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Contax G System - Focus Problems
Old 07-11-2016   #1
Mjd-djm
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Contax G System - Focus Problems

Hi everyone, I know that Contax G focus problems have been discussed many times in the past but I need some advice to help keep me using the system. Firstly let me say that I have been massively impressed with the camera quality and the lens optical quality. I am even ok with the viewfinder. The key problem I have is focus accuracy. Let me say at this point that I always use the right focus bracket as the focus point and have tried all the tricks etc to get consistent focus.

Despite this, my G1 silver label is experiencing consistent back-focusing problems.

My 45mm (most used lens) seems to have the hair behind the head in focus instead of the eye (so maybe 3cm to 4cm of back focus at close distances. My 28mm is slightly better but still suffers. And my 90mm is the worst, with the focus point being metres behind my target at mid range distances (when I'm 100% sure the focus point was correct and distance was correct on camera display). I have also purchased another 45mm lens to test and saw the same problems. My last roll had around a 35% hit rate in terms of perfect focus (compared to 95% on my M6) and a further 25% where the focus was off but not enough to ruin the picture.

My suspicion is that the camera doesn't seem to focus well on eyes / faces and instead finds the vertical lines of hair behind.

I have spent a lot of time testing the focus distances displayed by the camera and have noticed that the displayed distance on camera is always more than the actual measured distanced. Using tape measure at 1m the camera displays 1.05 etc. etc. Focusing on the same object multiple times in a row I can see significant differences on the camera readout.

So my question is whether this is a problem with the G1 silver label or a more general system problem. If I upgrade to a G1 green label will this improve? I heard that the focus tables were improved with this upgrade. What about the G2? Is the AF accuracy significantly better? Enough to warrant the upgrade?

I am willing to invest in a new body but not if this is normal for the G system. I don't mind quirky, I don't mind noisy, but I absolutely need to have the focus where I want it to be.

Any help / advice would be massively appreciated.
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Old 07-12-2016   #2
Mjd-djm
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Can anyone help me with this?
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Old 07-12-2016   #3
sevo
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There will be no difference between silver and green label - but front/back focus is service adjustable, you may want to hunt down a service manual if you have a consistent error. If the error is inconsistent, the camera might be broken - or a camera like the Contax G, whose focus system is far from WYSIWYG, might be unsuitable for the tasks you put it to or the kind of handling discipline you have. The G1 simply is no camera to use wide open on difficult subjects in low light (especially if you do so with the 90mm - it does very well in Jürgen Teller style, with the 28 or 21mm, stopped down with lots of flash).
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Old 07-12-2016   #4
froyd
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I would test your suspicions on a static focus target, rather than a model.

There are many instructions and videos on how to do this, but here is a place to start: http://bobatkins.com/photography/tec...s_testing.html
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Old 07-12-2016   #5
PaulCooper
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I had a similar problem with my G2. Especially, shots taken with 90mm Sonnar wery out of focus. It's hard to get somebody even to look at those Contaxes. Nowadays very good condition G1 green label goes for less than $100 on ebay. Unless you enjoy spending your time fixing your G1 do consider that. Oh, by the way ; the focusing problem went away when I replaced the body.
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Old 07-12-2016   #6
Bob Michaels
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The ContaxG system, both G1s and G2s, were my primary cameras for about 5-6 years. I always found their focus to be very accurate when used properly. Any focus problems were either that they would not focus at all or you focused on something other than what you wanted. I never had one that focused inaccurately although that may be possible.

Mine were all very reliable and never needed servicing in spite of hard use. I did learn from the techs at Kyrocera, the official repair site, that their most common solution to focusing problems was cleaning the external surfaces of the viewfinder windows and battery replacement solved most electronic problems.

I did find the digital readout of the focus distance to not be so accurate but that seems to not relate to where the camera actually focused. The distance could read 7' when the subject was 6' away but it always focused at 6'.

I always though it was a great system as I worked with them considering what they could and could not do. Other folks simply wanted a Leica or something that functioned just like a Leica and therefore disliked the ContaxG system.
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Old 07-17-2016   #7
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Thanks for all the great feedback. I decided to bite the bullet and purchase a green label G1. Put two rolls through it and the focus is spot on, even with the 90mm. That suggests to me that there was a serious problem with my two silver label G1s or the green dot versions did indeed update the focus information. Even comparing the distance readouts from the two cameras there is typically a difference of 15%. i.e. green label shows 1m at a distance of 1m, but silver labels show 1.15m. This is the case at all distances and with 3 different lenses. I thought I would update this information for anyone else who has had similar problems. Interestingly the green label G1 has an early serial number 003***, which must mean that it was a silver label updated to green label.
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Old 07-31-2016   #8
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The only thing the green label designates is that the G1 was provided with a firmware upgrade to make it compatible with the 21mm and 35mm lenses. The original silver versions could be 'upgraded' to green labels by sending the unit to Contax.
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Old 07-31-2016   #9
lxmike
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I had a green label G1, nice camera to hold and use except l could never get consistancy with the focus of my shots, probably my fault not the cameras
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