Yashica FX-3 Super 4000 anyone?

 I recently acquired a Map KF-M1 camera. Made by Phenix in China using a Yashica FX-3 chassis, it has a Nikon lens mount and a top shutter speed of 1/4000 sec. It's the same camera as the Kenko KF-2N which was clearly an attempt to create a camera with the same specification as the Nikon FM-2n. The Map version was made exclusively for Map Camera in Japan and, unusually, has no branding on it. There was another version called the Phenix DN66 sold in the Chinese domestic market.

I was intrigued how the top shutter speed was achieved. The Nikon FM-2n uses the same Copal shutter as the Contax S2 and I knew that shutter will not physically fit into a Yashica FX-3 chassis - I've tried it. The shutter is larger and has slightly different mounting positions. So, to find out how it was done, I had to get a camera. All the variants are rare and, if you do find one, expensive. But I found a KF-M1 in China. The seller accepted an offer but it still cost me nearly £190 with the import tax paid.

With the camera dismantled, first inspection of the shutter suggested it was the same shutter as is fitted to the Yashica Super 2000 (and many other cameras) but it has an extra position on the shutter speed selector. A check of the shutter speeds shows it is struggling to get to 1/4000 and the general shape of the test results graph is very similar to that from a Yashica Super 2000.

(Note: The upper and lower limits on the above results sheet are from a Contax S2 and are not correct for the KF-M1. They should be the same as the FX-3 limits below.)

It's not unusual for the Yashica Super 2000 shutter to be slow at the top speed but some adjustment will usually bring it into specification. I'll have to see if I can get the KF-M1 shutter closer to what it should be.

So it appears Copal produced a further upgrade to the 2000 shutter, which was itself an upgrade of the original 1000 shutter as used in the original FX-3. So I'm surprised that a Yashica Super 4000 never appeared if the shutter was available and could be fitted with no modification to the existing FX-3 chassis. Maybe it was because it would be competing with the Contax S2.

Now I need to decide what to do with the dismantled KF-M1. I don't want a camera with a Nikon lens mount. I could fit the shutter into an existing FX-3 Super 2000 or I could fit a Yashica lens mount to the KF-M1. The camera is quite well made and, unlike the Yashica with plastic top and bottom plates, the KF-M1 has metal top and bottom. The focus screen is the original Yashica one with the diagonal split prism, which I don't like, but if I change the lens mount I'll also have to change the viewfinder so that's not an issue. Whatever I do, the camera is unlikely to get a lot of use from me so if someone out there has an urge to own a Yashica Super 4000, get in touch and we can discuss.

Update: There is now a part 2 to this post at https://contax139.blogspot.com/2021/02/yashica-fx-3-super-4000-part-ii.html

Contax 50mm f/1.7 AE/MM differences

I've worked on both AE and MM versions of this lens before but have never done a direct comparison of the two. Recently I had reason to work on one of each at the same time so was able to do some direct comparisons of their construction. I thought it was worth recording what I found.

The two samples I compared had serial numbers 6504056 (AE) and 7380543 (MM). The differences noted may not be the same for all AE or all MM lenses.

Plastic/metal

The lens uses metal components for the focusing helical, plastic for the internal block that includes the aperture mechanism and carries the lens elements and a mixture of metal and plastic parts for the focus and aperture controls and front cover and dress ring. This is mostly the same in both lens versions except the focus ring on the MM version is metal but plastic on the AE version. The AE version I had showed why this change was probably made - it had cracks in the plastic around the screws that attach the ring to the focusing mechanism. This had caused the focusing ring to become loose and allowed the focusing helical to separate - which is how I came to have the lens. I have seen some cracks like this before so is clearly a potential issue.

Focus guides

Lenses of this general construction usually have one or more guides that allow the focus helical to move back and forth but stopping it from rotating. If these guides, or the slots they move in, become worn, slop or backlash can appear in the focus mechanism. Many lenses have one of the guides split so that its width can be adjusted to take up any excess. The AE version didn't have a split guide while the MM version did.

The slot in the helical component was also different in cross section which means the guide only contacts the helical at the edges in the MM version. What difference this would make I don't know.

Lens mount

The construction of the lens mount is completely different on these two lenses but I think the mount changed before the MM lenses were introduced so this isn't a AE/MM difference as such. The mount, of course, works in exactly the same way but the parts and their assembly is different.

I guess the question has to be, if the differences are so small, why is one lens suited to MM mode cameras and the other not. There may be other differences between the aperture mechanisms that are not really visible. The small constructional differences I could see between the two assemblies were not worth mentioning but maybe they do have some significance. The basic operation of both look identical.

Edit: I have, of course, passed over the infamous 'ninja star' aperture shape of the AE lenses. This is minimal on the 50/1.7 but it is present and shows the shape of the aperture leaves on the two lenses are different.

A new 139 fault

There's not many faults on the 139 I haven't previously seen but I did find a new one recently. The camera had very inconsistent shutter speeds with variations of up to half a stop in either direction. The shutter speeds are often out of specification, maybe 50% of the time, but I've never before seen a 139 with such variations.

The problem was caused by a contaminated shutter magnet so the solution was quite simple - clean the magnet. It's something I do anyway if I service a 139.

The shutter magnet is not to be confused with the release magnet, which can also become contaminated but the symptoms are different. Here's a picture of the shutter magnet. The white plastic arm has a metal plate at the top which contacts the magnet face. This plate and the magnet face are the parts that need to be cleaned.

The more usual symptom of a contaminated shutter magnet is the shutter staying open due to the plastic arm staying permanently stuck to the magnet.

Yasuhara T981

I've created a new website for the above camera. Nothing Contax related but there is some Yashica interest. You can find it at www.t981.co.uk.

Strap Lug Replacements Available

Following on from my previous post. I went ahead and had some replacement strap lugs made. These are made from stainless steel so won't wear like the originals did. Made for the 139 but they will also fit the 159, 137, RTS and RTSII.

The lugs can also be supplied if anyone wants to fit them themselves. Please contact me for prices.

Old strap lug. Insert has moved and lug has been badly worn.

New stainless steel strap lug.

Strap lug replacement

The strap lugs on the 139 are made of brass with a steel insert to stop the soft brass being worn away. Unfortunately, the idea doesn't work that well and the steel inserts move and allow the brass to be worn away. Later cameras, such as the RX, have stainless steel lugs which don't wear.

I managed to get a small quantity of the stainless steel ones but have now used them all so am investigating getting some made. I would be interested to hear if anyone would be interested in purchasing replacement lugs (or having them replaced by me) so I can judge the potential use.

Please let me know if this is of interest. Now available. See later post.

An unusual fault

Thought I'd document a fault I saw recently as it's an unusual one.

The symptoms are that, when a manual shutter speed is selected and the camera not cocked, when the shutter release button is pressed, the LED in the viewfinder that indicates the selected shutter speed will come on immediately but the LED showing the shutter speed required will not come on until after a period equal to the selected shutter speed. And if B is selected, it will never come on.

The cause was a faulty transfer switch - the first type which is a sealed micro switch. Normally, when these fail the camera won't release the shutter as the transfer switch goes open circuit and the processor never gets the signal to say the shutter is cocked. In this case, the switch went short circuit so the processor thought the shutter was cocked even though it wasn't. Consequently, the processor would activate the shutter magnet for the selected shutter speed and, for reasons I don't understand but it's probably just part of the programming, the meter is not activated and the LED showing the suggested shutter speed isn't lit.

This is only unusual in the way the transfer switch failed. I've never seen one fail this way before. And, because the camera otherwise worked normally, there was little to indicate what the issue was.