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| Exposure: Aperture F8| Shutter Speed 60s| ISO 200 |
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| Exposure: Aperture F8| Shutter Speed 15min| ISO 800 |
I borrowed Panasonic Lumix GX1 from my friend Alex to do a night photography field test, to see if it can be used for night photography. Night photography requires long exposures, this feature is a must, and surprisingly GX1 does support up to 60 seconds exposure and bulb mode. On the plus side, it also has long exposure noise reduction(LENR), this feature is useful if we are not going to do image stacking for star trail, otherwise it should be turned off.
To do a field test, I used Steve Harper's Moony 8 Rule - Aperture F8, Shutter Speed 4-8 Minutes, ISO100. Since base ISO of GX1 is 160 and maximum 60 seconds shutter speed without cable release, I chose to test with the setting of Aperture F8, Shutter Speed 60 Seconds, ISO400 and the result had sadden me, I dialed to ISO 200 to lose one stop of light and see how things go.
Here's the original copy of first image, you can click the image to zoom in -
And its 1:1 aspect ratio -
Notice the hot pixel noise? And this is at ISO 200 with 60 seconds exposure. The noise pattern is always the same. I have confirmed this by taking the dark frame with the lens cap on. As this is not luma/color noise, you can only fix it using dark frame subtraction.
So the question here is, can we use GX1 for night photography, the answer is tough one, if you are into learning night photography and this is the only camera you have, then go ahead and experiment with it, however if you are serious about night photography, and plan to make large print of your image instead of just looking good on the web, then the answer is no.
Updates: Regarding the hot pixel noise issue(fix speckle pattern), it maybe sensor defect on my friend's GX1 camera, Not many people will notice this defect unless they shoot long exposure(more than 1 second shutter speed and the speckle will start to appear). I'm yet to fully confirm about this until my friend sends to Panasonic for checking.
Did you ever figure out the issue? I was taking night exposures as well and noticed the speckle pattern as well. Hard to edit it out.
ReplyDeleteThe camera belongs to one of my friend, I have already asked him to send the camera to Panny service support but he hasn't done it yet.
DeleteI have seen night photos come out cleanly from other GX1 units, but there are small group of users affected by this issue so it may only happen to certain batch of GX1 cameras.
The reason I think this is a problem because I have run the same test on Panny GF1 and the long exposure night photos didn't appear to have similar issue.
I think what you should do is to look for any GX1 owner and if their camera doesn't have that problem, you can compare yours to theirs when sending your camera for warranty service, if not showing them the photo which has a lot of speckles.
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ReplyDeleteI recently purchased a GX1 to take on a trip; I noticed the same issue you did with "speckle" noise even at ISO 160 for 60s exposures.
ReplyDeleteThe noise is difficult to eliminate with lightroom's luminance noise reduction. It is disappointing.
I have actually asked other GX1 owners in the forum, some of them have similar problem but some are not, maybe you should go to Panasonic service centre to ask about it.
DeleteI did a test and enabled long shutter NR on 60s exposures at various ISOs and it eiminates most of the noise up until about ISO 3200, at which point the output is quite noisy.
DeleteI wonder if there's a way to do the black frame subtraction after the fact...
I guess long exposure NR is necessary on this camera; it's disappointing since it doubles exposure time and I never had this issue with my Nikon D40 or D700 (although to be fair those are limited to 30s exposures when not in bulb mode, but still, there's not even a hint of long exposure noise).
Do you know of a good way to do black frame subtraction in post? I converted the RAWs to DNG but for whatever reason photoshop doesn't let you save as DNG. Lame.
hi Spotpuff, sorry I didn't notice your follow up comments, for offline dark frame subtraction you can use pixelfixer or starstax, however one thing to make sure prior doing the processing is you need to take the dark frame(with lens covered) during the photoshoot in the field because the noise pattern maybe vary from time to time.
DeleteLENR will be a problem if you want to take startrails because you can't do proper stacking anymore as there are gaps, that's why the problem of this camera needs to be fixed or it's not suitable for night shoot, I never see the same problem with GF1 which is "inferior" to GX1.
i have same issue with my GX1. but not with GF1.
ReplyDeleteYes, and unfortunately unlike EM1 during the time I wrote about this, not many people raise this issue. Panasonic never fix this, this is not hot pixel I have mentioned about in my blog though, it is just weird it happens in certain sensors only, regardless of camera brand. And I suspect most of camera companies never do stress test on their camera for the purpose of. long exposure photography since it is not mainstream. From 43rumor readers, it's glad to know GX7 doesn't have the same problem.
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