Mirrorless for macro

Many mirrorless cameras have an articulated LCD screen these days and one advantage of this is how easy it makes using a camera attached to a macro bellows. No more fear of poking yourself in the face with a focussing rail while trying to squint through an eyepiece.

 

The easy adaptability of MILC mounts means that almost any old set of bellows can be used too.

 

Like this venerable Pentax set -

The back end is fitted with an M42 to Sony E mount adapter, and the front end has a reversed enlarger lens fitted. The lens reverser was made from an LTM T-mount and a cheap 43mm UV filter with the glass removed.

 

Here's a selection of enlarging lenses tested on the above rig for their macro suitability.

And the results at about 3.5x magnification with the bellows almost at full stretch.

 

1. Durst 50mm f/2.8 Neonon

100% crop

 

2. Schneider 50mm Componon-S

100% crop

 

3. Komuranon-S 50mm f/3.5

100% crop

 

4. Apo-Rodagon N 50mm f/2.8

100% crop

 

The subject was a 9.5 mm diameter Leica-type cable release end. Boring, but the shiny plated metal shows up LoCa like almost nothing else.

 

As you can see, none of the lenses, including the Apo-Rodagon, was free of LoCa at this magnification, but only the Komuranon shows it to an unacceptable degree, IMO.

 

If you need to get even closer, a 40mm f/3.5 Hoya 'Super EL' allowed over 4x magnification.

100% crop

The crop here is verging on microscopic magnification, and in my view isn't at all bad.... considering. The bellows extension turns the marked f/5.6 aperture used into an effective f/25 or thereabouts, with consequent diffraction softening.

 

Just some food for thought.

An old bellows like the above can be had for a few £/$/€. And enlarging lenses can still be bought a lot cheaper than a proper macro lens. Add a couple of adapters, a bit of DIY, and you could still be up-and-running with a high-magnification macro rig for under 100 £/$/€, if you buy wisely.

 

The Durst Neonon lens, for example, was bought quite recently for only £10 and competes with the Apo-Rodagon extremely well. As does the Componon-S.

 

I just wouldn't go out of my way to seek out a Komuranon-S enlarging lens though personally.

Edited January 1, 2021 by rodeo_joe|1

I do this frequently with my Z6, the FTZ adapter and a Nikon PB-5 bellows. Never thought about comparing enlarging lenses for LoCa, but I certainly have enough of them. One thing I found helps with my setups is to make a lens hood for the business end of the lens out of black paper and some tape. I've also mounted actual microscope objectives, but the results are usually less than great, and with large quality variations between types. I remember seeing some very old macro stuff done with large format and huge bellows extension. Pretty cumbersome by todays standards. Edited January 1, 2021 by conrad_hoffman

One thing I found helps with my setups is to make a lens hood for the business end of the lens out of black paper and some tape.

That reminds me of something I forgot to mention:

Most enlarging lens have a light-pipe to illuminate the aperture these days. If used un-reversed, that red-filtered light-pipe will allow light to leak past the lens into the bellows and cause a red fog. You need to cover the light-pipe entrance at the rear of the lens in this case. A bit of black electrician's tape is all that's required.

 

Alternatively, you could tape over the illuminated aperture scale, but then you wouldn't be able to read the aperture set!

Alternatively, you could tape over the illuminated aperture scale, but then you wouldn't be able to read the aperture set!

Is there much focus shift to worry about?

 

I guess focus stacking takes care of it?

Is there much focus shift to worry about?

It's best to focus at the working aperture.

 

All enlarging lenses require manual alteration of the aperture ring, so there's always a risk of 'bodging' the rig out of focus or changing the aim of the lens when stopping down. Especially at such high magnification.

 

Luckily modern MILC viewing systems can easily cope with a stopped-down lens, and present you with a clear image even at small apertures, and in dim light.

I guess focus stacking takes care of it?

I'm ashamed to say I haven't got into focus-stacking yet. It's on my to-do list!:oops:

I'm ashamed to say I haven't got into focus-stacking yet. It's on my to-do list!

New Years (Hi) Resolution......:p

Boring, but the shiny plated metal shows up LoCa like almost nothing else

So the 'It's all made of multi-colour pixie glitter' look is just LoCa?

 

I'll have a try at doing a stack of something similar and see if the colours average out to monochrome.

So the 'It's all made of multi-colour pixie glitter' look is just LoCa?

I think not.

LoCa only appears in OOF areas.

 

My first thought was that it was an interference effect between the surface texture of the metal (or specular reflections therefrom), and the sensor Bayer filtering. But it's too regular from picture-to-picture to be random aliasing.

 

The colouration is fairly consistent from lens to lens, and with slight changes in magnification. It's also stubbornly present in areas that are definitely in focus.

 

It needs further investigation, because I really don't know the cause.

Edited January 3, 2021 by rodeo_joe|1

Hmmm.

After looking at the Hoya image, which is heavily diffraction blurred, the colouration itself is still present, but also blurred. That wouldn't happen with a Bayer aliasing effect. Or at least I'm pretty sure it wouldn't because the diffraction acts like a low-pass AA filter.

 

I'm leaning toward the theory that this is 'genuine' colouration, caused by diffraction from the metal surface. Like a rainbow, but from selective reflection rather than refractive splitting.

 

Or something???

It is the genuine result of genuine colour abberation.

It is the genuine result of genuine colour abberation.

Then prove it q.g., with your own examples.

 

And if the Apo-Rodagon N still exhibits the same effect, what worth is that lens, and how can it be bettered?

 

"A picture is worth a thousand words." Or an infinite amount of unsupported blather.

Edited January 3, 2021 by rodeo_joe|1

I'm leaning toward the theory that this is 'genuine' colouration

I've noticed before when shooting textiles from 1:1 to maybe 10:1 that the individual fibres, especially silk, can act as thin cylindrical prisms.... and show bizarre colour behaviour. Synthetic extruded fibres such as polyester are very uniform in cross section, unlike caterpillar bum extruded silk and show much less colour patterns.

 

I wonder if the V section machining grooves, with maybe a hint of oil, do something similar? or maybe an effect of the plated finish?

I found my EL Nikkor 2.8 Enlarging lens showed pincushion distortion when used as a macro lens. Its edge performance was nothing special either. I largely put this down to it not being optimized for 1:1 use. My 75mm f4 Apo-Rodenstock-M designed for 1:1 use is predictably streets ahead.

I've now spent some time trying to get to the bottom of the 'psychedelic speckles' effect. The theory quickly got very complex when I attempted to Google an answer*, but the practical solution is thankfully much simpler.

 

Basically, it all comes down to the light source. Diffusing the light almost completely eliminates the effect.

 

To ring the changes I used this rig:

Would a proper macro lens eliminate the 'pixie dust'?

Nope!

 

What about using a camera with an AA filter, like my D800?

Definitely not!

 

A shorter lens and more magnification?

Again no.

That's the whole frame.

Here's the above at 100%

Cool effect, but not what we're after.

 

I tried a polarising filter - no change.

Then I just placed a diffusing sheet between the flash and close to the subject.

Success! No speckles.

 

Now that I had the 'trick' of an un-speckled image; I went back to comparing the enlarging lenses.

 

The Apo-Rodagon N

 

Componon-S

 

Durst Neonon

And to be honest, I see almost no difference between them. Let alone several hundred £'s worth more for the Apo-Rodagon.

 

* My web research threw up papers about e-field phase inversions at air-metal interfaces, Fresnel equations, explanations of the difference between dielectric and conductive material properties, and other esoteric treatises.

 

It does seem that dielectric (non-conductive) materials aren't susceptible to coloured speckling -

Emery board lit by un-diffused flash.

 

And sandpaper.

 

Not a conclusive set of examples I admit. But I think the organic/dielectric versus metals thing is worth investigating. Since the effect appears to have almost nothing to do with lens colour aberrations or Bayer filter aliasing.

 

Whatever. You can't really go wrong using a diffuse light source for macro work.

Edited January 7, 2021 by rodeo_joe|1