Single Element Lens based on Helios 44
About
In short, this is soft focus lens of a poor man. Pentax produced some proper soft focus lenses but they cost far more than this one.
In long, if you take any lens and remove all its elements but the front (rear) one, you'd get the soft focus lens probably a little slower than the original probably with a little longer a focal length.
This is very fascinating lens to deal with. For starters, to focus a soft focus lens is a trick, even if one looks through wonderful viewfinder of ME Super. Naturally, this kind of lens has some serious color aberrations. Finally, it has some geometrical aberrations just as well.
Well, if you're still interested, you can make one from very cheap Helios 44 lens and try it for yourself.
How to make one
Credit
The lens that we have modified was generously provided by Levente (Levi) Littvay. As of this writing he seems to agree to answer the questions about the lens performance.
The modification itself was performed by Vladimir Feodorov. His site is in Russian, but since it is basically his photo gallery all you need to know is how to click on thumbnails. Which I hope you could do quite well.
I think I'd claim a credit for putting this page together and nagging two people above a little.
Warnings
Obviously none of the people above will be held responsible if you damage your lens beyond any possibility of repair.
The modification process is irreversible. To reassemble even so simple a lens as Helios 44 requires some very special equipment that would allow for proper alignment of all the glass elements inside the lens. So, one could characterize this lens as a "deliberately destroyed" one.
Furthermore, it takes some experience to make such a lens. So, perhaps, first one or two times you try it would yield no satisfactory result. However Helios 44 lenses are very cheap. So you won't loose much.
A word about Helios 44 lenses. There are several varieties of this lens. Some are made in K-mount, some others are made in M42 screwmount. Some have automatic aperture, some have two aperture rings - one for setting the aperture value, another for actually closing the aperture manually before the shutter is released. The procedure below was performed on Helios 44-K4 version which is K mount and automatic aperture. It can be done on any lens, but probably with some alterations.
By automatic aperture I mean that the aperture would close automatically to the value set by the photographer when the shutter is released. It does not mean that this lens has A setting on its aperture ring. In fact, I am unaware of existance of any Russian made lens that has KA mount.
Tools For the Procedure
1. Special screw-driver for lenses or plyers with thin ends and/or clock screw-driver(s).
2. Some ear buds, some rice paper, and some benzine. Cheap ZIP variety will do just fine. If you deal with the lens that has plastic front element, instead of benzine you have to prepare your favorite lens cleaning liquid.
The Procedure
Figure 1 - The lens
Figure 2 - The K mount
1. Ideally, you need to have special screw-driver for screwing off the lens rings. Instead you could use plyers. So you take the plyers and accurately unscrew the blocking ring just on top of the front element (Figure 3 )
Figure 3
Figure 4 - The lens and the blocking ring unscrewed.
2. Now the most sensitive part. Take small/clock screwdriver or pair of screwdrivers and carefully unscrew the front element. (Figure 5)
Figure 5
3. Take a piece of soft tissue and put the front element you've just unscrewed aside. Figure 6 - the lens element closest to the Helios itself is the one you'd want to keep. Another lens element you'd have to throw away. Keep! all the stopper elements (rings that do not carry any lens element). Remember their order in order to put some of them back in place later.
Figure 6
4. Unscrew pair of bottom elements. This is done similarly as you did with the front element. Again keep all the stoppers for later assembly. Be sure not to touch the aperture mechanism.
Figure 7 - The lens without bottom elements.
5. From the bottom element assembly you have to unscrew the glass itself. The insert ring has to be returned back to the lens. You need to take a piece of tissue and clean up excessive oil from the ring.
6. Figure 8 - the back element insert without the glass. The lens without any glass in it. Now it would be time to see from the close distance that the diaphragm mechanism of your lens works properly. You can also play a little with the automatic diaphragm mechanism if your lens has one.
Figure 8
7. Screw back in the rear element ring. Don't apply too much force while screwing in. Otherwise the diaphragm would stop closing automatically. It is the time to make sure diaphragm works properly. When you'd be dealing with front elements, you'd have no way to affect the diaphragm.
Essentially you're starting to assembly back the would-be monocle.
8. Now you can pre-assemble the front element and the front rings. At this time you would have to check that your lens can focus to the infinity. Usually it should not. So you would have to re-position the glass by switching the position of the glass and (wider) stopper ring. Naturally, when you cannot focus to the infinity you have to move the glass forward, so you need this swap procedure. For various lenses it could be different. It is essentially try and error process.
For Helios the focusing range would become 0.5-0.8 or so meters, where 0.8 would become infitinty and 0.5 would become something like 1 meter. That is on the original focusing scale.
9. Assembling the front. Figure 9 - the elements you would assemble in order from right to left.
Figure 9
This is a good time to finally clean the glass. Benzine (clean ZIP variety Figure 10) is the best for that purpose. Use ear buds and very soft tissue. This "liquid" is of course best for real photo glass optics. For plastic based optics use something else :). From the experience benzine wouldn't harm even SMC and filter coatings. Feel free to use blower to remove the (tissue) particles. Obviously the final stage of cleaning is done by rice paper. You probably should have pack of rice paper anyway. If note buy one.
Figure 10
If at this time you'd discover that the glass in your hands has an air bubble inside don't be upset. This won't really upset the monocle anyway.
10. Important : you can use one of the ear buds in order to put the glass element into the lens. Blow off the particles again once you've done it. Do not forget the ring that goes in before the glass.
11. Put in the last stopper ring. Screw on the front element holder, one that has all the lens data printed on it. You're done! Notice that the rear element (on the foreground) could be used to make a rear variety of monocle.
Figure 11 - Your monocle is assembled
Ideally, you need to use macro ring No. 1 in order to get full focusing range. However as it is, it is just as useful.