GX200 AF problem

[odklizec]

I'm sure, many of you noticed an overall image softness at tele end. Aside the slightly soft starting aperture (f4.4), the problem seems to be caused by GX200 AF. It's not consistently reproducible, but there is a consistent cure for this problem All you need to do is to use the Macro mode. Unfortunately, this will make the already slow GX200 AF even slower. But it definitely helps.

Here are some samples...

 

[odklizec]

In the end it looks to be HW rather than a SW issue. There is quite the same problem described at DPReview Ricoh forum...
http://forums.dpreview.com/forums/read. ... e=33084304

What's interesting, the serial numbers of both affected cameras are pretty similar. My is VW34101973, his is VW341038XX. Is there anyone else with the same GX200 AF problem and similar serial number?

 

[rui fernandes]

Mine is VW 14101473, FW v 1.25

One of the first things I noticed with GX200, coming from R3+R4 experience, was the accuracy of the Infinit Focus, not needing to set the Macro Mode like I was used to. So this problem made me curious ;-)

I did a quick comparison between all the AF modes (except Manual), and also between each one + Macro. Macro mode superimpose every Focus mode in a similar way. First run was made in P Mode, with F 8.9; 1/400, and some undexposed shots. Turning to A Mode, with F 5; 1/1000, I've got much better results. BTW, all done with a mini tripod and Camera Shake Correction Off.

Conclusion: no problem with AF in the Tele End.

Now, after the test, while posting this I did another comparison between the center and marginal areas (thanks to Faststone Viewer comparison mode). So I found another problem that puzzles me: the center area is very similar, but the left and the right areas are different. Where it's better with Infinit is worst with Macro, and where's better with Macro is worst with Infinit... it happens the same between Macro and the other modes (except SNAP, of course), and there's no difference between all the shots taken with Macro. So the lens behaviour seems consistent with this mode but not between modes?

First one set to Infinit, second with Macro (100% crop):






Conclusion? :roll:

 

[rui fernandes]

Maybe you can find the full size shots useful. Remember that it was done with the Tele end, and focused on the "as far as possible" center area. The first set of shots was made with a different frame than the one's I've posted, placing the trees in the center wich confused the AF sensor because of the strong wind. So, please, don't pay attention to the green stuff ;-)

Infinit AF
http://farm3.static.flickr.com/2498/394 ... 9a47_o.jpg

Macro Mode
http://farm4.static.flickr.com/3485/394 ... 1826_o.jpg

 

[odklizec]

Now this is interesting The first pair of crops looks exactly like the problem I have with my GX200. But the other crops are something different? To be honest, I have no explanation for that weird results. Part of the softness seems to be caused by heavy noise reduction, but it does not explain why one part of the photo is sharp and the other is soft, even though all parts should be in the same depth of field? It's really weird.

 

[x_holger]

Well, I'm the one with serial number VW341038XX ;-)

With my GX200 most of the AF-problem occur at widest setting (f=5.1mm) near infinity. Multi-AF and Spot-AF produce soft pictures, manual focus at infinity produces sharp images ....

So far Ricoh Service in Germay claims that my GX200 is within specs and no problem is to be found .....

Multi-AF

manual focus at infinity

 

[odklizec]

Welcome here x_holger! I as I mentioned at dpreview forum, I would try your luck with German service one more time. If you send me your RMA number, I can forward it to my contact in Ricoh Europe so he can personally look over it. There is no way to call that big difference "normal" or even "withing the specs"!

 

[silvio]

...,

Serial Number: vw14100229 ... aaaand ... "no problems" :geek:
I'm a happy camper with my GX'es, sorry for you guy's :roll:

 

[x_holger]

My camera came back from Ricoh this morning and I took it on a walk.

So far I didn't find any problems with AF in tele photos. Multi-AF and Spot-AF gave me the same results as manual focus.

At wideangle setting it's a bit different. Maybe I expect too much from a small compact camera like the GX200, usually I use a Nikon D300 for critical shootings.

I have a standard subject just for testing if cameras and lenses are properly working and the GX200 unlike any other camera failed exactly in this situation, so I was really worried. I posted the results of this quick test.

Now the camera has come back from service, but Multi-AF (and sometimes Spot-AF) still fails from time to time to deliver sharp pictures in wideangle setting, surprising as this may sound given the enormous depth of field at f=5.1mm. It usually depends on the subject and the lighting conditions.

Certainly not perfect .... but on the other hand the user interface of the GX200 is highly customizable. It's no problem to switch from AF to MF by just pressing the function button and estimating the distance at wideangle is easy ...

So my impression is that the autofocus system of the GX200 has its quirks and issues and I can also imagine situations where AF will fail at tele-setting, especially in low contrast or weakly illuminated conditions.

I decided not to worry anymore, Ricoh says that the camera is within specs and the service has tested it thoroughly. They included a test report when they sent it back to me.
So good, so bad .... I guess I have to live with the camera's limitations.