Worth a comparison

[NikonUser]

I have replaced several lenses used for macros, with mostly small working distances, with one lens with a minimun WD of 10.6 cm.
With extension I get anywhere between 1x and 5x.
The lens is a Leitz Wetzlar Germany 0.32:1 microscope relay lens; sells on ebay for around $300.00.
It would be nice to compare images between it and the Laowa 2.5-5x macro, about $400.00 new.
If anyone has a Laowa and a Camponotus ant (hasn't everybody?) then a valid comparison can be made.

[ray_parkhurst]

Hmm, I have never thought about using a relay lens for taking. Maybe you're onto a whole new thing, like scanner lenses and such. I apologize if this has been covered already (Robert?) but has anyone done any in-depth testing of these relay lenses? Which ones have wide coverage, good sharpness, low CAs, etc? Or is this a completely new field?

[Pau]

Time ago I tested the Zeiss 63mm "0.25X" relay lens for afocal SLR adapter (more or less the same function than the Leitz 0.32:1) and, despite working well for its intended function, as taking lens alone it's an absolute disaster.

[Lou Jost]

Hmm, I have never thought about using a relay lens for taking. Maybe you're onto a whole new thing, like scanner lenses and such. I apologize if this has been covered already (Robert?) but has anyone done any in-depth testing of these relay lenses? Which ones have wide coverage, good sharpness, low CAs, etc? Or is this a completely new field?

The Repro-Nikkors are often used as relay lenses, so the connection has been recognized in the other direction.

[enricosavazzi]

I have replaced several lenses used for macros, with mostly small working distances, with one lens with a minimun WD of 10.6 cm.
With extension I get anywhere between 1x and 5x.
The lens is a Leitz Wetzlar Germany 0.32:1 microscope relay lens; sells on ebay for around $300.00.
It would be nice to compare images between it and the Laowa 2.5-5x macro, about $400.00 new.
If anyone has a Laowa and a Camponotus ant (hasn't everybody?) then a valid comparison can be made.

There are at least two (possibly more) different Leitz 0,32:1 relay lenses, possibly the same optics in different barrels. It might help to see exactly how yours looks like. Did you use yours in normal or reversed orientation? On full frame (which it should cover)?

PS- I have the Laowa 25 mm, but our Camponotus will be sleeping under the snow for another month or two.

[NikonUser]

normal position.
It simply unscrewed from the camera, and then screwed into a Nikon ring

SEE HERE

[Beatsy]

Yowsa! That looks pretty special. The working distance makes it "special-er".

I use a Canon MP-E65 1x-5x adapted onto Sony mirrorless cameras. Mainly because the working distance is better than objectives and because it's relatively easy to use for short, handheld focus bracketing (for stacks). I rarely use it past 3x though because the quality just isn't there (for me) at the higher mags.

Using a relay lens like this is a new idea to me! I hope more folks here have a go too, so I can see more results. I don't need any new diversions right now though, so it's only on the list to try in future. If I can resist seeking and buying one

Not sure why I missed this when you first posted, but glad I found it. Thanks very much for pointing it out.

Cheers
Beats

[enricosavazzi]

This is a Leitz 0.32:1 I was able to get a hold of, shown mounted on a Leica M to Nikon F adapter and Nikon bellows (the bellows are slightly modified with an Arca-compatible plate instead of a lower geared platform).

The collar with branding and model engravings is easily screwed away and can be mounted also reversed. It only has the thread for the objective barrel and no other thread or bayonet, so I am not sure of its function. It has a conical slope inside but it is wider than the conical adapter.

The threaded barrel of the lens has apparently a 26.5 x 0.7 metric thread. The barrel is stuck to the conical adapter and has resisted my attempts to unscrewing with a belt wrench. There is a locking ring or thread adapter between lens barrel and conical adapter, also stuck. The front element diameter is 17.8 mm and the focal length approximately 65 mm, so an f/3.7 lens. Pupil ratio seems close to 1, but it is difficult to tell because there is no diaphragm. The optical design is in any case not strongly front-to-rear asymmetric, and the number of elements really low.

An eBay ad (item n. 164755532722 ) shows a different Leitz 0.32:1. The threaded barrel of the lens looks different, so I don't know whether the optics are also different. There is also another Leitz 0.32x relay lens (e.g. eBay item n. 254186931054), but it is more modern. I have one of these somewhere but cannot find it at a moment's notice. It is used for example in the camera adapter of the Wild/Leitz M420 photomacroscope.

I will post here once I get some time to test this "relay lens" and compare it to the Laowa 25 mm 2.5-5x. It is probably better to just continue this thread than create a new one.

PS - The collar is actually not needed to use the lens in photomacrography:

[NikonUser]

My lens simply unscrewed from the camera:

[Scarodactyl]

I had a try with the one I have, the version that is probably most abundantly available

Alas it must be a different design, while its resolution is pretty impressive at higher mags enough spherical aberrations creeps in that it wouldn't be a great option imo. I tried it forward and backwards.

[PeteM]

Leitz and then Leica infinite tube microscopes did a mish-mash of objective corrections in the tube lens and eyepieces depending on the age. It's possible the chromatic aberrations in that last pictured relay lens are intentional?

[Scarodactyl]

In this case I don't think so since this lens was used as part of the MPE system both for Wild stereos and for Leitz compound scopes. The corrections (or lack thereof) would likely have been handled in the photo eyepiece beneath it, which for the Wild stereo was just a viewing eyepiece in some configurations.
But who knows? It's being pushed way out of nominal spec. I'm impressed by the resolution though, I can see how it's related to a fantastic imaging lens. Maybe it would be good stacked...

[enricosavazzi]

OK, I did have time for some tests. The magnification is approximately 0.8x, the minimum I can get with the bellows setup shown in my earlier post in this thread. Images shot on Olympus E-M1 II (Micro 4/3). All pictures SOOC (straight out of camera) JPG, quality reduced to 85% for web.

The target is a Thorlabs version of the NBS-1963A, up to 228 lp/mm, mounted in a Thorlabs cage equipped with an opal diffusor and a diffused 45° mirror for side illumination by electronic flash (cage not shown). With the same test setup, other lenses, like the OM System 90 mm macro, easily resolve the 228 lp/mm pattern at 2x (i.e. 114 lp/mm on sensor) with much better contrast, but not at 1x (i.e. 228 lp/mm on sensor, which is not surprising, since I calculated that the theoretical resolution of an ideal Micro 4/3 sensor is around 150 lp/mm, both as Nyquist limit and as 30% MTF).

Whole image, reduced. Focus set on the finest patterns. There seems to be some curvature of field spoiling the peripheral resolution (not a problem in focus stacking, if not accompanied by spherical aberration).

Same as above, 1:1 pixel crop. Visually I can read up to 114 lp/mm on the target resolved, i.e. 140 lp/mm on sensor.

Target tilted at -5°, 1:1 crop of coarse pattern used as MTF slanted target. Some lateral CA visible because halfway to left margin of image.

MTF graph, showing less than 20 lp/mm resolved at 50% MTF (around 8 lp/mm at 80% MTF). The poor contrast of the lens is no doubt the largest factor ruining its MTF performance.


I tried going up at around 3.5x, and contrast improved. Still some trouble with curvature of field.

Whole image, reduced.

I can read 161 lp/mm resolved on the subject, i.e. approx. 46 lp/mm on the sensor. This is worse than at 0.8x, so 3.5x is too much for this lens.

I did not make MTF computations nor a direct comparison with the Laowa 25 mm at this magnification, but based on my previous use of the latter lens, I think it almost certainly fares better.

On the other hand, the Leitz lens in conical mount makes a handy hand-held magnifier to read small serial numbers and the like, and works well in this application. The distance between eye and lens helps to keep the highly aberrated periphery out of sight, and contrast is visually fine. I don't think I will use it for imaging in photomacrography, however.

[NikonUser]

I tried stacking the Leitz lens onto an old Nikon 105 micro (the MF one that goes to 0.5x).
Thought it might be useful for field work to photograph ants.
Has potential.

[enricosavazzi]

I tried stacking the Leitz lens onto an old Nikon 105 micro (the MF one that goes to 0.5x).
Thought it might be useful for field work to photograph ants.
Has potential.
5iii23 ant f-22 1024.jpg5iii23 ant f-32 1024px.jpg

It is not my intention to start a polemic debate, but with due respect, a 1024 x 696 image is not enough to judge the resolution of a lens. Most lenses would probably look tack sharp at this image size.

A 1:1 pixel crop of some detailed part of the image would be indispensable for this purpose.