Shade & Protection For Some Reversed Componons

[Harold Gough]

I have these two lenses, neither tried yet but the 40mm is likely to be my “go-to” lens for much macro work from 1:1 upwards. The rear elements of neither is recessed very much and shading is always desirable to maintain contrast.

Schneider Kreuznach Apo Componon HM 40mm F2.8 enlarging lens, the version with variable aperture (f2.8 –f16) (M39 with adapter to M42). Said to be very good for a wide range of magnifications, from 1:1.

Schneider Kreuznach-S Componon-S 50mm f2.8 (M39 with adapter to M42) I believe it to be optimised for 4x to 8x.

I was considering the need for a hood and remembered that I had a Bolex cine lens:

Kern Paillard Macro-Switar 1:1.3 12.5mm HB RX.

The hood for the above lens is for a filter thread of about 32mm. It (threaded end) fits fairly snugly in the back of either lens. It is slightly off-centre, due to the window which transmits light from an enlarger to illuminate the selected aperture, irrelevant for photographic use, being positioned on one side. This could be overcome by cutting a piece out of the hood thread but any vignetting should not be seen on my m4/3 sensor and I like the snug fit (to be improved slightly by wrapping some tape around the thread or, more likely, glued in place).

The following, hand-held, images were grabbed during brief spells of good light, as our wet weather continues.

This shows the back of the lens with the circular groove into which the hood fits. (The curved surface extending from about 5'oclock to about 6 o'clock, with a red dot on it, is the light transmision device):



A side view of the lens without the hood



With the hood




Whether the M39-M42 adapter is in place or not does not affect this modification and the protruding hood can be left in place when the lens is used in conventional orientation on some extension tubes (e.g. Olympus OM, M42 manual). It will also fit in the original box (blue hexagonal base & clear lid) with the hood in place (and a couple of step rings on the front of the lens)

If you possess such a lens (I don’t know how many other models this will work for) a visit, with it, to where cine lenses are sold cheaply (car boot sales?) might be fruitful.

There are a variety of 32mm hoods available on Ebay but none of them seem to be the cylindrical shape wich works so well for this application.

Harold

[canonian]

I use a similair solution for shading and protecting.
I ran into a cheap M42 lens that had a C-Mount adapter on it and use it for shading many of my enlarger lenses like the Componons and El-Nikkors, together with a M39 to M42 ring:

[Harold Gough]

Thanks, Fred

That reminds me that I have a C-adapter, used only on this occasion:

http://www.photomacrography.net/forum/v ... acroswitar

It became parted for the lens at some stage since then and, altough I have come across it at times, I can't put my hands on it right now.

Harold

[ChrisR]

39mm rear caps are available, eg ebay 221152173385, £1.99.
Periodically 39mm extension tubes appear too, which I use for hoods (if not a simple tube of black paper).
The "aperture" arm on those lenses can be reversed, by the way, or removed altogether and the screw used to change the aperture, if the arm gets in the way.

The 40/2.8 is a good little lens for around 3x but not at its best for 1:1, where the Apo Rodagon 75mm D is better.

[Harold Gough]

Thanks, Fred

That reminds me that I have a C-adapter, used only on this occasion:

http://www.photomacrography.net/forum/v ... acroswitar

It became parted for the lens at some stage since then and, altough I have come across it at times, I can't put my hands on it right now

I found it. The cunning little devil was hiding in my adapter box, looking rather less bulky then I expected. It is a +/- flat disc, C to m4/3 and no help for shading. I have just won a Kodak 32mm push-fit hood which might be slim enough and cost nearly nothing.

Thanks, Chris. The M42 adapters will be left on but I need some M42 caps.

The seller advised me that the arm could be removed but my stacked step rings make that unnecessary.

[Harold Gough]

The "aperture" arm on those lenses can be reversed, by the way, or removed altogether and the screw used to change the aperture, if the arm gets in the way.

I like to be different. While I have a temporary, wider than the permanent one, step ring in place, I have loosened the screw and turned the arm through 90 degrees and retightened, there been adequate thread for this.

If the arm is removed there is no need to leave the screw in place as the cam-like protruson to which the arm was attached is a more comfortable option for closing the diaphragm to the selected aperture, after framing and focusing at maximum aperture. Of course, the selection of the aperture is via the front ring of the lens barrel. When the lens is reversed the aperture has to be selected by rotating the barrel.

Harold