DP1 failure - Bye, bye Sigma ...

Started May 25, 2009 | Discussions thread
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pkaliaf Regular Member • Posts: 327
DP1 failure - Bye, bye Sigma ...

Hi to all,

In the last days the AF noise and laziness were obvious. Yesterday, the lens could not retract fully, the message "Replace cup and retry" was in the screen but nothing worked. I never was so careful with any other camera as my DP1, but after appr 3,300 shots the failure appeared.

What happened? I dismantled the camera (I am a mechanical engineer doing a lot of industrial design and I have serviced a lot of cameras for friends as a hobby) and as suspected the problem was in the lens - sensor unit.

The AF mechanism acts on the last lens element by a small motor and nut-bolt transmission. The nut was broken and the rear element which is pushed by a weak spring was out of position and trapped between the sensor and the lens barrel so the lens could not be retracted fully.

It seems that the design team did not do any Hazard and operational study, to check what will happen if ... (ie a small circlip could prevent such failures...)
I cannot do the repair as the small nut is broken and where can I find spares?

Even if the camera was repaired I should not used it anymore because what I saw behind the body made me uncertain for a lot of things. for example :

  • A lot of wear in the lens unit plastic barrel grooves, not justified for less that 3,000 starts appr

  • The sensor unit is bolted in the lens unit with a lot of various thickness shims between, obviously to compensate the production tolerances and inaccuracies. This means that unavoidable some cameras should not have perfect positioned sensors (resulting in decentering, left and right or top and bottom different focal planes etc). And for service, no chance to be done by anyone but only in Sigma Japan. I don't like to send the camera there for service. But if the production standards were higher maybe there should not be the need for such shims.

  • The ribbon cables are so thin and fragile - what specs here? - I haven't seen such cabling in any other camera.

  • The optical design in not fine tuned between lens and sensor - the IR filter is in the sensor unit, while the last element is so close and the coatings seem not to be the best for this application - now I could understand all the flares and strange patterns whenever there was a strong light in the scene (sun, moon, lights etc). Don't they shoot / test in the sun? only in the lab?

  • There is no environmental protection against dust, sand etc - I noticed dust in the sensor, but if someone sees the gaps between metallic body cap and plastic body elements will not be surprised. No gaskets, no seals, no glue at least ...

Finally DP1 is not a high quality construction, I have the suspicion that the same applies for DP2. For DP2 worst problems like slower AF, lens units failures, start up failures are to expected, due to obviously more mass to be moved.

For sure DP1 is a "camera with principles" as they say, but for them and for IQ, this is to be respected. But it is not with principles and respect for the consumer's money. Especially in the case of accidental falling or whatever, the camera has to be sent in Japan for service and calibration (due to the shims between lens and sensor and substandard cabling and connections). Good luck...

Overall this camera reminded me the Italian motorcycle and car designs of 70's and 80's, ie Ducati. Brilliant ideas so badly executed.

By the way with the money I was prepared to buy DP2, I can have a Pentax K-m (K2000) and DA40 Ltd, not compact exactly, but portable.

So for now, bye, bye Sigma for me. Good luck to all of you.
A lot of photos are available for anyone interested.

I will miss two things : First this wonderful forum and all of you nice people and second the DP1 exceptional lens


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