balplan. I would assume that the 4X,10X,20X,40X and 50X diascopic objectives may work therefore too but probably not as wel as dedicated epi objectives with annular illumination..

The DIC unit Bill has, used to be mine but I have no experience of using one. I always assumed that the lenses fore and aft of the prism were to adjust for the requirements of the individual objectives, since most systems use different prisms for different objectives. There should be no need for any optical compensation for tube length since the system is infinity at that point.

Bill's image capture system is above the telan lens, which is inside the Balplan head. The fact that he did not use a camera relay lens is normal because the Balplan has fully corrected optics by the time the eyepieces pick up the image, or in his case the sensor.

The doublet in the objective holder is a common back element for the semi-objectives, essentially making the parfocal distance of the entire objective system about 60mm.

I have used a newer B & L epi met 80X .90 flat field fluorite objective marked 215mm on it in a Balplan and it seemed perfectly happy. 5X flat field achromats from the same system were much less happy. It is typical for low power objectives to be more sensitive to tube length changes.

I do not know what microscope the epi met objectives came from. They have a 24mm thread and likely came from a Balplan era metallograph. I bought a 24M to R.M.S. adapter for that 80X Flat Field fluorite.

microb
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Re: B&L Balplan Pol Adapter

#5 Post by microb » Tue Jun 30, 2020 7:00 pm

apochronaut wrote:
Tue Jun 30, 2020 4:30 pm
Bill's image capture system is above the telan lens, which is inside the Balplan head. The fact that he did not use a camera relay lens is normal because the Balplan has fully corrected optics by the time the eyepieces pick up the image, or in his case the sensor.
Thanks!

So the head does have a lens in it. I had thought that it didn't as I kept thinking this was somehow a 160mm set-up based on the DIC having lenses. So that answers my questions.

I take it there are corrections in the head being done by the telan lens making it so I couldn't just take the head off and replace it with a single port configuration based on an Edmund Optics tube lens and not get chromatic aberrations.

Maybe I can use an eye piece camera for testing as I don't have the trinocular head.

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Re: B&L Balplan Pol Adapter

#6 Post by wporter » Tue Jun 30, 2020 8:57 pm

OK, here's a big apology to all from me, I screwed up. I ran some more tests this morning on camera attachment methods to the Balplan, and found that shooting through the naked trino opening with a naked camera is not as good (at all) as through the naked eyepiece port using a 23mm eyepiece adapter on the naked camera. I had said it was, in the DIC thread comment, and for that error I apologize. The reason it is not as good, is that (taking my trino head apart this morning) the telan lens is, on the trino head at least, attached to the eyepiece prisms assembly, and after the trino/bino moving-switchover-prism. So in trino-port mode, there no optics in between the head entrance and the trinoport exit. This is why that image was not great, but I mistakingly thought it was with a brief look (I was looking at the camera-back screen, instead of running a cable over to my usual HDTV). Failing geezer eyesight. OK, Boomer.

So if you don't have a trino head, I wouldn't bother getting one. What would it do for you? It is made for that B&L camera adapter, which wasn't sharp, for some reason that I have yet to discover (it could be that it is made for a 4x5 or other camera attachment, and may be in focus when using them.) Plus they are rare. So I would also stick with the 23mm eyepiece tube adapter or an eyepiece cam.

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Re: B&L Balplan Pol Adapter

#7 Post by apochronaut » Tue Jun 30, 2020 10:18 pm

B & L made a photo tube with a dedicated relay lens and one that took a photo eyepiece. They look very much like the AO photo tube.
I'm surprised at your information regarding the telan lens. Obviously, they must have incorporated whatever needed corrections there were into the photo relay lens, then.

It is anybody's guess as to what level of corrections leave the common lens.

Your results , photographing through the Balplan photo coupler must be due to the model of photo coupler. There were 3. 35mm,. 3 1/4 x 4 1/4 polaroid. and 4 x 5 sheet film or equivalent polaroid back. As you surmise, probably a lens designed for a large format would not be great for a much smaller sensor. The photo tube, similar to the AO system, would probably be a solution to setting up a digital system with a smaller sensor.

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Re: B&L Balplan Pol Adapter

#8 Post by wporter » Wed Jul 01, 2020 3:55 am

Here are two of the B&L photo tubes (relay lens, shutter) mentioned by Apo, along with a 4x5 sheet film cone. This cone is made for the tube on the right. The tube on the left is the more modern one, and is shown with an adapter sleeve for who-knows-what. The more modern tube's small black end is loose in the Balplan trino head, so obviously is missing a sleeve similar to the one shown, but made to mate with the trino port. Yet another project. When I get a 4x5 back made up for the cone, I will shoot some 4x5 film, and shame you all into admitting that large-format is still king, all of you early-adopters, with your fancy new-fangled digital cameras, HA!

Also shown is page 42 from the 1981 Bausch & Lomb Industrial Optical Aids Buyers Guide.

balplan camera tubes and 4x5 cone-1024x1024.jpg
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balplan photomicrography page 1981-1024x1024.jpg
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Re: B&L Balplan Pol Adapter

#9 Post by Scarodactyl » Wed Jul 01, 2020 4:03 am

wporter wrote:
Wed Jul 01, 2020 3:55 am
with an adapter sleeve for who-knows-what.
ooh, ooh, I do. it's for the older-style threaded camera port on a stereozoom 7.

I guess a 42-12-30-15 is what's called for, or at least the 3x adapter from one. I imagine it is vanishingly rare, as I've never seen one.
Edit:here's a pm thread about one. Looks like you'd need a mirrorless camera to get the right flange focal distance.
edit 2: helps if I actually paste the link https://www.photomacrography.net/forum/ ... 5ad80a47e1
Last edited by Scarodactyl on Wed Jul 01, 2020 6:12 am, edited 1 time in total.

microb
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Re: B&L Balplan Pol Adapter

#10 Post by microb » Wed Jul 01, 2020 4:49 am

wporter wrote:
Wed Jul 01, 2020 3:55 am
The tube on the left is the more modern one, and is shown with an adapter sleeve for who-knows-what. The more modern tube's small black end is loose in the Balplan trino head, so obviously is missing a sleeve similar to the one shown, but made to mate with the trino port. Yet another project.
So is the one on the left just a tube? No lens inside?

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Re: B&L Balplan Pol Adapter

#11 Post by wporter » Wed Jul 01, 2020 4:51 am

No, it has a big lens on the wider end.

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Re: B&L Balplan Pol Adapter

#12 Post by Scarodactyl » Wed Jul 01, 2020 6:16 am

Incidentally, does anyone know which b&l this one went to?
https://www.ebay.com/itm/Bausch-Lomb-Mi ... SwcdxcBuFl
I assume it isn't to a balplan? But it also doesn't seem to have any lenses to compensate for tube length, and the arm is pretty long.

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Re: B&L Balplan Pol Adapter

#13 Post by apochronaut » Wed Jul 01, 2020 2:16 pm

The camera is Bausch & Lomb but not the arm.

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