Canon will release the EOS Ra astrophotography camera

Quite the contrary. If used on a sensor with a Bayer filter array, an AA is quite beneficial for astrophotography.

Most stars are point sources of light that without an AA filter would only be recorded by a single sensel. Both the intensity and the resulting color after demosaicing would be affected by which color filter is over that single sensel. Some folks have theorized that the reason some cameras are known as "star eaters" is because without an AA filter the camera's NR routine mis-identifies those single pixels with significant signal surrounded by dozens of pixels with no significant signal to be noise.

With monochrome sensor and various filters placed between the telescope and the sensor that affect the light falling on every sensel equally, the AA filter is indeed a liability.

I don't think there's a lens as sharp so it converts a star into a single physical pixel. Also small vibrations and atmospheric aberrations will prevent the stars from being absolute points. Sony cameras are known as star-eaters because of in-camera noise reduction at long exposures in raw files https://www.lonelyspeck.com/sony-star-eater-and-how-to-fix-it/. Say A7RIII doesn't eat stars with exposures <= 3.2 sec, and it doesn't have an AA filter.
 
Upvote 0
Jan 29, 2011
10,675
6,121
So Canon is saying that the market is clamoring for a specialized astro mirrorless which makes it worth their putting their efforts on it now rather than a 7D like mirrorless? Never would have thought it with the Olympics coming up, but I'm not on top of the market trends in mirrorless cameras!
No but I expect they can pull 90% of the R&D off the shelf from previous iterations of 'a' model cameras, so its a low cost no brainer really.
 
  • Like
Reactions: 1 user
Upvote 0
I do the same type of photography - typically I'll have numerous frames for the sky, single very long exposure for the foreground with low ISO all taken without moving the camera or changing composition, and then blend them together - if that's all you're curious about then you probably don't need to read the rest - a lot of detail to follow if you're curious.
All the sky frames need to be properly aligned because of the planetary rotation, so I'll typically choose the first/middle/last sky exposure to align to as not not feel like I'm cheating in putting the milky way somewhere it wasn't or changing composition (personal guideline - otherwise I feel like it's not that different than a sky swap from another location or night, which I'm not into). Occasionally I'll put a lit tent into the frame, and in those cases I'll also need to add some exposures to manage the brightness of the tent, and light leak from the tent on to the foreground. I've included a couple examples below with what I did to get it done as examples. Admittedly, these are not for everyone's taste, but I do like them.

View attachment 186679
5D IV, Rokinon 14mm f/2.8.
Sky - 8 frames, ISO 8000, 20 seconds. All frames manually aligned using warp (that distortion is nasty - this takes forever), then converted to a smart object and set to median blend in PS.
Landscape - 2 minutes (speaking from memory here) at around ISO 2000, brought back to darker luminance in photoshop
Tent - two frames with a light on - one to illuminate the ground around the tent appropriately, one to not blow out the luminance in the tent (I can't remember the settings of each for the life of me)

View attachment 186680
This one didn't work as well because of the tree overlap with the sky, and a lot of haze in the sky requiring me to push ISO higher than usual. If you look closely near branches, you can see spots which couldn't median stack (because when you align the stars, the tree will appear to be moving) and had to be included with only noise reduction from a single exposure. I've included this example because I think comparing those less than ideal spots near the branches against the open sky gives you an idea of how much noise reduction and increases in detail you can get from an 8 image median stack relative to a single frame in one instance.

5DIV, Rokinon 14/2.8.
Sky - 8 frames, 20 seconds, ISO 10000 (honestly, increasing to 16 frames would have been a good idea here)
Foreground rocks - 1 frame, 2 minutes ISO 2000 (speaking from memory).


Awesome shots!

I was looking at the manual and wanted to ask you some questions. In the manual it notes this:
"noise in your shots may increase due to image sensor heat if, for some time before shooting long exposure, you record or leave the camera in standby
"noise will increase when taking long exposure, or shooting repeatedly"

Isn't the point of this camera for astrophotography, yet it claims that with long exposures which is needed for astrophotography will cause photos with noise that are unideal? Could I ask you your two cents on these two points pointed out in the leaflet
 
  • Like
Reactions: 1 user
Upvote 0

Joules

doom
CR Pro
Jul 16, 2017
1,801
2,247
Hamburg, Germany
"noise in your shots may increase due to image sensor heat if, for some time before shooting long exposure, you record or leave the camera in standby
"noise will increase when taking long exposure, or shooting repeatedly"

Isn't the point of this camera for astrophotography, yet it claims that with long exposures which is needed for astrophotography will cause photos with noise that are unideal? Could I ask you your two cents on these two points pointed out in the leaflet
It seems like a standard disclaimer. That is true about any camera, after all. They are just pointing it out because the application this will be used in makes it more noticeable I guess.

If they wanted to avoid that, they would have to add active cooling to the sensor and that is probably something too difficult or costly to put into a body like this.
 
  • Like
Reactions: 1 users
Upvote 0
Awesome shots!

I was looking at the manual and wanted to ask you some questions. In the manual it notes this:
"noise in your shots may increase due to image sensor heat if, for some time before shooting long exposure, you record or leave the camera in standby
"noise will increase when taking long exposure, or shooting repeatedly"

Isn't the point of this camera for astrophotography, yet it claims that with long exposures which is needed for astrophotography will cause photos with noise that are unideal? Could I ask you your two cents on these two points pointed out in the leaflet
Thanks for the compliment!

I'm not sure that I'm the ideal person to comment on the camera, as I don't think I'm the target market, so definitely take my comments with a grain of salt. First off, that happens to every camera on long exposures when the sensor gets hot. I find that when I do a lot of long exposures the corners of the sensor may have some weird colors (it often goes kind of purple) when you start processing. I just try to process that out.

In this case, Canon may make that disclaimer because the target market for this camera is likely to be more discerning than me when it comes to the final images and wants to be clear on performance. If you're ready to buy a camera for astrophotography which Canon even suggests won't be great for daytime photography, then you already have a very niche need. Most of the astrophotographers I've met, that have modified cameras for the medium, and are doing deep sky photography where being a bit more sensitive to specific wavelengths of light is of great value. I believe this becomes more important when you need fine detail in distant nebulae and etc. Also, I believe these photographers are often overlaying even hundreds of images (or more) to extract more detail out of their images - often capturing images of one subject over multiple nights. That kind of fine detail would be largely lost in the types of images I create, so I'm not sure it is necessary for me.

Here's a review of the 60Da, an earlier astrophotography camera created by Canon, by someone who started shooting astrophotography in their back yard with really simple equipment and progressed quite far. The article is a bit old, but it gives a good run down of why a specialized astrophotography camera has value: https://astrobackyard.com/canon-60da/

Hopefully that was helpful!
 
Upvote 0

knight427

CR Pro
Aug 27, 2018
156
284
There is software that can stack the sky and ground separately if you draw a border between them on one reference frame. Sequator is a good example of this, as it is free and provides really good results.

The alternative to getting better astro images is using a sky tracker, but in that case you still have to do processing because you have to merge a shot of the sky (where the ground is blurry) and one of the ground (blurry sky) in post. No free lunch.

So far I've used the former method but I purchased a tracker (Fornax Lightrack II) recently and this weekend looks like I'll have some time and good weather so that will get a chance to shine.

Sequator has been an awesome tool, but I still find I need to use Photoshop. Sequator does an excellent job of masking off the foreground to allow auto alignment and staking of the sky. But the ground always looks very noisy, like the stacking made the noise worse there instead of better. Also, now that I am using the Samyang 24 mm f/1.4, I find that I absolutely must take a separate ground frame after refocusing on a terrestrial object in my near-to mid-foreground, otherwise the softness is unbearable. But, I still find that the Sequator image is much easier to mask and blend in Photoshop because the sky-foreground intersection is clean, so I can I can either blend at a deep shadow (for trees) or mask along a clean line (for buildings). As compared to Photoshop staking, where your sky-foreground intersection is a complete mess and needs to be tucked away behind a very carefully masked foreground frame.
 
Upvote 0
I wish the same could be applied to an M6II with integrated EVF, or dual card slots in anything, or higher DR, or 24fps in video, or...
Question - has anyone actually fully tested the DR on the M6ii? Photons to photos is often the first to measure and publish the DR results from cameras, but they've got nothing on it. Considering that the M6ii isn't yet available, and there are (to my knowledge) no full examinations on its DR which are publicly available at this time, isn't a bit soon to berate the camera for its DR?

Comment - I actually prefer the M6ii without the integrated viewfinder - with a viewfinder it is less attractive to me. Different needs for different people though. Also, I'm more excited about the 14 fps with tracking than frustrated over anything M6ii appears to be lacking.
 
  • Like
Reactions: 1 user
Upvote 0
Question - has anyone actually fully tested the DR on the M6ii? Photons to photos is often the first to measure and publish the DR results from cameras, but they've got nothing on it. Considering that the M6ii isn't yet available, and there are (to my knowledge) no full examinations on its DR which are publicly available at this time, isn't a bit soon to berate the camera for its DR?

Comment - I actually prefer the M6ii without the integrated viewfinder - with a viewfinder it is less attractive to me. Different needs for different people though. Also, I'm more excited about the 14 fps with tracking than frustrated over anything M6ii appears to be lacking.
Given they merged the M5 and 6 lines, M5 owners and potentially owners are quite exasperated. Great that the M6 suits you, but the general audience takes a jaundiced view at the overall situation.
As for DR. The initial reports show an imperceptible increase (something like 0.002) from the 90d at 32MP vs 80D 24MP. Maybe DXO will show something marginally better. As the Mk6 II shares the same sensor as the 90D, let the rejoicing begin for 12 1/2 EV DR. ¯\_(ツ)_/¯
[For reference, a6500 starts at 13.67, release date 11/2016].
[Yes I own a Canon M5. Love the damn thing.]
[Yes I'm finally working on moving over to something other than Canon. ]
 
Upvote 0
Given they merged the M5 and 6 lines, M5 owners and potentially owners are quite exasperated. Great that the M6 suits you, but the general audience takes a jaundiced view at the overall situation.
As for DR. The initial reports show an imperceptible increase (something like 0.002) from the 90d at 32MP vs 80D 24MP. Maybe DXO will show something marginally better. As the Mk6 II shares the same sensor as the 90D, let the rejoicing begin for 12 1/2 EV DR. ¯\_(ツ)_/¯
[For reference, a6500 starts at 13.67, release date 11/2016].
[Yes I own a Canon M5. Love the damn thing.]
[Yes I'm finally working on moving over to something other than Canon. ]
I don't think Canon has publicly said they merged the M5 and M6 lines - there was a good back and forth in here a few weeks back which suggested that really only DPreview suggested that it was merged, but Canon hasn't said the M5ii isn't coming yet or that the M6ii replaces both the M6 and M5. Here's the article from Canon news which was looking at that. With that said, Canon doesn't seem to announce when something isn't coming, so I'd call that one up in the air.

As for the DR, to my knowledge there was only one review of DR using the images released, and that showed a marginal increase at base ISO, but significant increase at higher ISOs. Again, depending on what you shoot, that could be more or less valuable. Also, if we're comparing the the M6 and the a6500, according to photons to photos they're less than a stop apart across all ISOs, so if we take this one review of DR as gospel where there was a near 1 stop increase in DR at ISOs from ~800 and onward over the previous sensor, we would then expect that the m6ii would have better low light ISO than the a6500. With that said, I think all of those were based on the test images released and not by actual testing for DR (i.e. what DXO or photonstophotos does). I wouldn't bet on DR based on review photos; I'd wait for actual tests to validate that. I'm not expecting the m6ii to match that of other manufacturers at base ISO, but I do think it is probably a bit early to assess exactly what these cameras do and do not deliver.

Then again though, people will vote with their wallet, as they should. If people don't like the feature set they'll buy something else as you've said you're doing. Nothing wrong with that. I buy what suits my need too and have been pretty happy with the results.
 
Upvote 0
Jul 21, 2010
31,088
12,851
which are going to be quickly outdated with higher res sensors.
Truly, you have a dizzying knowledge of optical physics.

Great that the M6 suits you, but the general audience takes a jaundiced view at the overall situation.
Sorry, I think I missed your election as spokesperson for the general audience. Allow me to offer you a belated congratulations!
 
  • Like
  • Haha
Reactions: 3 users
Upvote 0

Don Haines

Beware of cats with laser eyes!
Jun 4, 2012
8,246
1,939
Canada
EOS Ra. A camera special-purposed for solar photography, with a built-in non-removable 20 stop ND filter.
For solar photography, you want the filter away from the sensor, preferably somewhere where air can circulate between it and the lens. When you point your lens at the sun, that filter will absorb most of the light and it will get HOT! You don’t want to cook your camera or melt bushings in your lens
 
Upvote 0