CI Photocommunity

Register a free account now!

If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.

Contax G1 upgrade to green label

pfharrison

Well-Known Member
I know that this has been covered elsewhere using the G2 repair manual, and I tried this when I managed to borrow a green label G1 to check against my Silver label G1. The 2 cameras are similar serial numbers between 80000 and 81000, and 1 got the upgrade the other didn't. The sliver G1 has all sorts of focussing problems with the 90mm and sometimes with the 45mm. One thing that I noticed comparing the lens data between the 2 cameras, is that the table entries for the 45mm and 90mm lenses are different, it would seem that the green label upgrade did more than add support for the extra lenses, it appears to included a modification for the 90mm and 45mm lens support. I suspect the data that changed are motor commands, I have seen it claimed that some of the G1 left the factory with he wrong numbers set up in them, that caused the lens to be moved to the wrong place, and so the image to be out of focus, even in manual focus mode. I have managed to adjust the auto focus on the camera as well to set it to match the green label G1. Sadly there are enough differences between the 2 cameras for the method used for the G2 to not work on the G1 without some modifications. I suspect the differences in lens data may explain the whole the autofocus is terrible, no it is user error debate, as some of the cameras are set up incorrectly and will never work reliably with the 90mm and 45mm lens until the correct motor data is entered. This does however seem like it may be possible. I have noticed that the Green Label G1 performs a lot better than my Silver label one did. Is anyone interested in the results I get?.
 

pfharrison

Well-Known Member
It seems that there are quite a number of differences between the G1 and G2 eeprom data layouts, the lens data from my upgraded G1 for the 21mm and 35mm lenses does not match that extracted from the G2 and posted on the web, and it seems that the whole autofocus adjustment set up is different between the G1 and G2, the G1 has less data points that the autofocus has to be measured at and the method of calculating the correction is different. I have used the data from the green label G1 to update the Silver label G1 for the 21mm and 35mm lenses. Interestingly when setting up the autofocus for the G1, you are supposed to wait 15 secs before taking the current autofocus value to use to calculate the correction for the distance point you are setting u[p.
 

exloco

New Member
Please, Log in or Register to view quote content!
Hello, it looks like I found your video on Youtube about the update of lens data values.
And it looks like here you explain why my values in G1 silver label are different from those you've posted in the video and which have been taken from G1 green label
Do you have any recent feedback on this topic?:)
maybe some info how your silver G1 operates after the lens data values modifications and with which lenses have you tested it?)
Thanks!
 

pfharrison

Well-Known Member
The G1 silver label has been tested with the 90mm, 45mm, 35mm, and 28mm lenses it works as I would expect with all of them. I have not tested the 21mm as I do not own one. Obviously you still get issues with the autofocus getting the wrong distance, but it seems to be focussing the lenses at the correct place, when the autofocus looks sensible. The values in my G1 silver label originally did not match the values in the green label G1, so I upgraded the values to match the values in the green label G1. The G1 and G2 lens data formats are not identical as listed in the factory service manuals, my best guess is that they put some fix into the data for the G1 Green label update, I seen it claimed in a review that the put the wrong numbers into some G1's online in a review.
 

exloco

New Member
Please, Log in or Register to view quote content!
Thanks! Yes, I also think that copying values from G2 is not a good idea, because they have different autofocus mode from G1 and definitely different operational firmware.

Have you noticed any improvements/difference/changes in lens AF operations after updating the values in your silver G1?
 
Top