arbitrage wrote:
You are correct about that, they didn't tell us that general use of the camera would also shut down the record times of the high end video modes. I still don't think they will be motivated to do a recall on that basis alone though. I still think a FW is likely to allow some more recording times. The limitations seem too arbitrary and FW should be able to make up for some of it without damaging the camera or people's hands.
Canon sorta told people that with the footnote on their media alert recording times chart that said the times were based on a cold-start and that idle periods in LV with the camera on could reduce that. Not the most direct way to say it though.
Sy Sez wrote:
I would assume that with most of us on the forum, photography is a hobby rather than a means of livelihood; so missing an occasional shot due to an equipment glitch is merely an annoyance.
For those where photography is a primary source of income, there is one attribute that exceeds any others, be it resolution, DR, etc., etc, and that is ---reliability!!!
Canon's "5" series DSLR bodies offered that "Pro-level" dependability; but the R5 , sadly, does not live up to that reputation.
I think the price is comparatively fair for what it offer's, and I still hope to own one before long; but if I was a Pro Wedding photographer, I'd either "look elsewhere:, or plan on buying 3 or 4 bodies to fill in for the "time outs" ...Show more →
I have not seen anything that shows it’s not reliable when used for stills and low-res video.
When you sent in your 5D Mark IV for C-Log, I believe they also installed a copper heat-pipe at the same time. It was a $199 fee to send the camera in for a "firmware update" that included hardware as well. I could be totally wrong because I can't find anything about it that mentions the heat pipe, but do remember reading it.
Everyone seems to be assuming that as long as the camera doesn't shut down due to temperature while shooting stills, there is no problem with stills. I've been looking, but haven't seen a thing about thermal noise in still photos, which should be of particular concern with this camera. It would be interesting to see comparisons of photos when the camera hot, but not at the point where the white indicator turns on, and when it's cold. I certainly wouldn't buy one until that's available.
dmcphoto wrote:
Everyone seems to be assuming that as long as the camera doesn't shut down due to temperature while shooting stills, there is no problem with stills. I've been looking, but haven't seen a thing about thermal noise in still photos, which should be of particular concern with this camera. It would be interesting to see comparisons of photos when the camera hot, but not at the point where the white indicator turns on, and when it's cold. I certainly wouldn't buy one until that's available.
People don't do long exposures, and short exposure noise is only weakly temperature dependent. Photon shot noise (the dominant noise in most cases) isn't temperature dependent at all. Snapsy recently presented data showing the read noise at ISO 100 to increase by just 8% with the sensor temperature rising from 42 C to 62 C.
bobbytan wrote:
Why buy the camera in spite of the over-heating problem? Because (a) it's a fantastic stills camera, and (b) the over-heating is not a major problem for stills - which is all that I do - I don't shoot video, period. Is the R5 overpriced? I don't think so, and most people would agree with this judging by the over-whelming success of this camera. The R5 is hybrid of the 1Dx III and 5Ds or 5D IV i.e. it's the best and most loaded camera (specs and feature-wise) that Canon has ever released. Even with the over-heating problem, very few people are cancelling their pre-orders. That says a lot.
But I am still thinking about cancelling my pre-order as I don't want to have to bother returning the camera if there should be a recall. So I would like to know what Canon is thinking about doing to resolve this issue.
People don't do long exposures, and short exposure noise is only weakly temperature dependent. Photon shot noise (the dominant noise in most cases) isn't temperature dependent at all. Snapsy recently presented data showing the read noise at ISO 100 to increase by just 8% with the sensor temperature rising from 42 C to 62 C.
really? 'when the blind lead the blind they all fall in the ditch'.
photos taken with long exposure times and low light intensities at low ISO settings, most of the noise in the resulting image will be read noise. That is, it will be noise caused by the camera's electronics. All such noise is influenced by heat. The warmer the sensor, analog amplifiers, and digital processing units are, the more dark current they will generate that will be recorded as noise.
If a photo is taken with the lens cap on and the viewfinder covered all of the noise in the photograph will be read noise, which is affected by thermal conditions. This is just one among many reasons why testing a camera with a lens cap on is pretty much useless for predicting actual noise in real world scenarios in any meaningful way. To measure a signal-to-noise ratio, one must include signal (light) as well as noise (thermally induced dark current).
As a camera is cooled, the improvement would be more noticeable in low ISO images than in high ISO images. This is because low ISO images tend to have more dark current (read) noise while high ISO images tend to have more Poisson distribution (shot) noise. The improvement would also be more noticeable with images made using very weak light sources for longer exposure times, such as astrophotography, than with images made using very strong light sources for shorter exposure times.
Since shot noise is not affected at all by temperature, but by the very nature of light and the way photons oscillate in waves as they move, you'll never be able to have a zero noise image. In theory one could probably cool an image sensor and related electronics to the point that dark current noise would be undetectable.
InnomnateViem wrote:
really? 'when the blind lead the blind they all fall in the ditch'.
photos taken with long exposure times and low light intensities at low ISO settings, most of the noise in the resulting image will be read noise. That is, it will be noise caused by the camera's electronics. All such noise is influenced by heat. The warmer the sensor, analog amplifiers, and digital processing units are, the more dark current they will generate that will be recorded as noise.
If a photo is taken with the lens cap on and the viewfinder covered all of the noise in the photograph will be read noise, which is affected by thermal conditions. This is just one among many reasons why testing a camera with a lens cap on is pretty much useless for predicting actual noise in real world scenarios in any meaningful way. To measure a signal-to-noise ratio, one must include signal (light) as well as noise (thermally induced dark current).
As a camera is cooled, the improvement would be more noticeable in low ISO images than in high ISO images. This is because low ISO images tend to have more dark current (read) noise while high ISO images tend to have more Poisson distribution (shot) noise. The improvement would also be more noticeable with images made using very weak light sources for longer exposure times, such as astrophotography, than with images made using very strong light sources for shorter exposure times.
Since shot noise is not affected at all by temperature, but by the very nature of light and the way photons oscillate in waves as they move, you'll never be able to have a zero noise image. In theory one could probably cool an image sensor and related electronics to the point that dark current noise would be undetectable....Show more →
Writing short posts doesn't mean one is blind.
You confuse dark current and read noise. Dark current is the false signal induced by the temperature. It is accumulated as charge in the photosites capacitors during the exposure. It is the uneven distribution of thermal black current between the pixels that is causing thermal noise in the image. It can be cancelled by subtracting a black frame of the same exposure length.
Read noise is the noise introduced when the signal (the sum of the captured photons and the dark current) is read from the capacitors in the photosites. That noise is much less temperature dependent than long exposure dark current noise.
Dark current also gets amplified at higher ISO, making the combo of high ISO and long exposures the worst temperature dependent scenario. Read noise is quickly surpassed by black current in this scenario.
Read noise is really only relevant for long exposures if you do black frame subtraction for cancellation of dark current thermal noise. Then you get the read noise twice, and added in quadrature, as addition and subtraction of random signals is the same thing.
Lastly, I disagree that measuring thermal noise with a black frame is useless for predicting signal to noise ratio. Unless if you have no idea of how you expose.
Dark Shot Noise (σD): Dark current is a current that flows even when no photons are incident on the camera. It is a thermal phenomenon resulting from electrons spontaneously generated within the silicon chip (valence electrons are thermally excited into the conduction band).
Read Noise (σR): This is the noise generated in producing the electronic signal. This results from the sensor design but can also be impacted by the design of the camera electronics. It is independent of signal level and temperature of the sensor, and is larger for faster clock rates.
Photon Shot Noise (σS): This is the statistical noise associated with the arrival of photons at the pixel. Since photon measurement obeys Poisson statistics, the photon shot noise is dependent on the signal level measured. It is independent of sensor temperature.
Fixed Pattern Noise (σF): This is caused by spatial non-uniformities of the pixels and is independent of signal level and temperature of the sensor.
i don't incorporate dark frames as of yet. i use LENR instead. i also have not done a comparison for the 2 methodologies to determine which produces the best results. the court is out of session on which method i'll end up using.
however, people do do long exposures. and sensor temperature does have negative effects on long exposure. the question remains.
what will be the impact of the R5's sensor temperature on long exposure imaging applicable to astro photography particularly at high ISOs?
Lastly, I disagree that measuring thermal noise with a black frame is useless for predicting signal to noise ratio. Unless if you have no idea of how you expose.
i agree to disagree on this. because that is not what was stated, "If a photo is taken with the lens cap on and the viewfinder covered all of the noise in the photograph will be read noise, which is affected by thermal conditions. This is just one among many reasons why testing a camera with a lens cap on is pretty much useless for predicting actual noise in real world scenarios in any meaningful way. To measure a signal-to-noise ratio, one must include signal (light) as well as noise (thermally induced dark current).'' because he is referring to measuring or predicting noise and measuring a signal-to-noise ratio not using a dark frame to extract or cancel noise.
there is a difference. we don't do lens cap imaging to generate a dark frame. at least i don't. we cover the OTA and take an image with the same exposure time and temperature as the sensor to produce dark frames.
InnomnateViem wrote:
Dark Shot Noise (σD): Dark current is a current that flows even when no photons are incident on the camera. It is a thermal phenomenon resulting from electrons spontaneously generated within the silicon chip (valence electrons are thermally excited into the conduction band).
Read Noise (σR): This is the noise generated in producing the electronic signal. This results from the sensor design but can also be impacted by the design of the camera electronics. It is independent of signal level and temperature of the sensor, and is larger for faster clock rates.
Photon Shot Noise (σS): This is the statistical noise associated with the arrival of photons at the pixel. Since photon measurement obeys Poisson statistics, the photon shot noise is dependent on the signal level measured. It is independent of sensor temperature.
Fixed Pattern Noise (σF): This is caused by spatial non-uniformities of the pixels and is independent of signal level and temperature of the sensor.
i don't incorporate dark frames as of yet. i use LENR instead. i also have not done a comparison for the 2 methodologies to determine which produces the best results. the court is out of session on which method i'll end up using.
however, people do do long exposures. and sensor temperature does have negative effects on long exposure. the question remains.
what will be the impact of the R5's sensor temperature on long exposure imaging applicable to astro photography particularly at high ISOs?
i agree to disagree on this. because that is not what was stated, "If a photo is taken with the lens cap on and the viewfinder covered all of the noise in the photograph will be read noise, which is affected by thermal conditions. This is just one among many reasons why testing a camera with a lens cap on is pretty much useless for predicting actual noise in real world scenarios in any meaningful way. To measure a signal-to-noise ratio, one must include signal (light) as well as noise (thermally induced dark current).'' because he is referring to measuring or predicting noise and measuring a signal-to-noise ratio not using a dark frame to extract or cancel noise.
there is a difference. we don't do lens cap imaging to generate a dark frame. at least i don't. we cover the OTA and take an image with the same exposure time and temperature as the sensor to produce dark frames. ...Show more →
Regarding "people don't do long exposures", it was not meant literally. It means the people who are not concerned about thermal noise, don't do long exposures. That's why we don't hear about it from all the members here who have the camera.
If you excuse me, it is a bit difficult to follow what is your point. If it is that temperature affects long exposures, I never said otherwise and there is nothing to discuss.
alundeb wrote:
Writing short posts doesn't mean one is blind.
You confuse dark current and read noise. Dark current is the false signal induced by the temperature. It is accumulated as charge in the photosites capacitors during the exposure. It is the uneven distribution of thermal black current between the pixels that is causing thermal noise in the image. It can be cancelled by subtracting a black frame of the same exposure length.
Read noise is the noise introduced when the signal (the sum of the captured photons and the dark current) is read from the capacitors in the photosites. That noise is much less temperature dependent than long exposure dark current noise.
Dark current also gets amplified at higher ISO, making the combo of high ISO and long exposures the worst temperature dependent scenario. Read noise is quickly surpassed by black current in this scenario.
Read noise is really only relevant for long exposures if you do black frame subtraction for cancellation of dark current thermal noise. Then you get the read noise twice, and added in quadrature, as addition and subtraction of random signals is the same thing.
Lastly, I disagree that measuring thermal noise with a black frame is useless for predicting signal to noise ratio. Unless if you have no idea of how you expose.
Do you still need to subtract dark frames these days? I recall reading that many modern chips have dark current suppression at the pixel level. I think it was on Roger Clark's website (clarkvision) - he does a lot of astro stuff.
NonDecaf wrote:
Do you still need to subtract dark frames these days? I recall reading that many modern chips have dark current suppression at the pixel level. I think it was on Roger Clark's website (clarkvision) - he does a lot of astro stuff.
At ISO 100 it is usually not necessary up to 10-15 minutes exposures, as long as I don't raise the shadows much.
alundeb wrote:
At ISO 100 it is usually not necessary up to 10-15 minutes exposures, as long as I don't raise the shadows much.
Hmm I'm guessing the Long Exposure NR is just superfluous in those situations then. I think the auto setting kicks in for all exposures > 1s. Wonder what its doing.
This link, sent to me by another member, proved useful. The reviewer bought the camera, but if you're doing long exposures you should definitely be aware of this.
"Any exposure of more than two minutes will be unusable for me without Long Exposure NR active."
Reading this thread with some interest, as I have an R5 preordered, albeit my intended use is pretty much exclusively for stills, so I'm unlikely to be personally affected by the overheating issues discussed here.
That said, it does seem to me, based on the discussion here, that there is a workable solution, which is to shoot 4k HQ or 120 using external recording, then switch back to internal - if desired - for other modes and stills. Obviously that isn't practical for underwater shooting, but would it be too cumbersome to be workable for shooting weddings? Connect the HDMI, pull the cards for 4k HQ or 120, then disconnect and replace the cards when done. A nuisance, sure, but a deal killer? I'm asking because it just seems like a natural solution, but I don't shoot weddings/events and haven't used external recording, so I don't know.
That said, if folks are thinking about cancelling their r5 orders, please go ahead so I can get mine faster.
NonDecaf wrote:
Do you still need to subtract dark frames these days? I recall reading that many modern chips have dark current suppression at the pixel level. I think it was on Roger Clark's website (clarkvision) - he does a lot of astro stuff.
For astro photography, 5DIV sensor performs magnificently, even during hot summer nights. I take maybe 8 dark frames after I'm done with light frames to remove thermal noise, which naturally shows up at 3-4-5 minute exposures at ISO 800 or 1600. My ancient 40D which I use for telescope stuff is horrific with dark current in Summer. In winter it's surprisingly good and noise free even at 1600, but you really need to saturate the pixels to avoid dark current streaks.
