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.

Zeiss -v- Yashica ML lenses - 200mm f/4

I've had the opportunity to do a side by side comparison of a couple of Zeiss and Yashica lenses. It's not the sort of thing I normally bother about but one of the lenses is the Yashica 200 f/4 ML C (compact) which has an excellent reputation and I was interested to see how it compared to its Zeiss equivalent. The other comparison is between the Yashica 50mm f/1.7 ML and its Zeiss equivalent. That will appear in another post (eventually). Sorry, won't be happening as I've sold the Yashica lens.

Zeiss                                     Yashica

The two lenses are very similar in size and weight. Here's the specifications for both:

	Elements/Groups	Angular field	Min. Focus	Aperture range	Size (mm)	Weight
Zeiss	6/5	12° 40’	1.5m	f/4 – f/32	66.5 x 122	550g
Yashica	5/4	12° 30’	2.5m	f/4 – f/22	64 x 113.5	535g

The Zeiss has a filter size of 55mm, the Yashica 58mm.

This is not a scientific comparison, just a few shots on each lens compared against each other. I attached the lenses to my Sony A7II and photographed the roof of a nearby house putting the corner of the roof alternately in the middle of the frame and in the corner of the frame. I took photographs at f/4, f/11 and f/22.

I also took photographs of some out of focus highlights and also of a blank wall to check for vignetting and another wall to check for distortion.

The last photographs of the wall (not shown here) showed both lenses have slight pincushion distortion with nothing to choose between them. What they also showed was the focal length of the  Yashica is about 95% of the Zeiss. This is contrary to what the specification suggests. I'm not able to measure the exact focal length but just did a comparison of the two.

Vignetting at f/4 was very similar with both lenses.

Yashica

Zeiss

The images of the out of focus highlights are similar.

Zeiss

Yashica

Here's the rest of the images to compare for sharpness and contrast. All the images are 100% crops.

Yashica centre f/4

Zeiss centre f/4

Yashica centre f/11

Zeiss centre f/11

Yashica centre f/22

Zeiss centre f/22

Yashica corner f/4

Zeiss corner f/4

Yashica corner f/11

Zeiss corner f/11

Yashica corner f/22

Zeiss corner f/22

Both lenses are showing chromatic aberration when used on my Sony A7II. More so towards the edge of the images as is usual. I don't think there's any significant difference between the two lenses though.

One area of difference between the lenses is their compatibility with converters. Zeiss made x1.4 (Mutar III) and x2 (Mutar II) converters specially matched to some of their lenses including the 200/4. These converters can't be used with the Yashica as they are mechanically incompatible. But other converters can be used including the Zeiss Mutar I x2 converter. I took some more photographs using the Mutar I and Mutar II converters. The images are 100% crops.

Yashica f/4 Mutar I

Zeiss f/4 Mutar II

Yashica f/8 Mutar I

Zeiss f/8 Mutar II

My conclusion is that there is negligible difference between the two lenses. Yes, you could say one is better than the other in some instances but it's not always the case that the Zeiss is better than the Yashica which is what might be expected. In normal use, I would be happy to use either based on these results.

FX-3 Super 2000 - spot the difference

Can you spot three differences between these bodies? (click on the images for larger versions).

So what's the difference and why.

The top one is the earlier version of the FX-3 Super 2000 (I call it the mk1), the bottom one is the later version (mk2). The visible differences are the strap lugs, the badge and the finish on the grip - the mk2 has a moulded finish to the grip while the mk1 has a stick on, leatherette, cover that matches the other covers.

There are a few internal differences as well but they are pretty insignificant. A few changes to the cover mouldings to reduce the part count mainly. I did replace the shutter in the top one of the two examples shown and found a slight difference between the one fitted and the spare one I had which may have come from a later camera. But it only required the swap of one gear to make it compatible.

I don't know why these changes were made. The later one appears slightly simpler in construction so it may have been a cost saving exercise to make assembly easier and quicker.

Anyone looking to buy an FX-3 shouldn't have any concern about the differences - they make no difference to the function or the reliability of the camera.

Note: In calling these two versions 'earlier' and 'later' or 'mk1' and 'mk2' I'm making assumptions about their age. I might be wrong. It's possible what I consider to be the later one might be the earlier one. But as the mk1 is more similar to the earlier versions of the FX-3 I'm assuming that one came first. It's also possible they were made in parallel but in different factories. If anyone has any information, I would be interested to see it.

Documents update

I've just added the Yashica FX-D repair manual to my documents page.

One useful item in it is a clear description of how to align the viewfinder LEDs. This is just as relevant to the 139 and as I always end up turning the wrong screw in the wrong direction, I'll be keeping a copy of this somewhere to hand.

Is your 139 locked up? This may help.

The Contax 139 is an electronically controlled mechanical camera. 'Mechanical' in that all the physical operations are driven directly by operating the film advance lever or by springs that are tensioned by the same action. Those springs subsequently drive the mirror up, rotate the shutter main shaft, drive the shutter curtains and return the mirror back to its normal position - in that order. Without any electronic control, all the steps in the sequence will still happen if manually triggered. The electronics just introduce a delay between the release of the first and second curtains by blocking the release of the second curtain with an electro-magnet and so controlling the period the shutter is open for.

Sometimes the sequence might not complete, or maybe fails to start, leaving the camera in a blocked condition where it's not possible to operate the film advance lever and the shutter release does nothing. Here's some tips on identifying where the problem could be and what might be done about it.

The first step is to identify if the sequence has started and, if so, at what point it has stalled. This is done by inspecting the position of the mirror and the shutter curtains. Check if the mirror is up or down. Also check if the shutter is open or closed and, if closed, whether it is still cocked or not. The following two pictures show the shutter in both cocked and released condition looking at the back of the shutter.

Shutter cocked

Shutter released

Possible scenarios:

1. Mirror is down and shutter is still cocked.
The sequence hasn't started. Watch the data back LED located at the bottom left of the shutter (visible in above pictures) and press the shutter release. If the LED flashes, the most likely fault is the release magnet is stuck. The release magnet is a permanent magnet which holds the mirror mechanism in its cocked condition. To release the mirror, an electro-magnet, wound around the permanent magnet and in opposition to it, is energised so cancelling the permanent magnet field and releasing the mechanism. The face of the magnet can become contaminated causing the release lever to stick to it even when the magnetic field is cancelled. The solution is to clean the magnet and release lever faces. There is more information on this on my DIY page. If the data back LED doesn't flash, the release signal is not getting through to the magnet driver circuit. Most likely cause is the transfer switch but there could be other reasons. More investigation is required.

2. Mirror is up and shutter is still cocked.
When the mirror reaches its up position, the mirror mechanism triggers the shutter. See the bottom of the page for a description of the couplings between the mirror mechanism and the shutter. With care, it is possible to manually trigger the shutter.

Triggering shutter

If the shutter triggers, the shutter is not at fault and the problem is with the mirror mechanism. Most likely cause is the lever of the mirror mechanism that contacts the shutter release lever is seized due to corrosion of the snap rings holding the lever onto its pivot. Another possible cause is that the mirror has not moved up far enough to trigger the shutter. This can be caused by the mirror foam being too thick.

Corroded snap rings

If the shutter doesn't release even when manually moving the release lever, there is a fault with the shutter. It's possible something is blocking the shutter, such as a piece of broken film, so it's worth trying to blow any debris out of the shutter with a can of compressed air. Other than that, the shutter needs removing for investigation.

3. Mirror is up and shutter is open.
The first shutter curtain opens immediately the shutter is triggered. The second curtain is held by the shutter magnet. If the second curtain fails to close the magnet may be contaminated and the lever that releases the curtain is stuck to it. This is easy to check visually. See the 'Triggering shutter' picture above. The white plastic lever that is held in position by the magnet is clearly visible. In the picture, the lever is in its released position. If the magnet has released the lever but the second curtain doesn't close, there is a fault with the shutter. See previous scenario.

4. Mirror is up and shutter is closed but not cocked.
In this instance, the first thing to check is if the shutter has fully closed. Compare the shutter with the 'Shutter released' picture above. There may only be a millimetre of difference in the position of the shutter blades but that is enough to cause a problem. If the curtain isn't fully closed, it may be pushed upwards by pushing against one of the rivets. This may close the curtain and release the mirror. If this happens, the problem is likely to be the second curtain brake which can become seized, or very tight, and prevent the curtain from fully closing. There is information on my DIY page about this issue. If the shutter is fully closed but the mirror hasn't returned then the problem is likely to be with the mirror mechanism again as in 2 above.

5. Mirror is down and shutter is not cocked.
The sequence has completed normally.

Mirror box/shutter couplings

These pictures of the shutter and mirror box show the two points of contact between them. The green arrows show the coupling used to trigger the shutter and the red arrows show the coupling used to lower the mirror.

Does your 139 over expose?

If your 139 has never been serviced or had its meter adjusted, chances are it will over expose.

Almost every 139 I've seen has had a degree of over exposure. Usually between a half and one stop but sometimes more. Recently I had a 139 that overexposed by a couple of stops and decided to investigate further. This lead to me discovering that the meter sensor had become cloudy. Checking the sensors in some other cameras I found nearly all of them were cloudy to some extent and this seems to be the reason why 139s generally over expose. Looking closely at the sensors, there is a glass filter fitted over the sensor and the cloudiness is under the glass. It's impossible to remove. The glass filter is very thin and is stuck down and any attempt to remove it results in its destruction. Under the glass is a clear compound - could be silicone or something similar. It seems it's this which is going cloudy.

Here's just three I picked at random from my collection of donor cameras. You'll see two have cracked filters also although I don't think that's a problem.

To compare, here's a clear one.

In a few cameras where the cloudiness has been quite bad, I've replaced the sensors but I only had ones removed from donor cameras and they were also cloudy to some extent. What I needed was a new replacement and, amazingly, I seem to have found one.

The sensor I found is mechanically identical and has the same glass filter on it. The specification says it's sensitive to the visible spectrum with the filter removing an extended sensitivity into the IR region. As I had no specification for the original, the only way to find out if the new sensor was a good replacement was to try it. I removed a sensor from a working camera, having first done some exposure checks, then replaced it with the new one. Repeating the exposure checks gave almost identical results but probably half a stop less exposure which would be about correct as the original sensor I removed was cloudy.

For anyone who wants to replace their own sensor, the replacement I found is part number VTB8440BH from Excelitas Technologies. I bought mine from RS-Online (UK).

Edit: Couldn't resist adding this picture of a sensor removed from a 159. The 159 clearly also suffers the same problem. This one appears to have flowers growing in it and it was over exposing by one stop.

And in case anyone is wondering if the flash meter sensor also has the same problem, it seems it doesn't. The flash meter sensor appears to be the same, or a similar, sensor but there is no filter on it and the ones I've checked are perfectly clear.

UPDATE: It seems the new sensor is now out of production. DigiKey still has stock but it won't last. Buy while you can. 

https://www.digikey.co.uk/en/products/detail/excelitas-technologies/VTB8440BH/5885859