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I’m currently using a canon 1300D but I can feel the new camera itch beginning,

if I decide to scratch it I’d like it to be a modified DSLR, my confusion comes when trying to decide APS-C or Full Frame ? Will my images from a 61 APO be too small on a full frame ? Would cropping a FF give better images than aps-c ?

Full Frame my assumption would be a 5D of some description or should I be looking at Nikon ?  The cost of a dedicated Astro camera for DSO is too much for me at this time I think.

suggestions and any experience with both FF and APS-C would be appreciated.

thanks

Andy

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Difficult to know whether your scope would be good for full frame - not sure what it is and what manufacturers claim - though might want to take this with pinch of salt anyhow TBH.  I'd have thought that a full frame DSLR is going to be similar cost to astro camera, though not 100% up to speed with prices. I would say if you want to use the camera for non-astro too then go for DSLR maybe but you wont get such a good result as cooled dedicated camera. Also Canon software integrates better than Nikon.

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Covering the full 35mm format is difficult, and usually expensive. If the telescope / flattener is advertised with a spot diagram take a look at the 22+mm and you will usually see quite a bit bigger circle of confusion.

If you are looking at Canon 5D territory then it's not far off a dedicated astro camera. As good as Canon DSLRs are, a dedicated cooled astro camera will knock it out of the water.

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As others have said, very few scopes cover full frame and a small apo is unlikely to do so. You'd need to check the corrected and illuminated circle which will need to be at least 44mm.

Given the limitations of uncooled DSLRs and the cash value of a full frame CCD I wouldn't entertain the idea of modding one when you can get a far better cooled CMOS for a reasonable price. Modding DSLRs made some kind of sense when the alternative was expensive CCD but that's no longer the case.

When you say, 'Will my images from a 61 APO be too small on a full frame ?'  I think you may be falling into an error with its origins in terrestrial photography and the term 'crop factor.'  This term is used as if the size of the sensor had a bearing on the focal length and/or image resolution. It has no bearing on either and should only be used in terrestrial photography for comparing lenses and formats, never in astrophotography where it leads only to confusion.  In a given telescope one number alone tells you how large an object will finally appear on screen: the size of the pixels. The scope's projected image on the chip is a constant size whatever the camera. The size of the output image depends on the pixel size, smaller pixels producing a larger final image of the target. (The more pixels you put under the objects projected image the bigger that image will end up.) In general full frame DSLRs have larger pixels, I think, so this may be exactly what you don't want.

The amount of sky around your target depends on the chip size but, if you don't want it, you can crop it.

Olly

Edited by ollypenrice
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Appreciate all the feedback, food for thought.

Yes I did mean smaller relative to frame size, I realise the object image itself will be same but wasn’t sure if. FF image would withstand aggressive cropping in post processing. When it comes to price I should have said I would be looking at 2nd hand market and decent CCD/CMOS seem to be like finding hens teeth, then also finding one suitable for DSO and the price rockets, unless I’m missing what the optimum bang for buck price point is on them ?

Which is the first rung of the ladder that would be better than a modded DSLR ? Maybe that’s where I should be looking ?

thanks again

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Slightly different take from me.

If the OTA has a large enough image circle, a second hand 5D could be a decent option. You could pick up an umodded one for £250 for eBay, although I'd assume that the only reason you're after such a wide field would be for nebulae, and so modding may be essential. To make it viable cost wise, I think you'd need to do the mod yourself, as the full frame sensors tend to command a premium with the modders. 

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42 minutes ago, rnobleeddy said:

Slightly different take from me.

If the OTA has a large enough image circle, a second hand 5D could be a decent option. You could pick up an umodded one for £250 for eBay, although I'd assume that the only reason you're after such a wide field would be for nebulae, and so modding may be essential. To make it viable cost wise, I think you'd need to do the mod yourself, as the full frame sensors tend to command a premium with the modders. 

You’d be right, it’s wide field DSO that interest me the most atm and more forgiving for my noob skills but it does tend to send me down the path of most expense 🙈

Ideally a modded DSLR to not have the extra cost as you say of getting it modded. The cheapest option would be to send my 1300D away to be modded but before that I wanted to check on others experience of FF vs APS-C. I have an old 30D aps-c and it’s just way better screwed together than the 1300D, maybe a 60D/70D would be the sweet spot for DSLR.

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10 minutes ago, Newforestgimp said:

You’d be right, it’s wide field DSO that interest me the most atm and more forgiving for my noob skills but it does tend to send me down the path of most expense 🙈

Ideally a modded DSLR to not have the extra cost as you say of getting it modded. The cheapest option would be to send my 1300D away to be modded but before that I wanted to check on others experience of FF vs APS-C. I have an old 30D aps-c and it’s just way better screwed together than the 1300D, maybe a 60D/70D would be the sweet spot for DSLR.

An APS-C sensor with something like the Samyang 135mm will show most nebulae and their surroundings.

Modding is not necessary if you get the right dslr, Canon 7DMK2 shows Ha quite well and if you want full
frame the 6D is good at Ha, you can use the 6D with the Samyang lens as well.

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As others have said, full frame is difficult to correct for but can be done if your willing to accept some mis-shappen stars at the edges. I bought an Altair 70mm quad and it was very good at correcting, not perfect at the edges but acceptable imo.. You could probably pick up a used 5D/6D for not much more than £300, add another £200 to mod it and you've got a very capable camera. Yes, a cooled astro cam would be better with less noise but then you need a PC of some sort, 12v power source etc and portability becomes a question if you want to travel.

I love my 6D. I have it paired on a star tracker with a Samyang 135mm. At f4 it's still nice and sharp in the corners. Great camera imo. Below is around 5 hours worth with just an L-Pro clip filter. That's another issue in itself, choices of filter a very limited.

 

NGC896 135mm.jpg

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31 minutes ago, david_taurus83 said:

As others have said, full frame is difficult to correct for but can be done if your willing to accept some mis-shappen stars at the edges. I bought an Altair 70mm quad and it was very good at correcting, not perfect at the edges but acceptable imo.. You could probably pick up a used 5D/6D for not much more than £300, add another £200 to mod it and you've got a very capable camera. Yes, a cooled astro cam would be better with less noise but then you need a PC of some sort, 12v power source etc and portability becomes a question if you want to travel.

I love my 6D. I have it paired on a star tracker with a Samyang 135mm. At f4 it's still nice and sharp in the corners. Great camera imo. Below is around 5 hours worth with just an L-Pro clip filter. That's another issue in itself, choices of filter a very limited.

 

NGC896 135mm.jpg

Wow love the dark dust lanes coming off that. 

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Thanks all for your opinions and advice, After doing a some more research based on that advice I'm starting to go against the subject topic & come down on the side of a dedicated astro camera 🤦‍♂️, I think something like the Altair 183 Pro could be a good option for me after trying various chip size/scope/target combinations on astronomy tools, and pleasantly surprised it wasn't silly money.

I'll still keep a DSLR in the quiver but think I might just stick with my 1300d &/or get it modified for now, the Full Frame ambitions might have to be side lined or for terrestrial only as I've just spent money on the William Optics field flattener for my Z61 and I don't want to get into another round of buying more flatteners/reducers etc to correct images.

 

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Just to give a price comparison I picked up a second hand low shutter count canon 6d for £500, Add ti this £150 to have it converted for astro use if required, i had the same debate with myself as your having, however what swayed me to the dslr were not just funding but that i have a skywatcher esprit 120ed pro which is well suited for the full frame of the canon 6d.

Edited by dark knight
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On 17/02/2021 at 16:12, Newforestgimp said:

stick with my 1300d &/or get it modified

+1

An astro camera with a sensor anywhere near the size of the aps-c of your 1300 is going to cost €silly. Modern software and processing techniques produce excellent images with data from a DSLR. 

Cheers

Edited by alacant
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