35mm Barlow lens thread?

[Capie]

Hi guys

Think this is my first posting on your forum. Been "setting up" for quite a while now which is proving expensive.... Already bought a few batches, as well as singles, of old mechanical watches cheaply. Although some are Eterna, Girard Perregaux, Avia, Cyma etc etc and other nice makes, the fog is starting to clear up to see why they went so cheaply! Missing stems and crowns, damaged dials, missing hands, (probably) broken mainsprings etc etc. Anyway, its going to be a learning process in ALL aspects of watch repairing.

Now my problem. Got my hands recently on a beautiful well cared for German made Askania GSZ stereo microscope with 12,5x eyepieces fitted (and hot, yellow Halogen spot-lighting...) . In its current configuration, I'm getting 10 to 50 magnification at a working distance of about 70mm. In order to get my working distance up and my magnification down, I'd like to fit a 0,5x or 0,32x Barlow lens. BUT.... the normal thread size it seems is 42 or 48mm for these lenses!!! By measuring with a ruler, it looks as if I'll be needing a 35mm thread.

I have contacted the friendly and helpful folk of Askania in Germany and they do have stock, but at a cost of 131 Euros plus shipping to South Africa by UPS of 167 Euros. I paid about 200 Euros for the mic! Its such a nice microscope and would like to keep it, but not only for close-up inspections. I need one doitall mic.

Do you guys know where I can look for 35mm Barlow lens (35mm tbc by Askania, if they are willing to divulge that info).

[Capie]

Confirmed, its actually a M36x0,75 that I'm looking for.

[Capie]

Apologies for bombarding you, but if I can't find a M36 Barlow lens, do you think I may be able to use a M36 to M42 adapter. Will my setup still be optically sound?

[Paul80]

Hi

The adaptor ring should make very little if any difference, any difference would be adjusted by your base focus.

[Capie]

Thank you Paul, and I suppose the working space shouldn't be compromised? Spoke a bit too soon, prove to be also difficult to find one. I'll also look for m36 to m48, which is also more common

[Capie]

Ok, so I decided to get a M36x0,75 to M42x0,74 (T2) male-female adapter and a 0,5x M42 lens. Got two adapter manufacturers/suppliers of which one sits in Belarus and won't currently export to South Africa (Rafcamera) and then Lacerta in Austria.

The lens I ordered is a Hayear with the M42 thread, of which the quality I'm not certain of. At least its made of metal and glass!! Saw the same Hayear lens on various sites but at a very wide price range!!!  Also ordered a 56 LED ring lamp with the lens. The current yellow, hot Halogen spot lamp is not working for me.

Should I decide in future (not that I have any reference) that the lens is crappy, I'll be able to get a more readily available M42 to M48 adapter, and then can choose among the wider range of M48 lenses.

I'll post some pics as soon as I get these items.

[Capie]

I'm not getting real joy from the Hayear 0.5 Barlow lens I bought. Working distance before was 7,1cm. With the Barlow its about 8,5cm, instead of the quoted and expected 16,5cm.

By looking at a Barlow lens operation diagram, perhaps the 5mm adapter moved the Barlow lens too far away from the objective lenses? Or perhaps the Hayear is just plainly inferior?

I'm on the verge of ordering the original 131Euro lens at 160Euro shipping!!! For my 200Euro Askania uscope..... Lol

Edited December 12, 2022 by Capie
mm vs cm

[rehajm]

1 hour ago, Capie said:

I'm not getting real joy from the Hayear 0.5 Barlow lens I bought. Working distance before was 7,1cm. With the Barlow its about 8,5cm, instead of the quoted and expected 16,5cm.

By looking at a Barlow lens operation diagram, perhaps the 5mm adapter moved the Barlow lens too far away from the objective lenses? Or perhaps the Hayear is just plainly inferior?

I'm on the verge of ordering the original 131Euro lens at 160Euro shipping!!! For my 200Euro Askania uscope..... Lol

Some watches are a hole where one tosses money to make it disappear. I've yet to experience a similar experience with the microscope. Thanks for the warning!