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Low light/night problems with new Canon 6D
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May 31, 2017 10:07:16   #
bobwalder
 
Just purchased a 6D so getting to know it. I took it to Big Bend to photograph the Milky Way last week and though I got some nice results I struggled with the camera. Lens was the f4 11-24mm zoom.

I was shooting alongside 2 Nikon owners and a Canon 5D MkIII owner. The Canon owner, being experienced at night photography, was helping me with exposures. He said the sensor on the 6D should get better low light results than even his.

Here's the issue.... everyone else was shooting at ISO 3200, f2.8 for around 20 seconds. I bumped up to ISO 6400 to make up for the extra stop (f4) but ended up with exposures of 45-50 seconds just to get results comparable to the others. When they tried light painting, they were getting some amazing results (brief 1 second flashed from LED lamps on the foreground) but my camera picked up virtually none of it.

So on the face of it, my sensor was WAY less sensitive than any of theirs. I had long xposure low noise reduction set to Auto, by the way... only on certain shots did I get the long delay as it wrote to memory card so clearly it was being used occasionally... there was no discernible difference to the exposures or results so I doubt that setting was the culprit.

So..... any ideas? Faulty camera? Faulty lens? Settings I need to look at? Or is the 6D just really bad at night photography (not something's no I would have expected based on reviews)?

Would really appreciate some help, especially from other Canon owners. REALLY not looking for "switch to Nikon" type advice, thanks :0) I need to decide quickly if I need to return camera, lens or both, or if I can fix this via camera settings

Thanks in advance

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May 31, 2017 10:15:39   #
ebbote Loc: Hockley, Texas
 
You said everybody was shooting f2.8 lenses and you were shooting f4, might the lens be the culprit?


bobwalder wrote:
Just purchased a 6D so getting to know it. I took it to Big Bend to photograph the Milky Way last week and though I got some nice results I struggled with the camera. Lens was the f4 11-24mm zoom.

I was shooting alongside 2 Nikon owners and a Canon 5D MkIII owner. The Canon owner, being experienced at night photography, was helping me with exposures. He said the sensor on the 6D should get better low light results than even his.

Here's the issue.... everyone else was shooting at ISO 3200, f2.8 for around 20 seconds. I bumped up to ISO 6400 to make up for the extra stop (f4) but ended up with exposures of 45-50 seconds just to get results comparable to the others. When they tried light painting, they were getting some amazing results (brief 1 second flashed from LED lamps on the foreground) but my camera picked up virtually none of it.

So on the face of it, my sensor was WAY less sensitive than any of theirs. I had long xposure low noise reduction set to Auto, by the way... only on certain shots did I get the long delay as it wrote to memory card so clearly it was being used occasionally... there was no discernible difference to the exposures or results so I doubt that setting was the culprit.

So..... any ideas? Faulty camera? Faulty lens? Settings I need to look at? Or is the 6D just really bad at night photography (not something's no I would have expected based on reviews)?

Would really appreciate some help, especially from other Canon owners. REALLY not looking for "switch to Nikon" type advice, thanks :0) I need to decide quickly if I need to return camera, lens or both, or if I can fix this via camera settings

Thanks in advance
Just purchased a 6D so getting to know it. I took... (show quote)

Reply
May 31, 2017 10:19:06   #
bobwalder
 
ebbote wrote:
You said everybody was shooting f2.8 lenses and you were shooting f4, might the lens be the culprit?


That is one of the questions I am asking, yes. Clearly either camera or lens is at fault. I really wish I had tried a different lens... but I didn't. I will be doing additional night tests at home to try and narrow this down. Thought it was worth asking here to see if other Canon owners have had similar experience with e 6D

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May 31, 2017 10:51:43   #
SS319
 
you have larger pixel size (6.55µ v 6.25µ for the Mark III), the same filters - unless(??) - and possibly slightly better sensitivity.

I suggest that you and the Canon guy go back outside the city and set up your cameras exactly the same. If he is using a f/2.8 and you are using a f/4, then set his aperture to f/4. Take shots of the same feature in the milkyway (I'd go for the teapot), and shoot for 5, 10, 20, and 60 seconds.

Trade lenses! repeat shots at f/4 (By the way, give him a 4 or 8 gig card to shoot in his 5D so you can take it home). Evaluate shot by shot.

The unless from above. For Astro, Canon - and others will remove the anti-halon layer to gain a few ev on the sensor and to allow the photos to be used for spectrographic evaluation of the stars. IF your Canon friend has had that done, or bought the Astro version of the camera, you are seeing the effects of that.

How long were your cameras set up before you started shooting - temperature will make a difference in the sensitivity - if you inserted a battery straight from the charger.... heat! On the other hand, keep your lens cover in place until you are ready to shoot. A lens aimed at (nearly) empty sky will get colder than its surroundings!

Question for you - Stars move! in 45 seconds a star will elongate. Why don't you use the capabilities of your camera and set it to 12,800 ISO?. Put the dust cap on, cover the viewfinder with the cap or a piece of tape and shoot several 10 sec, 20 sec, and 30 sec shots with the cap on. Then, either in camera, or in Post, you can subtract the data from your sky image. I would prefer to take several shorter frames (5 sec - 10 sec), subtract the dark frame from each and then stack them. You will end up with rounder stars and big beautiful Nebulae.

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May 31, 2017 10:54:05   #
CPR Loc: Nature Coast of Florida
 
I would vote for the lens. ISO increase will amplify the light reaching the sensor BUT the 2.8 lens lets more light reach the sensor. Therefor in my mind increasing ISO can't amplify what is not coming in.................

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May 31, 2017 10:56:11   #
SS319
 
SS319 wrote:
A lens aimed at (nearly) empty sky will get colder than its surroundings!


And collect moisture on the lens, fogging the image.

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May 31, 2017 11:04:43   #
bobwalder
 
No cold. No moisture. 70 deg or more

ISO increase was purely to counter the 1 stop difference in max aperture

In other words, our exposure setup was identical, yet he needed 20secs and I needed 45 secs to get comparable results. And his camera could see the light painting effect whereas mine could not

So... was the lens ACTUALLY opening to f4 or stuck on smaller aperture? That is something I need to test. Also swapping lenses and going for same exposure at same f stop with different lenses. I will test. I am a scientist so OK with how to test for faults. What I am hoping for here is some "ah ha" moment from another Canon user, preferably 6D

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May 31, 2017 11:17:00   #
SS319
 
Your local Astrology club typically will have monthly or bimonthly viewing sessions with knowledgeable people using cameras on tripods and cameras on telescopes. They like it when people ask them "How do I..."

Scientists do not typically change two variables on the same test run. Match all settings between cameras.

By the way, I have a book titled "Wide Field Astrophotography, Exposing the Universe Starting with a Common Camera" It is from 2000 so it is film oriented, but it may offer some help. PM me if you are interested.

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May 31, 2017 11:19:41   #
bobwalder
 
SS319 wrote:
Scientists do not typically change two variables on the same test run. Match all settings between cameras.
.


I made a career out of testing complex computer security devices... believe me when I tell you I know how to test stuff.... ;o)

Good idea re astronomy club... but I can't really wait for that given short return window on this equipment....

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May 31, 2017 11:28:16   #
PGHphoto Loc: Pittsburgh, PA
 
bobwalder wrote:
No cold. No moisture. 70 deg or more

ISO increase was purely to counter the 1 stop difference in max aperture

In other words, our exposure setup was identical, yet he needed 20secs and I needed 45 secs to get comparable results. And his camera could see the light painting effect whereas mine could not

So... was the lens ACTUALLY opening to f4 or stuck on smaller aperture? That is something I need to test. Also swapping lenses and going for same exposure at same f stop with different lenses. I will test. I am a scientist so OK with how to test for faults. What I am hoping for here is some "ah ha" moment from another Canon user, preferably 6D
No cold. No moisture. 70 deg or more br br ISO in... (show quote)


If you were basing the results on the camera viewfinder, without seeing a print or viewing it on a full size monitor, it could be simply they had their viewfinder brightness turned up. I do not have a 6D but have shot astro on a 70D and taken very good shots at less than 25 seconds with a 2.8 aperture and 1600 ISO. You really should use 30 seconds as an absolute max shutter due to the rotation of the earth causing star trails at longer intervals. A friend with a 6D has not seen the issues you describe.

I am assuming you were shooting manual exposure during light painting attempt ?

Good luck identifying the problem and let us know what you find

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May 31, 2017 11:30:35   #
JimH123 Loc: Morgan Hill, CA
 
bobwalder wrote:
Just purchased a 6D so getting to know it. I took it to Big Bend to photograph the Milky Way last week and though I got some nice results I struggled with the camera. Lens was the f4 11-24mm zoom.

I was shooting alongside 2 Nikon owners and a Canon 5D MkIII owner. The Canon owner, being experienced at night photography, was helping me with exposures. He said the sensor on the 6D should get better low light results than even his.

Here's the issue.... everyone else was shooting at ISO 3200, f2.8 for around 20 seconds. I bumped up to ISO 6400 to make up for the extra stop (f4) but ended up with exposures of 45-50 seconds just to get results comparable to the others. When they tried light painting, they were getting some amazing results (brief 1 second flashed from LED lamps on the foreground) but my camera picked up virtually none of it.

So on the face of it, my sensor was WAY less sensitive than any of theirs. I had long xposure low noise reduction set to Auto, by the way... only on certain shots did I get the long delay as it wrote to memory card so clearly it was being used occasionally... there was no discernible difference to the exposures or results so I doubt that setting was the culprit.

So..... any ideas? Faulty camera? Faulty lens? Settings I need to look at? Or is the 6D just really bad at night photography (not something's no I would have expected based on reviews)?

Would really appreciate some help, especially from other Canon owners. REALLY not looking for "switch to Nikon" type advice, thanks :0) I need to decide quickly if I need to return camera, lens or both, or if I can fix this via camera settings

Thanks in advance
Just purchased a 6D so getting to know it. I took... (show quote)


How good of focus did you have on the stars? When photographing stars, the intensity drops off rapidly as it falls out of focus. You can see this easily in that the stars become fatter as they move out of focus and the same amount of light is spread over this larger area.

When I focus on stars, I use the focus magnifier and do a focus on a brighter star. But I watch carefully for dimmer stars to come into view. Once I see dimmer stars, I concentrate only on a dim star and adjust for max brightness.

You are also using a very wide angle lens and it is difficult to even see the stars with wide angle, but it still has to be done. Focus has to be perfect to see lots of stars.

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May 31, 2017 11:34:20   #
bobwalder
 
PGHphoto wrote:
If you were basing the results on the camera viewfinder, without seeing a print or viewing it on a full size monitor, it could be simply they had their viewfinder brightness turned up. I do not have a 6D but have shot astro on a 70D and taken very good shots at less than 1600 ISO under 30 seconds with a 2.8 aperture. You really should use 30 seconds as an absolute max shutter due to the rotation of the earth causing star trails at longer intervals. A friend with a 6D has not seen the issues you describe.

I am assuming you were shooting manual exposure during light painting attempt ?

Good luck identifying the problem and let us know what you find
If you were basing the results on the camera viewf... (show quote)


Thanks. I do think that he had his viewfinder turned up brighter than mine for sure, but final results on computer monitor were also strikingly different. With 11mm focal length 40-45 secs is acceptable without seeing trails. I did try bumping ISO even higher to get same 20 sec exposure they were using, BUT even by doubling ISO again I was still looking at closer to 25-30 seconds for equivalent results compared to their 20 secs.... truly weird....

Note that the situation you just quote - 1600ISO, under 30 seconds, f2.8 - is pretty much what I was seeing from the others. What I did was double the ISO to 3200 in an attempt to use same 20 sec exposure at f4.... didn't work... had to increase to 45 secs... so I was exposing for double the time as the others.

Need to check that lens is not stuck at f5.6... or camera/lens communications are broken somehow...

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May 31, 2017 11:36:22   #
bobwalder
 
JimH123 wrote:
How good of focus did you have on the stars? When photographing stars, the intensity drops off rapidly as it falls out of focus. You can see this easily in that the stars become fatter as they move out of focus and the same amount of light is spread over this larger area.

When I focus on stars, I use the focus magnifier and do a focus on a brighter star. But I watch carefully for dimmer stars to come into view. Once I see dimmer stars, I concentrate only on a dim star and adjust for max brightness.

You are also using a very wide angle lens and it is difficult to even see the stars with wide angle, but it still has to be done. Focus has to be perfect to see lots of stars.
How good of focus did you have on the stars? When... (show quote)


Thanks for that. 11mm lens focused on slightly less than infinity gave me everything from around 3ft to infinity in focus. I also tried focusing on infinity... did not actually try to focus on stars specifically... was almost impossible to see them in VF

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May 31, 2017 11:43:41   #
TriX Loc: Raleigh, NC
 
Were you shooting raw or JPEG, and if raw, what were you using to post process? My son has been experimenting with dark sky photography of the milky way with a 5D3 and a 28 f1.8 with exposures in the 12 second region. Shooting raw, he was surprised by the difference between processing with DPP (Canon's digital photo professional) and Lightroom's ACR (less noise with DPP).

The 6D has slightly better low light performance than the 5D3, so given the same lens, you should be seeing similar results. Since yours was a stop slower but you compensated with a stop higher ISO, then I would expect your results to be similar, so it is puzzling. What about posting one of your shots (and click on store original) so we can see if there's any clues in the EXIF data?

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May 31, 2017 11:44:46   #
JimH123 Loc: Morgan Hill, CA
 
bobwalder wrote:
Thanks for that. 11mm lens focused on slightly less than infinity gave me everything from around 3ft to infinity in focus. I also tried focusing on infinity... did not actually try to focus on stars specifically... was almost impossible to see them in VF


This is the problem then. You cannot treat stars like terrestrial objects where everything within a range appears to be in focus. Stars require EXACT focus, or they go away. This is what you need to practice on. Not all cameras are equal when it comes to focusing on stars. I shoot Sony and Olympus and they are rather easy to get good star focus. But I have known Canon shooters that really struggled to see the dimmer stars for focus.

Start with a longer FL lens and practice your focus so you can see the stars. Even a 50mm will allow you to go for a few seconds without star trails, but the stars will be easier to see. But master that focusing, and then repeat, and you will have better success.

And one more thought. Some lenses don't actually go all the way to infinity. In the case of a wide angle lens, this is not likely to impact terrestrial images. But for stars, it can be a disaster, since they will not tolerate the slight focus error. You will need live view, focus magnifier at max, and a wide open aperture to check it out.

Also, wide angle lenses do not gather much light. A 20mm lens at f2.8 captures light with a 7.14mm objective. A 20mm lens at f4 is only a 5mm objective. This means that it captures 1/2 as much light. Now you lens is 11-14mm at f4. When at 11mm, the objective is 2.75mm. This is about 1/7 the amount of light as the 20mm f2.8. And this is also part of the problem of using wide angle lenses. I have done some panoramas using a longer lens and creating a wide angle effect and it works well considering how much additional light it gives you to work with. For example, a 50mm f1.4 uses an apterture of 35.7mm. Compared to the 11mm f4, it is gathering 169 times as much light! Plus, it is easier to focus.

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