The Beauty Biokor-S 45mm f1.9 Conversion

This is an interesting camera.  I never knew this brand even existed until I got this camera.  Some Googling reveals there are some fanatic followers for some of its rangefinder camera.  The one I have, unfortunately (or fortunately), has damages, and was dead.  I don't have to feel bad gutting it for the lens to transplant it for use on digital.

A Beauty, no?

I originally wanted to preserve the built-in focus mechanism, but the lens has some strange designs that prevents this from happening.  On most rangefinders, there are two focus guides; one on each side of the lens and are small and very close to the helicoid.  On this lens, there is a single focus guide and is placed quite a distance away from the helicoid.  If I were to retain the original focusing, I would have to machine the mount much larger than the diameter of the lens to accommodate the focus guide.  If I were more skilled, I could probably create my own focus guide, but I am not there yet.  In the end, the built-in focus is abandoned, and the Pentax 17-33mm focus helicoid is used.  There are many advantages of using a helicoid with 16mm of focus travel, and one of which is extreme close focus while still retaining infinity focus.  Another advantage is the focus feel.  The Pentax helicoid is smooth as silk and what a pleasure to use.

The skin on the front of the camera need to be removed, which will expose the screws that secure the lens module.  The top plate probably does not need to be removed, but I did it anyway.

Once the screws were removed, the lens module can be pulled out easily.  Note the focus guide circled in red.  

I need to use an M42 mount for the lens, so that it could be screwed on to the Pentax helicoid. This M42 mount came from one of the three sections of a Pentax extension tube.  I have to somehow mount this onto the lens.  The obvious way to do it is to attach it to the inner helicoid.  The only problem is there is less than 3mm of space available between the lens and the focus helicoid.  I machined the inner helicoid tube from its original 25mm to about 1mm thick, and the M42 mount to about 3mm, just thin enough to achieve infinity focus.  I then epoxied the two parts together.  Since the weight of the whole lens is held together by the glue, I am not too comfortable trusting glue to handle this by itself, so I intend to drill/tap and screwed them together for some added assurance.

Remove everything at the rear of the lens, but keep the retention plate.  This plate is used to hold the M42 mount to the lens.  See next picture for the plate. The screw circled is a key that makes sure the plate does not move around.

On the left is the M42 mount I cut from the Pentax extension tube and machined to the required thickness.  In the middle is the retention plate that I machined so that it will fit inside the back of the M42 mount.  These two pieces are glued together with metallic epoxy. 

The retention plate is glued onto the M42 mount. Note the recessed groove; it's just small enough that the retention ring can't go through the hole.  This is where the retention ring on the right will be pressing on while screwed onto the lens.  This secures the mount on the lens.

All the pieces fitted together.  The notches circled in red is where you use the spanner wrench to tighten the retention ring and secure the mount.

Disabling the shutter

This is actually the trickiest part that took more time.  It involves disassembling the front of the lens.

Remove the retention ring with a spanner wrench and remove the diffuser piece. Next unscrew the front element group, and take out 3 pieces under it. Now remove the 3 screws circled in red.

Once the 3 screws are removed, lift this piece out, and the piece below it.  This will expose 4 more screws that need to be removed.  Note the small retention ring in the middle, pointed to by the blue arrow.  This one also needs to come out.

Take out the piece secured by the 4 screws, and now the inner retention can be removed.  Note the locking screws in red.  It needs to be turned so that it's not touching the retention ring.  Using a pointed spanner wrench, remove the retention ring.

Once the retention ring is removed, take it out, as well as the two other pieces under it. This is the end of the disasembly.

This is where you will find the shutter cocking mechanism, circled in red.  Find the part that actually engages/disengages the shutter, and glue/solder it in place.  For this particular lens, I just removed the shutter blades using a long nose plier since I didn't feel like I wanted to go through all the disassembly steps, but I did the steps here to show where you can do it without removing the blades.

Everything together.  Looks nice with the Canonet hood :)

A real beauty, ain't she?

One issue that this lens has, is the very stiff aperture ring.  I think there are two much gunk that gums it up.  But, I am not going to do further disassembly to fix it since I hardly use the aperture :)  I shoot mostly wide open.

Next time, we will look at some pictures taken with this lens, and see if Beauty is only skin deep, or it actually has substance.

Minolta Rokkor-QF 40mm f1.8 From Minoltina AL-s

I always thought 40mm is an odd focal length for a lens, but it was very popular with rangefinders, because it's a cross between a mini-wide 35mm and a standard 50mm lens.  In other words, it's a compromise, or if you are an optimist, the best of both worlds.  In actual use, I kind of like this focal length on the full frame A7. It has a wider view than the 50mm lens, but still used like a normal/standard lens, at least psychologically.

Minolta Minoltina AL-s with Rokkor-QF 40mm f1.8

The Minolta Rokkor-QF 40mm f1.8 came from the Minoltina AL-S rangefinder.  The camera had sticky shutter below 1/15 second, although everything else seemed to work fine. Anything not perfect is an excuse to take the camera apart for the lens :)

I removed the lens from the camera, removed the shutter blades, and used a 58mm reversing E-Mount adapter.  I must say, this is by far the best hand converted rangefinder lens I have ever done.  It looks pretty nice too.  With a short flange, this lens did not need much space between the mount and the lens.  It looks compact and small when it's mounted on the A7, and it's solidly built, like most old lenses.  I really like it.

Rokkor-QF 40mm f1.8 on Sony A7

The hardest part of this conversion was infinity calibration.  Having to file the shim for exact thickness took the most time, and at the end, it was still a bit too thin and focuses slightly past infinity, but I am not ready to go through another hour and a half to do it again.  Next time, I think instead of a metal retention ring I used from the filter as a shim, I should just cut the shims using plastic sheets.  Should be much more precise and take far less time, until I get my lathe to machine the mount to the exact measurement I need.

Bokeh with busy background

The lens board was cut and filed to the diameter of the lens, and fits perfectly within the 55mm filter ring.  The only problem is the focus glide column that protrudes when focused to infinity, and hits the mount.  I had to file a gap on the adapter to allow it to extend fully.  The focus guide, which is a small piece of metal that guides the focus glide column so that it won't move or wobble sideways when focusing, used to be on the outside of the lens board, I made a smaller version of it and mounted inside.  This looks neater and when I eventually have a metal lathe, it would be much easier to machine the mount and screw on top of this lens board.

Wide open, very sharp, but vignetting is quite severe

I retained the original focusing mechanism, to keep the lens as compact, and original looking as possible.  The minimum focus distance for this lens is normally at 0.8 meters.  Far too long for my liking, so I modified the focus travel stopper to allow the focus ring to turn the lens outwards more, which increases the space between lens and sensor, and thus closer focus.  It now focuses to about 0.4 to 0.5 meters, like most modern standard lenses.  The only cosmetic issue is that there is a small gap between the focus ring and the lens body at minimum focus distance.  Oh well, can't have everything!

At f8.  Very sharp across the whole frame.

At maximum aperture, the lens behaves like most old lenses: it's quite sharp, but lacks contrast.  I think the shim I filed wasn't perfectly flat.  The left side of the image is slightly sharper than the right side, and this is noticeable at large apertures.  From f8 on, the lens is sharp across the frame with relatively good contrast.  But it's the bokeh I am most interested in.  This is what shows the most characters of the lens.

More Bokeh Shots

More Bokeh Shots

The bokeh is quite similar to many of the Japanese rangefinder lenses I have used.  Slightly swirly wide open.  This is not to say the bokeh is not pleasing.  In fact, I think it's quite nice to my eyes. It's just not so unique.

I really like this lens, for its compact size and relatively good optical quality.  It really is a nice walk around lens with a focal length that falls between a wide angle and a standard lens.

No Lens evaluation is complete without a hydrant shot :)

The February [Thrifty Store] Challenge

Matt at the Fixed Lens Flickr Group has a couple of DIY challenges running.  One is the a monthly challenge to adapt a piece of optical glass to be used on your digital camera, and the other is the Thrifty store challenge.  The idea is to find a camera, any camera, in a thrifty store, take a picture of it, and then post it to the group before the start of conversion to refit the lens on your digital camera.  Since I got the camera from a thrifty store, but I didn't take a picture of the camera in the store, I enter it as a February challenge, with a Yashica MG-2 plastic wonder, which cost me $6.77CAD ($5.99 + taxes).  Frankly that bothers me.  I doubt all the parts used in this piece of, er, beautiful engineering would cost more than $5 at the time of manufacturing.  I could buy a real rangefinder with an excellent lens for $10 at the camera show.  But, it's all for the challenge!

The ultra cheap plastic wonder: Yashica MG-2

Everything about the MG-2 is about cheapness.  In most cameras, the lens is the most expensive part, but in this case, I think the flash and the big capacitor, was more expensive than the plastic lens.  The lens has no aperture inside, but instead, a piece of plastic with a hole behind the lens that can be selected as "landscape" mode, which probably stops the lens down to about f8-f11.  Normal mode, or wide open, it's roughly f5.6 when I compared it to another lens with a constant light source.  Also, there is no focus, but that's a feature of being "focus free"!  This plastic micro coke bottle was optimized for hyper-focal shooting, no doubt.

The lens is surprisingly easy to take apart, since the plastic body is held together by a few screws, but if you want it apart even quicker, I would recommend a hammer.  The flange is very short, too short to be used even with the petite Pentax M42 focus helicoid in the normal fashion.  But I can't shoot a "focus free" lens.  What fun is it that everything is in focus?  I had to improvise.  The solution was to sink the lens deeper into the helicoid, closer to the sensor.  So I cut out a piece of plastic from the back cover of the film chamber the size slightly smaller than 42mm, drill a hole in the middle for the lens, and stick the whole thing inside the helicoid.  Voilà!  Focus from very close to infinity.  I didn't even bother with glue, just electrical tape to secure the lens to the piece of plastic and the plastic inside the helicoid is held by friction.  The total cost is just the lens itself.  The only downside?  Flatness is not guaranteed, but I am not about to measure it with a micrometer.  The whole purpose of this endeavour was to have fun, and expect the unexpected!  I will be shooting the lens naked, wide open, going for that artsy LOMO effect :)

The Body Cap Lens

You know, I kinda like how the lens looks on the camera.  This is like a DIY Body Cap lens, but with focus.  It's much cheaper than the "real" Body Cap lens, even cheaper than a LOMO lens :)

The result is somewhat expected.  The lens is more than sufficient for 4x6 inch prints, but it can't satisfy the 24MP sensor in the A7.  The centre of the image is reasonably sharp, but the edges fall apart.  Contrast is low, especially at infinity. Shooting without a hood, it flares easily.  Surprisingly, colour fringing isn't that bad at all, probably due to the nice coating treatment on the lens.  Vignetting, however, is quite severe.  This could be good or bad depending on your artistic needs.  It doesn't bother me; the vignette helps to hide the horrible corners.  Aside from the lack of sharpness and mushy corners, the colour is also a bit weird.  It's true some lenses render colours very untastefully, and this is one of those.  Moreover, this lens is not kind to blown highlights.  The roll off is abrupt and unpleasant.  When all these negatives are combines, one would wonder, is there anything left to redeem itself?

Bokeh - Not too bad, right?

On the positive note, this lens has a couple of shining spots.  One is its much better resolving power at close range than is at infinity.  For macro shots, there is quite a bit details.  The other nice thing about this lens, is the bokeh.  Bokeh for a 34mm f5.6 wide angle lens?  Yes, the helicoid makes the close focus possible, and the bokeh is actually not awful most of the time.  If the background supports it, the lens can sometimes render pleasing looking bokeh, but only sometimes, and lets lower our standards for a camera/lens created to be the bottom of the rank.

Boats -- My wife does not like this one at all.  She said it was too depressing.  I am kinda OK with it.  Moody.

So what have I got from spending the $6.77 and 60 minutes making it work on the digital camera?  I had fun.  A few of the pictures actually turned out ok, and, the lens with the helicoid makes a nice body cap for the camera.

Sunset at the Keating Channel

Cintagon II 48mm f2 from Argus V-100 Rangefinder

The Argus V-100 I got from the camera show was a nice surprise.  That beautiful 48mm f2 Cintagon II lens caught my eye immediately :)  I was afraid the price would be high, as the seller has some very expensive stuff, but it turned out to be very cheap, because it was in the junk bin.  Fast lenses were expensive and not often seen in the old, old days, so I was super excited.

This V-100 was made in Germany, probably by Iloca.  I read somewhere that Iloca was bought out by Argus.  This may explain why this American company had cameras made in Germany.  Most models of the V-100 came with a 52mm f2.8 Triplet lens, rather than this faster 48mm f2.  If you are looking for a V-100 with a specific lens, be sure to check what lens it has.

Blue Eye looks good, no?

The camera seemed to be working; shutter opened and closed, winder worked too.  The only issue it had, was the missing plastic button that ejects the knob/crank to rewind the film, and also to opens the film chamber as well.  I was hesitant to take it apart, fearing the reprisal from Camera God, but now that it was "broken", I guess it was OK to take the lens out to give it a second life :)

The lens module was easy to take apart, and the lens is more or less self-contained, which was a relief.  I will post some pictures in a later post on how it was taken apart and how I converted it to Sony E-Mount.  One surprise was that this lens shares the exact same helicoid/focus design as the Rodenstock Ysares 50mm f2.8 lens.  There is a certain mystery about who made some of the lenses for Argus.  I know Steinheil and Enna were two of the manufacturers that made lenses for Argus.  It's interesting that the Cintagon 48mm f2 has the same focusing mechanism as a Rodenstock lens.  Could there be some links between the two companies?

Argus Cintagon II 48mm f2 on Sony E-Mount, with Series VI hood

Another nice thing about the lens is that the front group of elements can be unscrewed, exposing the shutter blades.  I used a pair of long nose pliers to remove the blades, so that I don't have to worry about the shutter closing on me.  It also allows me to clean the lens easily.

But wait, there is more!  The lens uses Series VI filters and hoods, which is relatively easy to find, and I have few hoods in this size.  How's that for nice surprises?

My gut feeling was correct.  This is a nice lens. It's relatively sharp at f2, and even the edges are not bad wide open. From f8 on, the edges are reasonably sharp too.  Of course, even a coke bottle can be sharp at f8 at infinity, I am more interested in the rendering characteristics in closer distance. This Cintagon does not disappoint.

Wide open at minimum focus distance, the bokeh is a bit swirly but not distracting, not unlike the Rodenstock Heligon 50mm f2, which I rather like. I won't be surprised if they share similar optical designs.  Sadly, the Lens Collector's Vade Meccum (http://antiquecameras.net/lensvademecum.html) does not have any information on the Cintagon II 48mm f2 lens.  I rather like the rendering characteristic of this lens.  To be sure, it's not a very contrasty lens, but pictures hold a lot of details, and very malleable in post processing from RAW.

I only had one session shooting with this lens.  The rather long minimum focus distance sometimes leaves me wanting, and I may convert it again to be used with a focus helicoid, I found it to be an enjoyable lens to use nevertheless.  Who knew a few dollars could provide so much fun?  New Year Resolution be damned!

All pictures below were taken with Cintagon II 48mm f2 & Sony A7