Camera Test

[RyanJones]

A problem I've been having for a long time is a serious lack of reds in my images. I've learned to accept it as there are a lot of beautiful Nebs out there that aren't only red.

Two nights ago I tried to capture the Cone nebula. 2 1/2 hours of data and still very faint reds. Last week, Rosette gave me the same issue. Its time to accept that need to do something about it. Astro modding my 5d seemed less desirable than pulling apart my old 350d, purely given the value the two cameras untouched.

Out of interest, I thought I'd test the cameras on the same object at the same time to give me a good base line comparison. And why not throw my fiances new 200d in the mix too ( i must say I'm a big fan of live view for focusing ).

The results are quite stark between the 3.

The region is Eta Carinea ( It's bright and has a lot of red cloud and can be imaged from my Bertole 7-8 skies )

All 3 are sets of the best 8 subs x 30 Seconds @ ISO 800

The only post processing that has been done is 100% saturation of the red channel.

The images are in this order :

Canon 200d
Canon 5d
Canon 350d

[raymo]

Canon DSLRs vary hugely in their Ha sensitivity. My old 1100D was better
than my 600D is. Unfortunately it didn't have the articulated screen which
my ancient neck finds invaluable. Some other brands have models which are
more Ha sensitive than Canon.
raymo

[casstony]

Are those through the C5 Ryan? 0.63 reducer or f/10?

[RyanJones]

Hi Tony,

They're through the C5 prime focus. I don't have a reducer, I use my Newt or Refactor for my faster, larger stuff.

[casstony]

Then I'd say f/10 is a bigger part of the problem rather than your camera. Compare the cameras at f/5 or f/6 and see how they look.

[RyanJones]

Given that the 3 imags below are all captured using the same equipment and the 350 shows more red sensitivity than both the 5 and the 200, I'm not sure how using a faster scope will change the ability of the camera ? For sure a fast scope will collect more light and also being at a dark site will improve the Ha capture but surely apples for apples the 350 will still out perform the other two cameras ?

[Outcast]

Hey Raymo,

If you have an android tablet by any chance you can use a USB On the go cable & DSLR controller app to use your 1100d again & avoid the neck issues. That's what I am doing now & it works really well...

Cable was about $8 from Office Works, app was around $10 from memory.. I'm using a 10.5" Samsung Galaxy tablet (not that new or powerful) & it makes using it a breeze with a much bigger screen to boot...

[casstony]

Yes you've got a comparison, but I think you're being too hard on all of the dslr's with 30 second subs at f/10.

[RyanJones]

Don't get me wrong Tony. I wasn't actually expecting anything of use out of those subs. Periodic clouds were coming through all night and 30s was just a short sub length that I chose that I was confident I could do between them but also long enough that I would expect to capture some red. The test was purely a Ha sensitivity comparison test.

For the record, I've only just in the last month moved to an EQ mount. All of my early imaging was with the C5 on an Alt Az mount that could only be relied on for 22s subs. I've been a lot harder on my poor DSLRs than this :rofl:

[Ukastronomer]

You forget image processing needs to be done also

https://noiseware-community-edition.en.softonic.com/?ex=BB-765.0

[RyanJones]

I'm sorry if I haven't articulated it well but the test is for Ha sensitivity of the camera sensor in each camera. It's not processing or longer subs to extract more red. i am well aware of everything else that is involved in producing Astro images. This thread is purely showing the differences between the Ha sensitivity of each of my unmoddified Canon DSLR cameras.

[raymo]

Sorry, slight hijack. Thanks for the idea Carlton, but I gave the 1100D to my brother in law.
raymo

[glend]

You want Red, do the astro mod on the 350D. Really easy to do, instructions available online complete with step by step photo guide.

You can use Gary's excellent instructions here:

http://dslrmodifications.com/rebelmod450d1.html

Note that they start with thec300D model, so just pick the one that matches yours best. I

[RyanJones]

Thanks Glen. Now that I've got a good base line test to know the 350 is the best with the reds in stock form, I've done a proper set of subs on it which I'll process tonight to make sure I'm happy with the image quality. If everything goes well, I think astro modding it will be the next step. Thanks for the link :)

[sil]

I don't know if this is actually a useful test if you are going to mod. Ha sensitivity is down to the IR filter which gets removed in modding. So you really need to remove the filter on all three cameras then do the test again. You've only tested which is most sensivity in stock form and thats it, so you know which is best to use in stock form NOT which is best to mod.

[RyanJones]

You're right Sil. I had a feeling someone was going to point that out when I read what I wrote in my last post. A better way to articulate it would have been I'll use the 350 in it's stock form because it's the best performer stock and if I want more Ha again then the next step is to mod it. The run of subs I did last night with the 350 is to see if I'm happy with the image that particular camera gives me. Not just Ha sensitivity wise but also the quality of the actual image. If I do want more Ha but the image is really pixilated or has hot sensor issues then it will be pointless modding that one and I maybe need to look at a different camera all together.

[RyanJones]

I think what is kind of being missed and seems to get missed a lot is that my posting of this test ( although I had my own personal reasons for doing it ) was to share information. If someone was looking into getting into astrophotography and had a friend selling one of these cameras cheap or had one sitting in the cupboard and wanted to know if it was a good one to use, reading this post might give them some insight as to what to expect from them. Yes I did the test for my own benefit but I'm not too selfish to share my findings to help others. Sometimes the dissection of people's work on this site can be a little disheartening. I thought we were all in it together to help broaden the interest level in this amazing hobby.

[casstony]

The Nikon D5300/5600 is the default recommendation for an affordable, low noise dslr. There are other similar options from Sony and Fuji.

My Nikon D5600 is dramatically less noisy than my previous Canon 600D. If you want more red sensitivity it still needs to be modded though.

Goodguys sometimes have 20% off on ebay or ebay itself has sometimes 10% off.

[RyanJones]

Thanks Tony. I've heard a few tines the the Nikons are good DSLRs for astro.

[glend]

Those two Nikons, which both use the same sensor, are very good with the red end as well for some reason. Just make sure you turn off all the extra software features you don't need but which generate heat. For example, you don't need in camera dark processing.

[sil]

I think key here is its vital to test for yourself the gear you have and understand what your tests tell you. Its also noy always essential to buy this years model cameras when last years are just as good and a quarter of the price second hand so just because its not state of the art do not automatically discount it.

Ryan's test is interesting to see and yes a good test of the red end of the spectrum the camera can grab. EtaC is difficult and faint for me to grab but that may be due to the filter i have permanently installed. I'd suggest you try plieidies (can never spell it) - seven sisters as it has so much faint blue structure. would be interesting if you find similar differing results especially if the same camera goes further into the blue as well as the red. Ideally you want the camera to go widest on the spectrum so you can be confident of good results on everything.

[RyanJones]

Excellent points there Sil. I hadn't considered the blue end of the spectrum but you're 100% right. I will do the test on Subaru ( I'm a mechanic and also can never spell plieadies either lol ).

Thank you for your input Sil. :thumbsup:

[JA]

If you want a way to easily test the Hydrogen Alpha line response of various cameras WITHOUT having to resort to imaging DSOs and the variability that that might provide with say light pollution etc... then you could use a RED light laser of the type typically employed in laser pointers. These typically have a wavelength of 650-660nm depending on model, but more usually 650nm. That wavelength (650nm) is very close to Hydrogen Alpha line wavelength of 656.3nm and has a very narrow bandwidth.

In addition to the red (650nm) laser you could even pimp your test rig to include a purple (405nm) laser pointer and a green (532nm) laser pointer as a reference. Then simply take an image of the laser/s illuminating a white diffuse surface like paper. Do not image the laser beam head-on in to the camera and take care with laser usage and safety and not look in to the beam.

In addition to visual comparison of the images from various cameras, you could easily quantify the image brightness in the coloured areas in terms of a pixel value in most photo editing suites and compare this with other cameras imaging the same scene at the same exposure and ISO sensitivity.

Best
JA

[RyanJones]

Another excellent suggestion there JA. Certainly a much more scientific way to carry out the tests. This however may be where the problem lies. A test on real DSOs is a real world test WITH the uncontrollable variables in place. Agreed that these variables will affect the quality if the data. If all 3 cameras are being tested under the same conditions ( as much as is practical as obviously time of the night can change sky glow etc ) then the results should have a greater applicability to the reason for testing which is creating images of DSOs. The other small consideration is the need for more equipment ( cheap as it may be )to carry out the test.

Thank you for your input JA. It's good to get other perspectives to validate the quality of the test. :thumbsup:

[Cimitar]

Hi Ryan,

When compared to the 350D, the difference between the 200D is significant. The red barely shows in the first image!
Thanks for sharing mate. I would have found this type of information very helpful when I started in astrophotography :thumbsup:

Evan

[gb44]

Hi,
IMHO the Pleiades would be an even more difficult test as DSLRs are even less sensitive to blue than to red.
Tarantula nebula is the most spectacular object in my book, so it must be an ideal test comparison. And its up early in the evening at the mo...

Cheers
GlennB

[RyanJones]

Thanks Evan

[RyanJones]

I've got about 6.5 hrs of data on tarantula taken with the 5d and it seemed to love the blues. I do intend to get back to tarantula now I've got my new mount and can get some decent length subs. I don't think the target really matters as long as it's heavy in the blues so maybe I'll do the test on that instead.