Chromatic Aberration When Shooting Lunar Eclipse?

[basspig]

This is an issue that's been of some concern to me since I got my replacement EX1: I've been noticing green & red fringes on contrasty edges in a number of my shots, that I did not notice on the first EX1 that I got on Feb 5th.

When I shot the lunar eclipse this evening, there was tons of it on the edges of the moon, when the moon wasn't in the middle of the frame.

I'm curious if any one else is observing CA on their EX1 under certain conditions. I wonder if maybe the flare adjustments are not quite set right in the service menu. Anyone know anything about tweaking that? I don't want to touch it unless I have a good handle on how to adjust it and how to restore the original factory setup.

How many of you EX1 owners are seeing CA, particularly at full tele? (I also saw it at wide angle, with some ceiling fluorescent lights having purple edges in a wide angle shot. Didn't recall seeing ANY CA on the other camera, but I'm not sure if it also had it because the circumstances are different.

[Essami]

Would love to see some pics and footage.

Sami

[basspig]

I can't upload attachments here, so I put it on a server.

http://aamserver.dnsalias.com/images/Eclipse%20ca.jpg

I also thought the images were soft, even after fine tuning manual focus with the Expanded Focus.

Curious note: on all my cameras, "infinity" is out of focus with stars and moon. I have to turn the barrel just short of the infinity symbol to bring them into focus. Wouldn't infinity be 'infinity' on the lens barrel?

[William_Robinette]

I think a lot of lenses (all?) are like that. My Nikon SLR lenses as well as my DVX behave this way.

[Stevet]

I agree with William on the infinity setting.

Also, it does seem soft, maybe a bit over exposed. I've seen some EX1 moon shots that are tact sharp.

[basspig]

Yes, I've noticed that even my Olympus D-SLR's infinity would result in out of focus stars, moon and fireworks. I had to back the setting off just a smidge.

The moon shot looks very soft and has red and green fringes on it. It looked overexposed to my eyes, but I was only getting 70% zebras, so I assumed it was the LCD that was washing out. I found it odd that as I opened the iris, I could not obtain 100% zebras, even though the camera is set to "both". Not sure what happened with these shots. Maybe the 20ºF temperatures affected the camera's performance. But I did manually (full manual) focus the lens and it seemed to be maximally focused. We had some haze in the sky too, which may have added to the fuzzy look, but I don't think it should have been that soft.
That CA issue really concerns me though. I still can't reproduce it in the studio with bright point light sources, so I really don't know what caused it with the moon shot.

[matthew77]

Since the lens is all servo, even in full manual, I suspect that the cold had something to do with it.

The internal lube (assuming there is lube) was probably viscous and the elements didn't make it where they needed to go. Could also be the case with the mechanism that does OIS - if things were a bit off center then I can see how CA might appear. Or if the elements were in the wrong place longitudinally, the built in CA correction would mis-correct the CA and perhaps even make it worse.

I especially believe this if you say you can't reproduce the problem indoors.

When I've shot in the Arctic with Panavision gear, the techs there completely change out the grease inside the lenses so that you can turn them in the cold.

[basspig]

I just got through reading a thread on another forum about CA being a problem on the LONG end of the zoom with this camera. A photo was posted of some tree branches showing horrendous CA against an overcast (white) sky. Worse than my moon shot. So it appears that there may be issues with tele and high contrast scenes.

Now even more odd is some studio testing I did tonight. The fluorescent lights in the ceiling were visible in the top of the frame and had a blue outline at their edges in wide angle, but when I zoomed past 20mm, the CA was gone (tracking the tilt to keep the edge of the light at the same place in the frame.

I can't confirm that there even IS CA correction on this camera. The Service menu has a R,G,B Flare adjustment, but it offers no relief to the problem when tweaked, so I returned them to their factory settings.

Ironically, my moon footage shot with my V1U last year looks considerably better, albeit with compression artifacts. It was sharper, and of course, larger due to the 20X zoom lens.

With the EX1, CA is sort of fickle--it's there in one shot, gone in the next. Some footage I shot of trees against a white overcast sky showed barely visible CA. It's situation dependant.

[Stevet]

Actually, I believe CA is worse on any camera at full tele and wide open aperture.
The JVC-HD100 is real bad at this setting on high contrast edges.

[basspig]

I shot some "spectacular" scenery Sunday afternoon, mostly cliff overlooks, a dam/waterfall and some forest shots on a sunny, clear day with snow still falling off the connifer trees.
I did all my shooting in Full Manual focus, and I found example after example of severe CA, particularly at or near full tele. Much more pronounced than on my V1Us, which seem to have it more on the wide than on the tele end.
Another disturbing thing I just discovered was a zoom out shot, in which the camera was prefocused on an old dead tree trunk and I slowly pull back with the zoom. Focus is full manual, servo not engaged, and as I back out, the tree that was in sharp focus gets softer and as the whole scene comes into view, the entire picture is out of focus. But it's just certain shots--not ever one.
It seems like a backfocus issue, but I wonder if it's related to the higher-than-I-recall CA with this second camera as opposed to the first camera I received on Feb 5th.
The temperature was almost 40ºF and I was keeping the camera in an insulated bag, only taking it out after I setup my tripod to shoot about 45 seconds of video at each stop along the trail, so I don't think the camera was malfunctioning due to low temperature. The camera body had to be at least 15º warmer than the ambient.
Here's an example of the CA problem I'm seeing. Ths is typical at this zoom level, but I don't remember it catching my attention with the earlier shipped camera: