Zeiss GFL compatible objectives?

[jbjoyner]

Hello everyone,
I just purchased a Zeiss GFL as my first microscope. It came with four Zeiss achromatic objectives (2.5x, 10x, 40x, and 100x w/ oil). I am not going to upgrade the objectives yet, but I wanted to ask if anyone knows what brands and models are compatible? The Zeiss objectives from that era include Achro, Plan, Epiplan, Neofluar, and Planapo. The prices seem to vary dramatically so if anyone has a recommendation for a good set, I would appreciate the input!

[BramHuntingNematodes]

The epiplan hd objectives require a special set up, larger threads and different lighting. No problem, the others work well. If I'm not mistaken, all Zeiss objectives from that era were designed to work with compensating eyepieces, so they should be interchangeable. The neofluars are famous for.being decent and cheap. Delamination is freq a problem for Zeiss objectives from yesteryear, so be on the lookout.

Technically any 160 tube length, RMS threaded objectives could work if you also obtained the matching eyepieces. Zeiss lenses would look the best on a Zeiss stand imo.

[jbjoyner]

Thanks Bram,
I will stick with Zeiss optics for now, but I think I have already seen the delamination problem. My binocular head lenses have a sort of spidery effect which I imagine I will have to replace.

[Phill Brown]

It's fungus.
Get some Zeiss coated lens cleaning solution.
Not expensive.
Don't cheap out on IPA.

[jbjoyner]

Phil,
Can you confirm if this is fungus on the lens?

[Phill Brown]

Phil,
Can you confirm if this is fungus on the lens?

Mostly. I can't say for the cloudy patch in the middle but also that doesn't look like delam as I've seen.

Definitely worth getting the Zeiss coated lens cleaning solution anyway.
It will still emove fungus that looks like it's eaten the coating.
Could be delaminated, I don't know if that is a single lens element as is often the case.

[imkap]

Delamination sometimes degrades the image quality noticeably, sometimes not. Therefore delaminated objectives don't need to be rejected before trying out, especially if found cheap.

For photography, eyepieces and objectives need to be matched.
For visual observation, I'm not bothered by a bit of CA and/or distortion...

I've been using Olympus objectives on my GFL, mainly because I found them really cheap. Leitz Wetzlar too. Sometimes odd combinations give good results. I'm not saying you should buy non-matching stuff, but just don't steer away if you found something locally for a bargain price. It should be fun and the image might be good...

Here is a combination of Olympus NFK 2.5 and a 1920s brass Leitz 10x objective.
https://www.youtube.com/watch?v=gjsQwkOya70

And an another, with Olympus Splan 20x and Zeiss KPL10x
https://youtu.be/eZXcrP9l3Q4

Letiz 40x Fluotar worked great, I sold it. I think you can buy Leitz with no problem...

A trusted member (not me) is selling these, I almost bought them, but realized I might have too much stuff already so opted out:
http://www.photomacrography.net/forum/v ... 30&t=45933

[Hobbyst46]

For visual inspection (not photography), Olympus eyepieces like the WF10X and WHK10X work OK with the Zeiss west objectives. Wide field eyepieces (whichever make) are most convenient, especially for eyeglass wearers but not only.

Likewise, alien 160mm tube length DIN objectives can be used as mentioned by others above, provided the thread is RMS. I have tried Nikon, Olympus, and unbranded Chinese. Chromatic aberration was evident (least so in the Nikon). However, parfocality of any of the aliens with Zeiss west objectives was poor. So a mixed objective set is not a good idea, mostly.

The Zeiss KPL eyepieces, especially the WFs, are indeed prone to delamination. Delamination appears as colored crescent-like shades around the outer rims. when you look through against bright light; better yet, place them on a stereo microscope stage, with bottom (trans) illumination, and try to focus on the inner glass layers, one by one.

Zeiss WF KPL eyepiece glass parts are two lenses (one of which is actually a doublet). Take care of the order and exact layout if you bother to take the eyepiece apart. Apparently, delamination can sometimes be remedied or minimized by soaking the delaminated glass element in immersion oil, in a vacuumed container. IMHO chances of success are very small.

The GFL focusing mechanism works great but its inner parts are sensitive. Operate the microscope with reasonable force, and protect it from falling down from any height. Take care when tightening or loosening the coarse focus tension, by rotation of the special collar.

LED illumination proves much brighter field of view than the original 6V 15W incandescent lamp of the microscope.

BTW, in the case your scope came with non-KPL eyepieces, these can potentially serve well for photomicrography.

Edit: the downloadable document Zeiss Optical Systems shows many or most glass from that era and somewhat later.

[PeteM]

That looks mostly like fungus to me.

While lens cleaner can often remove it, something stronger may be useful to keep it from coming back. This would include removing any fungus visible on adjacent metal surfaces inside the head. In some cases, fungus may have eaten the lens coatings, but I suspect you can mostly catch it in time. As said above, if there's remaining delamination it may or may not adversely affect the view.

I've had pretty good luck using a mix of household ammonia and H2O2. Some shudder at this, but it's worked for me. There are multiple other suggestions on the Web, mostly from camera folks with the same problem.

If you live in a humid area, you might consider keeping your scope in a dehumidified room where the humidity doesn't get above 55RH for any appreciable time.

[Phill Brown]

I've seen the tracking left by fungus in the coating.
Tried IPA and all the suggested.
Looked for all the world like it was damage.
Zeiss cleaner worked where all else failed so I'm happy to stick with it.
Are we looking at the lens on the underside of the head?
Use the correct tools or risk slipping and doing actual damage to the lens.

[jbjoyner]

Thanks for all the advice everyone! It was definitely fungus. I was able to carefully disassemble the whole binocular head and clean off contaminated areas with q-tips, alcohol, and lens cleaner. I am now able to compare the clearer optics and notice debris in some objectives more than others. I guess I will do some shopping around for objectives as they become available for reasonable prices. I only have 8x non KPL eyepieces at the moment. I want to make sure I don't get carried away with too many objectives and eyepieces being incompatible .

My next project is to repair or upgrade the lighting system which is currently inoperable. I will either need to find a bulb and transformer or convert to an LED. I saw in another thread that "retrodiode" provides a system for this. Does anyone have recommendations?

[Phill Brown]

Usually designed around a square filament in a precise location.
LED will probably need a diffuser.
I would compare it to the difference between a bright cloudy day and direct sunlight.
Each to their own but calling LED an upgrade is not entirely accurate.

[imkap]

My next project is to repair or upgrade the lighting system which is currently inoperable. I will either need to find a bulb and transformer or convert to an LED. I saw in another thread that "retrodiode" provides a system for this. Does anyone have recommendations?

If you have nothing currently you can just put any G4 12V 2-3W LED bulb inside and power it with any 12V adapter you may have around. It's ok for a start.

I did this for my GFL:
It worked nice, except that I should have chosen a smaller LED (not weaker, just smaller in size)
https://www.microbehunter.com/microscop ... 12&t=14944

If you don't mind the cost you can buy the finished product from Retrodiode or someone, I found these expensive and opted for DIY...

Now I use a different microscope with 100W halogen and prefer that over a LED, they both have their pros and cons... Unlike a LED, you can't fit a 100W halogen into a GFL base, you'd need an illuminator housing on the back.
LED keeps the microscope compact and can be quite powerful with very little heat, on the other hand I feel halogen light is more 'natural', some don't like that it changes colour temperature proportionally with intensity, but I don't mind that. I see much less chromatic aberration with halogen, which is a big deal for me.

LED should last longer, but I still haven't changed the bulb I got with my microscope when I bought it in August (was probably installed 20 years ago or more). I bought 5 spares they are still waiting.

GFL is a beautiful piece of equipment. Zeiss had the best design... It was my first scope too, I disassembled (and assembled) it completely, had a great time, now it works like new.

[Hobbyst46]

I guess I will do some shopping around for objectives as they become available for reasonable prices. I only have 8x non KPL eyepieces at the moment. I want to make sure I don't get carried away with too many objectives and eyepieces being incompatible .

For any Zeiss objective/eyepiece I consider buying, I would inquire the seller if the item is delaminated or fungus-infected.

My next project is to repair or upgrade the lighting system which is currently inoperable. I will either need to find a bulb and transformer or convert to an LED. I saw in another thread that "retrodiode" provides a system for this. Does anyone have recommendations?

I like my retrodiode illuminator since it fits into the base and provides Kohler illumination. There is also a European maker of LED systems for "antique" microscopes. A DIY project would definitely be cheaper than the two above options, if practicable.
I fully agree with imkap about the advantages of halogen light over LED; an external 60W halogen lamp should also do the job. Zeiss sold such illuminators in the past.
BTW the original collector lens inside the GFL base is a diffuser as well.

[jbjoyner]

Hey everyone,
I am starting to plan the DIY lighting portion of the microscope. My plan currently is to use the bulb housing as a mount. I have removed the old wiring and would like to fasten this small dimmable LED (https://www.amazon.com/gp/product/B00KW ... GP8JC&th=1) into the end of the mount with thermal conductive glue as it fits perfectly into the removable screw in ring. From there I would run wiring back through the two holes and out the back of the old bulb housing.

This is where I am not sure how to proceed. The led has the following specs: Current - 700 mA, Min/Max Input Voltage - 3.2/3.6 Vdc, Wattage 3W. I am a novice with electronics and wondering how I would correctly complete the circuit for this LED without burning the light out or worse. I have seen suggestions for a resistor but I am trying to add a dimmer knob (https://www.amazon.com/gp/product/B085T ... Q4A4V&th=1) to adjust brightness and don't know how if this affects the current or the voltage. Anyone with some electrical knowledge want to give some advice?

[imkap]

Hey everyone,
I am starting to plan the DIY lighting portion of the microscope. My plan currently is to use the bulb housing as a mount. I have removed the old wiring and would like to fasten this small dimmable LED (https://www.amazon.com/gp/product/B00KW ... GP8JC&th=1) into the end of the mount with thermal conductive glue as it fits perfectly into the removable screw in ring. From there I would run wiring back through the two holes and out the back of the old bulb housing.

This is where I am not sure how to proceed. The led has the following specs: Current - 700 mA, Min/Max Input Voltage - 3.2/3.6 Vdc, Wattage 3W. I am a novice with electronics and wondering how I would correctly complete the circuit for this LED without burning the light out or worse. I have seen suggestions for a resistor but I am trying to add a dimmer knob (https://www.amazon.com/gp/product/B085T ... Q4A4V&th=1) to adjust brightness and don't know how if this affects the current or the voltage. Anyone with some electrical knowledge want to give some advice?

I'm not a real expert, just did some DIY in life

This dimmer is for 12-24V, don't know if it will work with 3.2-3.6V LED, it might work but don't know how. And it is not very cheap
Check Mouser for Cree LED, price is similar and they are a big brand. They give you the specs for color temp, CRI index etc.
Didn't understand where exactly do you want to stick the LED. Just see that it can cool properly

For dimmer you can use a step down converter, it is cheap and works with any voltage. Just need to solder a pot in parallel to the trim pot provided. These are available locally, at least here. Probably there are other products available too, maybe check the local electronics store.

https://www.aliexpress.com/item/3271117 ... 1802XdJAzt

[Hobbyst46]

Placing the LED directly under the field aperture might produce adequately bright field of view, but without Kohler illumination, so contrast and brigthness uniformity will suffer.
Placing the LED at exactly the location of the filament of the incandescent bulb will enable Kohler illumination, but 3W in that case might suffice for brightfield, not for darkfield and phase contrast. A 10W LED will be better.
Whatever you do, an efficient heat sink is a must. At least, to avoid heating the glass parts within the base.
An 4000K LED of a 95+ CRI will give a nicely white/off white background.

[einman]

Phill,
When you say Zeiss cleaning solution are you referring to the spray solution available in wipes and bottles at Walmart, Amazon etc? Or something more industrial? I have plenty of teh regular lens solution and wipes as I use it often when cleaning my scopes optics.