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-   -   Image not from centre of lens (https://www.dvinfo.net/forum/panasonic-dv-mx-gs-series-assistant/6630-image-not-centre-lens.html)

Yow Cheong Hoe February 5th, 2003 02:51 AM

Image not from centre of lens
 
OK, here goes:

MX and other Panasonic users, please check if the image is actually captured from the centre of the lens.

My MX350 is taken about 20% more on the left side and slightly to the top.

I met up with Steven Khong, his MX300 image is taken about 10% more on the right side.

The 'image' mentioned is video image. For my MX350, the stills are also offset similarly.

Frank Granovski February 5th, 2003 03:36 AM

How are you playing it back? On the viewfinder, LCD or a TV or Monitor?

Yow Cheong Hoe February 5th, 2003 04:05 AM

On my Panasonic TV, thanks to the overscan, less obvious, but still lop-sided. On LCD which is almost the same overscan as my Panasonic TV, it is lop-sided. On monitor, where the whole frame is visible, it is severely lop-sided.

You can try this experiment at home:

1. Cut a piece of card the size of your favourite filter ring (or sheet, for Cokin users).
2. Cut a nice neat small hole of about 1cm in the centre.
3. For completeness, you can even cut some slots to simulate crosshairs!
4. Push the card in front of your UV-guard (this everyone should have!)
5. Turn on the cam and record.
6. Playback and compare on LCD, TV and monitor.

Premiere actualy has crosshairs on the preview window. Check that the 1cm-circle is where you have cut it - that is right in the middle.

My MX350 is NOT!

I didn't do the experiment above but I used an external rubber hood and the hood shows. That's not the problem, the problem is that the hood shows different sizes on the four corners, mostly on the left top, then the left bottom, sometimes on the right top, and none on the right bottom. Anyone knows where I can place a sample shot? Maybe I'll e-mail to Frank, what say you?

My digital still cam, Fujifilm Finepix S602Z, has the same vignet on all four corners.

Frank Granovski February 5th, 2003 04:17 AM

Sure, e-mail to me! I'll print these instructions and try it for myself, in the next day or 2. Why do you guys make me work all the time? Where's Terrence? Click here:

http://www.8palm.com/sadsingl.gif

Yow Cheong Hoe February 5th, 2003 04:21 AM

Didn't specifically wanted to make you work, just a general post to fish info from everyone here.

The implications are quite interesting. Filters with centre-ness will be a problem. I was considering the sharp-centre-soft-outside filter, but I can't use that now! :( And those multi exposure filters with honeycomb images will be lop-sided!

Thanks for your help, though.

Frank Granovski February 5th, 2003 04:28 AM

Don't get me wrong. I was joking with the comment, you guys are always making me work. This is interesting, so I do want to check this out. I'm going to try and do that test tomorrow, since here in Vancouver, it's almost 2:30 am! (I'm just winding down.)

Click here for pic:

http://www.dvfreak.com/mx300.jpg

Frank Granovski February 5th, 2003 07:22 AM

Okay, I'm still up, and it'll be another 5 hour night for me. I checked your pics. It looks like a problem with something in front of the cam: filter or more likely, lens hood. (Thanks for the pics and e-mail.)

I also did a number of tests with my NV-MX300A, Cokin UV and the original MX rubber lens hood. Sorry! All I see is a clean picture, through my LCD, viewfinder and TV playback via my AIWA MX100 AV/VCR converter. I did this in all the cam's optical zoom range.

Sorry about your former MX8! The weather here is cool and a tad humid, but warm and sunny during the day---so the days are when to carry around my SLR without my lil' flash. Cheeks! That''s where it's at.... Just shoot and be happy!

Any rumours of a MX600 in the works?

Yow Cheong Hoe February 5th, 2003 08:32 AM

I certainly wasn't saying that you are unwilling to test this out. I was really trying to ask for similar experiences from other users.

I understand that the vignetting is due to a rubber hood in front of the lens. I am fine with the hood causing vignetting. There was vignetting on my digital still camera also, but that's equal on all four corners.

What I am not okay with is that the hood is showing mostly on the upper left corner, a little less on the lower left corner and sometimes a little on the upper right corner.

This tells me that the CCD is not aligned to the centre of the lens!

The implication is that filters with a 'centre' cannot be used properly on my MX350!

This problem may not even be specific to Panasonic!

Jeff Donald February 5th, 2003 09:02 AM

More than likely the viewing device (cameras view finder, TV etc.) is not calibrated for precise viewing. I suspect if you view the footage on several different TV's they will all be different. That's why professional B & W viewfinders cost $1,000's. They are and can be precisely calibrated. The same with expensive production monitors. If the CCD and lens were not properly aligned, you would be complaining about the severe color fringing more than the slight misalignment.

Frank Granovski February 5th, 2003 04:36 PM

"That's why professional B & W viewfinders cost $1,000's. They are and can be precisely calibrated. The same with expensive production monitors."

Yup. But the extra monitor defeats the purpose of going with these small cams: portability, low price. But then there was the AG-EZ1! Pana don't make 'em like they use to, that's for sure. And the same could be said about Canon's Optura, Optura PI and Elura. Then there was Sony's TRV20 and TRV900....

Yow Cheong Hoe February 5th, 2003 07:11 PM

I can understand that TVs, LCD, viewfinder and monitors are not all precisely calibrated, but the lop-sidedness is seen on the un-cropped DV file on my desktop. Fringing is a problem, but in video, where everything passes in a moment, it is not as problematic for me as compared to still photos, where we scrutinise for days! The most annoying part is that we can't use creative photographic filters on the video cam.

Another point against the lop-sidedness, I have just reviewed my wide-angle lens footage and the 'fisheye' is not centred. This is seem as uneven distortion, and very obvious on a slow pan, and looks as if the camera is pointing to somewhere a little right of the centre.

I have checked on my ex-MX8 (I have it now because my friend sent it to me for repairs). Almost the same problems, and being wider angle than the MX350, the same rubber hood I used is viewable even on the cropped TV screen! The offset is roughly the same as that of my MX350.

I will be meeting another MX350 user soon, here in Singapore, I'll also check on his machine.

Jeff, is this very common? Or does it happen on non-pro cameras? A little off is probably acceptable, but on my MX350, it is getting a little frustrating.

Jeff Donald February 5th, 2003 07:32 PM

If it is as much a problem as you say, I would send it back to panasonic for them to check. It is possible the lens is not aligned properly. I've seen that happen from the camera getting knocked or bumped hard. The lens will still AF and AE but it is misaligned. Panasonic can check it easy with a registration chart.

Yow Cheong Hoe February 5th, 2003 09:17 PM

The Singapore service centre doesn't seem to know of this as a problem. More like "if there's something on the screen, it is not spoilt".

But I'll follow your advice and pester them. Right now, I see about 30 sets of camcorders (from VHS to MiniDV) in their service centre awaiting repairs!

Frank Granovski February 6th, 2003 05:06 AM

Re: "Right now, I see about 30 sets of camcorders (from VHS to MiniDV) in their service centre awaiting repairs!"

Well, I don't think that they like to advertise their faulty cams; it's bad for business.

Yow Cheong Hoe February 6th, 2003 08:14 AM

I agree that that's bad for business, but I have never been in a Canon repair shop or a Sony repair shop. May have more there! ;)


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