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Old 18-02-2009, 07:56 AM
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Originally Posted by luka View Post
Nikon was based on CCD technology which was not as good as CMOS for AP, but things changed.
All the major AP camera manufacturers, SBIG, FLI, QSI use CCD sensors and always have so I certainly dont understand this statement?

Cheers
Paul
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  #22  
Old 18-02-2009, 08:07 AM
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CCD techology was always better performer than CMOS in terms of sensor noise, and it was purely process problem, there were no fundamental theoretical problems that would favour CCD over CMOS.
Canon (and Foveon, I think) sensors changed that, so today both tehnologies give similar results.

However, the definite advantage of CMOS over CCD is power consumption: CCD requires relatively high voltages to operate, and CMOS does not. Also, CMOS allows direct addressing of any pixel in the array, and CCD does not (architectural reasons).
Also, CMOS process is used for digital circuit manufacturing, while CCD uses totally different process so it is not possible to mix digital circuitry on the same chip with CCD, one of things that bring the manufacturing costs down.
That is why affordable commercial cameras are much more likely to use CMOS sensors. If someone still uses CCD (in mass production) there must be a trade-off somewhere to offset the manufacturing cost.

While CCD is still better in terms of noise (one of the reasons is, there is no digital circuitry on the same chip so readout noise is easier to suppress), it is much more expensive to manufacture the cameras using it.

Last edited by bojan; 18-02-2009 at 09:55 AM.
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  #23  
Old 18-02-2009, 09:49 AM
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clarification

BTW, since I posted the link to Christian Buil's (old) article, let me clarify in more detail why I did it:
Firstly, it was because (as someone pointed out earlier) only this kind of comparisons, with enough support of facts and images and measurement data), are really useful.
Also, the models he was comparing they are still around (second hand), and for people with tighter budgets (and some people on this forum tend to forget the fact that the majority of prospective astro-photographers belong to this category) they are still a viable option.
Finally, I deeply respect the work of people like Christian, who share their knowledge, experience and expertise with the rest of us without thinking about their own material benefit.
In my opinion it is a good thing to keep an eye on such websites, there are always updates, and, by visiting them perhaps they will let be known that we appreciate their work
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  #24  
Old 23-02-2009, 07:13 AM
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Sorry to revive the great debate here but a couple more questions.
Through all the info from here and elsewhere Ive decided on the canon series. Question is, the new models usually come with say a twin lens kit. One would assume that these lenses are of a good quality, but how good ?.
Would I be better off buying the body only and buying a really good all round lens separate. I would like to use it for everyday use with a decent amount of zoom say 200 - 250 mm ? Would a lens of this type also be suited for wide field astrophotography.
The 450d seems very popular at the moment with proven results, should i go with this one or be looking at a higher model. There is a 40d second hand body only in the classifieds that looks good.
Your Thoughts

Cheers
Scott
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  #25  
Old 23-02-2009, 07:25 AM
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Originally Posted by rastis95 View Post
Sorry to revive the great debate here but a couple more questions.
Through all the info from here and elsewhere Ive decided on the canon series. Question is, the new models usually come with say a twin lens kit. One would assume that these lenses are of a good quality, but how good ?.
Would I be better off buying the body only and buying a really good all round lens separate. I would like to use it for everyday use with a decent amount of zoom say 200 - 250 mm ? Would a lens of this type also be suited for wide field astrophotography.
The 450d seems very popular at the moment with proven results, should i go with this one or be looking at a higher model. There is a 40d second hand body only in the classifieds that looks good.
Your Thoughts

Cheers
Scott
I used a Canon 350 D with a 90-300mm zoom lens. Stars all had flares like coma (which it wasn't because they were the same all over the field). The standard 18-35 mm zoom lens worked fine. If I were doing it again, I'd go for the body only plus a good quality non-zoom lens.
Geoff
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  #26  
Old 23-02-2009, 07:30 AM
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Kit lenses are not top quality, but good enough for normal everyday photography.
This is obvious on starfield photos where stars away from dead centre of the frame are not round and small at maximum aperture, so you have to close it down to f4 - f5.6 or even lower to achieve good result.. however that depends on individual criteria for "good" and of the purpose of taking images... Totally distorted star images are still good for photometry - which is quite serous work and could provide results of high scientific value.....
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Old 23-02-2009, 08:39 PM
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Thanks for the replies.
Geoff, with your 90-300mm lens trouble, was that a canon lens or a different brand. Ive been doing a bit of research on the cameras itself but when it comes to the lenses its a bit of a Grey area.
General question, what would the main difference be between the 450d and the 40d. I know the 40d has a lower megapixel but the same size sensor (im assuming lower noise across the chip) besides this most functions seem the same.

Cheers
Scott
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  #28  
Old 23-02-2009, 10:33 PM
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Scott,

Better build quality, and 14-bit over 12-bit imaging, which improves dynamic range.

I'd get the one in the classifieds. I'm seriously considering buying that and using it as a third backup camera.

If I were you, I'd go for either the 450D or a 40D ($800 to $1300), and buy the 200mm f/2.8L II USM for about $1,000.

Regards,
Humayun
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  #29  
Old 24-02-2009, 09:29 AM
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Quote:
Originally Posted by rastis95 View Post
Thanks for the replies.
Geoff, with your 90-300mm lens trouble, was that a canon lens or a different brand. Ive been doing a bit of research on the cameras itself but when it comes to the lenses its a bit of a Grey area.


Cheers
Scott
It was a canon lens.
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  #30  
Old 24-02-2009, 02:25 PM
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I always get a smile when the canon v. nikon debate arises whether its which is better for astro photoraphy or general/professional work. From a pro's point of view, it would clearly seem that Canon has cornered the market & once one person gets good results & builds on it, word soon gets around that its the way to go & that brands popularity soars. Ive been using Nikon for 25 years & shoot professionally with 4 bodies in continuous rotation. I was eyeing off a Canon 20Da a while back for astrophotography & it didnt even concern me one iota that it wasnt a Nikon.Didnt make the purchase as my $$$ went on a trip to Europe but that wouldnt stop me from considering a canon body if it was the best choice for astro photography. For my professional work, wouldnt touch anything else but Nikon.
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  #31  
Old 10-03-2009, 09:24 PM
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Hi all again,

Thought someone might be interested in this. I was about to ask the question what the difference was between a full frame sensor and a APS-C sensor found in the canon series. Then i found this article:

http://www.robgalbraith.com/public_f...hite_Paper.pdf

Bias towards canon of course, its a couple of years old but i think it contains tonnes of information for people considering buying a dslr, I still haven't gotten around to getting one myself yet but all in good time
Hope it helps someone, filled in a few blanks for me

Cheers
Scott
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  #32  
Old 24-03-2009, 10:34 AM
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As a current user of both Nikon and Canon cameras, I will say that for terrestrial uses, they are very much on par, They each have their strengths and weaknesses for certain tasks, I find the Canon to be the strong winner for "action" photography, where as the Nikon excels in landscape/portrait still life photography. The Nikon has better colour reproduction straight out of the camera, although the canon images can be made to look identical with a little tweak here and there in photoshop..

Lenses (for astro and terrestrial use):
Canon lenses in my opinion are nicer. They are more solidly built, they generally focus just that weeee bit faster than the Nikon equivalent, and also, are usually more accurate when continiously autofocusing on moving objects.. The one exception would be the Nikkor 70-200 F/2.8 VR, which I think outdoes the Canon 70-200 F/2.8L IS by the slightest of slight margins..

Astro work.
Canons are supported a lot more by astro imaging software, and seem to be easier to integrate into an astro imaging setup without having techincal difficulties.. Programs like DSLR Focus/DSLR Shutter etc do support Nikon cameras (some models) however there is near on total support for the Canon models.

In the older models, the Canon's were a lot less noisy than the Nikon's. This is going back to the days of the 20D and the D70s, however nowadays, comparing, say the Canon 5D Mk2 and the Nikon D3 or the Canon 1D vs the D3x, I think you would be very hard pressed to find a winner...

The choice then falls back on "what are you most likey to use it for the most?" If its purely for astrophotography, Buy a Canon...

There are plenty of reviews and comparison tests to look at online, but dont take one reviews word as gospel, definitely read everything you can, as some reviews can be biased etc. Also, try to look past the older comparisons (ie 20D vs D70/D70s) whilst they are good articles for historical purposes, the results are no longer true in the Canon vs Nikon great debate..

I definitely love my Nikon, for what I use it for its brilliant, I definitely love my Canons also..
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  #33  
Old 24-03-2009, 11:04 AM
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Excellent synopsis Alex - spot on. I, too, love both my Nikons (all four of them) and my Canon. As you say - I prefer the Nikon colour straight out of the camera for landscape and portraiture - the 350D comes no where near it - and I've tried all manner of white balance tweaks. For deep-space astro, the 350D wins for me because of the software available to drive it. I can use the Nikon for reasonably successful single-frame planetary but cannot get the same result on my Canon. Go figure.
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  #34  
Old 28-03-2009, 09:51 AM
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Thanks Alex for that informative writeup.

My first astro camera was a Nikon D70 and it was very good. Just as a point of interest - the 6.3mp chip in that camera is a Sony and is the same as used in the Starlight express MXx25C and the QHY8. In those days the Nikon had bad amp glow and also did not have true RAW files (unprocessed saved data).

As far as I know (please correct me if I am wrong) that is still true today.
Nikon has its own file format called a NEF file and this has some smoothing run on the image before it is saved. This is done to reduce noise (astroimagers know you sometimes need to smooth areas of noise in the dim areas of an image to get a pleasing result).

This has the effect of reducing smaller. delicate, fine detail in an astro image. Exactly how much is debatable - perhaps not much at all but it is present.

This was and still is one of the major arguments against using a Nikon.

I know up to the Nikon 200D (I think that was its designation) the Canons were clearly superior. However later models I have no knowledge of and Alex does.

Having said all that I believe a QHY8 would be far superior to any DSLR and a smaller SBIG 2nd hand would also be far superior.

Dedicated CCD cameras have the following advantages/disadvantages:

1. High cost - disadvantage although QHY have brought the costs down a lot and are closer to a DSLR with a couple of lenses.
2. Cooled - far lower noise, a major advantage
3. 16bit processing - this means a larger dynamic range although the new DSLRS are 14bit and it could be argued that 16bit is not fully utilised in CCD cameras as the image data is only in a small part of the range it can differentiate in.
4. SBIGs have internal self guiding which means autoguiding is all in one package and you have to add on the cost of a good autoguiding system to a DSLR to compare costs (as a guide I'd say $1000 minimum for a decent autoguiding/guide scope/rings/mounting gear setup and easily could go to $2500 for this alone + the problems of flexure can enter where the guide cam and imaging camera are moving very slightly from each other and you get eggy stars).
5. filtered imaging means each pixel counts when doing LRGB imaging versus a DSLR where it has a coloured grid overlay of microfilters on the chip so 4 pixels are required to create one colour pixel in other words your 10 megapixel chip is only really 2.5 megapixels of colour.
6. Unmodified DSLRs are a lot less sensitive than dedicated mono astro cameras and modified cameras are also although less so. Sensitivity is typically
3 times greater for a cooled dedicated astro camera than a DSLR.
7. If you want to do narrowband imaging (Ha filter for example) it is ideally done with a dedicated astrocamera. You can use Ha with a DSLR but it is less sensitive to this and unmodified it may be a waste of time as the standard Canon/Nikon filter blocks that light. Modified cameras it is not.
8. Dedicated astro CCD needs a laptop and a battery or power supply. DSLR is more portable and does not absolutely require a laptop so this could be a big advantage.
9. DSLRs can be used for other photography - this is often appealling as well. However point and shoot cameras these days do an awesome job and an excellent one costs less than $100 now and they are a lot more portable and fit in your pocket.

So if it comes down to money a one shot colour QHY8 would actually not be much more at all.
A 2nd hand SBIG camera would also not be much more when you consider not needing a separate autoguiding setup (which you will need to do serious imaging).

Results will be much better with the dedicated astro-CCD.

I guess it comes down to how hard are you going to get into this hobby - mildly interested or full on? If full-on you will eventually want the dedicated astro camera so you could just start at that level and save yourself some cost of changing over later.

Greg.

Last edited by gregbradley; 28-03-2009 at 10:05 AM.
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  #35  
Old 28-03-2009, 12:54 PM
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Well said Greg..

You are very correct, up until Nikon's D200, the Canon cameras were far superior.. These days its really a matter of personal taste more than a clear superiority...

I also could not agree more, that if someone was going to buy a Canon 40D/50D and get it modified, they may as well save that little bit extra and buy the QHY8. When used to its full potential, there really is no comparison between a DSLR and CCD for astro imaging. Yes, DSLR images can be great, and can have low noise. but how often do you see DSLR images where the photographer chose not to use Darks simply because they didnt deem it necessary?

I just got through posting in a thread on Cloudy Nights about this exact same topic, and the general gist of my post was that for astro photography, All roads eventually lead to a dedicated cooled CCD imager. be it mono or OSC, large format or otherwise, multi megapixel or small resolution... One way or another, every serious astro imager will eventually want a cooled CCD, and majority will convince whoever it is they have to convince in order to buy one..

Im currently looking for another CCD.... Horses for courses sort of thing..
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  #36  
Old 28-03-2009, 01:29 PM
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firmware mods and hacks

for whats its worth.. if your into hacking / modding at all..

It seems to me like are more firmware hacks and mods available for the Canon.. I have a low end Nikon (D40) and have not been able to find any (firmware) hacks at all

.. but I'm pretty sure I even saw a SDK mentioned somewhere for the Canon.. I certainly got the impression Canon might be more 'hacker' friendly..
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Old 30-03-2009, 01:22 AM
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Excellent info, and I agree with pretty much everything that's been said. Just a small point of clarification: for high ISO the noise levels are clearly in favour of Nikon over Canon at present (at the respective price points) and have been for some time. It's not a huge lead, but is quite measurable and definable, and to be honest its not really up for debate. Canon have definitely narrowed the gap with the 5DMarkII, when you take into account its higher resolution (not so with the 50D though).

Overall the Nikon D3 is the clear leader, with the D700 and D300 also VERY good, and better than their Canon counterparts - albeit with currently lower pixel counts. The D3X isn't so good, but at the price they have set, it can almost be ignored anyway ;-)

This of course doesn't change all the other various arguments for Canon being the better/more popular AP platform. But for high ISO noise Nikon wins.
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  #38  
Old 30-03-2009, 08:19 AM
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Guys,
do you have some numbers to support your comments?
Because words like "good", "better" etc do not tell the real story, it is more individual impression one has about various product.
Also, we have to take into account price/performance ratio.
Only when data are presented in such a way, the decision about what is better (for the purpose) and by how much is clear cut.
Christian Buil's form of presentation is the way to go.

Last edited by bojan; 30-03-2009 at 09:19 AM.
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  #39  
Old 02-04-2009, 10:41 PM
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This debate is like Holden and Ford or Ford and Holden. Both systems produce quality shots.

I am on my 8th or so Nikon, had them for years. I love the glass they make, bodies are another matter but one thing stands out in my mind in that regard. Nikon have the same mount as when they first started making DSLR's. I have old lenses that I still use from time to time.

In terms of terrestrial v Astro, I am one of the people that Mike mentioned who uses a Nikon for Terrestrial and a Canon for Astro. Why? Well that is simple. The Canon has been modified and cooled. No one seems to be doing this with a Nikon CMOS camera. If they were I would have gone with the Nikon.
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Old 03-04-2009, 08:04 PM
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Quote:
Originally Posted by rastis95 View Post
Chris,
Have you ever used your d40 for astro work, would be a far cry from the SBIG ST-8i (by the way looks like your getting the hang of that little puppy), and compared it with any shots from the 350d ?

Cheers
Scott
Here's one from the other night using the D40 Scott. The image has been compressed lots, so it's a bit nasty here at 1260px.

Compared to the 350D it has a much better rear LCD and the menus are far better. Battery life is double. Noise? Nah - not really. A little tiny bit of amp noise past 600secs, but otherwise fine. The only annoyance is the lack of a cable remote - so I use an IR one with a timer on my watch.
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