Best, Cheap Canon DSLR for Astro modding

[AntHart]

Hey

after some advice regarding DSLR’s to modify/ have modified professionally for a dedicated Astro imaging camera.

i have a Canon 6d mk1 , full frame that I use for wide angle nightscapes (14-50mm) .i know this would be a great one to modify but I’m keeping this for that and I’m after one with a crop/smaller sensor to take advantage of gaining focal length.

I’ll be using a portable tracking mount like the SkyGuider pro or star adventurer so loosing weight is a big priority...my thinking is ...I can gain more focal length from the same weight/size scope just by using a crop sensor dslr...correct 😕 

 

im looking to use a william optics ZS61 or ZS73, so around 400mm FL...640mm if using a crop sensor dslr...

I digress!....

 

im looking to stay with Canon

what dslr is recommended/ the ‘goto’ crop sensor for modding ... 

buying modded vs professional modding vs diy

I’m happy with older cameras if better

could I get the same(ish) effect with a non modded camera and use filters??

 

any advice greatly appreciated 😁

cheers

Ant 

[Johns22]

I chose the Canon 600D which has favorable reviews for astro modifying. I haven't modified it yet as with this being my first ever DSLR, I enjoy using it during the day too. I do use a Svbony CCD filter for light pollution - these are cheap at £40 - I would like to try the more expensive ones as a comparison.

I picked up the 600D with approx 1000 on the shutter count, in the original box with all the accessories for £140 earlier this year. It's immaculate!

Edited April 3, 2020 by Johns22

[Endolf]

Another 600D user here, it's supposed to have a good SNR for astro work, which is why I picked it. Sure, there are higher resolution sensors out there, but not at the price. I paid a bit more than @Johns22 did, but not much. 

I've not modded mine either, I'm tempted to hold off and just get a dedicated camera later in the year instead, I've got some reasonable shots of DSOs (for a nOOb), I know I'm missing the Hydrogen, but with a filter wheel and some dedicated frames I could possibly pull that back a bit.

Edited April 3, 2020 by Endolf

[Ian_M]

Hi,

Agree with the others - almost. I bought a second hand Canon 650d (body only) for £160 on ebay in December for use with my Star Adventurer Mini tracker. Successfully imaged Barnard's Loop in orion which was my winter project. Main advantage as far as I am concerned of both 600d and 650d is the articulated screen saves your back and neck as you don't have to contort into wierd positions to see the screen. The 650d has the further advantage that the screen is touch sensitive which, again, makes it easier to change things even when your camera is pointing upwards.

Next step is to get it astromodified probabaly with baader filter.

Clear Skies,

Ian

[michael8554]

I would get a camera with Liveview - 450D or newer.

Articulated screen on the 600D and newer is useful.

600D and newer have spring-loaded sensors, requiring very accurate measurement of the original position so that you can replace it without tilt.

19 hours ago, AntHart said:

I can gain more focal length from the same weight/size scope just by using a crop sensor dslr...correct 😕 

The focal length is always the focal length of the lens or telescope.

You've fallen for the Full Frame versus Crop Frame "Crop Factor" myth.

The Crop Frame has a smaller field of view so the image appears to be "magnified" - you'd get the same result cropping a Full Frame image to the Crop Frame dimensions.

So in your case I'd suggest  buy a used modded camera, or get one modified.

Michael

[Merlin66]

Full frame, 4/3, Crop factor etc are "normal" everyday photographic terms and in my opinion should not be used in the context of astronomical imaging.....

We are primarily interested in pixel size, frame size and QE....full frame etc looses it meaning.

 

Edited April 4, 2020 by Merlin66

[malc-c]

I have a 400D - it lacks live view, but for modding it was quite easy - mine has both IR cut filters removed both of which have been well documented on the net

[AntHart]

On 03/04/2020 at 23:36, michael8554 said:

I would get a camera with Liveview - 450D or newer.

Articulated screen on the 600D and newer is useful.

600D and newer have spring-loaded sensors, requiring very accurate measurement of the original position so that you can replace it without tilt.

The focal length is always the focal length of the lens or telescope.

You've fallen for the Full Frame versus Crop Frame "Crop Factor" myth.

The Crop Frame has a smaller field of view so the image appears to be "magnified" - you'd get the same result cropping a Full Frame image to the Crop Frame dimensions.

So in your case I'd suggest  buy a used modded camera, or get one modified.

Michael

Hi,

1. Does the spring loaded sensor mean that it’s not a camera that can be  ‘self modified easily’ due to re-alignment issues then?

If so that’s brilliant to know thank you! 
 

2. The crop factor myth...

I can’t get my head around this...

my 6d has a 35.8 x 23.9mm sensor - 20.2mp - (855.62mm2) - 5472 x 3648

take a 600d for example.. 22.3 x 14.9mm Sensor - 18.7mp - ( 332.37mm2 ) - 5184 x 3456

How can a FF sensor not far off the same Mp count as a 4/3 give the same result or ‘quality’ of image if there cropped to the same size? 
say I take an image with my 6d, crop it down to the size it would come out native on a 600d, there’s got to be more data in the native 600d image than my cropped one or am I going mad!haha!

Maths isn’t my strong point!
But surely the crop sensor has more pixels per mm2 for its size than the full frame...hence more detail and better once cropped? 
Also, the pixels are larger on the 6d , 6.54nm compared to 4.3nm on the 600d , I know that’s ‘how’ they cram more in by making them smaller, but in my mind if the pixels are smaller it will give a more detailed/sharper image? ...if both images are the same size, like a piece of A4 paper the one from the 600d would have more ‘information’  than the 6d right??

 

Its either too late and my brains running on fumes or I should have paid more attention at school   but this is something I can’t seem to get my head around!

If someone way more knowledgeable than me could please try to sum it up in a paragraph that would be really helpful! 
 

As always thanks for the reply’s and taking time to read 👍🏼 Ant 

[michael8554]

We started out discussing Crop Factor, which turned out to involve Field of View. 

You've now introduced another factor called Resolution, which only involves the size of each pixel. 

Take a Full Frame camera with 4x4 um pixels, and a APS-C with 4x4 um pixels. 

Crop the Full Frame to APS-C dimension, each image has the same Field of View, and the same number of pixels. 

Now this time the APS-C has 2x2 um pixels. 

Crop the Full Frame to APS-C dimensions, now each image has the same Field of View, but the APS-C image has four times the number of pixels. 

So yes, the APS-C image has higher Resolution, but the area of sky in the cropped Full Frame image is still the same as the APS-C image. 

You say this makes the APS-C "better". 

Better resolution - yes, but you could be Oversampling. 

And each smaller pixel receives less light than the bigger pixel, so is less sensitive, and to capture dim DSOs, sensitivity isn't something you reduce by this other myth, "more pixels is better". 

Michael 

Edited April 18, 2020 by michael8554

[AntHart]

5 hours ago, michael8554 said:

We started out discussing Crop Factor, which turned out to involve Field of View. 

You've now introduced another factor called Resolution, which only involves the size of each pixel. 

Take a Full Frame camera with 4x4 um pixels, and a APS-C with 4x4 um pixels. 

Crop the Full Frame to APS-C dimension, each image has the same Field of View, and the same number of pixels. 

Now this time the APS-C has 2x2 um pixels. 

Crop the Full Frame to APS-C dimensions, now each image has the same Field of View, but the APS-C image has four times the number of pixels. 

So yes, the APS-C image has higher Resolution, but the area of sky in the cropped Full Frame image is still the same as the APS-C image. 

You say this makes the APS-C "better". 

Better resolution - yes, but you could be Oversampling. 

And each smaller pixel receives less light than the bigger pixel, so is less sensitive, and to capture dim DSOs, sensitivity isn't something you reduce by this other myth, "more pixels is better". 

Michael 

I’ve got so much to learn mate! I know some of my questions must seem daft or obvious to some but I’ve always been taught it’s better to ask than guess an answer which is why I’m always so grateful for help 👍🏼