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Sunday, 2 August 2020

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.

Saturday, 4 July 2020

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.


Sunday, 17 May 2020

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. The same strap lugs will also fit the 159 and, I believe, the 137. May also fit the RTS and RTSII (if anyone can provide me with dimensions of RTS lugs I'll compare them).

The lugs are now available to buy from my For Sale page at http://www.contax139.co.uk/shop


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

New stainless steel strap lug.

Thursday, 30 April 2020

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.


Wednesday, 29 April 2020

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.

Sunday, 21 July 2019

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.
YashicaZeiss










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.

Sunday, 21 April 2019

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.