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Lomo T-43 4/40: Possibly the cheapest UV capable lens?

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#1 Fandyus

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Posted 12 June 2021 - 21:59

A triplet lens that comes attached to the soviet Smena 8M rangefinder that I've routinely seen go for 2€ on local flea markets.
Attached Image: IMG_8015.jpg
As is obvious from the name, it has the focal length of 40mm and a dark maximum aperture of f/4.
The in built aperture goes all the way up to f/16 and has 8 blades.
The lens seems to have a 35mm filter thread, I haven't messured it precisely though. Only disadvantage I can already see is that the tiny ring around the front element controls the aperture, so if a filter is mounted, it is impossible to adjust aperture.
The elements seem to have a single coating.
Attached Image: IMG_8010.jpg
Attached Image: IMG_8011.jpg
Attached Image: IMG_8012.jpg
To test the UV performance, I mounted the notoriously UV capable Soligor 35mm f/3.5 on my camera with a stack of QB39+ZWB1. I pointed the lens at the sky, color balanced on the sky as well to exaggerate the tint. There is barely any.
Attached Image: IMG_9301.jpg
I would do a pinhole test or such but I don't own bleeding edge filters like the Baader U or other trusty formulas, I also don't have any UV lenses to compare this to. I might try it if I make a pinhole though, unless anyone here is quicker.
Here's a review of the image quality this lens provides in the visible, it's not amazing but the major downfall seems to be field curvature, which means that shouldn't be much of an issue for closeups, it gets better stopped down too. https://radojuva.com...lomo-t-43-40-4/
For anyone out there with a good filtering solution and a mirrorless camera, this could be an interesting option.

#2 Stefano

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Posted 12 June 2021 - 22:44

Interesting, nice find.

Did you buy a Soligor? Having one, I can say it's a nice lens.

#3 Fandyus

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Posted 12 June 2021 - 23:06

Thanks.
I was actually gifted the Soligor by a member of this forum who wishes to stay anonymous. I'm really thankful though. It's a great lens for UV indeed.

#4 Stefano

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Posted 12 June 2021 - 23:17

We can't make direct comparisons because of so many factors, but we could look at the links here to have an approximate idea. With the Soligor your limit is the filter(s). The same can probably be said for me with my Chinese BG39.

#5 Fandyus

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Posted 12 June 2021 - 23:58

Yes, indeed, that's why I'd love to see someone with good filters get ahold of this lens. Maybe I'm wrong and it's curve ends at 330nm which would make it not that good. I do personally suspect it to be better though, again, it's a barely coated, dark triplet. It would make sense for it to pass UV well.

#6 Andy Perrin

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Posted 13 June 2021 - 05:15

Yeah, that looks like it could be good. Go take some pictures, as I discovered with the Kuri, there is more to a good lens than just bandpass.

#7 Dmitry

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Posted 13 June 2021 - 08:12

I tested it years ago and it best UV capable lens I have so far. Filter thread is 35.5mm

https://www.ultravio...o-t-43-40mm-f4/
https://www.ultravio...o-t-43-40mm-f4/

#8 Stefano

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Posted 13 June 2021 - 09:52

So, it surely reaches 334 nm, and probably goes below 330 nm. Not bad!

#9 Bernard Foot

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Posted 13 June 2021 - 11:22

I got one of these about 2 months ago and tested it. It's not bad and reached down to at least 315nm, but definitely not as good as Cassar S, Focotar-2, Soligor 35mm enlarger lens, or IgorOriginals. In the following table of exposure factors through various filters, the lower the exposure factor, the better:

Attached Image: UV Reach.jpg

In terms of image quality, the resolution wasn't brilliant:

Attached Image: Resolution.jpg

So my copy of the lens went into retirement before it was actually put to any work.
Bernard Foot

#10 Stefano

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Posted 13 June 2021 - 11:36

315 nm is really good, and for 2 € one can't really ask for more.

#11 Fandyus

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Posted 13 June 2021 - 16:32

Thank you Dmitry and Bernard! I knew that this lens would be UV transmissive.
And to reply to Andy, I'll see if I ever get to mounting it, it would require some rigging.

#12 Dmitry

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Posted 13 June 2021 - 16:36

Easy to adapt it for m4/3 mount or similar. You need m4/3-M42 adapter with removable M42 thread plate.
Attached Image: P5019652.JPG

Edited by Dmitry, 13 June 2021 - 16:45.


#13 Fandyus

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Posted 13 June 2021 - 18:08

Well that's nice, I assume it's a bit better on m4/3 since the rather bad corners are cut off, do you use it a lot for UV?

#14 Dmitry

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Posted 13 June 2021 - 18:25

Used it a little https://www.ultravio...o-t-43-at-vdnh/
Was on hold after this for winter and at home isolation until now.

#15 Bernard Foot

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Posted 13 June 2021 - 19:03

View PostFandyus, on 13 June 2021 - 16:32, said:


I'll see if I ever get to mounting it, it would require some rigging.


Mounting was quite easy. I standardise on 49mm filter mounts. If you take a 42mm-49mm strep up ring, the 42mm male thread fits neatly inside the silver surround that you show and can be fixed using epoxy resin. This gives you a 49mm female thread at the rear of the lens. Use a 49mm-M42 macro reversing ring to convert this to an M42 male thread. You can then fit it to something like an E Mount or EF-M mount using a thin M42 helicoid - infinity focus would need about 17mm extension. There's not enough space to fit it to a DSLR. Front filter mount is 35.5mm - step-up rings available to convert to other filter sizes.

The other thing about the T-34 (the Lomo lens, not the tank) is usability. The aperture setting ring is at the front of the lens and can't be accessed with a filter in place. So you would typically have to focus at full aperture with the filter in place, remove the filter, set the aperture, replace the filter, and then take the shot.

I don't think it's worth bothering with this lens except as an experiment. You would be better off spending a bit more and getting one of the "approved" 35mm f/3.5 lenses - Soligor, Hanimex, Prinz, etc. They will give better UV performance, better image quality, slightly wider angle of view, and slightly larger max. aperture. And they will come with an M42 mount.
Bernard Foot

#16 Andy Broomé

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Posted 14 June 2021 - 00:54

View PostDmitry, on 13 June 2021 - 16:36, said:

Easy to adapt it for m4/3 mount or similar. You need m4/3-M42 adapter with removable M42 thread plate.
Are you reaching infinity focus with that mount? The version I have is in L39/LTM mount with the shorter flange focal distance.

#17 Dmitry

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Posted 14 June 2021 - 16:38

Andy, I wrote about "removable M42 thread plate" for some reason :)
T-43 is placed instead of this plate, and you need to use 2-3mm shim to secure lens at proper distance.

Edited by Dmitry, 14 June 2021 - 16:39.