Full Frame or APS-C ?

[Waylandscape]

I'm a bit torn at the moment.

I'm looking to get into Astro-photography and the path I'm looking at is a mount first which I can use with my camera for wide and medium field shots with my existing lenses and then getting a Apo scope of around 80mm for the next step.

The problem I'm facing is whether to go for a decent scope that will cover the 35mm full frame of my 5D or buy a second APS-C body that will then allow me to use a slightly less expensive scope to cover the frame.

It seems like a backward step to me but one that may prove more effective in the future.

I would really value some good advice as virtually everything I have read so far on the subject seems to ignore full frame DSLR cameras, presumably because they are more expensive, but in my case it is what I already have.

[johnrt]

A scope to cover your full frame camera may prove to be an expensive outlay. The other consideration if you plan to use a DSLR is you may wish to use one with an ir filter removal mod, so a smaller chipped camera modded for just astro use may be a good purchase.

[Psychobilly]

For use on a scope I would look to pickup an APS-c sized sensor and think about either modding it yourself or having it done... Even the smaller sensors tend to need flattner/reducers to proviide a decent star shapes orner to corner and will need flats to tackle vignetting... You can also use clip-in filters with the smallers sensors...

The 5Ds full frame sensor and better low light and high ISO performance make it ideal for widefield work with those L's.

Peter...

[swag72]

If you are looking at buying a DSLR specifically for astro use, why not bypass it and buy a decidated astro CCD instead? Don't get hung up on mega pixel's though as far as CCD's go, AP is a very different world!

[nytecam]

At a budget level a Canon 1100d makes a lot of sense as cheaper than any CCD cam and has a large sensor in CCD terms. But as you already have a FF Canon 5d for wide field stuff then you should go for a mid/higher end CCD. Ok the smaller fov via CCD will hone your emerging skills but well worth it

[Waylandscape]

A scope to cover your full frame camera may prove to be an expensive outlay. The other consideration if you plan to use a DSLR is you may wish to use one with an ir filter removal mod, so a smaller chipped camera modded for just astro use may be a good purchase.

That is certainly one of my concerns. I was hoping to budget the whole package, mount, guider and scope, for 2 - 2.5K or there abouts so unless I get luck with some secondhand gear that gives me around a thousand for the scope.

The new SkywatcherEsprit looks interesting but I'm also considering the William Optics scope with a built in flattened which claims to cover full frame.

Any others suggestion worth looking at would be welcome.

As you suggest though, a modded APS-C camera might be a better option in the long run though.

[Waylandscape]

For use on a scope I would look to pickup an APS-c sized sensor and think about either modding it yourself or having it done... Even the smaller sensors tend to need flattner/reducers to proviide a decent star shapes orner to corner and will need flats to tackle vignetting... You can also use clip-in filters with the smallers sensors...

The 5Ds full frame sensor and better low light and high ISO performance make it ideal for widefield work with those L's.

Peter...

I'm hoping to get a lot of good use out of the lenses on a decent mount like a HEQ.5 and I can see that dovetailing well with my main interest of landscape photography.

I must confess that I am so attached to the image quality that the large sensor provides I find it hard to leave that behind but sadly I can see the logic of going smaller on a scope.

[Waylandscape]

If you are looking at buying a DSLR specifically for astro use, why not bypass it and buy a decidated astro CCD instead? Don't get hung up on mega pixel's though as far as CCD's go, AP is a very different world!

The CCD route is another option but seems expensive to get good returns.

I haven't bought into the megapixel arms race in cameras too much but I tend to think of 12mp as a base line for decent prints. (I used to work with medium and large format in the days of film so perhaps I'm expecting too much.)

I could change my mind down the line I suppose, but I think I might need some convincing.

[Psychobilly]

I use an EQ3-Pro for my portable widefield setup and have a HEQ-5 Syntrek which I can use with the Synscan controller off the 3 if needed - most of the time the 3 is ok though....

I actually regret buying my fracs should have invested the money in dual use primes instead simply beacuse they would have got far more use

....

Peter....

[Waylandscape]

At a budget level a Canon 1100d makes a lot of sense as cheaper than any CCD cam and has a large sensor in CCD terms. But as you already have a FF Canon 5d for wide field stuff then you should go for a mid/higher end CCD. Ok the smaller fov via CCD will hone your emerging skills but well worth it

I must confess the idea of a small, cheap body, perhaps modded down the line makes a lot of sense, not least because my life style can put me into some quite remote places and the self contained nature of a DSLR provides more flexibility in many ways.

Skills wise, I can see that I'm looking at a steep learning curve but I am fortunate that I find book study a good way to fill my spare time and seem to learn well that way. I consider myself a competent PhotoShop user and I think I understand the principles behind the Astro software I've seen so far but of course I'm sure I'll make plenty of mistakes along the way.

[Waylandscape]

I use an EQ3-Pro for my portable widefield setup and have a HEQ-5 Syntrek which I can use with the Synscan controller off the 3 if needed - most of the time the 3 is ok though....

I actually regret buying my fracs should have invested the money in dual use primes instead simply beacuse they would have got far more use

....

Peter....

That's a very honest thought and one that has been rattling around in the back of my head as well.

[Psychobilly]

If you want to see what a modded APS-C DSLR and decent L can do check out melsky images

http://stargazerslou...c/#entry1813783

And have a look at saturn5 images for 5D nightscapes...

A DSLR + decent lens on a capable mount when combined with APT or BYEOS will ill allow FWHM af etc...

My sig my let you know that I might have a bit of a bias towards DSLRs

Peter...

[Waylandscape]

I had noticed but we all have our own little bias', normally based on the roads we have travelled.

It takes a level head to admit we have turned the wrong way sometimes.

I've seen a couple of Melsky's very impressive shots before.

When I google Saturn5 I got a very big boy's toy... Doh...

Found him in the members section of course, nice shots and my kind of stuff too.

Part of the reason for taking things one step at a time is that I'm unsure of how far down this road I will eventually travel. A good scope appeals to me but I may find myself just using the scope for observation and with the camera piggybacking for wide field shots.

I am realistic enough to know that I am unlikely to produce anything that has not been seen before as far as deep space shots go but mixing landscape with wide field work Is something I would like to try.

[Gina]

Yes, I have an admission I thought a good DSLR modified to have the same cooling as an astro CCD camera as well as full spectrum, would be a good option for AP with it's large (in astro terms) sensor. Yes, some pretty good images can be obtained with one of these but the difference on changing to a mono astro CCD camera albeit with a smallish sensor has totally blown me away! With the truly professional capture software that Atik provide and their top-notch filter wheel the difference is totally amazing to the extent that I just don't feel like messing around with DSLRs any more. It's easier, quicker, and I can grab a very much better image in a shorter time. I love not having to bother with darks and the instant image view with so many controls in the Artemis Capture software means you can see what you're getting at the time - no need to use an additional piece of software to enhance and enlarge the image - it's all there ready to use.

A DSLR with lenses will get you started for widefield. Add a great value scope like the Skywatcher Evostar 80 ED DS Pro at around £400 plus the matching focal reducer and field flattener and you have a half reasonable system. Move on to a medium priced mono CCD astro camera such as the Atik 314L+ and you have a great system. The smaller sensor is not such a huge disadvantage - it's better for galaxies and other small DSOs. For widefield you can couple it up to prime camera lenses.

I did my utmost to "make a silk purse out of a sows ear" with my DIY efforts on the 1100D and I'd defy anyone to get more out of it, but it could never measure up the an astro CCD in terms of low noise and sensitivity. DSLRs no doubt have their place as a cheap starting camera and to be sure that you really do want to submit to the cost and dedication of astrophotography. But once sure, I'd recommend saving up for a mono astro CCD and filters with maybe a manual filter wheel at first, sooner rather than later.

[IanL]

In terms of building up to it, if you did buy an 80ED with an eventual view to moving to a CCD, you could still use your full frame DSLR provided you are willing to crop the image to the illuminate/flat field portion of the image. Even with an APS-C sensor, it is hard to get fully flat fields right in to the corners all the time; just a bit of mis-alignment or focuser droop and you will end up with some elongation in a corner or at one edge. On the other hand, using a DSLR with big sensor and live view is a really good way to get started since framing and focus are a lot less frustrating when you're still finding your way.

[Waylandscape]

Sadly my old 5D predates live view but it does look as if I may be sticking to the marque lenses for a while to get the coverage on the large sensor.

That may well suit my style of photography for a while anyway.

[ollypenrice]

I don't like DSLRs for DS imaging, I have to say, and agree with Gina. A smaller chipped CCD in a shorter FL scope will win. However, that's not what you asked!

I've just started using a full frame CCD and it's quite a step. I wouldn't believe everything you read about the ability of certain systems to cover full frame. As an experienced guest just said to me, big chip means big problems. All sorts of things become more difficult, notably tilt, focus and flatness.

Olly

[nytecam]

The expression full-frame DSLR is a throwback to the original Leica camera made a century ago this year using 35mm wide movie film stock and APS-C DSLR [half-frame] format is more akin to the cinema's movie format itself. Whilst full-frame film made sense historically its simple transfer to digital doesn't. IMHO APS-C is better matched to the DSLR for a lighter, smaller body and lens sizes and pixel resolution has improved rapidly in the decade since launched. That said I still think DSLR, whilst great for day use and learning AP on a budget, it pales when compared to dedicated CCD astro-cam's sensitivity to catch those scarce photons.

[Waylandscape]

As a photographer that learned my trade using 5x4 inch sheet film and then turned to medium format for a compact option, I still consider "full frame" 35mm cameras a little fiddly.

The short focal length lenses required for wide angle work with APS-C cameras do not seem really up to the job and the lack of differential focus can be a real pain.

Having said that, these are all things that are the opposite of problems for astrophotography I guess.

When shooting landscapes, often in very low light, it is the low noise characteristics of the larger sensor that makes me hang on to my 5D body even though it is considered old tech. these days.

I've used a few small sensor cameras and indeed carry a Fuji x10 as a visual notebook but I find the quality rather lacking when it comes to serious work I suppose.

I may have to look at a second body for use in AP but I doubt if it will see much use for anything else.

[starman1969]

A Sony NEX 5 has an APS-C sensor. It is proving to be quite a popular camera for astro. Very small body, too.

[StuartJPP]

Like Psychobilly I am also biased towards DSLRs...Who needs a scope, unless you are planning on "observing" ? Just use lenses instead...rather spend the money on a Canon 400mm f/5.6 L lens That way you can use it for daytime photography as well as astro work. Of course focusing isn't as easy as some scopes and liveview is a must in my opinion (which your 5D unfortunately doesn't have). If I progress further into this hobby then I will hopefully be more informed to make a better choice at that stage rather than trying to jump in with all guns blazing.

I started out with the Canon 7D (which I already had) but it really didn't capture any Ha so I bought and then modified a Canon 1100D for those targets that are rich in Ha. For now my kit suits my needs, though I would like a larger, sturdier mount, but there is still so much I can do with my current kit just the weather isn't playing along.

Ignore the 500mm f/4 in my signature as that is something I already had before taking an interest in astro, if I didn't have it I would certainly have the 400mm prime instead.

Kidding aside, if I were you I'd get a nice sturdy solid mount first, preferably one that is more than you think you will ever need, as that is something you are going to need regardless of scope/camera combinations. Then have a go with what you have already got and take it from there.

I know some people don't like DSLRs for imaging, but I don't think they are too bad, these aren't award winning and were taken on a "flimsy" mount but suit my current needs (click on them for a larger version and info):

M31 Andromeda Galaxy by StuartJPP, on Flickr

Horsehead and Flame Nebula by StuartJPP, on Flickr

The Pleiades - M45 by StuartJPP, on Flickr

[Waylandscape]

I did wonder about the Canon M to maintain compatibility with my lenses but it lacks a little in controlibility as far as I can see.

Having said that it will be a while before I have to make that sort of decision I think.

By the way, how do you rate your Astrotrac? It looks like an interesting option.

[Waylandscape]

Stuart, I've noticed a few of your shots and would be very pleased if I could achieve that kind of quality.

That makes a at least two people on here producing good results with the Astrotrac.

I had been looking towards the HEQ5 but it's not just the cost of the mount but also the power supply and the need for guiding which makes it a lot more cumbersome.

Are you guiding your Astrotrac or using it out of the box?

[StuartJPP]

Wayland, I am using the AstroTrac unguided, hence the 90 second sub limit at 500mm. I don't think that guiding will help too much as it can only guide in RA, so it will assist, but only to a point. I like the AstroTrac, however it isn't without its faults, 2 hour tracking time before resetting, no GOTO. At longer focal lengths, it does struggle and a lot of tweaking is necessary. Objects located in the east or west are worst affected, which is probably true of all mounts.

I bought my AstroTrac 2nd hand, so it was a cheap entry into imaging. If I had the space in the car (which I probably could make if I really had to) then I'd have an NEQ6, I don't think the weight difference between an HEQ5 and an NEQ6 is that much, I have carried both in the shop. Carrying either is just as cumbersome as the other, with the NEQ6 being just a little bit more so. But like you said, I would probably need guiding to get more than I am currently getting which is another set of cables and things to go wrong.

I am biding my time until I get to the point where I feel I can't progress any further, then I will take it from there. However with the weather like it is, I should be set for life.

[Cefiar]

I'm a bit torn at the moment.

I'm looking to get into Astro-photography and the path I'm looking at is a mount first which I can use with my camera for wide and medium field shots with my existing lenses and then getting a Apo scope of around 80mm for the next step.

The problem I'm facing is whether to go for a decent scope that will cover the 35mm full frame of my 5D or buy a second APS-C body that will then allow me to use a slightly less expensive scope to cover the frame.

It seems like a backward step to me but one that may prove more effective in the future.

I would really value some good advice as virtually everything I have read so far on the subject seems to ignore full frame DSLR cameras, presumably because they are more expensive, but in my case it is what I already have.

If you're planning to stay with Canon, then I would suggest just try with 5D first, and once you've taken a few reference shots, decide if you want to go to something like an 1100D or a 60Da, or a fully fledged imaging camera.

The advantage: Of sticking with a Canon EF (type) body is that you can use the same Canon EF to T-adapter. You can also use your other L series lenses on the other Canon EF body for other situations (eg: you may find that the 1100D gives you better shots with an existing telephoto lens than your 5D does). The fact you already have a full frame body camera and L lenses works in your favour here.

The con: If you go for a different brand body, or a dedicated imaging camera, you have to buy a new T- adapter to suit that camera.

IMO this isn't actually much of a con, as a T-adapter is not that expensive.

FWIW: If you're worried about artifacts at the edge of your shots (which is a common problem with the 5D anyway with a wide angle lens), then simply crop your shots.

From my point of view: You're not going to lose much by giving it a try, as a T-adapter is not really a huge cost, even if it proves to be the wrong decision in the long run. Not only that, it gives you something to play with even if you decide to use something different (while whatever you're planning to go with is on it's way to you). An added advantage is if you know someone with a Canon APS-C camera is that you might be able to borrow it and give it a try and compare it against the 5D. Getting hold of a dedicated imaging camera is no where near as easy to do a test, but even comparing full frame vs APS-C may give you some really good insights that allow you to make that decision with a good degree of confidence.

Note: The traditional view is that APS-C sized sensors are good for Telephoto stuff, whereas full frame are much better for wide angle shots. It'd be interesting to see just how much light you get across the full frame sensor (and from there you can tell if a 1.3x or 1.6 sensor would actually be a better fit), so if you do go this way, even just to test, please post a follow-up!