G2 lens alignment

[marc van gend]

Recently, I purchased a lensmate adapter for my G2. I had been looking forward to trying the reversed lens trick: using an old Olympus 50mm/f1.8, attached backwards, as a close-up lens. Doing this, I noticed something strange. My G2's lens is not centered in respect to the threaded ring on the body on which you screw the adapter.

To illustrate this, I made a picture with the lensmate and olympus lens attached, focal length 7mm, f8.0. I resized it, placed a red cross over it to pinpoint the exact middle of the image and resaved as 8-color gif (just to be nice to low-bandwidth surfers). As you can see very clearly, the center of the lens is not aligned with the center of the Lensmate with Olympus lens.



I checked wether this was caused by the lensmate or the Olympus lens by rotating them (unscrewing a little), but it wasn't. The white circle didn't move at all while doing this, so it's safe to conclude that the lens is not in the center of the threaded ring.

Of course this is not a serious problem, nor will it dramatically affect image quality. However, I would like to know if anyone else noticed this on his/her G2 and if it is considered 'normal'.

Thanks,

Marc

 

[marc van gend]

Sorry, I put the picture online but it seems to take a while to crawl from ftp server to http server. Please be patient if the image in the first message is not visible yet.
MArc

 

[B. H.]

Image file isn't showing up yet; again, the URL is



Yes, I have here what seems a misalignment of the lens barrel and adapter ring. My concern was with chromatic aberration which might be caused by this. I had done a simple test using thin cardboard with pin holes placed at the corners, center, and inbetween. With it backlit, the pin holes were dots of light and showed the well-known blooming effect but not color shift. The majority of blooms were to one side instead of perfectly centered on the pin hole but almost all facing away from center. Only one or two appeared nearly centered and those were a little to the left of middle of the photo (I think, been several months since I did this). My lens is toward right when looking from the back of the camera as you would for taking a picture.

I might ask for that to be checked when I send the camera on for the cracking fix. What I need to try is a test photo using a better way to check for misalignment, like a paper with thin concentric rings on it, but an adapter lens might really help with that.
--
Farewell,
Bob H.

 

[Ray Ransome]

Image file isn't showing up yet; again, the URL is



Yes, I have here what seems a misalignment of the lens barrel and
adapter ring. My concern was with chromatic aberration which might
be caused by this. I had done a simple test using thin cardboard
with pin holes placed at the corners, center, and inbetween. With
it backlit, the pin holes were dots of light and showed the
well-known blooming effect but not color shift. The majority of
blooms were to one side instead of perfectly centered on the pin
hole but almost all facing away from center. Only one or two
appeared nearly centered and those were a little to the left of
middle of the photo (I think, been several months since I did
this). My lens is toward right when looking from the back of the
camera as you would for taking a picture.
I might ask for that to be checked when I send the camera on for
the cracking fix. What I need to try is a test photo using a better
way to check for misalignment, like a paper with thin concentric
rings on it, but an adapter lens might really help with that.
--
Farewell,
Bob H.

This off-centre lens arrangement is used on ALL G2's....I remember one reviewer drawing attention to it, to support his theory that the G2 shared its lens with 2 or 3 other digicams....

Can't remember which review, except that it was definitely either on here, Steve's Digicams, DCRP or Image Resource...Shouldn't be too difficult to locate
--
Ray

 

[sap]

i believe the lens/ccd alignment is pretty well fixed so alignment between the 2 is not supposed to be an issue. how this assembles into the body should not impact image quality.
i'll try to find the thread that i read this in.

Recently, I purchased a lensmate adapter for my G2. I had been
looking forward to trying the reversed lens trick: using an old
Olympus 50mm/f1.8, attached backwards, as a close-up lens. Doing
this, I noticed something strange. My G2's lens is not centered in
respect to the threaded ring on the body on which you screw the
adapter.

To illustrate this, I made a picture with the lensmate and olympus
lens attached, focal length 7mm, f8.0. I resized it, placed a red
cross over it to pinpoint the exact middle of the image and resaved
as 8-color gif (just to be nice to low-bandwidth surfers). As you
can see very clearly, the center of the lens is not aligned with
the center of the Lensmate with Olympus lens.



I checked wether this was caused by the lensmate or the Olympus
lens by rotating them (unscrewing a little), but it wasn't. The
white circle didn't move at all while doing this, so it's safe to
conclude that the lens is not in the center of the threaded ring.

Of course this is not a serious problem, nor will it dramatically
affect image quality. However, I would like to know if anyone else
noticed this on his/her G2 and if it is considered 'normal'.

Thanks,

Marc

 

[marc van gend]